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01-09-2012, 06:58 PM   #1
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Help, new lens is bad?


I've mostly used kit lenses for the past years and still don't understand many things. So I finally got a decent lens, but I'm having trouble.

K-r camera, Tokina AT-X Pro f/2.8 28-80mm lens. Lens purchased in gently used condition from a reputable seller.

I hope it's not the lens but seems like it

My first problem is manual focus. AF seems to work fine. When I switch to MF, the focus won't change. I'm spinning that huge front dial and can't see focus changing at all. With my Tamron or other lenses I've used, the focus changes drastically with just a partial turn, as it should.

Second problem is most of the time, it's stuck showing Av mode. When I turn my camera dial to P, M, Tv, Sv, and those little icons, it will still say Av on my LCD. I made sure it's attaching properly, I tried taking it on and off a few times. It always clicks loudly in place.

Third, it shows my battery indicator incorrectly. It's a nearly full battery and it shows me the yellow mostly-empty battery icon. At one point, for some reason, the Av problem was NOT happening but the battery icon problem was still happening. I attached my Tamron and it showed the proper battery, I switched back to this lens, and it showed low battery.

Also when I switch the aperture on the lens, it doesn't show up in my camera properly, I think it should.

So this means a problem with the electrical contacts? Seems like the MF problem could be due to the electrical contacts too. They look clean and I did try to wipe them off just in case.

Last edited by Kitty; 01-10-2012 at 04:29 PM.
01-09-2012, 07:10 PM   #2
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You must keep the lens in the "A" position to get the various auto modes. If you move the aperture ring to any other setting all you get is Av (with the lens staying always wide open) and M where you must use the green button for setting correct exposure.

Check also the contacts on the lens and make sure they are clean. The "A" mode is communicated by a pin and if it not contacting the camera thinks you have a manual lens.

Are you by any change using Live View? If you are that can explain the battery drain. LV is notorious to use a lot of battery power and to incorrectly report the battery level. If you turn the camera off and on again, does the battery level recovers?
01-09-2012, 07:24 PM   #3
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Well auto is not the problem. Manual is the problem.

The battery varies. One time it showed low/yellow. Turned camera off and back on, battery was back to green. However, another time it showed low/yellow. Turned off and back on three times and still, yellow. Switched some other things around a little, still yellow.

I'm becoming more sure there's a problem. This time I took the lens off to wipe the contacts again. Lens snapped back into place. Turned on camera. Battery was already yellow.

Plus it seems to get the Av problem in all sorts of states. I'm not positive yet but I think with all the things I tried, I saw the Av problem in all states. By different states I mean whether I had AF/MF selected, A setting on the lens or other f-stop settings, and which mode on the dial (P, Sv, etc).

Not using Live View (except of course it kicks on if I switch to the movie mode).
01-09-2012, 08:32 PM   #4
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Do you have aperture set to permitted in the custom settings?

01-09-2012, 08:38 PM   #5
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Yes I do.
01-09-2012, 09:47 PM   #6
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QuoteOriginally posted by Kitty Quote
Tokina AT-X Pro f/2.8 28-80mm lens
Kitty, I think you have several different problems which might (or might not) be related.

First, manual focus. I believe this lens has a clutch system to shift it from MF to AF. The focusing ring slides forward and backward into AF or MF settings. I assume you have it in the AF position so no matter what you do on the camera the lens is still in AF mode. Try pulling straight back on the focusing ring. You may have to have it in a particular position in order to do this (or maybe not, depends).

Second, Av mode. If you are only showing Av mode then the camera thinks you have a manual lens or you have the aperture ring in a non-A position. Check and make sure it is in the A setting. Clean the electrical contacts with a soft cloth.

Third, battery issues. What type of batteries are you using, AA? or Li-ion?

Fourth, changing the aperture ring to any setting but A will NOT show the aperture on the camera. It should show "F--". If you take it off the "A" setting the camera and lens no longer communicate aperture info.

And lastly, the electrical contacts have nothing to do with the focus on this lens. It is purely a mechanical connection.

Try to solve one thing at a time to isolate what is going on. It is possible there is something wrong with the contacts but check the other things first. I suppose it is theoretically possible that the contacts are shorting somehow and causing a battery drain. But I have NEVER heard of that happening.

By the way here is a link to the review of that lens on Pentax Forums. Check to make sure that is the lens you actually have.
01-10-2012, 12:02 PM   #7
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Thank you. I did have to pull the ring back to go into MF. I thought I had tried to push & pull but I didn't do it right before.

Also didn't know about the "F--". So, in MF, it's normal to show Av when I have the dial on P, Sv, Tv, etc? That makes sense, but I didn't know.

Also I thought I was putting it into A, but sometimes I wasn't. Sometimes I was, so that's why I got varying confusing results. It all seems to be working now except the battery.

I have a second battery, fully charged, so I put that in, and it seems to be working so far.

Odd that I never had problems with either battery until I attached this lens, but maybe because of me trying to use it without A on, or without the ring slid into MF position. I am going to recharge the battery fully and maybe it will be fine again. Worst case, I hope it's just that battery, easy to replace.

I need to test to make sure there's no other odd problems, especially battery related.
01-10-2012, 04:25 PM   #8
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Hi Kitty

If someone has not mentioned this yet, if your camera has it, in the menu did you put the "allow aperture ring" to yes in setting in your menu?

good luck

01-10-2012, 06:26 PM   #9
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QuoteOriginally posted by Kitty Quote
Also didn't know about the "F--". So, in MF, it's normal to show Av when I have the dial on P, Sv, Tv, etc?
Kitty, that is not quite correct. Focusing (AF or MF) has absolutely nothing to do with your aperture mode settings.

The problem you are having with it showing Av mode (and "F--") has to do with the "A" setting. If it is in "A" then you can use all of the modes and the aperture can be changed on the camera. If it is NOT in "A" then the camera will show "F--" and Av mode. It will only work in Av and M mode, if you put it in any other mode it will say Av I believe.

Bottom line: put it into the "A" setting and leave it there. On a modern body there is really no reason to use any other setting.

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