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04-11-2010, 08:36 AM   #31
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That would be an interesting comparison - for those with both systems, as there must have been many, something they did a long time ago.

I have been tempted by a good deal on a 6x7 with 4 lenses, but in the end decided I should stick to my 645 one. Only when I would start to do studio work - I just might - I would reconsider that decision. I understood that the 6x7 shift lens is not stellar, and the focal length not ideal for architecture, which also is a factor for me (a shift lens being a long-term wish).

04-11-2010, 08:52 AM   #32
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QuoteOriginally posted by Ivan J. Eberle Quote
So can anyone tell me exactly which of the P67 lenses are such stellar performers that they're on equal footing with (or exceed the quality of) the equivalent P645 lenses-- when used on 645 format? Any of them?
I have a 67 to Pentax K mount adaptor. I once put my SMC 67 Pentax-M* 300mm ED[IF] lens and my 135 size SMC Pentax-A* 300mm f4 lens on my K-7 for a test. I zoomed in on the pixels of the results and they looked the same to me. I didn't test any of my other 67 lenses though.
04-12-2010, 08:13 AM   #33
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QuoteOriginally posted by tuco Quote
I have a 67 to Pentax K mount adaptor. I once put my SMC 67 Pentax-M* 300mm ED[IF] lens and my 135 size SMC Pentax-A* 300mm f4 lens on my K-7 for a test. I zoomed in on the pixels of the results and they looked the same to me. I didn't test any of my other 67 lenses though.
Super teles struggle to get achieve more than 60 lp/mm in all formats; 300mm is a sweet spot for optimum lens design so one might expect this focal length to be the closest in resolution another across formats. Too, teles have straightest light paths, and they're typically used wide open, which doesn't correlate to the light-spread and diffusion issues that can occur with other wider lenses more typically used stopped down. Digital sensors behave differently with light spread than film so prior comparisons may not be adequate.

Personally, I won't be speculatively buying up 6x7 lenses in anticipation of any land-rush once the 645D becomes widely available.
04-12-2010, 08:30 AM   #34
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Tuco, what is the crop factor for a 67 300mm lens on the K7? Must be considerable.
I am expecting a 645 to K adapter, which will give me some idea in general.

(I know focal length is not affected, but the projected image is cropped, etc, so I'm not into a sematic discussion but would like to know this. I am considering moving for a 645 4/300mm).

04-12-2010, 08:37 AM   #35
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Smolk, crop factor is exactly the same as any other 300mm lens - x1,5. Focal length is a lens characteristic and the angel of view depends only on the film/sensor size.

Last edited by matth; 04-12-2010 at 08:43 AM.
04-12-2010, 09:27 AM   #36
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QuoteOriginally posted by Smolk Quote
Tuco, what is the crop factor for a 67 300mm lens on the K7? Must be considerable.
I am expecting a 645 to K adapter, which will give me some idea in general.

(I know focal length is not affected, but the projected image is cropped, etc, so I'm not into a sematic discussion but would like to know this. I am considering moving for a 645 4/300mm).
Both were a 1.5 factor on the K7. I only had the 67 to K mount adapter for maybe using my 67 Lensbaby on the K7. I didn't get it to put my other MF lenses on the K7. That, IMHO, is just daft. Why bother with a hauling around a huge manual lens for the K7 where it defeats the automagic features when you can use either 135 Pentax-A or AF lenses or digital lenses for it.
04-12-2010, 09:29 AM   #37
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QuoteOriginally posted by Ivan J. Eberle Quote
Isn't the primary point to using a larger format that it's capable of outresolving the smaller format, not necessarily because lenses are superior (typically, there's an inverse relationship between image circle size and resolution) but due to the sheer amount of real estate covered by the format?

So can anyone tell me exactly which of the P67 lenses are such stellar performers that they're on equal footing with (or exceed the quality of) the equivalent P645 lenses-- when used on 645 format? Any of them?
P67 400/4EDIF, sharper than the P645AF400/5.6 and an extra stop on 645 chromes.
04-12-2010, 09:31 AM   #38
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I somehow thought that 67 would have a larger crop factor than 135, but obviously that was a mistake. I haven't been able to try either.
I agree, there's no point in using the heavy 67 gear on a fragile dslr.

04-16-2010, 10:23 AM   #39
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I use a Taky 67 135 macro with a Pentax 67/k mount adapter and extension tubes occasionally on my K20D. The Takumar 135 is amazingly light for all metal. The tubes and lens are hollow obviously and the old Taky just feels so good in quality and focus action. The size/bulk is obviously conciderably larger but actually aids me in table top hand-held stuff.

I aquired the Taky so cheaply that I couldn't resist fooling with that option. I would not be using this in the field because of the bulk. But you have to look again at the size and weight of a Lester Dine/Kiron/Vivitar 105, and the rest, they are not pancake lenses.

I wish I could afford the 67 100 macro or one of the better correct 105 K mounts.
04-16-2010, 06:59 PM   #40
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I suspect the 67 400mm ED-IF is stellar, but was there anything about the 645 FA 400mm f/5.6 that causes you to state this? Just curious if you had a bad experience with 645 FA 400mm.

QuoteOriginally posted by D W Quote
I will take my 67 400/4EDIF over the 645 AF400/5.6 any day. Beyond 600mm the 67 with adapter is the only way - that was why Pentax never made 645 lenses longer than 600mm
04-21-2010, 08:03 AM   #41
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67 lens on 645D body via Pentax adapter.

67 lenses on the 645D body Chris Willson's Blog
04-21-2010, 12:53 PM   #42
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thx for the link !
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