This is a big lens, much bigger than the Printing-Nikkors. It has M67 threads front and rear, and the rear case is 65mm diameter. I also ordered a 65mm-42mm protection circle adapter same time as the lens, but it hasn't arrived yet. After ordering I realized that necking down to M42 would limit me from being able to test the lens wide open, so when the lens arrived I did not wait for the adapter to start testing.
Turns out I had a cheap Canon tripod mount with 65mm ID (with flocking), and it fits and works perfectly.
I ended up using one of my taller stands based on the 4040 column with countertop tile base and 480mm Arca plate. The specs say 70.8mm WD (which is another reason I decided to go for this lens), and 651mm object to image distance. I set up the system with these two parameters, which required me to extend the Arca plate well above the 24" tall column. For interconnect/bellows, I made a tube of black flocking material and attached it to the camera, leaving it mobile around the lens. This is obviously not my preferred way to do this work, but it seems very effective.
I mounted the camera to the column / plate with an Arca clamp and a cheap Fotomate rail going horizontally. I centered the camera on the rail, so I can shift +/-50mm. I mounted the lens to the column directly, using another Fotomate rail going vertically to give some easy WD adjustment.
Manual fine focusing and framing is via a micrometer XYZ.
I'll take a picture of the setup and publish it a bit later. Results first...
My first subject is of course a Lincoln Cent, a 1955-S BIE. The BIE area makes an interesting subject since the metal is often taller there than anywhere else on the coin. The BIE is created by a die chip, which makes a hole in the die such that the corresponding raised area on the coin can be arbitrarily tall.
The published spec numbers were almost dead-on! Just a little adjustment and I was at 3.5x exactly. Zooming in 100% in Live View on the BIE showed a shockingly sharp image...a very promising beginning!
My first shots were an aperture sweep...f2.4, 2.8, 4.0, 5.6. Although there is an intermediate stop between 2.4 and 4.0, there is no such stop between 4.0 and 5.6. To my eyes the f2.4 is slightly sharper than f2.8 (!!!), so my next shots were a coverage sweep to see how far out the lens stays sharp at f2.4. I shifted the camera 21.5mm, 31mm, and 41mm to simulate the corners of FF, and the ends of 62mm and 82mm line sensors. See the images attached below:
Note: these are unprocessed 100% crops of single images, with critical focus on the flat high points on left and right sides of the die chip between the B and E.
Center, f2.4
Center, f2.8
Center, f4.0
Center, f5.6
I see very slightly more detail in the critical focus areas on the f2.4 shot, with slightly more CA vs the f2.8, which has slightly more than the f4.0. I also see false colors on the f2.4 and f2.8, and less on the f4.0 and f5.6. This gave me hope that the f2.4 may be usable across the frame, so I did the camera shift sweep at f2.4.
Edited to add: the below images are native 1024x900 to avoid forum scaling. Aperture sweep images above are still 1200x900 and have been rescaled to 1024x768 by the forum software.
Center, f2.4
21.5mm / FF Corner, f2.4
31mm / 62mm Line sensor end, f2.4
41mm / 82mm Line sensor end, f2.4
Amazingly, the lens holds up well at f2.4 all the way to the end of the 82mm sensor! In fact it looks like the CA improves at the FF corner, and then stays OK all the way to 82mm. This coverage is better than expected, at larger aperture...so far so good!
