Agfa 80mm F4: Process Lens

As you probably picked from my earlier posts I was unsure how to measure the mounting thread. How do you measure the pitch of the thread I would not know how to assess .7 from ,5 ( is it the angle of the thread or the number of threads per mm?).

To day while doing some thing complteely different I realized how I might adjust my system of testing resolution so I could measure cnr to cnr. To night I tried it out. It was a case of so close but so far... I need one more focusing rail to sort it. My idea involved changing how the two bellows are mounted .. One is now mounted turned on its vertical axis 90 degrees . This made tuning the whole set up much simpler and now I can bring the 10X objective into play.

At 1-1 the F4 variant. ( picture is very noisy)





I also realized I must be way beyond the DLA for the camera with this set up, so Diffraction is also having its effect. All that said the lens is resolving at group 7 element 2 comfortably. That is 143 cycles per mm. This is well beyond the resolution ability of the sensor.

It looks like Thorlabs has some M34x0.5 adapters, with external or internal threads.

You'd have to go from M34 to SM1 and then from SM1 to T-mount or M42, etc. (I've used SM2-sized adapters with Thorlabs SM2 tubes holding the tube lens for infinity-corrected microscope objectives.)


Just out of curiosity, I wonder what the thread pitch of the usual 34mm filter threads is, used in various step-up or step-down rings?

I have emailed Raf camera asking for two M34 X 0.5 to M39 adapters. From past experience he will have them made in about 2-3 weeks

Today I received proper adapters from RAF Camera. M34X.5( as correctly identified by rmpsrmps) to M39(my preferred mount) the adapters fitted the 80mm and the Staeble 105mm perfectly. Previously with the 80 mm I had to use an extension tube to fit the lens to my bellows as the lens barrel protruded too far out of the M39 mount. The RAF adapter fortuitously provided enough extension to fit the lens to the bellows without an extension ring. I see Raf Camera has a M34X .5 -M42 version so I am guessing rmpsrmps has one on the way to him.