Adjusting 35mm Ultron?

[Charles D. Orze]

Hi folks,

My 35mm Ultron is a bit off focus with my M8 (it backfocuses a bit). My 28 Ultron, 35mm Canon, and 50mm Nokton are spot on, so it is clearly the lens, not the camera. Does anyone know how to dismantle and adjust this lens (to anticipate--I've been working on optics for decades and have disassembled many lenses--but it is better not to reinvent the wheel if one does not have to).

By the way, the Canon 35mm f1.5 when sharply focused is a superb lens on the M8.

Thanks,

Charlie

 

[benjaminspell]

i am having the same problem. i wasnt sure if it was just my copy. Does anyone have any recommendations for repair of this lens? I emailed cameraquest and was told that it wasnt worth the cost.

 

[Quinn Porter]

The 35mm Ultron is LTM, right? If so, there's a good chance the thickness of the adapter is a little off. I found that the adapter for my 28mm Ultron was a little thin. Would you believe a little Scotch tape between the adapter and lens solved the problem.

 

[ferider]

Hi Charlie,

if you take the lens mount off, you will see another black ring, mounted with three Phillips screws, in long screw holes. If you loosen the screws and twist the ring just a little, you can adjust the cam/focus relation, and at least optimize for close focus.

Best,

Roland.

 

[baycrest]

I experienced the same BF issue when I bought the Ultron 2 years ago. The store advised that's what happens with the LTM adapter, I tried a couple of others and had the same experience.

So I exchanged it + a bit of cash for the Zeiss Biogon. Had the flanged milled by JM and am very satisfied with the Zeiss focusing.

Its really a shame about the Ultron cos it was very sharp and I found the BF was difficult for me to compensate for at various distances from the subject. I really wanted to use it....

Cheers
Rob

 

[Charles D. Orze]

Thanks everyone for your replies. Roland's reply did the trick. Here is the routine. Disassemble the mount. Tweak the cam slightly, reassemble, shoot front focus slightly, on focus, back focus slightly. Look at pictures, disassemble, adjust as needed, reassemble until close focus is correct wide open. Then check infinity focus, same routine, until both infinity and close focus are correct. If you are going to do this you need to work patiently and methodically taking note of which way the cam moves. The lens now rocks! I can't believe CV designed a lens that can be adjusted!!!

My CV 40mm is another thing--the M mount does not have the built in adjustment and it is off both at infinity and close up. Sigh.

Best,

Charlie