Lens: Zeiss 74 mm f/4 S-Planar 1:1 lens test
Vintage: About 1970.
Lens Mount: About 32 mm. A M32.5 enlarging lens adapter is a little loose.
Needed Adapters: Custom adapter to F-mount.
Preferred Mounting: Normal, not reversed.
Filter Thread: About 27.5 mm.
Street Price: $500-$800 in good used condition. Prices vary a lot online, shop around.
Controls: Aperture setting (displays effective aperture at 1:1, 2x the aperture).
Aperture: 6 blades.
Basic Function: Requires a bellows to set focus and magnification.
| Extension | Magnification | Working Distance |
| 5 cm | 0.66 | 153 mm |
| 7.55 cm | 1.00 | 114 mm |
| 10 cm | 1.33 | 96 mm |
| 14 cm | 1.87 | 79 mm |
| 19 cm | 2.57 | 69 mm |
| Est. Focal Length: 74.0 mm | ||
Appearance:
Resolution vs. Aperture:
The most resolving aperture is f/4. f/4 and f/5.6 have almost the same sharpness. Testing was performed at f/4.
Corner Fuzziness vs. Aperture:
The field is extremely flat at all apertures at 1:1.
Lateral CA vs. Aperture:
There is minimal lateral CA at all apertures at 1:1.
Performance: Sharpness vs. Magnification:
I have 4 lines that represent levels of performance from outstanding (top) to fair (bottom). This shows where this lens fits into the hierarchy that I have created.
This lens shows very good (almost outstanding) sharpness at lower magnifications and fair to poor sharpness at the highest magnifications.
Performance: Resolution vs. Magnification:
I have 4 lines that represent levels of performance from outstanding (top) to fair (bottom). This shows where this lens fits into the hierarchy that I have created.
This lens shows very good resolution (almost outstanding) at lower magnifications and good resolution at the highest magnifications.
Corner Fuzziness vs. Magnification:
This lens shows outstanding corner sharpness at 1:1 and good/very good at magnifications above and below 1:1. the slight improvement in corner sharpness at the highest magnification isn't a sign of improving performance, but rather an indication of the worsening central sharpness at this magnification. The center sharpness is degrading faster than the corners.
Resolving Power vs. Magnification:
This graph represents the smallest details that are able to be resolved by this lens at various magnifications. If the number doesn't get smaller as the magnification rises, there is little benefit to going up in magnification with this lens. This situation is also called empty magnification.
No problems in the magnification range.
Chromatic Aberration:
This lens show minimal color fringing in the center (about 0.04 - 0.25 pixel) and minimal on the periphery at 1:1. Above and below 1:1 it tend to the mild to moderate range.
There is mild axial CA on out-of focus details (see image below) as shown by a slight magenta fringe on the right and a slight green fringe on the left of the image. This long CA improves considerably at f/5.6.
Longitudinal CA:
Image Contrast: Image contrast is very good, although not quite as high as modern macro lenses.
Flare: This lens shows no significant flare during testing.
Distortion: This lens shows no significant distortion during testing.
Image Samples:
About 1:1 magnification, f/4, focus stack of 8 images, resized:
Pixel level crop from the image above:
There is very good pixel level detail, no problems.
Pixel level crop from the corner:
There is no significant fuzziness in the corners.
About 2.5:1 magnification, f/4, stack of 14 images, resized:
Pixel level crop from the image above:
There is some fuzziness present, compatible with the performance graphs above.
Pixel level crop from the corner:
There is slightly more fuzziness in the corners compared to the center.
Conclusion:
The Zeiss S-Planar 74 mm duplication lens is made to work very well at 1:1 magnification and it does live up to the design. Above and below 1:1 the performance drops off, although not quite as bad as some of the other optimized lenses that I have tested. About the only optical thing I can find to criticize this lens at 1:1 is that there is a little longitudinal CA present at f/4 that mostly resolves when the lens is clicked to f/5.6. I did all of my shooting at f/4, but f/5.6 is very nearly as good with almost the same sharpness and only slightly less resolution. The other problem is that it has a non-standard lens mount - the adapter it has was custom made for it. A 34 mm step-down ring and a little electrical tape would probably work in a pinch.
All-in-all, this is an expensive and hard to find lens, best left to collectors as you can get 95% of the performance for quite a bit less with other more easily found (and mounted) lenses.