- Ed Dozier
Minolta Rokkor-QF 50mm f/3.5 Macro on the Nikon Z9
Here’s another lens that got as much respect as Rodney Dangerfield. I got a cheap Fotasy MD-N/Z adapter to put old manual-focus Minolta lenses on my Nikon Z9, including this 50mm macro. The quality results have been very surprising using old Minolta lenses; some good and some bad.
This Rokkor 50mm macro lens falls into the “good” category. Actually, my lens copy beats the legendary Nikkor 55mm pre-AI Micro Nikkor that was used in the original Star Wars film. If you occasionally explore macro photography, where auto-focus is rarely even needed, it can be a smart financial move to get some old manual gear. This Minolta stuff is really cheap, and the photographic results can border on stunning.
The Nikon Z mount has made mixing and matching lenses very easy to explore. The very short flange distance and large mount diameter makes it possible to mount most anything onto the Nikon mirrorless cameras. My Fotasy adapter lets me explore old Rokkor MD and MC lenses, where I still get infinity-focus capabilities. This adapter has no electrical contacts, but that’s no problem on Nikons with non-CPU lens capability, which still permits auto-exposure in aperture-priority mode.
For non-macro photography, this Nikon Z9 lets me have IBIS (vibration reduction), aperture-priority, auto-exposure, and focus-peaking with any manual focus, non-CPU lens. It’s much easier to focus these old lenses using focus-peaking than it ever was with split-image or micro-prism screens in the film era. Here’s a link to various settings for getting the most out of any fully-manual lens used on a Z-mount.
This 50mm lens has 5 aperture blades, 6 elements (4 groups), and the “MC” in its name means it is meter-coupled. It stops down to f/22. It has a red “R” on its focus scale for a typical infrared photography focus-shift.
This pure metal-and-glass lens weighs 330 grams. It is built with very high quality, and it still has perfectly smooth focus action. It was made in 1967, but I’ll bet that photos taken with this lens could easily be mistaken for a totally modern lens. Since these old lenses don’t have electronics in them, they generally last a very long time if they’re not mistreated (e.g. used in the rain).
Since this 50mm Macro only focuses down to ½ life size, Minolta also made a set of extension tubes (EB, No.1, No.2, No.3, and EL) to get down to life-size. These tubes are also dirt-cheap to buy used.
If you like more extreme magnification photography, you can also combine bellows units, like my Nikon PB-4, with this old Minolta lens, too. Image quality is improved if you reverse-mount lenses when going beyond life-size magnification, so I also have a Nikon BR-2 ring for that purpose. This 50mm Rokkor has a 55mm filter thread, so I also need a 55-to-52 mm step-down ring to attach it to the BR-2 ring. As usual, you’ll need an FTZii adapter to connect the Z-mount camera onto F-mount equipment, such as this PB-4 bellows unit.
MC Macro Rokkor-QF f/3.5 50mm on Nikon Z9
Fotasy adapter to mount the Rokkor onto the Nikon Z9
Magnification: white = lens alone, orange = extension tubes
Macro range, lens alone
Reverse-mounted lens on Nikon PB-4 bellows
Note that a wired remote is attached to the camera 10-pin connector for taking the shots without any vibration. The “EL” and “No.3” Minolta extension tube is mounted on the lens to protect it and to act as a lens shade. The extension tube of course limits subject lighting options and also working distance; it isn’t mandatory. You can also swap the No.1 or No.2 tubes for better working distance and easier lighting setups, with a little less protection.
You might not even think of using a non-Nikon lens on this PB-4 bellows, but the Nikon BR-2 ring, step-down rings, and adapters like the Fotasy MD-N/Z open up a whole new world of possibilities.
Reverse-mounted lens on PB-4 bellows
The high-magnification shot above couldn’t have been done without using the bellows. The whole bellows rig was shifted along its rail to get a series of overlapping shots, which were then focus-stacked using the Helicon Focus program. The focus-peaking camera feature makes it pretty easy to observe how the focus shifts shot-to-shot as the camera is shifted along the bellows rail.
You can even see some of the facets on the bee’s eye. To me, this looks like first-rate optics in action.
Extreme magnification at maximum bellows extension
Focus-stacking was used here, too. Each individual shot in the stack has paper-thin depth of focus. These results look sharp, sharp, sharp.
Extra pieces of gear to mount the lens in reverse for best quality
Using the Fotasy adapter to protect and shade the lens
In the shot above, I substituted the Fotasy adapter to be used as a lens shade and protector (this is optional). Note that the FTZ-ii adapter is required to connect the camera to the PB-4 bellows. The Nikon Z9 must be rotated to vertical-format shooting if you want to slide it along the PB-4 rail, because its vertical grip makes the camera a bit too tall.
I used the MTFMapper program to analyze shots from the Nikon Z9, taken in raw HighEfficiency format, converted to DNG format. I used the free Adobe DNG converter program to convert the HE shots (1/3 the size of regular compressed raw) into DNG. As of this date, none of my photo editors understand the HE format, but most of them understand the DNG format. The Zoner Photo Studio automatically invokes the conversion into DNG, so at least that editor works seamlessly with the HE format.
The full resolution target
The chart above is what I used to get the resolution, contrast, and lateral chromatic aberration measurements. The target is 40 inches tall by 55 inches wide. The chart also works well to get a visual evaluation of vignetting. I don’t have a chart that is small enough to directly measure the optics performance in the macro range.
50mm f/3.5 Resolution
Resolution across the whole frame, with a peak of 50.9 lp/mm wide-open. I wouldn’t recommend this aperture, although the center resolution is entirely acceptable.
Resolution numbers and vignetting sample, 50mm f/3.5
The shot above shows some sample resolution measurements overlaid onto the resolution chart photo. This also demonstrates the worst-case (f/3.5) vignetting. Nearly any photo editor can easily rid this vignetting, if you don’t want it.
50mm f/5.6 Resolution
Stopping down to f/5.6 gets a peak resolution of 64.2 lp/mm. The edge-to-edge resolution is just now getting acceptable, while the center nears maximum resolution.
Resolution numbers and vignetting sample, 50mm f/5.6
Stopping down one stop helps vignetting, too.
50mm f/8.0 Resolution
Stopping down to f/8.0 smoothes the across-frame resolution, with a peak of 58.1 lp/mm.
Resolution numbers and vignetting sample, 50mm f/8.0
50mm f/11.0 Resolution
Stopping down to f/11.0 reaches this lens’ smoothest performance; going to 54.7 lp/mm. Image quality here is just excellent across the frame.
Resolution numbers and vignetting sample, 50mm f/11.0
The price-to-performance ratio here is excellent. As an overall lens line, I still give the edge to my old Nikkors, but photos made with this Rokkor 50mm macro lens can look excellent.
A camera like the Nikon Z9 makes shooting with a manual lens like this easier than it has ever been, especially at extreme magnifications. An adapter like the Fotasy MD-N/Z makes exploring the old Rokkors almost financially risk-free.
If you only shoot close up once in a while, then you can’t go wrong with a lens like this.