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08-16-2016, 08:58 AM   #1
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Beginner, old k mount lens issues

Hi, all! Hopefully someone here can help me out. I have a k-50 and was gifted some older k mount lenses, a rikenon 50mm and a sakar 28-70mm pk a/r. I have set the green button to step down. I have told the camera the focal length. I have said it to manual, but all images are coming out very dark unless 800 ISO or higher. A/r should be at least semi automatic, correct? But setting to any mode only gives me AV and even manual reads AV and tries to select shutter speed. What am I doing wrong? Any advice would be great thanks :-)


Last edited by photolady95; 08-16-2016 at 09:29 AM.
08-16-2016, 09:05 AM   #2
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If it is a k mount lens, you can only use M mode (with green button) to shoot. You also need to set the camera to allow use of aperture ring of the lens in the custom menu.
Not sure about the Sakar lens A/R means.. some Sakar lens has a wider aperture level guard which is impossible to mount on the camera.
08-16-2016, 09:13 AM   #3
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QuoteOriginally posted by aleonx3 Quote
If it is a k mount lens, you can only use M mode (with green button) to shoot. You also need to set the camera to allow use of aperture ring of the lens in the custom menu.<br />
Not sure about the Sakar lens A/R means.. some Sakar lens has a wider aperture level guard which is impossible to mount on the camera.
<br />
<br />
I tried looking up the a slash are lens and found no information about it but it mounted fine on my camera body. But even with it on manual mode it keeps trying to select shutter speed. Images come out dark but at ISO 800 they seem pale not sure what I'm doing wrong. They were originally for a Ricoh camera, maybe that's what's happening? Not sure if it makes any difference.

Edit: I did set aperture ring usage in menu, so not sure what's happening. Kit lens gives clear bright images at ISO 100 in same location.
08-16-2016, 09:23 AM   #4
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Share a picture with exif data to evaluate. Take a couple, actually, with the aperture ring in different positions and tell us which is which on the ring.

08-16-2016, 09:25 AM   #5
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Might be worth reading this before going further:

Pentax Green Button Guide - Articles and Tips | PentaxForums.com

The green button when used with an M lens will stop the lens down and then set the shutter speed to the correct value for exposure. You then change anything you want and take pictures. The information you have given is not complete as we don't know the exposures used by the kit lens and the lens on the camera. Note that no other mode (Av, TAv, Tv, etc. will properly work as expected...). The aperture will not be stopped down at all in modes other than Manual.
08-16-2016, 09:50 AM   #6
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I'll add photos one I get to a comp but thanks all for fast replies
08-16-2016, 10:19 AM   #7
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If the Sakar is truly an 'A' lens it needs to be set into 'A' position on the aperture ring to work that way, and you should be able to use it in Av mode or any mode. (But R stands for Ricoh, so it probably has a "Ricoh" pin or button -- most likely a button on a third-party lens but nevertheless should checked -- if you've already taken it on and off the camera it is probably fine.) Also a chance it is not a K mount at all, but a Konica A/R mount -- if it has a little notch in the middle of one of its bayonet tabs it is a Konica mount.
08-16-2016, 10:58 AM   #8
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QuoteOriginally posted by vonBaloney Quote
If the Sakar is truly an 'A' lens it needs to be set into 'A' position on the aperture ring to work that way, and you should be able to use it in Av mode or any mode. (But R stands for Ricoh, so it probably has a "Ricoh" pin or button -- most likely a button on a third-party lens but nevertheless should checked -- if you've already taken it on and off the camera it is probably fine.) Also a chance it is not a K mount at all, but a Konica A/R mount -- if it has a little notch in the middle of one of its bayonet tabs it is a Konica mount.
If it is shown with A/R only, it would likely Konica mount as suggested; but OP indicated it is also showing as PK on the base.. more likely Pentax K mount with Ricoh pin (for aperture control on Ricoh KR series camera); It is likely the pin in that position is not protruding too much to cause any harm to mount the lens.

08-16-2016, 11:11 AM   #9
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When you have the camera in M mode, make sure the AutoISO is turned off.
08-16-2016, 03:02 PM   #10
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Hey all-

I checked for a pin and didnt see any, and it does come off and on easily. There is a bayonet on the lens but there is also one on the 50mm and it seems to work okay? When i set the dial to m it still says av in the corner maybe i had it set to a on the lens? Ill have to check again when i get home. Ill also upload some pictures with details because i honestly have no idea how im messing this up so bad lol
08-17-2016, 12:48 PM   #11
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QuoteOriginally posted by Mijali Quote
Hey all-

I checked for a pin and didnt see any, and it does come off and on easily. There is a bayonet on the lens but there is also one on the 50mm and it seems to work okay? When i set the dial to m it still says av in the corner maybe i had it set to a on the lens? Ill have to check again when i get home. Ill also upload some pictures with details because i honestly have no idea how im messing this up so bad lol
With the K-50, if you have the ISO set to auto M mode is TAv. You have to turn the AutoISO off for it to work in M. This is because the K-50 firmware is inherited from the K-01, which only had one e-dial, so it needed a pseudo-TAv mode. The K-30 and K-50 don't need the pseudo-TAv because they have 2 e-dials, but the firmware wasn't changed.
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