Chuck,
I started with a sheet of 80 grit laid flat on the top of my table saw, then
finished up with 400 grit. The result is an adapter that is approximately
6.9mm in thickness. The only down side is that the lens screwed into the
adapter approximately 45deg further than before, so the lens index, formerly
at the top, is now down on the left side. No big deal.
Here are some representative photos, with f stops. Just as a reminder, you
can't use exact f stops in a title. I had to use dashes instead of periods.
Although I shot at all marked stops, from 1.8 to 22, I only posted four
images as examples. The sun was getting lower as the f stops got higher, so
the light does change somewhat.
http://gallery.leica-users.org/v/OldNick/Takumar+55+at+f1-8.jpg.html
http://gallery.leica-users.org/v/OldNick/Takumar+55+at+f2-8.jpg.html
http://gallery.leica-users.org/v/OldNick/Takumar+55+at+f5-6.jpg.html
http://gallery.leica-users.org/v/OldNick/Takumar+55+at+f11.jpg.html
Except for the softness of the lens at f/1.8, I think all of the images are
acceptable. f/5.6 appears to be the best.
Comments welcomed.
Jim Nichols
Tullahoma, TN USA
----- Original Message -----
From: "Chuck Norcutt" <chucknorcutt@xxxxxxxxxxxxxxxx>
To: "Olympus Camera Discussion" <olympus@xxxxxxxxxxxxxxxxx>
Sent: Monday, August 22, 2011 6:26 PM
Subject: Re: [OM] Was: mount mod; Now M42-to-4/3 Adapter Thickness
> What's this? A metal turning lathe in the basement?
>
> Chuck Norcutt
>
>
> On 8/22/2011 5:52 PM, Jim Nichols wrote:
>> I just thinned my M42 down to 6.9mm, to agree with Chuck's specs. I will
>> give it another try when I have time.
>>
>> Jim Nichols
>> Tullahoma, TN USA
>> ----- Original Message -----
>> From: "Chris Trask"<christrask@xxxxxxxxxxxxx>
>> To: "Olympus Camera Discussion"<olympus@xxxxxxxxxxxxxxxxx>
>> Sent: Monday, August 22, 2011 4:01 PM
>> Subject: Re: [OM] Was: mount mod; Now M42-to-4/3 Adapter Thickness
>>
>>
>>>>
>>>> I think my statement caused some confusion. It was poorly crafted, to
>>>> say
>>>> the least.
>>>>
>>>> The lens that I referred to is a Leica-R Summicron 50/2, and must use a
>>>> Leica-R to 4/3 adapter, so it won't work with the M42 adapter. What I
>>> found
>>>> with this lens is that the most distant object I can find comes into
>>>> focus
>>>> before the focusing index reaches the infinity mark. I have to back
>>>> off
>>>> from the infinity stop to get it in focus. This is the lens I used to
>>>> see
>>>> what an "infinity" image would resolve with my camera.
>>>>
>>>> I compared the previous image, made with a Pentax Takumar 55/1.8 lens
>>>> and
>>> my
>>>> M42 adapter, to the Summicron image, and, at a distance, I find little
>>>> difference. As Chuck pointed out, it appears that the earlier image
>>>> was
>>>> made at a smaller aperture, because the foreground was sharper.
>>>>
>>>
>>> Okay, now I better understand. To rephrase what I stated earlier,
>>> I'll
>>> have to keep in mind to open up the aperture fully so as to reduce the
>>> depth
>>> of field when doing the focusing test later. That adapter is on a slow
>>> boat
>>> from Calcutta, so it's going to take a couple of weeks before it
>>> arrives.
>>>
>>> Chris
>>>
>>> --
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>>>
>>
>>
> --
> _________________________________________________________________
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