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10-12-2014, 11:49 AM   #1
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If Pentax went Full-Frame would my APC Lenses work?

I think I probably already know the answer, but, if Pentax released a full-frame camera do you think it would be possible to use my current crop-sensor lenses?

I think the answer would probably be "No" but was wondering if it would be possible to set the sensor further back or lens mount further forwards???

Thanks

Mike

10-12-2014, 11:51 AM   #2
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All the APS-C primes longer than 40mm will support FF, as will the DA 35mm F/2.4.

None of the APS-C zooms support FF fully.
10-12-2014, 11:52 AM   #3
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Most likely the FF body would have a capability of recognizing non FF Pentax (like DA) lenses and only use the APS-c area of the sensor.

Seb

Edit: Maybe the 1.4x teleconverter would work?

Last edited by bassek; 10-12-2014 at 12:05 PM.
10-12-2014, 11:59 AM   #4
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QuoteOriginally posted by mdshooting Quote
I think I probably already know the answer, but, if Pentax released a full-frame camera do you think it would be possible to use my current crop-sensor lenses?

I think the answer would probably be "No" but was wondering if it would be possible to set the sensor further back or lens mount further forwards???

Thanks

Mike
I would expect to see an auto-crop feature like on Nikon cameras for instance.


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10-12-2014, 12:05 PM   #5
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Some zoom lenses from Sigma and Tamron will work on FF, cause they are made for this. Old Pentax Zoom lenses, SMC F, and SMC FA, and before them, will also work.
10-12-2014, 12:29 PM   #6
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QuoteOriginally posted by mdshooting Quote
I think the answer would probably be "No" but was wondering if it would be possible to set the sensor further back or lens mount further forwards???

Thanks

Mike
The sensor cannot be moved, and doesn't have to. The image is formed at the same distance from the K lens mount no matter the format of the sensor and that's where the sensor must be located.

If Pentax implemented an autocrop feature like Nikon has done then only an APS-C-sized area of the FF sensor would be used with APS-C lenses.
10-12-2014, 01:16 PM   #7
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Pentax K mount is not like canon where the aps c lenses protrude into the mount and hit the FF mirror. All lenses will fit on FF, but many will vignette quite badly (ie most wide angles/zooms) or require a different lens hood.

10-12-2014, 01:31 PM   #8
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The answer is that you could mount all of your lenses on such a full frame camera, they just might not cover the sensor with their image projection. Wide angle primes like the DA 14, 15, and 21 are guaranteed not to cover. Some, like the DA 40 and 70 would be usable stopped down, albeit with some significant vignetting. Most of the zooms would not cover the circle either (60-250 is probably closest).
10-12-2014, 01:32 PM - 1 Like   #9
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QuoteOriginally posted by Adam Quote
I would expect to see an auto-crop feature like on Nikon cameras
Agreed.

Sony does the same for NEX E-mount. Place a non-FF NEX lens on a FF Sony like the A7 or A7r and (if you have auto-crop mode or 'APS-C Sized capture' turned on in the menu), the lens works fine, just at reduced resolution - 24MP down to 10MP, and 36MP down to 15MP. No doubt Pentax will offer a similar option.
10-12-2014, 02:05 PM   #10
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QuoteOriginally posted by Rondec Quote
The answer is that you could mount all of your lenses on such a full frame camera, they just might not cover the sensor with their image projection. Wide angle primes like the DA 14, 15, and 21 are guaranteed not to cover. Some, like the DA 40 and 70 would be usable stopped down, albeit with some significant vignetting. Most of the zooms would not cover the circle either (60-250 is probably closest).
The DA40 and the DA70 are both incredibly usable wide open. There is no need to stop down in the least. Just had the 40mm on the Sony yesterday, just fiddling.
10-12-2014, 02:17 PM   #11
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Maybe these two threads will clear things up.
Various brands and Pentax;
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/183420-curr...me-lenses.html
Modern Pentax lenses tested on FF:
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/31629-da-le...ts-thread.html
Of course, FA and older series should work fully.
10-12-2014, 04:29 PM   #12
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I've shot film with the da35 f2.4, 50 f1.8, 40 f2.8 ltd, and all work well (although care needs to be taken when focussing at infinity, since the da's go beyond infinity on film slrs). Anything longer is fine, anything wider is not (in terms of primes at any rate)
10-12-2014, 06:43 PM   #13
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QuoteOriginally posted by mdshooting Quote
I think I probably already know the answer, but, if Pentax released a full-frame camera do you think it would be possible to use my current crop-sensor lenses?
Yes. Some of the DA lenses actually support a FF image circle on their own. The lenses that truly don't throw a big enough image circle will probably work in "auto-crop" or "APS-C" mode - the camera will take a FF picture and then auto-crop it down to the APS-C portion in the center of the image. Pretty standard feature most (almost all) manufacturers have implemented to help make an easy upgrade path.
12-02-2014, 02:21 PM   #14
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QuoteOriginally posted by mdshooting Quote
I think I probably already know the answer, but, if Pentax released a full-frame camera do you think it would be possible to use my current crop-sensor lenses?

I think the answer would probably be "No" but was wondering if it would be possible to set the sensor further back or lens mount further forwards???

Thanks

Mike
most of them will work fine, you will get a little switch to swap between full 35mm format and APS-C. Like that Pentax does not have to introduce 20 new lenses at once and we are all compatible with quite a little number of exceptions like the 2.8/14...
12-03-2014, 01:45 AM   #15
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Compatibility would be more than cool here yes, still have to get a full frame out though...
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