Help! Old M 50mm F1.7 on a K20D

res3567 · 05-06-2009, 05:38 PM

Originally posted by Robert S Donovan

I'm not clear what you are asking about. Are you referring to focus trapping?

Yes. It won't work on my M42 Takumer. It fires as soon as I press the shutter with the camera in AF-S mode. All of my K-mount lenses will allow me to focus trap.

johnmflores · 05-06-2009, 06:52 PM

Originally posted by johngs

Hi Bethy,

I'd be interested if you could post some photos you take with this lens.
I'm thinking of buying the same lens as there is a second hand one for sale locally.

cheers,

John (ex Aussie now in New Zealand)

Don't mean to interrupt, but I just did the same - mounted a M 50/1.7 to a K20d and love the output:

User Photo Gallery - Nature

It's soft wide open, but gorgeous starting at F2.2 or so. With the green button setting exposure and trap focus, Pentax has made it dead simple to use older lenses. Thanks Pentax!

Robert S Donovan · 05-06-2009, 07:29 PM

Originally posted by res3567

Yes. It won't work on my M42 Takumer. It fires as soon as I press the shutter with the camera in AF-S mode. All of my K-mount lenses will allow me to focus trap.

I'm afraid I don't know. Might have something to do with the focus contacts and the M42 mount. I'd try posting a new thread to get some M42 love.

xjjohnno · 05-07-2009, 03:31 AM

M42 lenses are not going to auto focus, same with M mount lenses, is that what you are trying to get happening Res3567? Auto focussing is only going to start happening with F series and later lenses where the drive mechanisms have been built into the lenses.

Robert S Donovan · 05-07-2009, 06:00 AM

Originally posted by xjjohnno

M42 lenses are not going to auto focus, same with M mount lenses, is that what you are trying to get happening Res3567? Auto focussing is only going to start happening with F series and later lenses where the drive mechanisms have been built into the lenses.

I don't believe res3567 is trying to auto focus the lens. He/she is trying to use the AF-S setting to prevent the shutter from firing until manual focus is achieved (focus trapping), but it seems the shutter just fires instantly when the M42 is attached.

Conducting a quick test, I find that my K10D will release the shutter w/o focus being locked in AF-S mode with no lens attached. This tells me that there is an electrical continuity issue with the contacts on the lens mount. I'd try newarts' tin foil suggestion.

res3567 · 05-07-2009, 08:35 AM

Originally posted by robert s donovan

i don't believe res3567 is trying to auto focus the lens. He/she is trying to use the af-s setting to prevent the shutter from firing until manual focus is achieved (focus trapping), but it seems the shutter just fires instantly when the m42 is attached.

Conducting a quick test, i find that my k10d will release the shutter w/o focus being locked in af-s mode with no lens attached. This tells me that there is an electrical continuity issue with the contacts on the lens mount. I'd try newarts' tin foil suggestion.

Thank you!

My name is Robert BTW.

Anyway I can still use my old K-mounts with what I learned from your Blog.

You ain't packing no Super Taks?

Robert S Donovan · 05-07-2009, 05:47 PM

Originally posted by res3567

My name is Robert BTW.

Nice to meet you, Robert

Originally posted by res3567

You ain't packing no Super Taks?

Not yet. I'm on what you would call a restricted LBA budget. Maybe once I have a steady source of income again I can pick up a Super Tak or two. Right now all I have is a Pentax-A SMC 50mm f/1.7, Takumar 135mm f/2.5 (non-SMC and non-Super version), FA 35mm f/2, and a MK I kit lens.

res3567 · 05-11-2009, 09:51 PM

Originally posted by Robert S Donovan

Nice to meet you, Robert

Not yet. I'm on what you would call a restricted LBA budget. Maybe once I have a steady source of income again I can pick up a Super Tak or two. Right now all I have is a Pentax-A SMC 50mm f/1.7, Takumar 135mm f/2.5 (non-SMC and non-Super version), FA 35mm f/2, and a MK I kit lens.

Nice to meet you to Robert!

05-07-2009, 08:35 AM	#21
res3567 Veteran Member Join Date: Sep 2008 Location: Houston Tx. Photos: Gallery Posts: 1,876	Originally posted by robert s donovan i don't believe res3567 is trying to auto focus the lens. He/she is trying to use the af-s setting to prevent the shutter from firing until manual focus is achieved (focus trapping), but it seems the shutter just fires instantly when the m42 is attached. Conducting a quick test, i find that my k10d will release the shutter w/o focus being locked in af-s mode with no lens attached. This tells me that there is an electrical continuity issue with the contacts on the lens mount. I'd try newarts' tin foil suggestion. Thank you! My name is Robert BTW. Anyway I can still use my old K-mounts with what I learned from your Blog. You ain't packing no Super Taks? Last edited by res3567; 05-07-2009 at 09:10 AM.

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05-06-2009, 05:38 PM	#16
res3567 Veteran Member Join Date: Sep 2008 Location: Houston Tx. Photos: Gallery Posts: 1,876	Originally posted by Robert S Donovan I'm not clear what you are asking about. Are you referring to focus trapping? Yes. It won't work on my M42 Takumer. It fires as soon as I press the shutter with the camera in AF-S mode. All of my K-mount lenses will allow me to focus trap.

05-06-2009, 06:52 PM	#17
johnmflores Veteran Member Join Date: Apr 2009 Location: Somerville, NJ Photos: Gallery \| Albums Posts: 5,361	Originally posted by johngs Hi Bethy, I'd be interested if you could post some photos you take with this lens. I'm thinking of buying the same lens as there is a second hand one for sale locally. cheers, John (ex Aussie now in New Zealand) Don't mean to interrupt, but I just did the same - mounted a M 50/1.7 to a K20d and love the output: User Photo Gallery - Nature It's soft wide open, but gorgeous starting at F2.2 or so. With the green button setting exposure and trap focus, Pentax has made it dead simple to use older lenses. Thanks Pentax!

05-06-2009, 07:29 PM	#18
Robert S Donovan Veteran Member Join Date: Mar 2009 Location: Anderson, SC Photos: Gallery Posts: 361	Originally posted by res3567 Yes. It won't work on my M42 Takumer. It fires as soon as I press the shutter with the camera in AF-S mode. All of my K-mount lenses will allow me to focus trap. I'm afraid I don't know. Might have something to do with the focus contacts and the M42 mount. I'd try posting a new thread to get some M42 love.

05-07-2009, 03:31 AM	#19
xjjohnno Veteran Member Join Date: Jan 2009 Location: Melbourne Australia Photos: Gallery Posts: 2,115	M42 lenses are not going to auto focus, same with M mount lenses, is that what you are trying to get happening Res3567? Auto focussing is only going to start happening with F series and later lenses where the drive mechanisms have been built into the lenses.

05-07-2009, 06:00 AM	#20
Robert S Donovan Veteran Member Join Date: Mar 2009 Location: Anderson, SC Photos: Gallery Posts: 361	Originally posted by xjjohnno M42 lenses are not going to auto focus, same with M mount lenses, is that what you are trying to get happening Res3567? Auto focussing is only going to start happening with F series and later lenses where the drive mechanisms have been built into the lenses. I don't believe res3567 is trying to auto focus the lens. He/she is trying to use the AF-S setting to prevent the shutter from firing until manual focus is achieved (focus trapping), but it seems the shutter just fires instantly when the M42 is attached. Conducting a quick test, I find that my K10D will release the shutter w/o focus being locked in AF-S mode with no lens attached. This tells me that there is an electrical continuity issue with the contacts on the lens mount. I'd try newarts' tin foil suggestion.

05-07-2009, 05:47 PM	#22
Robert S Donovan Veteran Member Join Date: Mar 2009 Location: Anderson, SC Photos: Gallery Posts: 361	Originally posted by res3567 My name is Robert BTW. Nice to meet you, Robert Originally posted by res3567 You ain't packing no Super Taks? Not yet. I'm on what you would call a restricted LBA budget. Maybe once I have a steady source of income again I can pick up a Super Tak or two. Right now all I have is a Pentax-A SMC 50mm f/1.7, Takumar 135mm f/2.5 (non-SMC and non-Super version), FA 35mm f/2, and a MK I kit lens.

05-11-2009, 09:51 PM	#23
res3567 Veteran Member Join Date: Sep 2008 Location: Houston Tx. Photos: Gallery Posts: 1,876	Originally posted by Robert S Donovan Nice to meet you, Robert Not yet. I'm on what you would call a restricted LBA budget. Maybe once I have a steady source of income again I can pick up a Super Tak or two. Right now all I have is a Pentax-A SMC 50mm f/1.7, Takumar 135mm f/2.5 (non-SMC and non-Super version), FA 35mm f/2, and a MK I kit lens. Nice to meet you to Robert!