A-Ring Question..


aadixon

Link Posted 28/02/2014 - 23:30
Hi all,

So, I recently got a prime lens online, and according to the charts I've looked up, it should be working. The lens should be working with the aperture on A.

Chart-->http://www.mosphotos.com/PentaxLensCompatibility.html

The lens is the SMC A 50mm 1:2 F2.
My cameras vary, but I bought it to work on the zx-30 (Crippled KAF) and my K-3.

Is this lens not made to work on these bodies, or is something broken inside of it?

-Aaron
Last Edited by aadixon on 28/02/2014 - 23:33

JAK

Link Posted 28/02/2014 - 23:37
Custom menu 4 - item 27 'Using aperture Ring':
Set this to 2 (enable)
John K

aadixon

Link Posted 01/03/2014 - 00:06
JAK wrote:
Custom menu 4 - item 27 'Using aperture Ring':
Set this to 2 (enable)

That fixes it for the K3, but I'm confused to as why. This is because on the crippled bodies, like the ZX-30, the ring must be set to "A". It can be changed manually still with the Av button, which is what I do for shooting manual.

These lenses work from the zx-30 when used on my K3, although they are not SMC A series like the one I'm questioning, but a SMC FA.

Still, according to what I've found online, the A series SHOULD work on both. I guess it's always possible the charts are wrong?

Bleh...I still can't figure out if it's A ring is broken or not though...sorry if what I said isn't making sense.
Last Edited by aadixon on 01/03/2014 - 00:10

johnriley

Link Posted 01/03/2014 - 00:10
Once set on "A" the lens should work quite happily.

What are the exact symptoms when you use the lens?
Best regards, John

Helpful

aadixon

Link Posted 01/03/2014 - 00:13
It does what would happen if I was to put a lens that isn't supported on it, such as the older Pentax K mounts do. It fits, but the aperture flashes with "--" on the meter.

It just confuses me, as an A series shouldn't be doing that, or so I thought.

johnriley

Link Posted 01/03/2014 - 00:17
No, it shouldn't be doing that. It sounds as thought the contacts are not making proper contact.

I would use a clean dry soft cotton or microfibre cloth to clean the contacts both on the camera and the lens. Then try seating the lens fully again. You could also check that all the contacts look right and one isn't damaged in some way.
Best regards, John

Helpful

aadixon

Link Posted 01/03/2014 - 01:28
I cleaned the entire lens, back, front, etc. Still nothing. I guess that's what I get for not paying attention online and buying it from a Goodwill...

Nothing appears broken on it, maybe it was dropped? Who knows.

JohnX

Link Posted 01/03/2014 - 10:34
If you haven't done it, clean/check the contacts on the 'offending' camera body too.

If the lens works on the K3, but not the ZX-30, then surely the problem lies with the ZX-30, not the lens? The camera was not designed to work with M and K lenses, but should work with A lenses.

aadixon

Link Posted 01/03/2014 - 14:19
JohnX wrote:
If you haven't done it, clean/check the contacts on the 'offending' camera body too.

If the lens works on the K3, but not the ZX-30, then surely the problem lies with the ZX-30, not the lens? The camera was not designed to work with M and K lenses, but should work with A lenses.

No it doesn't work properly on the k3. It should work as all of the other lenses do, with the aperture ring to "A", then change it manually with the Av wheel. It acts as if this is a non A-ring lens on both bodies.

What JAK said works if you're using an older K mount lens on the body. The contacts are not working on this SMC A that I got. I've returned it for a full refund last night.
Last Edited by aadixon on 01/03/2014 - 14:22

JohnX

Link Posted 01/03/2014 - 15:43
aadixon wrote:
No it doesn't work properly on the k3. It should work as all of the other lenses do, with the aperture ring to "A", then change it manually with the Av wheel. It acts as if this is a non A-ring lens on both bodies.

What JAK said works if you're using an older K mount lens on the body. The contacts are not working on this SMC A that I got. I've returned it for a full refund last night.

Apologies. I got the impression it did work on the K3. Pleased you'll be getting a refund. Better luck next time.

davidstorm

Link Posted 01/03/2014 - 17:17
I think the problem here is probably with the lens. All my 'A' lenses work no problem on the K-3, with the lens set to 'A', camera set to 'AV' and the menu setting for 'using Aperture Ring' set to 'Permitted'. I know this won't help the author of this post, but it does confirm that the K-3 has no problems with 'A' lenses.

Regards
David
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Nicola's Apartments, Kassiopi, Corfu

Some cameras, some lenses, some bits 'n' bobs

JAK

Link Posted 01/03/2014 - 20:05
Maybe there's some confusion as to what was expected.

Current Pentax lenses behave just the same as the older ones that had both the A setting and manual aperture settings, providing the older lenses are on the A setting. Take them off the A setting and they behave like an old K or M lens when they'll need green button stop down metering. The aperture setting in the viewfinder will show '--' as the lens is no longer communicating with the camera. I believe this to be the issue the OP was experiencing.

So put the old lens on 'A' and set the aperture with the camera controls (not the lens's) and it will behave just the same as the current lens line up.

If the lens purchased is set to 'A' and it isn't showing an aperture reading then there is something wrong, be it the lens or a dirty contact. But physically set the lens to say, f5.6, it will not show that in the viewfinder.
John K
Last Edited by JAK on 01/03/2014 - 20:08

johnha

Link Posted 01/03/2014 - 21:29
I was confused when I bought my K-5. Putting an FA lens on my manual focus MZ-M would display the aperture in the finder when the ring was not on 'A'. On the K-5 is doesn't, it's not directly due to the crippled mount as my Z-1 didn't do it either.
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