My C.V. Colour Skopar infinity issue

[Chris C]

I have a 35mm f2.5 C.V. Colour Skopar Classic LTM lens for use on my M8, it is mounted with a code-able John Milich adapter.

Focus is fine at near to mid-ground distances, it is a lens that I like for the things it does well. I'm not too interested in wide-open performance [preferring to work at f5.6 to f8], but it's infinity performance is far from desirable. This fact has been masked by f8 'landscape' type of work, but a different, recent, set of focus tests confirm that my lens is weak when focused at infinity.

Rangefinder infinity [i.e. the moon] and lens-barrel infinity seem to be coincident, so I wondered whether others owners of this tiny, popular lens have had dissatisfaction with far-range resolution. My internet searches have not revealed any known infinity focus issues, and my knowledge that Sean Reid still uses his lens for his series of 'beach-scape' photographs makes me suspicious that I might have a 'special' lens.

Have I described a characteristic of the 'Classic' lens design which others have doubted, or am I unlucky? If you have distance-focus experience of these lenses I'd be grateful to hear them.

.............. Chris

 

[wilsonlaidlaw]

I have a 35mm f2.5 C.V. Colour Skopar Classic LTM lens for use on my M8, it is mounted with a code-able John Milich adapter.

Focus is fine at near to mid-ground distances, it is a lens that I like for the things it does well. I'm not too interested in wide-open performance [preferring to work at f5.6 to f8], but it's infinity performance is far from desirable. This fact has been masked by f8 'landscape' type of work, but a different, recent, set of focus tests confirm that my lens is weak when focused at infinity.

Rangefinder infinity [i.e. the moon] and lens-barrel infinity seem to be coincident, so I wondered whether others owners of this tiny, popular lens have had dissatisfaction with far-range resolution. My internet searches have not revealed any known infinity focus issues, and my knowledge that Sean Reid still uses his lens for his series of 'beach-scape' photographs makes me suspicious that I might have a 'special' lens.

Have I described a characteristic of the 'Classic' lens design which others have doubted, or am I unlucky? If you have distance-focus experience of these lenses I'd be grateful to hear them.

.............. Chris

I have the same lens which also has focus issues. I took it to my usual lens man. He commented "what a crude little thing - there is no way that the lens cell can be moved relative to the RF cam." He felt that they may assemble the lens and then cut the RF cam afterwards. If it is wrong it is wrong. You can move the cell and RF cam together by shimming but this is only of very limited use. People have tried either filing the RF cam or building it up with solder but I have grave doubts as to the accuracy of either of these procedures. I only paid £100 second hand for mine, so no great loss. I am thinking of a C Biogon 35/2.8 for when I want to just take my M9 with no case or other lenses in a pocket.

Wilson

 

[Chris C]

... "what a crude little thing"... If it is wrong it is wrong....... I am thinking of a C Biogon 35/2.8...

Wilson - Hi. I'm grateful for your post. It's at times like this that I too wish I had a "usual lens man". I recall that you are part UK based [?], is the "lens man" you refer to operating commercially, and are they in the UK ? Were your Skopar focus issues similar to mine, or did it simply misfocus for near, mid, and far distance subjects?

When I calm down from obsessing that my camera is wrong, my lenses are wrong, and remember the moon isn't actually situated beyond infinity; I think the C-Biogon 35mm f2.8 might be a better solution for me as well. As much as I need Leica lenses, they are all out of my price range unfortunately.

............... Chris