Using "A" lens settings on a K2 Body??

**germar** · 12-01-2013, 10:58 AM

What happens when I use a SMC A series lens on a K2 body and the lens is set to "A?" I recently put a SMCA 50 1.4 on a K2 body and I noted that the meter behaved differently between "A" and a manually set f-stop, with the "A" setting reading about 2 stops wider. I did not fire the camera for fear of initiating the apocalypse. I know using the A lens on a K2 body is okay as long as I select manual f-stops, but what would happen if I left the lens on automatic? Would it just shoot wide open?

Just a curiosity, sorry if this is common knowledge.

Adam · 12-01-2013, 11:01 AM

Originally posted by germar

What happens when I use a SMC A series lens on a K2 body and the lens is set to "A?" I recently put a SMCA 50 1.4 on a K2 body and I noted that the meter behaved differently between "A" and a manually set f-stop, with the "A" setting reading about 2 stops wider. I did not fire the camera for fear of initiating the apocalypse. I know using the A lens on a K2 body is okay as long as I select manual f-stops, but what would happen if I left the lens on automatic? Would it just shoot wide open?

Just a curiosity, sorry if this is common knowledge.

It will simply shoot at the minimum aperture (F22).

vonBaloney · 12-01-2013, 11:01 AM

Originally posted by germar

What happens when I use a SMC A series lens on a K2 body and the lens is set to "A?" I recently put a SMCA 50 1.4 on a K2 body and I noted that the meter behaved differently between "A" and a manually set f-stop, with the "A" setting reading about 2 stops wider. I did not fire the camera for fear of initiating the apocalypse. I know using the A lens on a K2 body is okay as long as I select manual f-stops, but what would happen if I left the lens on automatic? Would it just shoot wide open?

Just a curiosity, sorry if this is common knowledge.

Good thing you didn't fire it. It does in-fact initiate the apocalypse.

But seriously...I think it would stop all the way down, not wide-open.

aoeu · 12-01-2013, 11:26 AM

It stops all the way down. I just checked on my K2DMD.

**baro-nite** · 12-01-2013, 12:36 PM

As they said. The "A" setting stops the lens down fully (look at the diaphragm when the lens is unmounted and the ring is set to "A"), and raises a pin that tells an A-capable camera that the lens is indeed set to "A". If the camera isn't A-capable, all you have is an ordinarily stopped-down lens.

builttospill · 12-02-2013, 10:37 AM

The lens A setting is unusable on cameras without the A contacts on the mount. As mentioned above, the lens can only shoot at the minimum aperture, e.g., f/22, when set to A.

Just to confirm for those reading this thread who might not be aware, A-series lenses can be used on all older, K-series cameras, but won't offer automatic aperture control. The camera in question, the K2, has an Automatic setting on the dial to provide aperture priority shooting. This allows the user to set the aperture using the aperture ring on the lens and the camera will automatically select a shutter speed to acquire a correct exposure.

An aperture ring on the lens is required unless someone plans on just shooting at f/22.

12-01-2013, 10:58 AM	#1
germar Site Supporter Join Date: Apr 2007 Location: North Palm Beach, Florida Photos: Gallery Posts: 728	Using "A" lens settings on a K2 Body?? What happens when I use a SMC A series lens on a K2 body and the lens is set to "A?" I recently put a SMCA 50 1.4 on a K2 body and I noted that the meter behaved differently between "A" and a manually set f-stop, with the "A" setting reading about 2 stops wider. I did not fire the camera for fear of initiating the apocalypse. I know using the A lens on a K2 body is okay as long as I select manual f-stops, but what would happen if I left the lens on automatic? Would it just shoot wide open? Just a curiosity, sorry if this is common knowledge.

12-01-2013, 11:01 AM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,594	Originally posted by germar What happens when I use a SMC A series lens on a K2 body and the lens is set to "A?" I recently put a SMCA 50 1.4 on a K2 body and I noted that the meter behaved differently between "A" and a manually set f-stop, with the "A" setting reading about 2 stops wider. I did not fire the camera for fear of initiating the apocalypse. I know using the A lens on a K2 body is okay as long as I select manual f-stops, but what would happen if I left the lens on automatic? Would it just shoot wide open? Just a curiosity, sorry if this is common knowledge. It will simply shoot at the minimum aperture (F22). Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

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12-01-2013, 11:01 AM	#3
vonBaloney Pentaxian Join Date: Oct 2011 Location: Albuquerque, NM Posts: 6,029	Originally posted by germar What happens when I use a SMC A series lens on a K2 body and the lens is set to "A?" I recently put a SMCA 50 1.4 on a K2 body and I noted that the meter behaved differently between "A" and a manually set f-stop, with the "A" setting reading about 2 stops wider. I did not fire the camera for fear of initiating the apocalypse. I know using the A lens on a K2 body is okay as long as I select manual f-stops, but what would happen if I left the lens on automatic? Would it just shoot wide open? Just a curiosity, sorry if this is common knowledge. Good thing you didn't fire it. It does in-fact initiate the apocalypse. But seriously...I think it would stop all the way down, not wide-open.

12-01-2013, 11:26 AM	#4
aoeu Veteran Member Join Date: Sep 2010 Location: Oregon Posts: 496	It stops all the way down. I just checked on my K2DMD.

12-01-2013, 12:36 PM	#5
baro-nite Loyal Site Supporter Join Date: Aug 2011 Location: North Carolina, USA Photos: Gallery \| Albums Posts: 5,294	As they said. The "A" setting stops the lens down fully (look at the diaphragm when the lens is unmounted and the ring is set to "A"), and raises a pin that tells an A-capable camera that the lens is indeed set to "A". If the camera isn't A-capable, all you have is an ordinarily stopped-down lens.

12-02-2013, 10:37 AM	#6
builttospill Pentaxian Join Date: Jun 2009 Location: Utah, Idaho Photos: Gallery Posts: 2,398	The lens A setting is unusable on cameras without the A contacts on the mount. As mentioned above, the lens can only shoot at the minimum aperture, e.g., f/22, when set to A. Just to confirm for those reading this thread who might not be aware, A-series lenses can be used on all older, K-series cameras, but won't offer automatic aperture control. The camera in question, the K2, has an Automatic setting on the dial to provide aperture priority shooting. This allows the user to set the aperture using the aperture ring on the lens and the camera will automatically select a shutter speed to acquire a correct exposure. An aperture ring on the lens is required unless someone plans on just shooting at f/22.

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