CA trick with non Pentax lenses?

Nass · 10-12-2010, 03:05 AM

Hello,

Just wondering if anyone had come across or invented a way to fool Pentax bodies into applying the inbuilt CA correction option onto non Pentax lenses? I do appreciate that PP can remove it - just wondering if there was some fudge I wasn't aware of.

Cheers

dlacouture · 10-12-2010, 05:18 AM

From memory, CA correction parameters are stored in the lens (except for a few FA ltd)... So, I'm afraid it's not possible, as 3rd party lenses would likely not have these parameters, and there is little chance they share the FA ltd parameters...

helios · 10-12-2010, 08:07 AM

One oddity I have noticed is that while the Pentax DA18-250 does the distortion and aberration corrections, the almost identical Tamron 18-250 does not but it does have the same delay between taking the picture and the image appearing on the screen that occurs with Pentax lenses while the corrections are being applied. I have not noticed a similar delay with any of my other non Pentax lenses.

I seem to remember reading that a recent firmware update allowed the camera to apply correction to recently released Pentax lenses.

It may be that the information needed for the corrections is held in the firmware in the camera body and the only information the camera needs from the lens is its make and identification. If this is the case then a firmware modification might make it possible to correct aberrations in non Pentax cameras.

It is unlikely that Pentax would do this but there might be an ingenious hacker somewhere who could.

Nass · 10-12-2010, 11:00 AM

Thanks, didn't think there was an obvious trick, but if you don't try you'll never get

. I'm guessing these Pentax lenses have some sort of electronic signature or something, I wonder how these are stored. I didn't think they had chips inside them?

Jasvox · 10-12-2010, 11:08 AM

As I stated in this other thread, with my Tamron 17-50 as well as my Tamron 18-250 on my K-7, the CA/Distortion correcting can be enabled. Not sure about any other third party lenses.

https://www.pentaxforums.com/forums/pentax-beginners-corner-q/117958-tamron-1...rrections.html

Jason

Jasvox · 10-12-2010, 11:09 AM

Originally posted by Nass

Thanks, didn't think there was an obvious trick, but if you don't try you'll never get

. I'm guessing these Pentax lenses have some sort of electronic signature or something, I wonder how these are stored. I didn't think they had chips inside them?

No idea about chips, but must be some sort of embedded information since most of the time in a decent EXIF viewer, the lens shows up correctly as model number. brand, etc.

Jason

fccwpe · 10-12-2010, 12:00 PM

When I have the Sigma 150-500 attached to my K-x, the info screen show the lens correction as being enabled. Hmmmm....

10-12-2010, 03:05 AM	#1
Nass Veteran Member Join Date: Aug 2009 Location: The British Isles Photos: Gallery Posts: 2,402	CA trick with non Pentax lenses? Hello, Just wondering if anyone had come across or invented a way to fool Pentax bodies into applying the inbuilt CA correction option onto non Pentax lenses? I do appreciate that PP can remove it - just wondering if there was some fudge I wasn't aware of. Cheers

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10-12-2010, 05:18 AM	#2
dlacouture Veteran Member Join Date: Jul 2008 Location: Var, South of France Photos: Albums Posts: 1,074	From memory, CA correction parameters are stored in the lens (except for a few FA ltd)... So, I'm afraid it's not possible, as 3rd party lenses would likely not have these parameters, and there is little chance they share the FA ltd parameters...

10-12-2010, 08:07 AM	#3
helios Junior Member Join Date: Sep 2007 Location: Peterborough UK Posts: 37	One oddity I have noticed is that while the Pentax DA18-250 does the distortion and aberration corrections, the almost identical Tamron 18-250 does not but it does have the same delay between taking the picture and the image appearing on the screen that occurs with Pentax lenses while the corrections are being applied. I have not noticed a similar delay with any of my other non Pentax lenses. I seem to remember reading that a recent firmware update allowed the camera to apply correction to recently released Pentax lenses. It may be that the information needed for the corrections is held in the firmware in the camera body and the only information the camera needs from the lens is its make and identification. If this is the case then a firmware modification might make it possible to correct aberrations in non Pentax cameras. It is unlikely that Pentax would do this but there might be an ingenious hacker somewhere who could.

10-12-2010, 11:00 AM	#4
Nass Veteran Member Join Date: Aug 2009 Location: The British Isles Photos: Gallery Posts: 2,402 Original Poster	Thanks, didn't think there was an obvious trick, but if you don't try you'll never get . I'm guessing these Pentax lenses have some sort of electronic signature or something, I wonder how these are stored. I didn't think they had chips inside them?

10-12-2010, 11:08 AM	#5
Jasvox Veteran Member Join Date: Oct 2007 Location: Melbourne, Australia Posts: 3,107	As I stated in this other thread, with my Tamron 17-50 as well as my Tamron 18-250 on my K-7, the CA/Distortion correcting can be enabled. Not sure about any other third party lenses. https://www.pentaxforums.com/forums/pentax-beginners-corner-q/117958-tamron-1...rrections.html Jason

10-12-2010, 11:09 AM	#6
Jasvox Veteran Member Join Date: Oct 2007 Location: Melbourne, Australia Posts: 3,107	Originally posted by Nass Thanks, didn't think there was an obvious trick, but if you don't try you'll never get . I'm guessing these Pentax lenses have some sort of electronic signature or something, I wonder how these are stored. I didn't think they had chips inside them? No idea about chips, but must be some sort of embedded information since most of the time in a decent EXIF viewer, the lens shows up correctly as model number. brand, etc. Jason

10-12-2010, 12:00 PM	#7
fccwpe Veteran Member Join Date: Mar 2009 Location: Perris, CA Photos: Gallery Posts: 380	When I have the Sigma 150-500 attached to my K-x, the info screen show the lens correction as being enabled. Hmmmm....