Canon sonar focus optimization

[Iestrada]

I will be sending my newly acquired 50mm 1.5 sonar for a CLA.

I have read that they are optimized for sharpness at f4 and that some users have it optimized at f1.5.

What is your preference and why?

 

[Dez]

I don't think this is something that can be adjusted. Most f1.4/1.5 lenses seem at their best around f4.

Cheers,
Dez

 

[msbarnes]

I don't think this is something that can be adjusted. Most f1.4/1.5 lenses seem at their best around f4.

Cheers,
Dez

Ditto. I had the lens. I'm not sure but I feel that the ZMs shift more or it is atleast more pronounced. I didn't notice that much shift on the sonnars that I've owned (canon 50/1.5, nikon 50/1.4, contax zeiss 50/1.5). The few times I missed, I felt that it was my fault (f1.4/f1.5 at 1m is tough).

 

[Iestrada]

Thanks guys.

 

[Boris Stupak]

You are misunderstanding the difference between focus shift, and stopping down to optimum aperture for overall sharpness.

Also, it might not be a good idea to have the lens "CLA'ed". It means nothing. If the lens is not fogged, leave it alone, you might make it much worse. It is an old lens and you don't want some bozo taking it apart and playing with it.

 

[Iestrada]

The lens does need the CLA. It has haze that needs tending to. Youxin is my go to guy. He has done a superb job every time I have needed his services.

Thanks for the advice.

I am personally not inclined to change anything from factory specs. I was just curious as to other user prefer.