Archived posting to the Leica Users Group, 2007/04/01

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Subject: [Leica] Focus shift on 50/1.4 Nikkor on M8
From: leica at screengang.com (Didier Ludwig)
Date: Sun Apr 1 13:45:05 2007
References: <958D6C86-09C4-45D7-9346-8AE9076C1AB3@comcast.net> <000201c7749d$023b32b0$44300b44@GATEWAY>

Jeffery

It's the digital rangefinder cameras that allow to check the 
focusing accuracy much better and quicker than with film 
cameras. But the problem is old. I guess every RF lens always 
had it's own tolerance and focusing behaviour.

Past january I had received an email from a Robert White 
employee who told me about the focus accuracy tests they 
had made with some Epson R-D1. This test concerned focusing 
an object at 1m distance with open apertures, but I'm quite 
shure it would look similar with varied distances and aperture. 
Let me quote him:

>...we also tested 6 different lenses in our shop, these lenses were a 
>mixture 
>of new and old and from several manufacturers. We were truly amazed by 
>the different results. A number of well known manufacturers lenses faired 
>poorly with regards to this problem.

Didier




>>I suppose that I should set up some sort of contraption to find the "soft
>>spots" on all of my lenses. It would have been a prohibitive pain in the 
>>ass
>>without the M8. But the test I ran on the Nikkor tells me that if I took a
>>portrait of someone at 5' and at f/5.6, her eyes would be out of focus.
>>
>>For now, I think I need to decide which one of my 28's, 35's, and 50's will
>>reside most of the time on my M8 and test them.
>>
>>Jeffery Smith
>>New Orleans, LA

Replies: Reply from Frank.Dernie at btinternet.com (Frank Dernie) ([Leica] Focus shift on 50/1.4 Nikkor on M8)
Reply from jsmith342 at cox.net (Jeffery Smith) ([Leica] Focus shift on 50/1.4 Nikkor on M8)
In reply to: Message from len-1 at comcast.net (Leonard Taupier) ([Leica] Focus shift on 50/1.4 Nikkor on M8)
Message from jsmith342 at cox.net (Jeffery Smith) ([Leica] Focus shift on 50/1.4 Nikkor on M8)