
Comparison Test of Film Scanner Lenses for focus stacking
Nikkor ED 14, Nikkor ED 7 und Minolta 5400

There are three legendary film scanner lenses from Nikon and Minolta, all of which are excellent for focus stacking.
Robert O’Toole, the outstanding macro and microscope lens expert who sadly passed away far too soon in early 2024, was the first to discover that high-quality film scanner lenses possess characteristics that make them ideal optics for focus stacking photography. Among the many scanner lenses he tested and presented on his website https://www.closeuphotography.com/, three stood out in particular: Nikkor ED 14, Nikkor ED 7, and Minolta 5400.
These lenses are especially interesting for focus stacking because there are very few microscope objectives available in the 1:1 to 2:1 magnification range that offer a resolution exceeding that of standard 35mm macro lenses. The exceptionally sharp Mitutoyo M Plan Apo series lenses, for example, only become interesting from 5× magnification onward, though with a shorter tube lens focal length, they can be used starting around 3:1.
I have introduced these three outstanding lenses in separate blog posts on this website (Nikkor ED 14, Nikkor ED 7, and Minolta 5400), where I also describe in detail how to extract them from scanners and mount them on a camera or bellows system. In this article, I want to share my experiences with their optical performance and present test images. What can each of these lenses deliver? Is it worth acquiring all three, or is one sufficient for magnifications from 1:1 to 5:1? Are all three suitable for a full-frame sensor?
The Test Candidates
Nikkor ED 14

The Nikkor ED 14 with the sensor from its film scanner
Manufacturer: Nikon
Production Period: 2001 – 2008/09
Scanner Model: Coolscan ED 8000/9000
Optical Design: 14 elements in 6 groups, APO
Focal Length: 100 mm
Aperture (Normal Orientation): f/2.8
Image Circle: 57.5 mm
Active Sensor Length: 57.5 mm
Magnification (White Dot Facing Sensor): 0.9×
Magnification Reversed Orientation: 1.1×

The image circle of the Nikkor ED 14 is an impressive 57.5 millimeters, and in its normal orientation, the lens reduces at a ratio of 0.9:1

At 1:1, a completely distortion-free image with no chromatic aberrations and outstanding sharpness

This lens delivers the same performance in the corners as it does in the center
Nikkor ED 7

The Nikkor ED 7 with the sensor from its film scanner
Manufacturer: Nikon
Production Period: 2003 – 2009
Scanner Model: Coolscan IV and V, Super CoolScan 4000 and 5000 ED
Optical Design: 7 elements in 4 groups, APO
Focal Length: 45 mm
Aperture: Normal orientation (white dot facing sensor) f/2.8, reversed orientation f/2.6
Image Circle: 32 mm
Active Sensor Length: 32 mm
Scanned Film Width: 24.51 mm
Magnification in Normal Orientation (white dot facing sensor): 1.33×

The image circle of the Nikkor ED 7 is small at 32 mm, resulting in a magnification of 1.33:1 with slight enlargement

At 1.5:1, the darkening of the image corners, which is still quite noticeable at 1:1, is reduced. The image remains distortion-free and shows no chromatic aberrations

The image center exhibits excellent sharpness, though corner sharpness decreases on a full-frame sensor. However, this is not an issue for smaller sensors (MFT, APS).
Minolta 5400

The Minolta 5400 with the sensor from its film scanner
Manufacturer: Scanner by Minolta, Lens by Mirold Optics
Production Period: 2003 – 2005 (I), 2005 – 2006 (II)
Scanner Model: Dimage Scan Elite 5400 I and II
Optical Design: 8 elements in 4 groups, APO
Focal Length: 39 mm
Aperture: f/3.7
Image Circle: 43.3 mm
Active Sensor Length: 43.5 mm
Scanned Film Width: 24.51 mm
Magnification in Normal Orientation (gold line facing sensor): 1.78:1, according to other sources 1.83:1

At 43.3 mm, the image circle of the Minolta 5400 corresponds exactly to the diagonal of the 35 mm full-frame format

At 2:1, the Minolta 5400 is in its element, delivering a distortion-free, exceptionally sharp image with no chromatic aberrations

Unmatched image sharpness in the center, with very slight loss of sharpness and color contrast in the corners on a full-frame sensor
The Test Run
The comparative test covered various magnification ratios between 1:1 and 5:1. At each magnification, the film scanner lenses were compared to the Canon MP-E 65. The images show a heavily magnified central crop of an original image taken with the respective lens, created as a single frame, focused on the image center. Although a series of images was captured, it was done solely to select the sharpest frame. No focus stacking was performed.
The scaling ratio can be easily understood by referring to the grid structure, especially when considering the untrimmed images shown at 1:1, 1.5:1, and 2:1 magnifications at the beginning.
The same “silicon wafer” glass plate from computer processor manufacturing, which I also use for other lens tests, was photographed under studio LED lighting. A Canon R5 II was used as the camera.
For comparison, the Canon MP-E 65 macro lens is included at every magnification, and at 1:1 the Canon RF 100 Macro f/2.8 L macro as well, both with f/4 aperture.

From left to right: Nikkor ED 14, Nikkor ED 7, Minolta 5400
Magnification 1:1

At 1:1, the Nikkor ED 14 is in its element, while the ED 7 still lags behind in terms of sharpness. The Minolta appears to be absolutely competitive in terms of image sharpness, but this only applies to the center of the image shown here. In a very wide border zone, it loses significant sharpness on full-frame at 1:1.

The Minolta 5400 (left) in direct comparison with the Canon MP-E 65 (center) and the Canon Macro RF 100mm f/2.8 L; due to the massive enlargement of the 1:1 image files, the sharpness difference is only noticeable upon close inspection, but the RF Macro 100 shows noticeably softer details, the MP-E 65 is visibly sharper, though it doesn't match the detail rendering of the Minolta, which is actually a bit overwhelmed by this magnification ratio when considering the border zone, which is not visible in the image here.
Nikkor ED 14
At 1:1, the Nikkor ED 14 is outstanding in the center, with excellent color contrast, accuracy, and sharpness, even on full-frame. The image circle is a massive 57.5 mm, which could even cover a medium-format sensor. There is no corner vignetting.
Nikkor ED 7
The Nikkor ED 7 has a significantly smaller image circle of 32 mm compared to its larger sibling, the ED 14, and the Minolta. It was designed for a much smaller sensor, not only compared to the ED 14 but also the Minolta. Its active length is only around 33 mm (compared to 43 mm for the Minolta 5400). As a result, the objective ED 7 is magnifying by 1,33:1, and at 1:1 on full-frame, the corners are dark. On smaller sensors, however, this would likely be barely noticeable.
At 1:1, the Nikkor ED 7 is sharp in the center, almost comparable to the ED 14, and the difference is minimal in direct comparison. However, on full-frame, the usefulness of the Nikkor ED 7 at this magnification is limited due to the corner vignetting. For full-frame work at 1:1, the ED 14 is the better choice here. For smaller sensors like MFT or APS, however, the ED 7 would be ideal for this magnification.
Minolta 5400
The Minolta has a relatively large image circle of 43.3 mm, as its sensor, with an active length of 43 mm, exactly matches the image circle of full-frame. This lens is optimized for a magnification ratio of 1.78:1, so its best performance would be expected at around 1.5:1 and 2:1.
Even at 1:1 it shows no darkening of the edges or corners, and in the center it shows an astonishing sharpness, better than that of the ED 7 at 1:1. In full format, the image quality at this magnification drops noticeably towards the outermost edge, although this should not be noticeable with smaller sensors.
The Canon MP-E, which is always included for comparison, is slightly less sharp in the center than the three film scanner lenses, but it performs more consistently in the border areas than the ED 7 and the Minolta (not visible in the central image crop shown).
Magnification 1,5:1

Führungswechsel: Nikkor ED 7 und Minolta haben die Nase vorn, dahinter liegt dass Nikkor ED 14, doch alle bilden schärfer ab als das MP-E 65
Nikkor ED 14
At 1.5:1, the Nikkor ED 14 is slightly less sharp in the center compared to the ED 7; it's apparent that it has already moved away from its "sweet spot," the magnification ratio for which it was optimized. The ED 7 appears a bit sharper and is thus comparable to the Minolta.
Nikkor ED 7
At 1.5:1, the ED 7 is absolutely comparable to the Minolta, which can be explained by its optimization for 1.33:1. In terms of detail, there are almost no noticeable differences when compared to the Minolta. The corner vignetting that was present at 1:1 has disappeared here (not visible in the central image crop shown).
Minolta 5400
At 1.5:1, the Minolta is as sharp in the center as the ED 7, with little to no difference in sharpness. It also shows neither vignetting nor the sharpness loss in the corners that was present at 1:1 (not visible in the central image crop shown).
Magnification 2:1

Even at 2:1, the Nikkor ED 7 leads together with the Minolta, followed by the Nikkor ED 14, which is now even behind the MP-E 65
Nikkor ED 14
At 2:1, the ED 14 continues to lose sharpness and is now clearly inferior to the ED 7; it has moved too far away from its "sweet spot" at 1:1. It might be possible to squeeze a bit more sharpness out of it with an added aperture ring and optimal settings (with an aperture of around 9 mm), but this lens was not designed for this magnification ratio.
Nikkor ED 7
At 2:1, the ED 7 reveals more detail than its larger sibling, but the Minolta still edges it out slightly. However, the difference between these two is so small that it would likely be imperceptible in regular photos. There is no corner vignetting present in full-frame at this magnification. It's clear
that this lens performs very well at 2:1.
Minolta 5400
At 2:1, the Minolta comes out on top, but only by a small margin over the ED 7. Here, you can clearly see how much more detail the two film scanner lenses capture compared to the MP-E 65—of course, at the cost of depth of field, meaning focus stacking is essential.
Magnification 3:1

At 3:1, the Nikkor ED 7 is also out of the picture; the Minolta, on the other hand, is now sharper than the MP-E 65
Nikkor ED 7
Even at 3:1, the ED 7 is still in the game, while the ED 14 already requires such an extreme extension that a standard bellows would be overwhelmed, making additional extension tubes necessary. However, at this magnification, the ED 7 is clearly inferior to the Minolta, which shows noticeably more detail. The corners of the ED 7 also suffer significantly at this magnification on full-frame (not visible in the central image crop shown).
You can still work with the ED 7 at 3:1, but the resolution advantage that these film scanner lenses in general have over conventional macro lenses is already lost here.
Minolta 5400
At 3:1, the Minolta not only keeps up with the MP-E 65 but surpasses it noticeably, offering significantly more sharpness, particularly with more stable performance in the corners on full-frame (not visible in the central image crop shown), although it is already far from its "sweet spot." This lens can perform excellently at 3:1.
Magnification 4:1

Unbelievable but true: The Minolta performs remarkably well even at 4:1 against the MP-E 65 and matches it in terms of sharpness. In addition, it shows no color fringing, while the MP-E 65 has clear CAs outside of the image center shown here.
Minolta 5400
At 4:1, the Minolta still has plenty of power; it remains a bit superior to the MP-E 65! This is remarkable considering it was optimized for a magnification around 1.8:1. However, the difference is very small and comes at the cost of a smaller depth of field, which requires focus stacking; here, it’s up to each individual to decide which lens is better for their specific needs.
Magnification 5:1

The comparison at 5:1 was a small sensation for me, because it showed that the Minolta is still in the race even at 5:1. Although it is inferior to the MP-E 65 in terms of sharpness, you have to take into account that it is free of chromatic aberrations, which the MP-E 65 absolutely cannot claim: In the central image section shown here, you can only guess at it, but in the extended center and especially in the peripheral zone of the image file, this was not to be overlooked, unlike the Minolta.
Minolta 5400
Even at 5:1, this lens doesn't give up easily; it holds its own against the MP-E 65, although it can no longer match its sharpness. However, you wouldn't specifically choose this lens for 5:1 work—it's more of a bonus if it's already part of your setup and you happen to have an interesting subject in front of the lens that you want to approach a bit closer with minimal effort. The Minolta can handle that.
Both the Minolta and the MP-E 65, however, have met their match in the Mitutoyo M Plan Apo 5x, and here you can see how a good microscope objective can overshadow even an outstanding macro lens like the MP-E 65.
Conclusion
The three film scanner lenses bridge the gap between a conventional 1:1 macro lens and a Mitutoyo M Plan Apo 5x, which is used at around 3:1 with a shorter tube focal length. Chromatic aberrations are absent in these three film scanner lenses, as they all feature apochromatic correction.
The Nikkor ED 14 is only useful if you are working around the 1:1 magnification range. This is ideal for many prepared insects up to about 25 mm in body length. The distortion-free performance all the way to the outermost corners of the image is nearly unparalleled and can only be found in the legendary Printing-Nikkors, whose lens concept it also has in its DNA. The level of detail reproduction here is likely superior to that of a conventional high-quality 1:1 macro lens, and it works without limitations on a full-frame sensor.
The Nikkor ED 7 is perfect for shots between 1.5:1 and 2:1, and its sharpness is comparable to that of the Minolta 5400 in this range. However, it does lose sharpness in the corners on full-frame, which is not an issue with the Minolta. At 1:1, the corners also become dark on full-frame. This makes the ED 7 better suited for smaller sensors (MFT, APS), where it would still perform well at 1:1, although it is slightly less sharp than the ED 14 at this magnification.
The Minolta 5400 is the standout performer. It remains unclear how the manufacturer, Mirold Optics, managed to design a lens with such exceptional sharpness that remains consistent across a wide range of magnifications. Excellent images are possible even at 4:1, and the sharpness at 5:1 is still impressive.
However, the absolute sharpness of the Minolta 5400 is not significantly higher than that of the two Nikkor lenses, as statements by Robert O'Toole indicate that all three of the lenses compared here offer values around 4000 dpi. The key difference is that the two Nikkor lenses are more limited in their optimal magnification ranges, as illustrated in the diagram, while the Minolta offers a fantastic solution for focus stacking at magnifications ranging from 1.5:1 to 4:1 on full-frame.


The suitability of the three film scanner lenses on the full-frame sensor (top) and on the MFT sensor and APS formats (bottom)
Full-Frame
For those using a full-frame sensor, the ideal solution would be a combination of the Nikkor ED 14 plus the Minolta 5400. Robert O'Toole recommended the ED 14 for 1:1, the ED 7 for 1.5:1, and the Minolta from 2:1 onwards.
Smaller Sensor Sizes
On smaller sensors, the Nikkor ED 14 could also be replaced by the Nikkor ED 7, as its center sharpness is not significantly worse here. The difference lies in the much smaller image circle, which not only costs sharpness outside the center on full-frame but also leads to noticeable darkening of the edges and corners. However, these areas are not captured on smaller sensors. Due to its sharpness performance, it is an ideal lens for 1.5:1 and 2:1 with these sensor sizes.
One for Everything
The simplest solution for high-quality images that are sharp and distortion-free even in the corners is the small and somewhat unassuming Minolta 5400. From 1.5:1 to 4:1, it’s the perfect solution, with a slight sharpness compromise even at 5:1, and on smaller sensors, it can also perform well at 1:1.
More about the Nikkor ED 14 –how to obtain it, remove it from the scanner, and adapt it to a camera can be found here.
More about the Nikkor ED 7 – how to obtain it, remove it from the scanner, and adapt it to a camera can be found here.
More about the Minolta 5400 – how to obtain it, remove it from the scanner, and adapt it to a camera can be found here.