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03-31-2009, 07:41 PM   #1
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6X7 lenses on 645

Glad to have found this forum.

I have 8 6x7 lenses and would like to start using them on a 645n or nII which I will still have to source. How well do these lenses work using the 645 adapter? Also what is the magnification factor and are these much heavier lenses hard on the 645 mount?
And the last question is-- how well one can focus these manual lenses with
the screens in the newer n and nII bodies?

thanks for any help with this,


03-31-2009, 10:06 PM   #2
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A 6x7 lens will work just like a manual focus 645 lens when used with the original Pentax 6x7 to 645 adapter. This means that you'll have open aperture metering and the lens will stop down to the set aperture when the shot is taken.

The "crop factor" is 1.3 (horizontally).

How well you can focus depends on your eyesight! If you're really concerned you could go for a 645 with split image focusing screen.

How hard the lens is on the lens mount depends. I'd assume that you would support a heavy lens with your hand or a tripod so that it becomes a non-issue. Some of the 6x7 lenses, e.g. 200mm, are not that heavy to begin with and shouldn't be an issue.
03-31-2009, 10:38 PM   #3
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Ole: Some of the 6x7 lenses, e.g. 200mm, are not that heavy to begin with and shouldn't be an issue.
You are correct about the "later" model lenses, distinguished with the "67" prefix. These 67 lenses do tend to be lighter than the earlier, "6 x 7" lenses. The older 200mm 6 x 7s are a bit weighty though, coming in at nearly 2 pounds.
04-06-2009, 05:49 AM   #4
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These work well. As someone stated earlier, it is a crop factor. There are no lens elements in the 67-645 adapter. If I recall correctly (sold my 67 gear a while back) with the 645n I got focus confirmation with the 67 lenses (at least that is what my memory is telling me). The brighter viewfinder in the 645n series helps with focusing.


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