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Posted

I bought a Pentax K1000 and three lenses that fit on it at my local flea market. Two of them work nicely but the third causes the mirror to stick in the upwards position. Removing the lens and firing the shutter helps the mirror come back down.

Looking on the back (the mounting side), it appears ever so slightly different than the other two lenses, but not in any way which I would think would cause this. Is this just an incompatible lens or some other issue?

Posted

Will do soon! I went out to buy a battery for the camera's light meter. I'm also wondering if that may be the reason it doesn't work.

Another interesting thing: for the lens that doesn't work, adjusting the aperture actually causes the view through the viewfinder to dim or brighten. The apparent brightness doesn't change with the other lenses.

Posted
34 minutes ago, NMGPhotos said:

I went out to buy a battery for the camera's light meter.

The K1000 only needs a battery for the exposure meter. Otherwise it's completely mechanical and will work without a battery. The troublesome lens seems to have an issue with the aperture. It should have a small lever on the rear which opens and closes the aperture - that's the set of blades in the lens which open and close to control the amount of light passing through. This lever should move freely. If it's stuck it could be affecting the mechanism of the camera.

Posted
2 hours ago, John Seaman said:

The K1000 only needs a battery for the exposure meter. Otherwise it's completely mechanical and will work without a battery. The troublesome lens seems to have an issue with the aperture. It should have a small lever on the rear which opens and closes the aperture - that's the set of blades in the lens which open and close to control the amount of light passing through. This lever should move freely. If it's stuck it could be affecting the mechanism of the camera.

 

Yeah, I assumed as much, but a battery doesn't hurt! As for the lever, it does indeed move freely, but the lever mechanism itself is shaped slightly differently than the others. That may be the difference here. Photos incoming!

Posted (edited)

Also, I was wrong about the other lenses not changing apparent brightness when the aperture is adjusted. It just seemed more dramatic on that one lens for some reason.

EDIT: No, I was right. It's basically no change on the others.

Edited by NMGPhotos
Posted

If the bent one is the problem lens that gets dimmer as you select a smaller f/stop then the bent pin probably isn't coming in contact with the lever in the camera that causes the lens to stop down from maximum aperture when you press the shutter.  If all of these lenses cause the finder to get darker when you stop down then there is probably an issue with the diaphragm mechanism in the camera body.  K mount lenses stop down when the lever in the camera body moves to one side and the lens stops down with a spring loaded mechanism built in to each lens.  They open back up when the lever in the camera body returns to its original position after the shutter closes.  Some older Ricoh K mount lenses don't play well with Pentax bodies although usually the problem is that you can't remove them from the Pentax body when you want to. 

Posted (edited)
10 minutes ago, AJG said:

If the bent one is the problem lens that gets dimmer as you select a smaller f/stop then the bent pin probably isn't coming in contact with the lever in the camera that causes the lens to stop down from maximum aperture when you press the shutter.  If all of these lenses cause the finder to get darker when you stop down then there is probably an issue with the diaphragm mechanism in the camera body.  K mount lenses stop down when the lever in the camera body moves to one side and the lens stops down with a spring loaded mechanism built in to each lens.  They open back up when the lever in the camera body returns to its original position after the shutter closes.  Some older Ricoh K mount lenses don't play well with Pentax bodies although usually the problem is that you can't remove them from the Pentax body when you want to. 

The "bent" one is the only one in which the view through the viewfinder is dramatically changed when adjusting the aperture. The others show little to no change. I thought I noticed some change on one, but on repeat tests, I saw no change.

I also put "bent" in quotation marks because it seems to be how it was designed. The material does not appear weaker at the curve (which would be more likely if it was actually bent from its proper position).

As for the levers, I can move them on the lenses themselves, but when they are attached and I press the shutter, I see no movement on the aperture.

Additionally, to be specific, it's the Quantaray lens that does not work.

Edited by NMGPhotos
Posted (edited)

Ok, no now I see what you're saying @AJG. It is likely the lever mechanism. But I am not sure why it is different on the Quantaray. Is an adapter needed? Or is it just a crappy lens?

EDIT: Perhaps it is bent. If it is, that's impressive because it's pretty solid.

EDIT 2: Use some pliers to bend it back upwards. Seems to have fixed it? No idea how it got bent in the first place.

Edited by NMGPhotos
Posted
5 hours ago, NMGPhotos said:

Ok, no now I see what you're saying @AJG. It is likely the lever mechanism. But I am not sure why it is different on the Quantaray. Is an adapter needed? Or is it just a crappy lens?

EDIT: Perhaps it is bent. If it is, that's impressive because it's pretty solid.

EDIT 2: Use some pliers to bend it back upwards. Seems to have fixed it? No idea how it got bent in the first place.

My guess would be that it was dropped on the diaphragm actuating lever and it bent.  Don't be too surprised if it isn't optically fantastic,

Posted
21 minutes ago, AJG said:

My guess would be that it was dropped on the diaphragm actuating lever and it bent.  Don't be too surprised if it isn't optically fantastic,

Sounds interesting. And yeah, I don't expect much. But thanks for the help 🙂

Posted (edited)

If it was me I think that I would forget about the lenses that you have and invest in a few genuine Pentax lenses made for this camera. Pentax sold a lot of these cameras and there is a lot of used lenses around for sale. These were good cameras and Pentax made very good lenses. They are better than the lenses you have and will fit and work properly on your camera. There are a lot of them around and they are not that expensive. 

Edited by robert_bowring
wrong term
  • Like 1

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