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01-26-2013, 01:57 AM   #1
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Pentax 67 on 645 MFDB

I am considering using a legacy Pentax 67 300mm f4 lens with my Zoerk pro shift adapter on Contax 645 with MFDB for photographing wildlife, as it is much less expensive than the equivalent Contax lens or buying a DSLR even though I would like a zoom. Before going ahead I have two questions:

Will this Pentax 67 300mm lens bring me just as "close" to the subject as a 645 300mm lens? I am quite confused about what happens in this respect when a 67 lens is mounted on a 645 body. So far the explanation I have found that is most understandable is: the difference is the 645 is a smaller format and "crops" the inside of the image circle more than the 67 does. This always gives the "effect" of a longer focal length. Does this mean that I would get the same "magnification?" (for lack of a better word ie closeness to the subject) from a 300mm 67 lens as I would from a 300mm 645 lens with the only real difference being that with the 67 300mm lens I would get extra picture area above, below and to each side of what I would get with the 645 300mm lens?

I have also found threads that suggest some legacy Pentax 67 lenses perform better than others with digital cameras. The lens I have my eye on is Pentax 300mm SMC 67 f4. Does anybody have any idea if this would be a good, ok or lousy lens for this purpose?

01-26-2013, 02:07 AM   #2
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QuoteOriginally posted by windhorse Quote
I am considering using a legacy Pentax 67 300mm f4 lens with my Zoerk pro shift adapter on Contax 645 with MFDB for photographing wildlife, as it is much less expensive than the equivalent Contax lens or buying a DSLR even though I would like a zoom. Before going ahead I have two questions:

Will this Pentax 67 300mm lens bring me just as "close" to the subject as a 645 300mm lens? I am quite confused about what happens in this respect when a 67 lens is mounted on a 645 body. So far the explanation I have found that is most understandable is: the difference is the 645 is a smaller format and "crops" the inside of the image circle more than the 67 does. This always gives the "effect" of a longer focal length. Does this mean that I would get the same "magnification?" (for lack of a better word ie closeness to the subject) from a 300mm 67 lens as I would from a 300mm 645 lens with the only real difference being that with the 67 300mm lens I would get extra picture area above, below and to each side of what I would get with the 645 300mm lens?

I have also found threads that suggest some legacy Pentax 67 lenses perform better than others with digital cameras. The lens I have my eye on is Pentax 300mm SMC 67 f4. Does anybody have any idea if this would be a good, ok or lousy lens for this purpose?
A 300mm 6x7 lens on 645 gives you the same exact field of view as a 300mm 645 lens would. The rule of thumb is that focal length never changes, that this is no exception

Compared to the 6x7 camera, the 645 camera doesn't see as much of the frame, as you said. Thus, of you wanted to get an equally-tight crop on the 6x7, you would need a longer lens for it. Conversely, it will always seem like the 645 camera is "more zoomed in" than a 6x7 camera with the same lens, even though it really isn't.

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01-26-2013, 02:15 AM   #3
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Thanks Adam,

does this mean to get the same photo from a 6x7 300mm as for a 645 300mm on a 645 mount all I would need to do would be to chop off the edges of the 6x7 300mm image in photoshop or some other photo editing program?
01-26-2013, 05:05 AM   #4
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which 300 ?

windhorse,

there are two 300mm for pentax 67. One is the standard and one is the M star version . I believe the standard one is all black and sells for around 500 usd and the M star one has a green band around the lens hood and sells for around 1500 usd. Guess which one is way better .........

01-26-2013, 06:13 AM - 1 Like   #5
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the one i have found is all black, maybe I should paint a green band around it?
01-26-2013, 10:20 AM   #6
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The 67 and 6x7 generation of the 300mm has a reputation for a sharpness issues when cantilevered off the 67/6x7 body due to possibly deformation from the hanging weight. Use a telephoto support on the lens when using a tripod.
01-26-2013, 12:05 PM   #7
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hang on

Thanks for the good tip Tuco, I plan to use the 300mm on my Contax 645 & MFDB with a Zork adapter on a Kirk window mount like this one. Do you think it will provide sufficient support?
01-26-2013, 12:30 PM   #8
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QuoteOriginally posted by windhorse Quote
Thanks for the good tip Tuco, I plan to use the 300mm on my Contax 645 & MFDB with a Zork adapter on a Kirk window mount like this one. Do you think it will provide sufficient support?
You'll know it when you mount it, I suspect. But I got nervous just looking at the picture.

01-26-2013, 12:38 PM   #9
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yes maybe a good idea to keep the speed down to less than 100 per hour on rough roads
01-26-2013, 04:31 PM   #10
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QuoteOriginally posted by windhorse Quote
The lens I have my eye on is Pentax 300mm SMC 67 f4. Does anybody have any idea if this would be a good, ok or lousy lens for this purpose?
The older 300mm was not the most contrasty lens in the lens line, nor was it the sharpest. There was occasional chromatic aberration wide open as well. I own both 300s. If you can afford the 300 EDIF, I suggest it. If not, I suggest getting the 200 Pentax and put the gray 1.4X converter on it. That combination is better than the old 300.

I should mention that it is possible to get some fine shots with the old 300mm once you get used to its idiosyncrasies but it is more aggravating to use.

Last edited by desertscape; 01-26-2013 at 04:38 PM.
01-29-2013, 12:05 PM   #11
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looks like i better start looking for a 400mm instead
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