Darktable is a free multi-platform, raw-image editor and camera control program. It uses ‘sidecar’ technology, which leaves the raw image files untouched and saves all edits in an “.xmp” file (one per photo). Since Darktable receives ongoing support, it is capable of editing raw files from your new digital camera. I’m reviewing version 2.4.4 for Windows10 x64. You can download Darktable for Windows from here. User manuals from the authors are available. The link to the English version is here. Darktable The Darktable program is geared toward managing the entire workflow of image editing, grading, storage, and retrieval. The workflow is divided into the following five areas: Import/export (lighttable) Image editing/grading (darkroom) Slideshow Print Camera control (tether) The supporters of darktable (at darktable.org) have provided pretty extensive documentation, and many of the dialog samples in this article are taken from that documentation. Many software helper tools mentioned in the documentation only apply to Unix/Linux platforms. I wasn’t entirely happy with the darktable documentation, so I thought I’d take a stab at creating some documentation myself. This program is very powerful, and in many ways I find it superior to Adobe Lightroom. Darktable is a complicated-enough program that I felt it was worthy of a few articles. This first article is going to give a gentle overview of its main features, without going into extreme detail. One of the best features of darktable is its masking capabilities. I’ll only give a light touch on the masking topic now, because I feel it’s worthy of a more extensive treatment in a future article. No, darktable doesn’t support the Nik/Google/DxO plugins; at least not yet. This is probably my biggest disappointment with darktable. Lighttable Lighttable dialog The image import/export dialog is called “lighttable”. It is recommended that you import photos in chunks of single folders, versus recursively importing multiple folders. It’s possible to connect to a camera via USB and import from there directly. If you desire, you can filter the import to omit ‘jpg’ files, etc. There are many configurable options for Darktable, which you access via a little “gear” button near the top-right of the screen. The left-hand panel is generally used for image importing. You can hide/show this panel by clicking the little triangle on the edge of the panel. After your photos are imported, you click on “collect images” and “recently used collections” to select the folder images you want to display and make available for editing. As a side note, you can go back to any folder you have already imported from and re-import. Only the new image files will get imported; you won’t get any duplicated imports. The lighttable right-hand panel is generally for exporting edited images in formats such as jpg and tif. Once multiple images are selected, the “selected image[s]” option lets you delete them or make an HDR image from bracketed shots. Once an image has been edited (inside ‘darkroom’), its history of editing steps can be copied/pasted into other image files. Access this feature from the right-hand panel “history stack”. This is how you can achieve ‘batch’ editing. To paste the history, first multi-select the target thumbnail pictures and then select “paste” or “paste all”. The “paste” lets you select just pieces of the history stack, versus every single editing step. Because lighttable doesn’t use a conventional menu system, you can see how busy its interface can get. For most people, it would probably take a few days of use to get comfortable with this interface. Most buttons have “tooltip text” if you hover over the control, so be aware of this feature. Darkroom Darkroom dialog The image-editing dialog is called “darkroom”. The left side panel in darkroom is mostly informational, including the photo EXIF information and the editing history. The darkroom editor adaptively uses this EXIF information in a few of its edit module settings, such as the ISO setting and camera model, and lens type. The right-hand side panel holds the selected file histogram and a collection of editing modules below the histogram. The histogram can be used to adjust exposure and the black point, depending upon if you mouse-drag in the right or left sides of the histogram. The bottom of ‘darkroom’ has a film roll, as selected by the ‘lighttable’. You can navigate through the photos via the mouse scroll wheel, the spacebar, and the backspace key. Double-click an image to edit it. The top-left of the ‘darkroom’ view shows a small image of the entire photo. Drag the rectangle inside it with the mouse in order to pan through the photo, or just drag inside the large edited image to pan. Just to the right of this little image view is a control to select common zoom levels. There is no “save” option in darkroom, because all edits are automatically saved into a “history stack”. This history stack can be copied/pasted into other image files to perform batch editing. You can click Ctrl-Z to undo the last edit (history) step. If you click on one of the history steps in the left-side panel, and then activate a new editing module, all steps after the selected history step will be deleted. Beware of this operation, since it can’t be un-done. Whenever you want to see a full-screen view of your edited image, just click the Tab key. Click Tab again to restore the panels. You can zoom the main image by using the mouse scroll wheel while the pointer is on the image. To view blown color channels in the selected Raw image, click on the little icon just above the film strip that has Red, Blue, and Green squares in it. Next to that button is a light/dark square to view blown highlights in your image. Keep these controls active while you adjust exposure and highlights to tame the overblown areas. Modules The module types are designed to contain a specific type of edit step, such as noise removal, color control, and sharpening. Each module has its own optional mask, which can be either geometrical (brush, circle, ellipse, path) or parametric (such as an adjustable color or luminance range). The edit modules will be applied in a fixed, carefully controlled sequence of steps. This means that you can choose editing steps (modules) in any order you like, while the output results will have the steps applied in an optimized order. As an example, image sharpening is applied at a later stage than image de-noise. Some of these modules are really smart, and are capable of responding in a customized way to things like the camera model sensor type and ISO setting. To view a module, just click on its name. Beware that making a module visible doesn’t make it active. To make a module active, you need to click its “On” button. The buttons just below the histogram will let you select module categories, such as “Basic”, “Tone”, “Color”, “Corrections”, and “Effect”. When you click on a module name to expand it, the previous module will collapse. The sample module name above is “sharpen”. If you really want multiple modules expanded at once, then hold down the shift key as you click on another module name. If there are modules you use frequently, you can select “favorite” inside the “Module presets” button, shown above. Module Sliders It’s worth mentioning that most modules have “sliders” in them. You can ‘drag’ the slider to change values, and you can also left-click them to make large changes and use the mouse scroll wheel or the arrow keys to make small changes. Masking (module ‘blend’ option) Masks are an integral part of the majority of the edit modules; they let you make changes to selected portions of the image. They can be quite cryptic to understand, until you learn the meaning of the various icons and GUI controls they contain. When you select one of the blend operations “drawn mask”, “parametric”, or “drawn & parametric mask”, you are ready to construct a mask. Since they’re so complicated, I’ll devote a full article to the use of masks in a later article. For now, I just want you to be aware that you can use a different mask with nearly every edit module, by expanding the “blend” option. The “drawn mask” has options to use a brush (drag a circle around to trace a wide path), a circle, an ellipse, a gradient, and a path (to encircle a complicated shape). You can change the size of drawn masks using the mouse scroll wheel. If you use the Shift button with the scroll wheel, you can change the feathering width on the mask edge, and the Control button/scroll wheel will change the opacity of the mask. The “parametric mask” lets you construct an image mask by selecting a characteristic such as range of light or a range of hue. This can enable creating a mask that is far more complicated than you could ever draw with a brush or a path. There’s a little “circle-in-square” button that lets you see where your mask is located, drawn in yellow, when you click it. If you click the “circle-in-square” again, the mask will be hidden. Healing/Hiding Defects: spot removal Spot removal using the circle shape Use the “spot removal” module in the “correction group” to do healing (e.g. clone/stamp). It will let you create circles, ellipses, and drawn paths to fix problems. The usual scroll wheel is available to adjust spot size, while you use the Shift-scroll to adjust the edge feathering width. The shot above shows that the feathering of each circle was minimized, which was adjusted by using the Shift key with the scroll wheel on the mouse. You’d see a dashed line outside the solid line if feathering was increased. The nice thing about this spot tool is how obvious the source/destination indicators are. The source is connected to the destination by an arrow, to indicate how the source points to the destination. Spot removal using a path shape Spot removal paths are created by mouse-clicking along an enclosed path. When you have enclosed the shape you want, just click the right-mouse button to finish it. Your “source” shape is drawn automatically, but it probably isn’t located where you want it. When you draw a “path”, you can hold down the Control button if you want the path edges to be straight instead of curved. You can alter the path shape by selecting one of its “nodes” and drag it after you have drawn the whole path. The source --> destination arrow isn’t shown in the case of a path shape, unfortunately. Drag the source shape over the pixels you want to use to replace at the destination. It will copy the source pixels over the destination pixels and obey the size/feathering/opacity, according to how you use the scroll/Shift-scroll/Ctrl-scroll wheel. If you have fixed up several spots but then change your mind about a previous spot, you can go back and select it with a click and then use the right-mouse button to delete that particular edit without affecting the others. If you leave this module and later return to it, you might find that you’ll need to deactivate/reactivate it to see your previous work (e.g. the source/destination markers). Until you see your previous work shapes drawn, you can’t select them to move/resize/delete them. Perspective Distortion Correction Typical “keystone” perspective problem Perspective correction module This shows an example of a typical editing module. Just click on the button for the vertical correction and also select “automatic cropping”, “largest area”. Two clicks, and the problem is solved. Available edit modules If a module isn’t displayed when you select its group, then activate the “more modules” at the bottom of the screen and scroll down to the module you want and click it. If you frequently use a particular edit module, you can click on its “module presets” button and select “favorites”. “Basic” module group: Crop and Rotate (also has perspective, flip, etc. options) Orientation (only rotates by 90 degree increments) Shadows and Highlights (tame clipped highlights and reveal shadows) Base Curve (alter the manufacturer’s base curve drawn from EXIF data) Exposure Contrast Brightness Saturation Color reconstruction (repair blown highlights) Demosaic (choose algorithm to interpret Bayer filter data) Highlight reconstruction (reconstruct clipped channels) White balance (camera presets, kelvin temperature) Invert (invert scanned negatives) Raw black/white point (activated automatically for raw images) “Tone” module group: Fill light (local exposure modification) Levels Tone curve (operates in Lab color space, however) Zone System (ala Ansel Adams, with selectable number of zones) Local contrast (adjust local contrast, but avoids haloes) Tone Mapping (‘local surroundings’ tone mapping of HDR shots) Global Tonemap (less sophisticated, faster tone map of HDR shots) “Color” module group: Velvia (simulate the film) Channel Mixer (reassign proportions of RGB color channels) Output Color Profile (alter the color profile) Color contrast (between green/magenta or blue/yellow) Color correction (global saturation, tint, split tone) Color checker LUT Monochrome (convert to black and white) Color zones (selectively modify colors) Color Balance Vibrance Input color profile (override darktable auto-color profile allocation) Unbreak input profile “Correction” module group: Sharpen (unsharp mask) You need this on virtually every photo. Make it a “favorites”. Equalizer (local constrast enhance, denoise) Denoise (profiled) Uses camera model and ISO to apply noise removal Denoise (non-local means) Control chroma and luma noise separately Denoise (bilateral filter) High ISO pictures. Uses lots of CPU. Lens Correction Liquify artsy distortions Perspective correction Includes “automatic fit” and “automatic cropping” to fix “keystone” issues with buildings. Spot removal (healing brush) Use circles, ovals, paths. Very useful to hide small skin blemishes and sensor dust specks in the sky. Raw denoise (rid noise before demosaicing) Dithering (help with banding) Hot pixels Chromatic aberrations (lateral chromatic aberration) Haze removal (atmospheric effects adjustment) Defringe (longitudinal chromatic aberration remove) “Effect” module group: Watermark (text overlay) Framing (frame around edge) Split toning (separately alter the hue in shadows and highlights) Vignetting Soften (Orton effect) Grain (simulate film) Highpass Lowpass (Gaussian blur) Can blur with contrast, brightness, saturation. This is the module you’ll want to use for skin retouching in portraits. Lowlight vision (simulate human low light vision) Bloom (highlight blooming effects) Colorize (add a solid layer of color to image) Color mapping (transfer source image colors to target image colors) Graduated density Missing Modules There are a few features that you’ll probably miss in darktable. Here’s a couple examples of how to survive their absence. Red Eye Removal There isn’t any “red eye removal”, but here’s how you could do it: Channel mixer module, and turn it “on”. Select blend: “drawn mask” and place circles over the red pupils (use the mouse scroll wheel to fit the circles inside the pupils). Destination = “red” channel, with red=0, green=0.5, blue=0.5 This procedure will replace the red channel (the red pupils) with an even mix of blue and green instead, which will make the pupils dark. Always make the three channels add up to 1. Infrared Blue Sky Infrared “blue sky” effect from a color white-balanced infrared shot: Use “channel mixer module” to swap the red/blue channels. For destination = “red” channel, make red=0, green=0, blue=1 For destination = “blue” channel, make red=1, green=0, blue=0 Multi-shot Bracketed HDR It’s not really missing, but it’s a bit hidden. In lighttable, do the following: “Collect images”, to get to the folder with exposure-bracketed shots. This is on the left-hand panel. Select the already-aligned shots (use Ctrl and Shift keys). “selected image[s]” from the right-hand panel. Pick the “create HDR” option to make a DNG HDR file. Select “tone mapping” module in darktable to adjust the HDR file to taste. Single-shot HDR To merge an image with 2 more copies of itself, with the other copies over-exposed and under-exposed. Take a single shot, then apply the “base curve” module “fusion” option. Select the fusion “three exposures”. Select an exposure shift (typically 1 stop, or EV). Select an exposure bias of 0 to maintain overall lightness. Select the “tone mapping” module and adjust to your taste. A Typical Darktable Editing Session Start Darktable Go to the “light table” tab Import | folder Browse to your disk folder of raw image files Click the folder, then click “Open”. Images will be imported. Click the “collect images” button and select your imported folder, if you can’t see your desired thumbnails. Double-click on the desired image thumbnail to edit. (it goes to the “darkroom” tab automatically) Click the “blown highlights” button above the filmstrip, just in case. Click on the “Basic” modules icon (a circle icon) Click on a desired edit module, such as “shadows and highlights” Click the “On” icon to enable the module. Make adjustments (decrease highlights, for instance, until the blown highlights in the photo go away). Press TAB to see the edited image full-screen, then TAB to restore. Use the mouse scroll wheel while over the edited image to zoom in/out. (Select/turn “On” other modules and make more edits) Click “Ctrl-E” to export the edited photo into a subfolder of the raw shot, called “darktable_exported”. Tethering Connect and control your camera via USB. You can adjust exposure settings, white balance, focus mode, and even see your camera Live View on the computer. This tethering module lets you do HDR bracketing and time lapse shots. There are alignment guides and overlays that you can add to your screen as well. Behind the scenes, darktable is using the “gphoto2” program and its command-line arguments to control your camera. The people at gphoto.org are actively supporting this multi-platform tool, and it now supports hundreds of camera models from all vendors, including Nikon, Canon, Sony, Panasonic, Olympus, and Fuji. Make sure you charge you camera battery before using this; it’s a pretty heavy energy drain to be using Live View and USB continuously. Summary Don’t be afraid of this program just because it’s free. This is really good stuff, and it’s still actively supported, as of this writing. Since darktable doesn’t alter your raw photos (it just alters the sidecar files) you aren’t faced with any risks to try it out. Maybe someday the darktable.org people will add plugin support, which would make this program truly powerful. As I had mentioned, I'll be adding more articles about darktable features in the future, in an attempt to demystify some of its more advanced features. #howto

If you haven’t read it, you should take a look at my Darktable Overview article prior to reading this . It will give you some needed context for the use of this masking discussion. Masks let you make changes to selected portions of the image. Most of the Darktable “darkroom” edit modules have a blend option, which is where you access the masking operations. The blend operation has options for “drawn mask”, “parametric”, or “drawn & parametric mask”. The default blend is “off”, or no masking. Until you select something other than “off”, you won’t see any masking controls. Any photo editor that doesn’t have a good set of masking tools just isn’t fully useful for me. This is the main weakness of Adobe Lightroom, in my opinion. Darktable has what you need. Drawn Mask The “drawn mask” has options to use a brush (drag a circle around to trace a wide path), a circle, an ellipse, a gradient, and a path (to encircle a complicated shape). You can change the size of drawn masks using the mouse scroll wheel. If you use the Shift button with the scroll wheel, you can change the feathering width on the mask edge, and the Control button/scroll wheel will change the opacity of the mask. A typical module “blend” mask dialog: the “drawn mask” You’ll note in the above “drawn mask” dialog, you get icons indicating (shown left to right) a brush (looks like a pencil), circle, ellipse, path, and gradient. To see the masking bounds, click on the little “hole in a square” icon at the bottom of the dialog. The mask bounds will be rendered in yellow. Pure yellow will indicate an opacity of 100%, for the full masking effect. The icon is a toggle, so click it again to hide the yellow mask. You’ll generally want to enable this feature while you draw the mask, but if you don’t, there’s still an indicator of where you draw. To toggle the module actual masking effect on or off, click on the “eye” icon at the bottom of the dialog. The “blend mode” is used to alter the extent of the mask effect on the selected pixels, such as color, lightness, or normal (all). The mask tool (such as the brush) size is controlled by the mouse scroll wheel. The mask hardness is controlled by Shift-scroll, and the opacity is controlled by Ctrl-scroll. You can also “invert” the “drawn” mask effect by selecting On/Off for the “invert mask” near the bottom of the drawn mask dialog. After you draw a mask (and release the left mouse button), you can alter it after the fact. Click the “view mask” icon (square with a hole in it) to make the yellow mask visible. Click on the drawn mask to select it, and you can still use the scroll wheel to alter its size, feathering (with shift-scroll), and opacity (ctrl-scroll). There are also little square “handles” along the mask path you can select and drag. If you want to rid the path, just click the right mouse button when the mask is selected. If you leave the module and later return to alter the mask, you’ll need to click the “edit mode” button to the right of the “drawn mask” text. The button looks like an arrow pointing at a dashed line. If you want to prevent mask alteration, just re-click the same “edit mode” button. To draw a path for a mask, use the mouse to left-click some nodes on the path where you want it to be (the “destination”). When you have enclosed the shape you want, click with the right mouse button to finish the path. If you don’t want rounded lines in the path, then use Ctrl-click to get sharp corners and straight lines on the path segments. This works great for selecting things like a box. In this case, just enclose the straight-edged shape without having to right-click to finish it. In the path “edit” mode, you can change nodes back and forth between smooth and straight by using Ctrl-click on the node. To alter the path, use the left mouse button to select the path and also to select nodes to drag. Path mask showing the nodes that define it You can delete a path node by first selecting the node (it gets highlighted) and then right-click. Be careful, because if you just select the path and right-click it, the entire path will be deleted. Mouse-scroll to alter the size of the whole path, and use Shift-scroll to alter its edge feathering. Parametric Mask Blend: “parametric mask” A module “parametric mask” blend selection will draw a mask based on pixel characteristics, instead of where the pixels are in the picture. If you want to select something like a garment by its color or a light background, this is what you would use. You can generate some extremely complicated masks with this technique, which would be impossible to manually draw. Depending upon your edit module’s color space (e.g. Lab space or RGB), the dialog will look different. The example above is for Lab color space, where “L” is “lightness”, “C” is “chroma” (saturation), and “h” is “hue” (color tint). If you select “L”, the slider bar will switch to black-and-white. To select a photo color, use the eye-dropper “color picker” icon (shown above). To invert a color channel, click on the “invert” icon as shown above. There is also a “reset” icon to return to default settings. There will be a little white vertical bar (see the “picker color bar” above) drawn on the “input” slider to indicate the color picker selection. Triangles above and below the little “picker color bar” must be dragged to narrow the selection range (from 100% to 0% opacity). The range inside the solid triangles will be 100% opacity, and the hollow triangles control the extent of the mask feathering. If you don’t slide the triangles to narrow the selection, the whole image will be selected by the mask, and your image will be a giant yellow rectangle. Just like the “drawn” mask, the parametric mask has an “eye” icon to turn the mask effect on/off and the circle-in-square icon to view/hide the yellow mask itself. You’ll need to exhibit a little patience when clicking the “eye” to see the effect fully rendered on your computer. Drawn and Parametric Mask Drawn and Parametric Mask, parametric shown It’s possible to have both kinds of masks in a single module, called “drawn & parametric mask”. Shown above, I selected a small area of the structure (via the eyedropper) and made a parametric mask of the “L” channel, where I dragged the little input triangles to select a range of “lightness”. I clicked on the “show mask” button, so the masking results can be seen in yellow while I adjusted the slider triangles. Note the parametric mask sliders are shown in black-and-white here, because I chose the “L” channel. If I had chosen the “h” channel hue, then the slider would be shown as full-color. The mask above “spilled over” a little bit from what I wanted. This is really common with parametric masks. You typically need to do some cleanup using a drawn mask. Drawn and parametric mask, path ‘drawn’ on top of parametric Shown above, I used the “path” and drew over the parametric mask to add some more masking. The little “toggle polarity of drawn mask” is set to a “+”. This lets me erase part of the parametric mask using a drawn mask and clean up its boundary. This demonstrates how I was able to combine the two kinds of masks together. As shown above, I held down the Control key while clicking the points for the drawn “path”. This keeps the mask edges straight, instead of rounded. I used the “Shift-Scroll” mouse scroll wheel to reduce the drawn mask path feathering. Since I wanted this path to be an enclosing shape, I clicked the right mouse button to complete the shape. Portrait retouching mask If you’re a fan of using Gaussian blur on skin when retouching portraits (you probably should be), I’d recommend that you set the mask “opacity” slider (just underneath the “blend mode”) to something around 90% for starters. You want a little skin texture to peek through the mask. You’ll probably be using the “brush” drawn mask the most for this. Lowpass, Gaussian blur with mask to avoid eyes, mouth, nostrils The “effect” group “lowpass” module is what you want to be using for Gaussian blur. Summary As you can see, there are many, many mask features in Darktable. I hope this little guide will help ease the pain of learning how it all works. #howto

Darktable can do more than edit your photos; it can also help you capture them with your camera attached via a USB cable. This kind of photo capture is known as tethered shooting. Darktable uses a program called gphoto2 to control your camera. If you haven’t read it, you should probably read the first part of this series on Darktable here. If you are using Windows, then there is some setup you’ll need to do before you can use Darktable to control your camera. If you don’t do this, then Darktable won’t be able to see your camera. Tethered shooting in Darktable To enable Darktable under Windows 10 to see my camera, I had to download the program called Zadig-2.4.exe (or whatever is most current). I got the zadig program at http://zadig.akeo.ie/ , as shown below. Zadig download site To use this program, start by connecting your camera via USB and turn it on. Next, run zadig-2.4.exe and select Options | List All Devices. You should see your camera in the list; select it. Select your connected camera When you see a screen like what’s shown above, click on “Replace Driver”. It should set up the proper device driver that enables gphoto2 to communicate with your camera. Successful driver replacement for your camera Now, you should be able to use Darktable tethering for remote camera control. Stop the zdiag program, but leave your camera connected and turned on. Don’t turn on Live View on your camera, because it needs to be controlled from Darktable itself. I can’t promise that this driver won’t affect other camera communications software. Start up Darktable, with your camera still connected via USB and powered on. You should be able to see that your camera is visible to Darktable. Darktable sees your connected camera at startup When you first start Darktable, you should see your camera mentioned just underneath “scan for devices”. If you don’t see it, you may need to click the button to scan. If your camera driver is correctly installed, you should now be ready for tethered shooting. Begin tethered shooting Now that Darktable sees the camera, just click on “tethered shoot”. You will automatically get to the correct screen in Darktable, but you won’t yet be able to see what your camera sees. Start Live View to see your camera’s view on the computer Click the little eyeball button as shown above, in the “tethering” tab, under the expanded “live view” option. Now, your camera will be placed into Live View mode, although the camera LCD screen won’t activate. The screen update rate is a bit less than what your camera LCD can do, but it’s pretty good. USB 3 connections, if your camera and computer both support them, will of course be much better than USB 2. The “tethering” options will need to be expanded to both view and operate them. Add an overlay to the view: “grid” In shot above, I added a “grid” overlay. There are several guides to select from. You can also “flip” your live view and select “vertical”, if you wish via the same “live view” dialog. Select the shooting mode, depending on if you intend to do single shots, exposure-bracketed shots, or time-lapse shooting. Before you shoot, you’ll want to be able to see the camera settings. You’ll probably have to scroll down to see those settings. Camera shooting properties To change the camera shooting settings, click the little down-arrows next to the current settings in the expanded “properties” dialog. If you want a setting shown above the Live View window, then click the little eyeball to the right of the control, such as “aperture”. You will probably want to change the “focus mode” setting to continuous-focus, at least until you’re happy with the focus. For a time-lapse, you’d of course want to leave it on “AF S”. When everything is configured like you want it, you click on the “capture image(s)” button to start shooting. If you are doing long time-lapse shooting, turn off the “live view” screen update (the eyeball button) mode. Your screen will only get updated with the latest captured shot, which will help conserve your camera battery. You’ll probably want to switch your “program mode” to “M”, for manual exposure, too. By default, your captured shots in Windows 10 will automatically get transferred into a folder underneath your “Pictures” folder on your computer, and not saved into your camera itself. The shots go into a folder named with the current month and day. For time-lapse shooting, the default tethered photo storage option is ideal, so that you don’t have to worry about running out of space on your camera storage card. Summary Darktable is more powerful than most people would think. By taking advantage of the gphoto2 program, its power is greatly increased. Be aware that tethered shooting is power-hungry, so it would benefit you to charge your battery before using this feature. For extended photo sessions, I know that Nikon sells power adapters EP-5B, EH-5A, and EH-5B that allow you to use external power instead of a battery. #howto

There are many times when you want to adjust only a portion of a photo. In Lightroom, you can accomplish this using what Adobe calls an “Adjustment Brush”. Most people refer to this operation as “masking”. This discussion uses Lightroom 6.14. Mask overlay shown in red To show the mask (adjustment brush) option, select the Tools | Adjustment Brush or else just press the “K” key. When using the mask, the mask brush will look like two concentric circles. The inner circle is solid, showing how far the full masking effect extends. The outer circle is dashed, and shows the extent of the mask edge feathering. The start of the mask (the ‘pin’) is a little white circle with a black center. There are two more sliders for masking control called “Density” (mask opacity) and “Flow”, which is the percent opacity per overlapping brush stroke. Change the diameter of the masking brush by using the mouse scroll wheel. Change the diameter of the feathering effect by using Shift+Scroll wheel. View the mask as you draw it by selecting the Tools | Adjustment Mask Overlay | Show Overlay. While you’re drawing the mask, the middle of the brush mask will have a “+” to show you’re adding to the mask. You can also click the “O” letter to toggle viewing/hiding the (red) mask. To fix masking mistakes, click the “Erase” button (shown above). The middle of the brush mask will have a “-“ to show you’re subtracting from the mask. If you decide to get rid of a mask, click on its ‘pin’ marker and press the Delete key. You may have to scroll down to see the “Erase” button. There’s an option to change the color of the mask overlay, in case you’re masking something that’s already a shade of red, for instance. Mask “Effect” menu To choose an effect with predefined settings, you can select from the Effect menu. The “Exposure” setting is shown above. After you select an effect type, you’re free to adjust the sliders to customize the effect to your own taste. In the example above, the goal is to select just the sky. Note above how difficult it is to try selecting only the sky by just brushing. There is a solution to this problem, and it’s called “Auto Mask”. Mask just the sky with “Auto Mask” to select a color If you’re trying to mask an area that has a particular color, then “Auto Mask” is for you. As shown above, I was able to paint the mask onto the blue sky, and it left the white sails alone. In this example, I decided to selectively adjust the saturation. I clicked the “O” key to see the saturation effect, instead of showing the red mask. Adjust the sky saturation After the mask drawing is finished, remember to click “Done” to complete the mask operation. “Soften Skin” effect Use Keys to Control Masks in a Hurry For a common task such as skin smoothing, invoke a mask by pressing the K key. Next, you can select “Soften Skin” from the “Effect” drop-down menu and immediately start drawing with the mask. Use the mouse scroll wheel to adjust the brush diameter and use Shift-scroll for the feathering. To see the overall mask, press the O key to see the (red) mask, and you can toggle it off by pressing O again. If you make a mistake and draw the mask somewhere you don’t want it, then click on the “Erase” button to fix the mistake. Click the “A” brush (next to the Erase button) to go back to adding to the mask where you want it. The “Auto Mask” option might help minimize drawing mistakes, depending upon the color contrast between the skin color and the hair/background color. When you’re happy with the mask effect, click the “Done” button at the bottom of the mask dialog. Enhance an eye iris with a mask To make eyes sharper and more saturated, you can select the mask effect called “Iris Enhance”. Zoom in (Ctrl +) and use the mouse scroll wheel to get the mask to just cover the iris. The left-hand side of the ‘Develop’ window has a little white triangle that you can click and open up a thumbnail view of your photo. Mouse-drag the little white rectangle in the thumbnail view to navigate around the zoomed view and center the eye being worked on. You will need a separate mask for the other eye. Again, remember to click the “Done” button to complete any individual mask. Navigate around the zoomed picture via the thumbnail The shot above shows the thumbnail navigation window, with a white rectangle representing the zoomed view. Drag the white rectangle to see that part of the zoomed picture. Remember that you can use “Ctrl +” to zoom in and “Ctrl –” to zoom out. Conclusion Masking in Lightroom involves memorizing a few keyboard key shortcuts and use of the mouse scroll wheel. I hope this little guide will make it a bit easier to effectively use the adjustment brush. #howto

People who photograph starscapes know all about lens coma, even if they don’t know it by name. Unless you have some high-end optics, this is probably one of your bigger obstacles against capturing distant lights as pinpoints. Especially in the frame corners. Coma is confusingly defined as “a variation in magnification over the entrance pupil”. It means that off-axis light rays (corners of the frame) are focused to look similar to a comet with a tail or a teardrop. Nearly all lenses have this defect to some degree. Keep in mind that optics almost always exhibit a mixture of defects. You probably won’t see a clear teardrop-shaped defect. This article shows you how easy it is to evaluate coma. It’s cheap and easy to do. My go-to lens for photographing stars has been the Tokina 11-16mm f/2.8 DX. If you stick with 16mm, you can actually get full-frame coverage (e.g. Nikon FX sensors) with this lens. There is a price for doing this, however: pretty bad coma in the corners. If you want to see just how bad coma can get, and if you want to see how different aperture settings affect it, then this test is for you. Coma defect ray trace "Pure" coma photo Tokina 11-16mm f/2.8 DX What materials do you need to test coma? I use a small and cheap laser pointer (literally only 2 bucks) to substitute for my ‘star’. You want a really small and intense light source for this test, and lasers are just the ticket. A cheap laser with some aluminum foil and lens tissue As shown above, you will also need a sheet of lens-cleaning tissue and a piece of aluminum foil. I put the tissue/foil layers over the business end of the laser, and hold it in place with some tape. Note the little buttons above: the front one is the laser button and the rear one is for an LED light. It should go without saying, but I’ll say it anyway. Don’t stare into a bare laser beam. During construction of this testing device, don’t point it at your eyes. Foil and lens tissue taped over laser As shown above, wrap the lens tissue and foil layers over the end of the laser, and tape it in place. I wrapped the tape loosely, so it doesn’t activate the laser beam button. I lightly pressed the foil over the dent where the beam is located, so I know exactly where to place a pinhole. I used a small needle to make a tiny hole in the foil. You want this hole to be really small, so that it will act like a distant star in the sky. Laser, hose clamp, and holding fixture I got a little hose clamp to slip over the laser and its button. To activate the laser, use a screw driver to tighten the hose clamp until it just depresses the button. Loosen the hose clamp to turn the laser off again. Verify the laser beam can be seen shining through the little hole in the foil before you turn it off. Next, place the laser/hose clamp onto a holding fixture as shown above. I like this fixture for being able to position small stuff in nearly any orientation. I also use this fixture to hold small items for macro photography. To perform coma testing, I put the test fixture at one end of a room and mount my camera/lens on a tripod at the other end of the room. Focus the lens at or near infinity, and set your camera on ‘manual’. Align the camera until the laser device is in the corner of the field of view, or wherever you want to evaluate coma. If you want to look at long-focal-length lenses, you’ll probably have to move outdoors and try this at night to get the distances you need. Now, get out that screw driver and tighten the hose clamp to turn on the laser beam. Set your camera exposure and get into self-timer mode. Turn out the room lights and shoot away. Check exposure to make sure the laser spot clearly registers in the photograph. Coma test results I’m showing you the results of the coma testing, where the photograph is shown at 100% zoom (pixel level). The beam is photographed very near the frame corner. This test is using a DX sensor, which is only fair. FX sensor corners look much worse (although Tokina probably thought nobody would ever try it in the first place). Really pixel-peeping at f/2.8 and f/4.0 As expected, the smeary coma looks worst at f/2.8. Just one stop down, and the f/4 shot has already nearly eliminated coma. By f/8, the laser dot is really small and nearly perfect. This lens is considered pretty decent in regards to coma, but it certainly isn’t perfect; on full-frame, it gets pretty bad when shot wide-open. Since a lens aperture’s job is to cut off light rays from the outer portions of a lens, stopping down an aperture is the cure for coma. Conclusion As you can see, the test equipment I used is pretty simple. If you really want to see how a lens handles coma, this is how to do it. Notice how you can dramatically reduce coma by stopping down a lens even a small amount. This is, of course, of little comfort to starscape shooters who are after those wide-open shots to drink up every photon of light. #howto

Nikon made a design change that is perhaps the smartest thing they’ve done since 1959. Their new Z6 and Z7 cameras sport their new lens Z-mount with a 55mm throat diameter and 16mm “flange-focal” distance. This design change wasn’t possible for Nikon until they made a camera that got rid of its flipping mirror. On a full-frame camera, the mirror rotates through an arc with a radius of about 35mm, and their F-mount lenses had to have a long flange-back distance to keep clear of this flipping mirror. The F-mount has a 46.5mm flange-focal distance, while its throat diameter (lens rear diameter) is 44mm. F mount versus Z mount Many lenses designed for other lens mounts could have an adapter to fit the new Z mount, if they have a sufficient image circle for full-frame coverage. The main key here is that their flange distance must be longer than 16mm, which most lenses have. These adapters don’t need any optics in them, so the resolution won’t get messed up. The new design means much faster optics, given a larger mount throat diameter and fewer lens elements needed for the shorter flange distance. Fewer lens elements mean less light loss from absorption and reflection. The larger throat diameter means lens elements with wider diameters and less severe surface curvature is required. The larger rear lens element diameters and aperture mean a physically larger area to capture more photons. It’s much easier to design a wide-angle lens when you can avoid the severe retro-focus required for the long flange distance. Retro-focus means the lens focal length is smaller than the distance to the sensor from the rear of the lens. Now, lenses down to about 16mm don’t need a complicated, expensive, resolution-killing retro-focus design. Imagine some of the cool wide-angle lenses we'll see in the future. You get less chromatic aberration, due to the large throat diameter permitting the less severe surface curvature in the lens elements. More light rays hit the sensor edges at a less steep angle from the larger diameter rear lens element, so conversion of the photons into an image is more efficient. Vignetting can be reduced. Being closer to the sensor and a wider rear diameter, the light rays have a shorter travel distance to the sensor edges. This directly leads to higher resolution throughout, but particularly in the corners. The simpler wide-angle designs will lead to sharper, cheaper, brighter optics with many fewer lens elements. Telephoto lenses benefit less from the wider throat diameter, but you still can make brighter optics via the larger lens elements at the rear of the lens. Of course, the camera body thickness can also be reduced by about (46.5 – 16) mm or 30.5mm. The larger physical rear lens diameter means more room to provide a larger and more powerful focus motor. Except for losing the auto-focus capability of the Nikkor “AF-D” lenses, their FT-Z adapter still lets you use your existing F-mount lenses. Way to go, Nikon. #review

I wanted to alert you about an update for both the Contemporary and Sports versions of the 150-600 mm lens. Sigma announced this update to fix an overexposure problem with using the Sigma TC-1401 teleconverter when using the Nikon D500. Sigma cautions that you will need to update Sigma Optimization Pro to version 1.3 prior to updating to version 1.4.1 if you’re still using the old version 1.1 or earlier. Their download page is located here. You of course need to have their USB dock to perform this lens update. Their Sigma Optimization Pro software will then update your lens firmware to the latest (1.02) when you connect the lens/dock to your computer. This is still my most-used lens I own. If you haven’t tried it (or their new 60-600 version), you should. I’m not getting anything from Sigma to say this, either. #howto

There’s a long-standing bug in the D500 firmware, where you can’t get the camera to focus in Live View by pressing the AF-ON button. This problem occurs when you use “custom controls” and assign different AF modes to different buttons. When you do this, the AF-ON button is dead, and the only way to auto-focus in Live View is to touch the Live View LCD. You may be a big fan of using the touch-screen to focus, and this issue is therefore a “don’t care” for you. My fingers are so hard-wired to use back-button auto-focus that it messes me up virtually every time that I switch to Live View. As of firmware version 1.15, this bug still exists. Custom controls ruin the Live View focus via AF-ON My D500 is configured so that my depth-of-field preview button is assigned AF-ON with an AF-area mode of “Group Area AF” (nearest subject focus). My joystick button is assigned AF-ON with “Single-point AF” (precision focus). My AF-ON button is assigned with AF-ON and “Dynamic-Area AF-25” (far subject focus). The custom auto-focus button assignments are one of my absolute favorite things about the D500. They solve most of the missed-shot focus problems. One solution to get the AF-ON button to work for Live View focus is to simply un-assign the custom controls for different AF-ON modes. I find this solution unacceptable, because I rely heavily on these different instant-on AF modes. A better solution, which I use, is to assign my “Custom Settings Bank D” for Live View mode, and I un-assign all custom controls related to AF-ON for just this single bank. Finally, my AF-ON button works normally for auto-focus in Live View mode. This solution is a bit of a hack, but it works. Fortunately for me, I was only using the other 3 settings banks (A=sports, B=portrait, C=manual). Now, I have a use for the “D” bank: Live View. My settings banks If you tend to forget what each settings bank is used for (like I sometimes do), make sure that you give each bank an identifying name. Good luck using the LCD touch-focus with an LCD viewfinder If you have ever tried using Live View in the sunshine, you have a pretty good idea of how well you can see and focus; Live View is nearly useless. That's what LCD viewfinders are for. LCD viewfinders don’t cooperate too well with touch-focus features. It’s mandatory to have a way to force the focus via buttons instead. I had assumed that Nikon would get around to fixing this D500 bug, but I’ve long since given up hope. I guess that in their own minds, this is merely a feature and not a bug. #howto

It’s popular lore that you shouldn’t use shutter speeds beyond 1/500 second when you activate vibration reduction. Is this actually true? Is it the same for all lenses? How about different lens brands? People aren’t generally aware of how helpful in-lens vibration reduction is, aside from enabling sharper slow-shutter shots. You get to see a steadier subject in your viewfinder, and it actually helps the auto-focus system work better. The AF system needs higher contrast to focus both quicker and more accurately; that’s exactly what the VR system provides. These are the reasons that I don’t want to turn off vibration reduction when I’m not using a tripod. There have been many times where I forgot to turn off vibration reduction when using a fast shutter, and I was cursing myself for being forgetful. But when I looked at those shots where I forgot to turn it off, they looked really sharp. Was I fooling myself? Was shutter speed that crucial? Instead of taking somebody’s word for it, I figured that I should find out the answer for myself. The obvious tools for this job are resolution measurement software and a good resolution target. I want to get actual measurement numbers, versus ‘impressions’ or guesses. The experimental design is pretty simple: hand-hold the camera with vibration reduction active and shoot the resolution target. I’ll shoot with shutter speeds ranging from 1/250 through 1/4000 second. Since this is probably a game of statistics, I should get a least 10 or 20 shots of the target at each shutter speed, to look for trends in resolution changes. I’m going to try my 105mm Micro Nikkor f/2.8 G VR IF-ED, the Nikkor 24-70mm f/2.8 E ED VR, and the Sigma 150-600 Contemporary. I’ll make a table of the MTF50 lp/mm resolution versus shutter speed for each lens, and any significant resolution differences should show up. I know from past experience that I need to keep a constant aperture, and I also know that different ISO settings have a negligible effect on resolution until very high ISO values. Therefore, I’m setting my camera on “manual mode”, but with auto-ISO active. I get to control both the shutter and the aperture this way. Normally, you’d want to be using Live View (with contrast detect) and lock the camera down on a sturdy tripod to get resolution readings, but that isn’t going to work in this scenario. My lenses have been carefully calibrated for phase-detect focus, and I’ll use continuous auto-focus (AF-C). I’ll use my gimbal head on a monopod, so that I won’t have to contend with changing distance while my camera/lens is still free to ‘wobble’ a little. This is my way of creating a “controlled hand-holding” experiment. Even if the testing environment doesn’t result in optimal resolution, the resolution results should at least be representative relative to each other. The goal of this test is to see if resolution degrades beyond 1/500 second, rather than measure peak lens resolution. So, how did it work out? I took a total of 150 shots (10 shots at each shutter setting), with stabilization active in every single shot. I photographed my “A0” resolution target, which is roughly 4 by 5 feet. I used the three mentioned lenses, and everything was shot with the camera mounted on a gimbal and a monopod. I used un-sharpened RAW for all resolution measurements, with the MTFMapper program. All photos were shot with AF-C, phase-detect focus on my Nikon D500. The camera was in manual-mode with auto-ISO, and I used shutter speeds ranging from 1/250 through 1/4000. The light level resulted in ISOs ranging from about 200 to 2800, depending upon the shutter speed in use. I only start worrying about the ISO affecting resolution beyond about 2400, so it’s just a minor concern. Shutter 1/1000 with Sigma OS active: awesome resolution on D500 Sigma 150-600 at 150mm and f/5.6 Shutter MTF50 lp/mm average Measurement Range lp/mm 250 72.0 5 500 76.5 10 1000 77.5 5 2000 73.0 5 4000 73.5 5 Micro Nikkor 105mm f/2.8 VR at f/4.0 Shutter MTF50 lp/mm average Measurement Range lp/mm 250 60.6 5 500 60.0 5 1000 60.5 5 2000 60.5 5 4000 61.0 5 Nikkor 24-70 E VR f/2.8 at 70mm and f/4.0 Shutter MTF50 lp/mm average Measurement Range lp/mm 250 64.0 5 500 65.0 0 1000 65.0 0 2000 65.0 0 4000 60.0 0 Conclusion Micro Nikkor 105 and Nikkor 24-70 lens VR: leave it on! Sigma 150-600 Contemporary OS: leave it on! The only lens that seemed to have a minor sensitivity beyond 1/2000 was my Nikkor 24-70 f/2.8 E VR. Even then, it was nearly a “don’t care” at 1/4000 shutter, since the resolution MTF50 lp/mm only dropped from about 65 to 60. The Micro-Nikkor 105 f/2.8 didn’t register any significant change in resolution with stabilization active at any tested shutter speed. The Sigma 150-600 resolution dropped about 5% going from 1/1000 to 1/2000 shutter. There wasn’t a significant resolution change going from 1/2000 to 1/4000. I wouldn’t necessarily generalize these results to represent all lenses with stabilization. Older-technology lenses should be “verified” before assuming you can ignore the lens stabilization status. All in all, this convinces me that I don’t really have to pay attention to turning off vibration reduction at higher shutter speeds for these lenses. Certainly I wouldn’t bother until shooting beyond 1/4000 before I worried about messing up resolution. Since I virtually never shoot beyond about 1/3000, I intend to keep VR active, unless my camera is mounted on a tripod. I’d consider this stabilization 1/500 rule to be “myth busted”. #howto

I have to admit that this is an item I never thought I’d own. Why in the world would you want to cover up your camera LCD screen? Number one: the sun. Number two: video. Number three: no concerns about focus calibration fine-tuning. I am a total infrared enthusiast. I use some IR filters that make exposures extend to a few minutes, so the only way I know what I’ve captured out in the field is by reviewing the shot on my LCD screen. Infrared only works well in bright sun, and I swear I can see next to nothing on the LCD screen on a sunny day. This gets totally infuriating. Enter the LCD viewfinder. It’s like being inside a movie theater, and the viewer magnification means you can actually see the individual pixels on the LCD. If you mess up the manual focus (infrared focus is very different from visible-light focus) then you’ll know right away, even if you’re standing in sunshine. Since I thought that I’d probably rarely use it once I bought it, I got a really, really cheap screen viewfinder called “Xit”. It was love a first sight. This thing comes with a couple of little metal frames that you can “permanently” attach to the camera LCD via sticky tape, and then connect to the viewfinder with its built-in magnets. Personally, I’m not interested in using these metal frames. The LCD viewfinder also comes with a lanyard to carry around your neck, which is how I use it about half of the time. There’s also a little neoprene case to hold everything on your belt or via a little clip. Probably the best-known LCD viewfinder brand is Hoodman. These viewfinders fall into the “Cadillac” category, and are priced accordingly. If you’re into video, an LCD viewfinder is just the ticket. You hold the camera up to your eye, and the eyepiece lets you look at the LCD screen without any distractions or interference from ambient light. You also get the steadiness that you have become accustomed to with still photography, since the camera can be pressed against your face via the soft rubber eyecup. If I did lots of video, then I might go ahead and add one of those metal frames to the LCD and keep the eyepiece attached with its magnets, but most likely I'd stick with what describe below for attachment. Nothing’s stopping you from trying stills with Live View and the viewfinder, either. At least you won’t have any concerns about focus fine-tune. This might be a great option when using lenses like the Nikkor 85mm f/1.4 AF-S that have that annoying focus shift whenever the aperture changes (due to excessive spherical aberration). My Nikkor 24-70 f/2.8 AF-S E ED VR irritatingly needs different focus calibration at different focal lengths; Live View and its contrast-based focus would cure this problem, too. This viewfinder clips a tiny bit off of the vertical dimension in Live View, so I scoot it a little bit up and down if the edges are important, such as seeing the exposure information. An LCD viewfinder is largely incompatible with action photography, due to slow refresh rates on the LCD and sluggish contrast-based autofocus. If you’re into landscapes or macro photography, though, I’d highly recommend you explore this option. Some LCD viewfinders (including some Xit models) come with attachments to connect the viewfinder to the camera via the tripod socket, but these only work if you don’t use a battery grip. I always use battery grips, so I avoided this style of viewfinder. For some specifics on this particular model, here goes. The inside measurements of the viewfinder are 65.5 mm by 39.0 mm. The little metal frame outside measurements are 73.0 mm by 47.0 mm. It’s specified as a “3-inch LCD Viewfinder”. The magnification is 2.0X. The viewfinder body is heavy plastic; only time will tell how durable it is, but they claim a 5-year warranty. You can buy other LCD viewfinders (again, including Xit) that have more magnification, but personally I find that 2.0X is plenty. The viewfinder is fixed-focus, but the focus was perfect for my copy. The viewing aspect ratio is a bit off for my Nikon screens, which means that I can’t read the screen text above/below the image. This doesn’t bother me, but you might want to explore other brands/models that are a bit larger in the vertical dimension. I believe that this model is more tailored to the Canon screen aspect ratio. Xit Viewfinder and Nikon D610 LCD I tried viewing the LCD screen both with and without the camera protective plastic LCD cover. In both cases, the Xit viewfinder focus was fine. You can see above how the viewfinder aspect ratio is a bit wider than necessary and a bit shorter than the Nikon’s LCD. You can see the whole image at once, but not the data below the image. Viewable area with metal attachment frame In the shot above, I laid one of the included metal frames over the LCD screen. It barely avoids interfering with the rear controls, and partially obscures the button labels. The frame aspect ratio makes it a little wider than it needs to be, and it cuts off some screen text. I quickly decided that I’d forego sticking this frame onto my camera. You can see why they offer viewfinders that attach via a bracket to the tripod socket. I refuse to give up my battery grips, so this style of viewfinder won’t work for me. So what can I do if I want hands-free operation for my viewfinder? A little bungee cord to temporarily attach it to the camera For the times that I don’t want to just hand-hold the viewfinder against the LCD screen, I use a little black bungee cord to hold it in place. The bungee cord came with a spring-loaded clip to adjust the cord tension. The cord presses the unit against the LCD in 4 spots, and I can adjust it to get the exact tension that I want. A little bit goofy, but it works. At least the cord isn’t colored red or orange. Bungee cord attachment, top view I was luckily able to position the bungee cord so that it doesn’t interfere with any camera controls. Bungee cord attachment, bottom view Xit kit with neoprene carrying pouch The photo shows what the carrying pouch looks like. It’s a snug fit for the viewfinder. I also keep the pair of metal attachment frames in the bottom of the pouch, in case I decide to use them later. Summary Mirrorless camera users with an electronic viewfinder probably snicker when they read an article like this. They’ve had the ability to effortlessly observe their viewfinder in daylight since day one. But for DSLR users, properly viewing the LCD screen under any conditions has been a point of frustration since day one. I have no financial stake in Xit viewfinder sales or any other hardware, for that matter. I just thought you might find it useful to gain an awareness about the benefits of LCD viewfinders, especially when they can be had so inexpensively. Even if you don’t use one very often, you’re not out much money to give it a try. For me, owning an LCD viewfinder has become a no-brainer. #review

Did you ever wonder how those 3-D images got created? You probably thought that the process was complicated or expensive. It’s a lot easier than you think, and can be a lot of fun. It’s possible to make a 3-D anaglyph using Photoshop and Gimp, but I find it easier to do it in Zoner Photo Studio. What equipment you need A wide-angle lens on your camera is preferred. Either red-blue glasses or red-green glasses. A tripod. Optional: a sliding platform mounted onto tripod. Many cinematographers that make videos have “dolly” tracks, which would be ideal. How to make the photos For a dramatic effect, you want a wide-angle lens that can emphasize perspective. This isn’t mandatory, but I think you’ll prefer the end result. Choose a subject that won’t move. Avoid windy days for landscapes, and avoid moving water (unless you make super-long exposures that blur the water completely). Take the pair of shots with a pure shift between them of at least 2.5 inches (the distance between your eyes). Camera rotation will generally spoil the final shot. If you’re really far from your subject, try a large shift of several feet. Take a few shots at different distances, so you have choices later. Use manual exposure, so that the exposure doesn’t change between shots. How to create the anaglyph in Zoner Photo Studio Select the following menu item: Manager | Create | 3D Images… Select your pair of shots (keep left side first). “Find points automatically” checked. Choose “Half-color” or else “Black-and-white”. There are also “Color” and “Optimized” choices, but I don’t like the effect as well. The image type will be “Anaglyph” versus “MPO/PNS”. Put on your glasses (red on the left) to preview the result! Save final anaglyph in jpeg format. “Half-Color” anaglyph The shot above was created using a pair of shots that were shifted by 3 inches. I used the Sigma 14-24 f/2.8 Art at 21mm, 1/125 at f/11, ISO 100 on a D610. The camera was about 4 feet from the subject. Shoot in manual exposure mode to keep a consistent exposure. Stop down your lens, because you want everything in focus. Some fancy red-green glasses Both red-blue and red-green glasses will work with these anaglyphs, but I like the colors better with the red-green glasses. An improvised platform to slide my camera Keep your left-hand photo first. Preview the effect of the anaglyph type When you’re using the dialog to select the anaglyph type, put on your red-blue or red-green glasses. You can decide which effect you like best before creating the final photograph. Black-and-white anaglyph I prefer the black-and-white anaglyphs, because the color versions always have a bit of a strange color mix. “Optimized Color” anaglyph This 3-D effect can be achieved in many image editors, including Photoshop. The principal behind the technique is to rid the red channel from one image and rid both the blue and green channels from the other image. The image pair is then combined into one photo. A NASA anaglyph of Pluto NASA has always been a big fan of anaglyphs. Most of their image pairs are taken with a very large image separation distance, since they’re usually many miles from their subject. Conclusion Anaglyphs are obviously a very specialized kind of photography. It can turn otherwise bland subjects into amazing photos. I think that you should try to keep it in mind during your travels. Given how easy it is to make an anaglyph, it’s a trivial amount of extra effort to take a few image pairs for times when you think a scene might be great to save in 3 dimensions. #howto

Proper monitor color calibration isn’t as expensive and difficult as many people think. But it does require real hardware to do it. This article shows you how a typical calibration product works. The Spyder and the mouse This is a shot of the Spyder 5 calibration device in its folded configuration. It’s about the size of a computer mouse. The wire on the Spyder is a USB connection. The little white circle in the middle is a sensor to measure room light conditions. The idea behind monitor calibration is to measure both ambient room lighting and the colors your monitor(s) makes. The Spyder software will save the required monitor color and brightness adjustments into a file that gets loaded when you start up your computer. The calibration hardware is separated into two different parts: the ambient lighting sensor and the spectral response sensors. The spectral response sensors measure the red, green, and blue components of your monitor screen. The spectral sensors are hidden inside the device, and you have to pull off its “lens cap” to expose them. The software will evaluate how bright your monitor is, compared to your room lighting, and guide you in adjusting the monitor brightness to compensate (if your monitor is capable of doing this). The software will also set different colors on your monitor and then compare them to reference standards. The software will adjust the red, green, and blue levels to match those reference standards. After the correct settings are known, they get saved into files that are used to reprogram the monitor settings each time you restart your computer. Hanging Spyder The shot above shows the Spyder hanging from its USB wire connection. It has its lens cap, or “sensor cover” removed (the upper portion). The calibration program draws a target on the monitor being calibrated to indicate where to hang the device during the calibration operation. Note that you are able to calibrate multiple monitors on your computer; you just have to select which monitor you wish to calibrate. You can also install the software on multiple computers, although the program will request that you input your Spyder license number that you receive when you register your hardware through the web. You’ll quickly discover that the Spyder program will complain to you about your ambient lighting, unless it’s quite dim. Ambient lighting “pollutes” what you see on your screen, and you’re encouraged to either turn down the lights or use a monitor hood to maintain good quality control over what you see on your screen. The software can try to adjust the screen brightness and contrast to suit your room lighting, but ambient lighting generally degrades your color quality control. The program suggests that you begin calibration with your monitor set to 6500K if possible, with a gamma of 2.2. You can calibrate against sRGB, AdobeRGB, or NTSC standards. After the calibration is completed, it will let you compare your finished calibration against these calibration standards. Many monitors are somewhat limited in their brightness capability, especially when competing against bright room lighting. The program will let you ignore this portion of the calibration if your monitor cannot get bright enough or doesn’t even allow brightness adjustments. My own monitors can get to about 200 cd/m^2, which is able to compete against only moderate room lighting. The Spyder software wants room lighting that allows for 120 cd/m^2, which seems a bit dim for my taste. The software has a “calibration reminder” feature, with a default of 1 month. You should check for calibration drift, and this reminder service makes it easy to keep track of it. Before performing monitor calibration, you should let your monitor warm up for about a half hour, since cold monitors can exhibit some color and brightness drifting. Before you perform screen calibration, you’ll need to open up the Spyder and hang it from its USB cable. On a vertical screen, it will probably start sliding down the screen. You can either tilt your monitor back to prevent the Spyder from sliding, or else you can place something on top of the portion of the USB cable that’s laying on your desk that is heavy enough to keep it from moving. It’s probably better to tilt your monitor back, because you don’t want the sensor to have any ambient light leaks from not laying flat against the screen surface. The monitor target position indicator The monitor target location to hang the Spyder is shown above. On a multi-monitor system, this screen should be displayed on the monitor being calibrated. Before running the calibration, you should un-do any custom settings for the monitor, such as an altered contrast setting. Also, it is suggested that you use a USB port that’s on your computer; don't use a USB hub, since hubs are notorious for poor USB communications. There are options for a “full calibration”, “re-calibration”, and a “check calibration” in the program. There are also options for calibrating a laptop versus desktop computer, although if you’re using a laptop docking station with a separate monitor, you should use the “desktop” option. Display selection for multiple monitors When you run the Spyder calibration program, it automatically detects multiple monitors. It will display its interface for the screen you select on that monitors’ screen prior to actual calibration. Mid-calibration screen The screen above shows one of many calibration screens. Different colors are displayed and then measured against the expected response. After several minutes of different colors and intensities being displayed and measured, the calibration is complete. Save the calibration measurement results The screen shot above shows the dialog that gets displayed after all measurements have been taken. The results are saved in a monitor profile name that you can specify. This also where you can specify how often to receive a reminder about monitor calibration verification. Calibrated versus un-calibrated screen After calibration, you’re shown a screen that lets you compare the calibrated versus the un-calibrated screen (via the “Switch” button). On my monitors, there was a noticeable difference in skin tones between the calibrated/un-calibrated views. The calibrated gamut compared to ideal The “Profile Overview” screen shows how close your monitor comes to the ideal display gamut. This is the last stage of calibration; there’s a button to do more calibrations (“Calibrate Another Display”) if you have a multiple-monitor system. Conclusion The Spyder 5 Pro certainly isn’t the most expensive available unit, but it did everything that I could have asked for in monitor calibration. Before calibration, my pair of monitors looked different, but I had no way to know which of the two was “correct”. In the end, I now know that neither monitor was correctly calibrated prior to using the Spyder 5 Pro. #howto