Thank you all for being so helpful!
The 'A' and 'M' function on my camera lens would appear to not be working as it should. I managed to get a hold of a second Jena DDR 50mm and the noticeable difference between the two was that, if I was to click between stops on the aperture ring, I could see it opening and closing. So I'm guessing the pin/mechanism in my lens body was faulty?

Just for anyone that's curious, or if anyone comes across this with a similar problem, when shooting in 'A' mode, you can preview the depth of field by pressing the shutter release half way, without actually taking the shot.

Thank you again everyone!

Quote Originally Posted by Prof_Pixel View Post
In the lens manual mode, you should be able to see the aperture open and close as you move the aperture ring. If I understand you correctly, this isn't happening.


My comments were based on an Exa I had in 1955-1957 which, after checking the web, is a far different camera from the later Exa 1B the original poster has.