TTL metering in K1000 not working through Vivitar 24/2.8?

pentaxk1000denver · 12-10-2011, 08:26 PM

I feel like I ask a lot of questions on here, but it's the only place I know to get help. Thanks to those who offer it!

I got another used lens in (Vivitar 24/2.8 Tokina), and when I attach it to my K1000, the light meter needle just sits at the bottom. With my Pentax-M 50mm at the same aperture, it works fine. The blades move fine when off the camera, and the aperture lever on the back works (although it goes about 1 or 2mm before it engages the mechanism that opens the blades). When I put the new lens on the camera, I saw that the aperture was open and could see the blades move when I fired the shutter. It just won't meter. Pointed directly at an overhead dome light in my kitchen about 8 inches away, I had to slow the shutter down to 1/4 second with the lens open at f2.8 to get any reading. With my Pentax,-M 50mm pointed directly at the light at 1/4 second, the needle was maxed out even at f/22. Is there something wrong with that lever in the back? Thanks in advance...

**Just1MoreDave** · 12-10-2011, 08:54 PM

On the opposite side of the K lens mount from the aperture lever, there's a tab in a groove. The tab moves a little less than the distance between two of the bayonet lugs. It should move whenever you move the aperture ring. The K1000 uses that tab to figure out where the aperture ring is set to. On the camera there's a corresponding tab that engages when a lens is mounted. Without a lens mounted, moving this camera tab should change the meter reading.

I think your used lens might have something wrong with that tab mechanism, so it doesn't engage the camera's tab when the lens is mounted. Worst case scenario, someone forgot to put it back when they were reassembling it. On a DSLR, the tab doesn't do anything because Pentax no longer uses the corresponding camera part. So a lens might work fine without the tab on a DSLR.

pentaxk1000denver · 12-10-2011, 09:07 PM

Ah ha, once again, thank you. That little lever only slides in one direction when using the aperture ring. I moved that lever to the left manually, and then I turned the aperture ring, and it moved the lever to the right, but it did not move it back to the left. It definitely seems like something's wrong.

Ouch, two in a row now... I'm thinking I'm not meant to own a wide angle lens!

pentaxk1000denver · 12-12-2011, 09:27 AM

Quick bump to see if anybody has any suggestions on repairing this one on my own. I've asked for a partial refund and will take the back off (as soon as I get a JIS screwdriver), and I'm hoping I can figure out the problem from there. If anybody has experience with this type of repair, please let me know. Thanks!

drougge · 12-12-2011, 09:41 AM

The tab is generally directly connected to the aperture ring (no fancy mechanics), so it might well be easy enough to just glue whatever has become unstuck.

But you could also see it as the lens that forces you to learn to expose without a meter. It's not so bad, at least with negative film.

pentaxk1000denver · 12-12-2011, 04:33 PM

I have an external meter for my Hasselblad anyway, so I could always use that. I'll attempt the repair and if it goes wrong or doesn't work, the lens will hopefully still function and I'll just use it with an external meter. It wasn't registering in my head that the actual aperture control still works and that the tab that is malfunctioning is only to control the meter. Thanks!

12-10-2011, 08:26 PM	#1
pentaxk1000denver Inactive Account Join Date: May 2011 Location: Denver, CO Posts: 159	TTL metering in K1000 not working through Vivitar 24/2.8? I feel like I ask a lot of questions on here, but it's the only place I know to get help. Thanks to those who offer it! I got another used lens in (Vivitar 24/2.8 Tokina), and when I attach it to my K1000, the light meter needle just sits at the bottom. With my Pentax-M 50mm at the same aperture, it works fine. The blades move fine when off the camera, and the aperture lever on the back works (although it goes about 1 or 2mm before it engages the mechanism that opens the blades). When I put the new lens on the camera, I saw that the aperture was open and could see the blades move when I fired the shutter. It just won't meter. Pointed directly at an overhead dome light in my kitchen about 8 inches away, I had to slow the shutter down to 1/4 second with the lens open at f2.8 to get any reading. With my Pentax,-M 50mm pointed directly at the light at 1/4 second, the needle was maxed out even at f/22. Is there something wrong with that lever in the back? Thanks in advance...

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12-10-2011, 08:54 PM	#2
Just1MoreDave Site Supporter Join Date: Feb 2007 Location: Aurora, CO Photos: Gallery \| Albums Posts: 6,340	On the opposite side of the K lens mount from the aperture lever, there's a tab in a groove. The tab moves a little less than the distance between two of the bayonet lugs. It should move whenever you move the aperture ring. The K1000 uses that tab to figure out where the aperture ring is set to. On the camera there's a corresponding tab that engages when a lens is mounted. Without a lens mounted, moving this camera tab should change the meter reading. I think your used lens might have something wrong with that tab mechanism, so it doesn't engage the camera's tab when the lens is mounted. Worst case scenario, someone forgot to put it back when they were reassembling it. On a DSLR, the tab doesn't do anything because Pentax no longer uses the corresponding camera part. So a lens might work fine without the tab on a DSLR.

12-10-2011, 09:07 PM	#3
pentaxk1000denver Inactive Account Join Date: May 2011 Location: Denver, CO Posts: 159 Original Poster	Ah ha, once again, thank you. That little lever only slides in one direction when using the aperture ring. I moved that lever to the left manually, and then I turned the aperture ring, and it moved the lever to the right, but it did not move it back to the left. It definitely seems like something's wrong. Ouch, two in a row now... I'm thinking I'm not meant to own a wide angle lens!

12-12-2011, 09:27 AM	#4
pentaxk1000denver Inactive Account Join Date: May 2011 Location: Denver, CO Posts: 159 Original Poster	Quick bump to see if anybody has any suggestions on repairing this one on my own. I've asked for a partial refund and will take the back off (as soon as I get a JIS screwdriver), and I'm hoping I can figure out the problem from there. If anybody has experience with this type of repair, please let me know. Thanks!

12-12-2011, 09:41 AM	#5
drougge Veteran Member Join Date: Jan 2010 Location: Malmö Photos: Gallery Posts: 787	The tab is generally directly connected to the aperture ring (no fancy mechanics), so it might well be easy enough to just glue whatever has become unstuck. But you could also see it as the lens that forces you to learn to expose without a meter. It's not so bad, at least with negative film.

12-12-2011, 04:33 PM	#6
pentaxk1000denver Inactive Account Join Date: May 2011 Location: Denver, CO Posts: 159 Original Poster	I have an external meter for my Hasselblad anyway, so I could always use that. I'll attempt the repair and if it goes wrong or doesn't work, the lens will hopefully still function and I'll just use it with an external meter. It wasn't registering in my head that the actual aperture control still works and that the tab that is malfunctioning is only to control the meter. Thanks!