trouble with focal length on m42 using K20

austina95 · 06-21-2008, 09:59 AM

Hello
I am having trouble setting the focal length on my new Pentax k20. I bought the genuine Pentax M42 adapter and have tried my SMC 28 3.5, smc 35 3.5, SMC 50 1.4, SMC 105 2.8, SMC135 3.5 and my SMC200 4 (all M42 mount). When I put any of these lenses I am not prompted to set the focal length and I cannot change it in the menu as the "change focal length" is grey (not white like the rest of the menu items). When I put my K mount SMC A 50 1.7 lens on the camera prompts me to confirm the focal length of the lens. The focal length is to allow the image stabilization (IS) function to work. I can still take great pictures but, would like to have IS functioning with my favorite old lenses. I haven't read any where that the IS function is unavailable with the m42 lenses. Clarification on this would be appreciated.
thanking you in advance.

KungPOW · 06-21-2008, 10:05 AM

have you tried setting the SR switch to "on" then turning the camera on? The prompt should be the first thing that appears on the back screen. That is the only way I know to set the focal length

austina95 · 06-21-2008, 10:18 AM

Thanks for the quick reply
Yes I have tried switching it on and off many times in combination with turning the camera on and off.

rburgoss · 06-21-2008, 10:48 AM

You have to set custom function 36 to "permitted" (Aperture ring use). If body does not allow aperture ring use, it will not know that you are using a non A type lens.

Once you set CF 36 to "permitted", when you attach any non A type lens, when you turn on camera it will prompt for focal lenght.

Hope this helps.

RB

austina95 · 06-21-2008, 10:54 AM

Thanks Rburgoss
Your solution worked. The strange thing is I thought I had done what you suggested before. I guess not. May the pentax gods shine upon you forever.

Zewrak · 06-21-2008, 01:23 PM

Originally posted by austina95

Thanks Rburgoss
Your solution worked. The strange thing is I thought I had done what you suggested before. I guess not. May the pentax gods shine upon you forever.

Can you try if focustrapping works on K20D? I know it did on K100D and that it does not on K10D without shorting the golden contact.

06-21-2008, 09:59 AM	#1
austina95 New Member Join Date: Jun 2008 Location: BC Posts: 7	trouble with focal length on m42 using K20 Hello I am having trouble setting the focal length on my new Pentax k20. I bought the genuine Pentax M42 adapter and have tried my SMC 28 3.5, smc 35 3.5, SMC 50 1.4, SMC 105 2.8, SMC135 3.5 and my SMC200 4 (all M42 mount). When I put any of these lenses I am not prompted to set the focal length and I cannot change it in the menu as the "change focal length" is grey (not white like the rest of the menu items). When I put my K mount SMC A 50 1.7 lens on the camera prompts me to confirm the focal length of the lens. The focal length is to allow the image stabilization (IS) function to work. I can still take great pictures but, would like to have IS functioning with my favorite old lenses. I haven't read any where that the IS function is unavailable with the m42 lenses. Clarification on this would be appreciated. thanking you in advance.

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06-21-2008, 10:05 AM	#2
KungPOW Veteran Member Join Date: Nov 2007 Location: Vancouver, Canada Photos: Gallery Posts: 1,699	have you tried setting the SR switch to "on" then turning the camera on? The prompt should be the first thing that appears on the back screen. That is the only way I know to set the focal length

06-21-2008, 10:18 AM	#3
austina95 New Member Join Date: Jun 2008 Location: BC Posts: 7 Original Poster	Thanks for the quick reply Yes I have tried switching it on and off many times in combination with turning the camera on and off.

06-21-2008, 10:48 AM	#4
rburgoss Veteran Member Join Date: May 2008 Location: San Jose, Costa Rica Photos: Gallery \| Albums Posts: 972	You have to set custom function 36 to "permitted" (Aperture ring use). If body does not allow aperture ring use, it will not know that you are using a non A type lens. Once you set CF 36 to "permitted", when you attach any non A type lens, when you turn on camera it will prompt for focal lenght. Hope this helps. RB

06-21-2008, 10:54 AM	#5
austina95 New Member Join Date: Jun 2008 Location: BC Posts: 7 Original Poster	Thanks Rburgoss Your solution worked. The strange thing is I thought I had done what you suggested before. I guess not. May the pentax gods shine upon you forever.

06-21-2008, 01:23 PM	#6
Zewrak Veteran Member Join Date: Mar 2008 Location: Nowhere, Sweden Photos: Gallery Posts: 654	Originally posted by austina95 Thanks Rburgoss Your solution worked. The strange thing is I thought I had done what you suggested before. I guess not. May the pentax gods shine upon you forever. Can you try if focustrapping works on K20D? I know it did on K100D and that it does not on K10D without shorting the golden contact.