• Ed Dozier

Using the Nikon PB-4 Bellows and Micro-Nikkor 60mm f/2.8 AF-D

If you want to explore the world beyond life-size, the Nikon PB-4 bellows is a terrific vehicle to get there. This 70s-era bellows is the best one that Nikon ever made, and you can still find it for sale (used) on sites like eBay.

Back in the day, you’d probably have purchased the Micro-Nikkor 55mm f/3.5 lens to use with this bellows. Nikon also sold a 105mm f/4 P lens that you could actually focus to infinity on the bellows! This 105mm lens would allow up to 1.3X magnification forward-mounted on the PB-4. The 105mm gives a better working distance than shorter lenses. This lens is essentially useless without the PB-4 bellows, since it can’t focus by itself.

It’s worth noting that the PB-4 bellows has both swing and shift controls. These controls were mainly intended for use with the Nikkor 105mm f/4 P lens. This lens has a large image circle, and in combination with the PB-4 enables you to have the same kind of controls as a “view camera” for manipulating the plane of focus and perspective control. As you’ll see, though, these controls can be useful for any lens attached to the PB-4.

As you will note below, there’s a lot of hardware and software involved in quality close-up photography. I hope that this guide gives you a better idea of what gear you will probably want to use.



Bellows PB-4 with Micro-Nikkor 60mm f/2.8 AF-D

Today, a really good choice for a lens on the PB-4 is the Micro-Nikkor 60mm f/2.8 AF-D, which you can still buy. It’s one of the only lenses you can still obtain new (as of this writing) that has an aperture ring. When you mount a lens on the PB-4, you won’t have any electrical contacts to control an aperture, so you need a lens with a mechanical aperture ring. The Micro-Nikkor 60mm lens works for FX format, which is helpful for its larger image circle. By itself, this 60mm lens will autofocus down to 1X (lifesize) magnification; the PB-4 is for going beyond this magnification.

Here’s a rare occasion where you will want to unlock the lens aperture ring, so that you no longer keep it locked at f/32. You will need to alternate apertures between wide-open (to focus) and the shooting aperture. Manually rotate the aperture ring, instead of letting the camera operate the aperture. Please remember to lock the lens back at f/32 before using it for regular photography on your camera without the bellows, or you’ll get the “f EE” error.




BR2, BR3, and Step-down rings on 60mm lens

For optimal sharpness beyond life-size magnification, most lenses work better when you mount them in reverse. Nikon used to sell a ring called the “BR2”. With this ring, you’d screw it into the lens filter threads and then mount the lens backwards. Unfortunately, the older Micro-Nikkor lenses had 52mm threads; the 60mm Micro-Nikkor has 62mm threads. To mount the BR2 ring onto the 60mm Micro-Nikkor, you need “step-down” rings that go from 62mm to 52mm. You can still buy a new Nikon “BR2A” ring today that does the same thing. Step-down ring sets (and step-up ring sets) are cheap and well worth the investment.

To protect the rear of your lens, now that it’s mounted in reverse, Nikon still sells a ring called the “BR-3”. This ring mounts on the back of the lens, and it has a 52mm thread that you can mount a protective filter onto. The BR-3 ring by itself acts like a lens shade. If you have a larger filter you’d like to use, then you can use “step up” rings for these.

To mount a modern Nikon camera on the PB-4, the bellows camera mount must be rotated into the vertical (portrait) orientation. After mounting the camera, you can then rotate the camera back into horizontal (landscape) orientation. Note that some camera models have a built-in flash that can slightly rub on the bellows while mounting the camera. The Nikon D610 is an example of such a camera; it still can be mounted, however. Also note that any camera battery grip must be removed before the camera will successfully fit onto the bellows. Models such as the D5 won’t work on this bellows.

My Nikon D850 camera fits onto the PB-4 just fine, as long as I remove its battery grip attachment first.

It would be possible to use an extension tube on the rear of the bellows to gain enough clearance for cameras to fit onto the bellows. I still don’t think that cameras with grips could clear the rack-and-pinion rails, though.

Once the camera is mounted, you can adjust the front (lens mount) and rear (camera mount) independently on the PB-4 rack-and-pinion focus rails. This is how you control the magnification you wish to use. There’s a handy millimeter-marked scale on the side of the focus rail.

Swing and Shift Bellows Capabilities

Nikon currently sells “PC” lenses, which stands for perspective control. These lenses, however, are only for conventional focus distances and low magnification. The PB-4 bellows, created in 1970, has perspective control built in. This bellows essentially takes over where the PC lenses leave off, to enable perspective and focus-plane control at high magnification and close distances.



Swing (rotate) adjustment

To change the plane of focus, you can alter the lens swing adjustment up to 25 degrees in either direction about the vertical axis. There’s a friction lever just under the mounted lens at the front of the PB-4 to enable this adjustment.




Shift adjustment

To shift the center of the subject, you can shift the lens on the bellows up to 10mm either left or right. There’s a separate friction lever at the front of the PB-4 to enable the shift adjustment; it’s near the ‘swing’ adjustment lever.

It’s also possible (and usually necessary) to combine both swing and shift at the same time. See the Scheimpflug principle down below; it shows you how to successfully use these controls.

You typically use these controls when the (flat) face of a subject doesn’t align with the flat face of the camera sensor. You need to swing the lens until its optical center plane (parallel to the lens diaphragm) intersects both the sensor plane and subject plane. Next, you typically need to shift the lens to center your subject in the viewfinder. Don't worry, I'll explain this procedure a little better in a minute.

The bellows only lets you make a swing adjustment about a vertical axis. The shift adjustment is only available along a single axis, as well.




Setup to photograph a rotated coin, viewed from above

The photo above shows the 60mm lens, the PB-4 bellows, and an LED ring light being used to photograph a coin held in front of the lens. The coin is rotated, so that its face is no longer parallel to the camera sensor.

The swing and shift controls were used to get the entire face of the coin in focus. Both the BR2 and BR3 rings were used to reverse-mount the lens and provide an attachment surface for the ring light. This arrangement as shown above results in a 2.5X magnification.

That Scheimpflug Dude

No, that’s not a bad word. Austrian army Captain Theodor Scheimpflug was determined to get rid of perspective distortion in aerial photographs. Theodor was born in 1865 and got interested in photography in 1902. Theodor combined photography with kites and balloons to make better maps. He read about a British 1901 patent from a French guy named Jules Carpentier. Jules had figured out the solution. Modest as he was, Scheimpflug insisted on giving credit to Jules Carpentier for the details of how to accomplish this distortion removal. Through the vagaries of history, credit for this “principle” was given solely to Scheimpflug.

When later questioned about the Scheimpflug Principle based upon his own patent, Jules said he didn’t mind that it was named after Scheimpflug, as long as his invention was found to be useful.

Scheimpflug, who got several patents of his own in the realm of aerial photography and panorama cameras with up to 8 lenses, shared his technique freely.

Nowadays, most architectural photographers are well-versed in his principle. They can get photos of the fronts of buildings that are dead sharp, even if they’re using a setup with a narrow depth of field. Lots of architectural photographers are now using those Nikon “PC” lenses.

But I digress, as I often do. How do we use this PB-4 to get sharp photos of stuff that might not be perfectly aligned with the camera sensor? By using the Scheimpflug Principle, of course.




Subject Plane, Optical Center Plane, and Sensor Plane

For starters, focus on the middle of your subject without any shift or swing adjustments. To get your rotated subject plane in focus, swing the lens until the red “subject plane”, the orange camera “sensor plane”, and the green “optical center plane” all intersect. In the sample above, the three planes all converge at a spot about 1 meter to the left of the camera (slightly out of the frame). You’re rotating the green plane (the lens), and leaving the other planes alone to achieve this intersection.

After the subject plane is in proper focus, you probably need to shift the lens to get your subject centered in the viewfinder. Since the shift movement doesn’t change the direction of the optical center (green line), the subject doesn’t go out of focus while shifting the lens.




Scheimpflug Principle

In a nutshell, that’s the “Scheimpflug Principle”. Scheimpflug was a smart guy, as was Jules Carpentier. You should thank the both of them.

This stuff is a bit complicated, until you go through the alignment exercise yourself a couple of times. It’s a lot simpler to just keep your subject plane parallel to the camera sensor, but where’s the fun in that?




Closeup results from setup shown above. Coin face is entirely in focus.

The photos above show a coin mounted with a significant rotation, relative to the camera sensor plane. Normally, it would be impossible at these magnifications to get the rotated coin face in focus even when the lens aperture is stopped down. The swing adjustment, combined with the shift adjustment, made getting everything in focus possible with a single photo. It would also be possible to get everything in focus by stacking several photos, where focus is shifted slightly between shots (see discussion below).

In the coin detail shot above, the reverse-mounted 60mm Micro Nikkor was stopped down to f/8.0, which gives a pretty shallow depth of focus. Thanks to the swing and shift controls on the PB-4, the coin face is entirely in focus. I didn’t have to stop down to a small aperture, which would have caused resolution-killing diffraction. The vertical field of view here is 9.75mm, or 2.46X magnification. I hope you can tell that this lens yields very, very sharp results.

You can get a pretty good idea of the distance to the subject from the lens when using the BR3 ring while mounting the 60mm lens in reverse (using the BR2 ring and step-down rings) by inspecting the overhead gear setup shots included above. The clearance between the light and the subject isn’t huge (about 2 inches), but it’s sufficient to get very good illumination.




The whole coin (NOT using the bellows)

The coin used in these examples is 39.1mm in diameter. The face itself is 0.55mm offset from the featureless coin surface. This is roughly as close as most people ever get when they use a macro lens by itself. The PB-4 takes you to a whole new level.

Since the invention of focus stacking, it’s now possible to get a huge depth of focus via multiple photos (see below). The stacking invention makes Scheimpflug no longer an imperative (unless you use film). It’s still quite nice to get the job done with a single photo, versus combining dozens of shots to get there.

Lighting Hardware Example



LED ring light mounted onto BR-3 ring

It’s often preferable to use a continuous-light source to illuminate small subjects, compared to using a flash. The BR-3 ring works as a nice surface to attach ring lights. There is still enough working range to your subject if you choose a small light. My ring light is about 34mm thick.

I like LED lights, because other types of continuous lights tend to cook your subject. Without continuous lighting, the (non-sunlit) subject is usually too dim to focus easily.

The light shown above has three tightening screws that grab onto the BR-3 ring.

Remote release



Infrared remote and 10-pin wired remote

Depending upon your camera model, I’d recommend that you use either the cheap ML-L3 infrared release or a 10-pin wired remote to minimize vibrations. Don’t forget to use the electronic front-curtain shutter mode if your camera has it, to really rid vibrations.

Working Distance



Example subject held in front of lens

The shot above shows a diamond ring that is in focus at a medium bellows extension. This should give you a good idea about how much working distance you have between your gear and the subject. There isn't a single "working distance" when discussing a certain lens on a bellows. The higher the magnification, the shorter the working distance.


I made a little device that uses an alligator clip to hold small objects. The device fits into the end of the bellows and has the necessary degrees of freedom to raise, shift, and rotate small objects.

I don’t know if you can buy any gizmos that will fit into the PB-4 bellows “slide copier” attachment hole for holding stuff. I was forced to make my own; I got tired of having to get my rig close to table tops with tripod legs always in the way.

The bottom control knob on the bellows is essentially used to balance all of your gear over the tripod. This collection of hardware can get heavy, so you’ll want to place it at the point of balance after setting the bellows extension.

Stacking Software

The depth of focus at high magnification isn’t much thicker than a sheet of paper. I recommend that you explore the world of focus-stacking, where you can combine many shots into a single photo. Each shot’s focus is slightly shifted, and the focus-stacking software combines them. The PB-4 bellows is ideal for letting you shift the camera/lens combination on its rack by small amounts between shots to have fine control over the focus shifting. You twist the bottom PB-4 knob to shift the whole camera/lens/light combination without changing magnification.

I have an article here where I discuss focus-stacking. The article shows how to use this free software; there are several programs (not free) that accomplish the same task. It generally takes 50 to 70 shots to get enough depth of focus in the final stacked photo. The magnification, lens, and subject will determine how many shots you will need.

One downside to photo-stacking is that you will need to crop the final stacked photo, because the edges are ‘fuzzy’. It’s almost as if an ‘FX’ photo ends up being a ‘DX’ photo. Try to allow for a liberal border around your subject by shooting at a lesser magnification.




Stacked photo result using CombineZM

I used 50 shots to make the finished photo of this wasp. I should have used a few more shots to get the tip of the leaf in full focus. There's about 15mm of focus depth here; without focus stacking, either the leaf or the wasp's eye would be in focus, but not both. I used my LED ring light for illumination.

Conclusion

I bet you didn’t think using the PB-4 bellows could be this complicated, did you? Close-up photography can get quite involved; think of it as a journey, and not just an end result. There’s a largely unseen world out there, even in your own back yard. Make it visible.

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