Pentax Full Frame DSLR (Well, sort of...)

721 · 02-04-2011, 07:42 AM

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Originally posted by Digitalis

impressive, I have considered doing this to my 1DSMKIII due to the fact that I am intending on buying a pentax 645D later this year and I will most likely never need to use it again, because I already use my nikon D3s for wildlife and I am quite happy with the results.

No need to. I am in a helpful mood today, so just send me your 1DsIII and you can have my MkI in exchange. Works with Pentax lenses out of the box and saves you all that bothersome trouble of modifying and maybe accidently killing your camera. And besides, who knows whether this even works with a MkIII at all, right?

Last edited by 721; 02-04-2011 at 12:30 PM.

**Digitalis** · 02-04-2011, 07:51 AM

Originally posted by 721

No need to. I am in a helpful mood today, so just send me your 1DsIII and you can have my MkI in exchange. Works with Pentax lenses out of the box and saves you all that bothersome trouble of modifying and maybe accidently killing your camera. And besides, who knows whether this is even works with a MkIII at all, right?

Nice try

I have had the AA filter removed from this particular 1DsMkIII because I just got sick of how strong it was. I have been using the Leica M9 with a pentax K mount adapter and I have really enjoyed the benefits of the image quality of the M9. Thanks to a certain adapter from novoflex, it also gave me the opportunity to test certain pentax lenses against their Leica counterparts (The FA31mm f/1.8 holds it's own against the 35mm 'cron) but this setup has the drawback of having no RF coupling so it is basically a stunt for all intents and purposes and has little practical value. Being able to use the Pentax FA limiteds and the legendary Pentax SMCP 50mm f/1.2, FA*85mm f/1.4 FA*200mm f/4 ED Macro on my Canon 1DsMkIII is something I have not considered up until now.

721 · 02-04-2011, 08:02 AM

So I just provided the solution to a problem you have been grappling with for a loooong time? You are welcome! To thank me, just send me your 1DsIII... oh, wait, we already had that before

Edit: Thinking about it, the M9 would be fine, too.

721 · 02-05-2011, 08:59 AM

Vivitar 28mm/2.0 Close Focus wide open

kangeroo82 · 05-05-2011, 08:21 PM

beautiful shots. I'm kind of new to the idea of modifying canons to fit pentax lenses. When you said that you were able to use pentax lenses with aperture rings, does this mean that you can use your A series lenses in aperture mode or are they fully manual just like it would be if you modified a 5d mirror?

**rparmar** · 05-06-2011, 07:18 AM

Originally posted by Digitalis

I have had the AA filter removed from this particular 1DsMkIII because I just got sick of how strong it was. I have been using the Leica M9 with a pentax K mount adapter and I have really enjoyed the benefits of the image quality of the M9.

Not related to FF at all, but have you considered removing the AA filter from a K-5 and checking the IQ? Is such surgery even possible?

**Digitalis** · 05-06-2011, 07:46 AM

Originally posted by rparmar

Not related to FF at all, but have you considered removing the AA filter from a K-5 and checking the IQ? Is such surgery even possible?

i'm sure it is but don't expect your warranty to cover it should anything go wrong.

but it did improve the IQ from my canon DSLR quite substantially...but of course it increased the chance that moire would rear it's ugly head.

**jeffshaddix** · 05-06-2011, 08:19 AM

Great job 721, very gutsy (and worth it) indeed! I love the motorcycle shot.

I've been considering doing the same on a Sigma SD1 when it comes out, albeit I'm not sure what it'll entail on the new 1.5 crop sensor mirror box. Regardless, you've inspired me to look into it!

**rparmar** · 05-06-2011, 11:48 AM

Reading up on the Photozone forums it seems that the AA filter cannot be replaced on the K-5. Not even by expert Germans who charge 500 Euro for the job (Optik Makario).

721 · 05-07-2011, 02:22 AM

Originally posted by kangeroo82

beautiful shots. I'm kind of new to the idea of modifying canons to fit pentax lenses. When you said that you were able to use pentax lenses with aperture rings, does this mean that you can use your A series lenses in aperture mode or are they fully manual just like it would be if you modified a 5d mirror?

There is no communication whatsoever between the lens and the camera, so the aperture has to be set by aperture ring. The A-button on A-series lenses is functionless. Of course one can still use Av-Mode on the camera, but it is stop-down metering only.
I do not think I get what this has to do with mirror shaving (?), though. Care to elaborate?

kangeroo82 · 05-07-2011, 06:12 AM

I think I remember that the other person that modified their Canon 5d shaved their mirror and then cut off the lens' aperture lever. I was thinking since you didn't modify your lens in any fashion that you might be able to use Av mode if you used an EMF PK to Canon EOS adapter that states it supports Av as well as manual.

EMF AF Confirm Pentax PK Lens to Canon EOS EF Adapter | eBay

721 · 05-07-2011, 02:07 PM

Ah, I see. Well yes, I can use Av Mode. But the aperture cannot be set via camera dial but via the aperture ring instead. Unfortunately that also means that the aperture stops down once I turn the aperture ring (and the viewfinder gets darker) instead of staying wide open until the shutter release is being pressed.
This is no different with the adapter that you linked. Apart from the option to add EXIF-data, the only effect the attached chip has is to produce a confirmation light and sound once the camera thinks that the image is in focus. From what I have heard this is anything but precise, so I never bothered with it. A proper, calibrated focusing screen is most certainly the better choice.

On a sidenote, it is essential to have the lens mounted at 12 o'clock on the camera here. Which, if I am not mistaken, the adapter linked above does not.

Huckster · 06-19-2011, 06:00 PM

Originally posted by 721

On a sidenote, it is essential to have the lens mounted at 12 o'clock on the camera here. Which, if I am not mistaken, the adapter linked above does not.

Wonderful work. You mention that you need an lens adapter that mounts the lens at 12 o'clock? Is this a particular brand of adapter you bought that does this? Or did you make a modification to one?

Which lens adapter did you use and did it require any alteration on your part in order to work with your mirror box modification?

Thanks.

721 · 06-19-2011, 11:57 PM

No alterations to the adapter whatsoever, you just have to find one that mounts the lens at 12 o'clock. Which, unlike a few years ago when all PK-EOS-adapters were like this, is not an easy task.

There are some mentioned in a thread over at mflenses. I own some of the black phototools24 adapters that are being reviewed. They are a bit more expensive than the standard brass ones, but they fit pretty well and infinity seems to be spot on which is important for lenses with floating elements, fixed rear-element extension and the like.

But as long as the adapter mounts the lens at 12 o'clock, it should work with any of them. I even tried modifying a cheap 2-o'clock brass adapter first, but it was just too much of a hassle.

Cambo · 06-20-2011, 08:34 AM

Originally posted by 721

Almost pocketable...

By the way, in case somebody else makes his Canon FF undergo that little surgery, I would be curious to read and see of it here.

in the BEST possible way - absolutely ******* brilliant!

Why don't you see if you can shoehorn a full frame sensor into an old Contax 645 so you can use some old Zeiss medium format glass?

And GREAT shots, btw.

Cheers,
Cameron

05-05-2011, 08:21 PM	#50
kangeroo82 Senior Member Join Date: Apr 2010 Location: Arlington, VA Photos: Albums Posts: 128	beautiful shots. I'm kind of new to the idea of modifying canons to fit pentax lenses. When you said that you were able to use pentax lenses with aperture rings, does this mean that you can use your A series lenses in aperture mode or are they fully manual just like it would be if you modified a 5d mirror? Last edited by kangeroo82; 05-05-2011 at 08:36 PM.

06-20-2011, 08:34 AM	#60
Cambo Veteran Member Join Date: Dec 2007 Location: Vancouver, BC Photos: Gallery \| Albums Posts: 1,016	You're insane.... Originally posted by 721 Almost pocketable... By the way, in case somebody else makes his Canon FF undergo that little surgery, I would be curious to read and see of it here. in the BEST possible way - absolutely ******* brilliant! Why don't you see if you can shoehorn a full frame sensor into an old Contax 645 so you can use some old Zeiss medium format glass? And GREAT shots, btw. Cheers, Cameron

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02-04-2011, 07:42 AM	#46
721 Forum Member Join Date: Feb 2010 Photos: Albums Posts: 56 Original Poster	Staff note: This post may contain affiliate links, which means Pentax Forums may earn a small commission if a visitor clicks through and makes a purchase. If you would like to support the forum directly, you may also make a donation here. Originally posted by Digitalis impressive, I have considered doing this to my 1DSMKIII due to the fact that I am intending on buying a pentax 645D later this year and I will most likely never need to use it again, because I already use my nikon D3s for wildlife and I am quite happy with the results. No need to. I am in a helpful mood today, so just send me your 1DsIII and you can have my MkI in exchange. Works with Pentax lenses out of the box and saves you all that bothersome trouble of modifying and maybe accidently killing your camera. And besides, who knows whether this even works with a MkIII at all, right? Last edited by 721; 02-04-2011 at 12:30 PM.

02-04-2011, 07:51 AM	#47
Digitalis Site Supporter Join Date: Mar 2009 Location: Melbourne, Victoria Photos: Gallery Posts: 11,694	Originally posted by 721 No need to. I am in a helpful mood today, so just send me your 1DsIII and you can have my MkI in exchange. Works with Pentax lenses out of the box and saves you all that bothersome trouble of modifying and maybe accidently killing your camera. And besides, who knows whether this is even works with a MkIII at all, right? Nice try I have had the AA filter removed from this particular 1DsMkIII because I just got sick of how strong it was. I have been using the Leica M9 with a pentax K mount adapter and I have really enjoyed the benefits of the image quality of the M9. Thanks to a certain adapter from novoflex, it also gave me the opportunity to test certain pentax lenses against their Leica counterparts (The FA31mm f/1.8 holds it's own against the 35mm 'cron) but this setup has the drawback of having no RF coupling so it is basically a stunt for all intents and purposes and has little practical value. Being able to use the Pentax FA limiteds and the legendary Pentax SMCP 50mm f/1.2, FA85mm f/1.4 FA200mm f/4 ED Macro on my Canon 1DsMkIII is something I have not considered up until now.

02-04-2011, 08:02 AM	#48
721 Forum Member Join Date: Feb 2010 Photos: Albums Posts: 56 Original Poster	So I just provided the solution to a problem you have been grappling with for a loooong time? You are welcome! To thank me, just send me your 1DsIII... oh, wait, we already had that before Edit: Thinking about it, the M9 would be fine, too.

02-05-2011, 08:59 AM	#49
721 Forum Member Join Date: Feb 2010 Photos: Albums Posts: 56 Original Poster	Vivitar 28mm/2.0 Close Focus wide open

05-06-2011, 07:18 AM	#51
rparmar Site Supporter Join Date: Jan 2008 Photos: Gallery Posts: 8,819	Originally posted by Digitalis I have had the AA filter removed from this particular 1DsMkIII because I just got sick of how strong it was. I have been using the Leica M9 with a pentax K mount adapter and I have really enjoyed the benefits of the image quality of the M9. Not related to FF at all, but have you considered removing the AA filter from a K-5 and checking the IQ? Is such surgery even possible?

05-06-2011, 07:46 AM	#52
Digitalis Site Supporter Join Date: Mar 2009 Location: Melbourne, Victoria Photos: Gallery Posts: 11,694	Originally posted by rparmar Not related to FF at all, but have you considered removing the AA filter from a K-5 and checking the IQ? Is such surgery even possible? i'm sure it is but don't expect your warranty to cover it should anything go wrong. but it did improve the IQ from my canon DSLR quite substantially...but of course it increased the chance that moire would rear it's ugly head.

05-06-2011, 08:19 AM	#53
jeffshaddix Site Supporter Join Date: Jun 2010 Location: Colorado Posts: 1,473	Great job 721, very gutsy (and worth it) indeed! I love the motorcycle shot. I've been considering doing the same on a Sigma SD1 when it comes out, albeit I'm not sure what it'll entail on the new 1.5 crop sensor mirror box. Regardless, you've inspired me to look into it!

05-06-2011, 11:48 AM	#54
rparmar Site Supporter Join Date: Jan 2008 Photos: Gallery Posts: 8,819	Reading up on the Photozone forums it seems that the AA filter cannot be replaced on the K-5. Not even by expert Germans who charge 500 Euro for the job (Optik Makario).

05-07-2011, 02:22 AM	#55
721 Forum Member Join Date: Feb 2010 Photos: Albums Posts: 56 Original Poster	Originally posted by kangeroo82 beautiful shots. I'm kind of new to the idea of modifying canons to fit pentax lenses. When you said that you were able to use pentax lenses with aperture rings, does this mean that you can use your A series lenses in aperture mode or are they fully manual just like it would be if you modified a 5d mirror? There is no communication whatsoever between the lens and the camera, so the aperture has to be set by aperture ring. The A-button on A-series lenses is functionless. Of course one can still use Av-Mode on the camera, but it is stop-down metering only. I do not think I get what this has to do with mirror shaving (?), though. Care to elaborate?

05-07-2011, 06:12 AM	#56
kangeroo82 Senior Member Join Date: Apr 2010 Location: Arlington, VA Photos: Albums Posts: 128	I think I remember that the other person that modified their Canon 5d shaved their mirror and then cut off the lens' aperture lever. I was thinking since you didn't modify your lens in any fashion that you might be able to use Av mode if you used an EMF PK to Canon EOS adapter that states it supports Av as well as manual. EMF AF Confirm Pentax PK Lens to Canon EOS EF Adapter \| eBay

05-07-2011, 02:07 PM	#57
721 Forum Member Join Date: Feb 2010 Photos: Albums Posts: 56 Original Poster	Ah, I see. Well yes, I can use Av Mode. But the aperture cannot be set via camera dial but via the aperture ring instead. Unfortunately that also means that the aperture stops down once I turn the aperture ring (and the viewfinder gets darker) instead of staying wide open until the shutter release is being pressed. This is no different with the adapter that you linked. Apart from the option to add EXIF-data, the only effect the attached chip has is to produce a confirmation light and sound once the camera thinks that the image is in focus. From what I have heard this is anything but precise, so I never bothered with it. A proper, calibrated focusing screen is most certainly the better choice. On a sidenote, it is essential to have the lens mounted at 12 o'clock on the camera here. Which, if I am not mistaken, the adapter linked above does not.

06-19-2011, 06:00 PM	#58
Huckster New Member Join Date: Jun 2011 Posts: 1	Originally posted by 721 On a sidenote, it is essential to have the lens mounted at 12 o'clock on the camera here. Which, if I am not mistaken, the adapter linked above does not. Wonderful work. You mention that you need an lens adapter that mounts the lens at 12 o'clock? Is this a particular brand of adapter you bought that does this? Or did you make a modification to one? Which lens adapter did you use and did it require any alteration on your part in order to work with your mirror box modification? Thanks.

06-19-2011, 11:57 PM	#59
721 Forum Member Join Date: Feb 2010 Photos: Albums Posts: 56 Original Poster	No alterations to the adapter whatsoever, you just have to find one that mounts the lens at 12 o'clock. Which, unlike a few years ago when all PK-EOS-adapters were like this, is not an easy task. There are some mentioned in a thread over at mflenses. I own some of the black phototools24 adapters that are being reviewed. They are a bit more expensive than the standard brass ones, but they fit pretty well and infinity seems to be spot on which is important for lenses with floating elements, fixed rear-element extension and the like. But as long as the adapter mounts the lens at 12 o'clock, it should work with any of them. I even tried modifying a cheap 2-o'clock brass adapter first, but it was just too much of a hassle.