new lens with aperature troubles

[MyOwnPath]

I just got a lens from ebay and have some questions someone may be able to clear up.

I'm actually baffled...looking through the lens (off the camera), it is clear that when I adjust the aperature ring, the aperature opening itself does not change. On all other lenses I've used, you can see the aperature change as you adjust it.

However, when the lens is on my camera and I adjust the aperature ring, the light meter reading changes. So it must be doing something. Could it be that the aperature snaps back to it's smallest setting when I remove it from the camera? Why doesn't the ring adjust it off the camera? The ring moves, so it isn't stuck on aperature priority.

In looking through the viewfinder with the lens on, it is very dark. I have a similar lens by another maker that I'm comparing it to. when I use it inside, I can barely see anything and when outside, bright lights and backgrounds are dull grey. I do a lot of evening photography and need a lens that registers light clearly. I may just be missing something, but compared to all others I have used, this lens is confusing me. Thanks.

--Trav--

 

[photong]

I don't know what to say except you should try it out use different aperture settings (using resiprocity of course to try the range of DOF it has so you can compare it to make sure it works)

I think I know what youre talking about, but I don't know if I can even see it on my lenses. I think I can. Ill have to go check.

You should try it out.

 

[malachite]

A few more details, like what kind of lens (brand) and camera would help a little more. Though when you mention that everything is really dark when you're looking through the viewfinder and turning the aperature ring makes no difference, it sounds like you're having some issues if you have an auto indexing system.

 

[photobug]

Not knowing what brand camera/lens you have this is just a guess- Perhaps the lens defaults to a small aperture off the camera because of the way the mount works.

Normally (in my experience), lenses default to a wide aperture and stop down when the shutter is released. In this case it may work in reverse. The light meter changes because the contacts on the lens tell the camera what the lens is set to.

Nothing actually moves (aperture wise) until the shutter is released.

 

[MyOwnPath]

it's a pentax k mount camera and an albinar 75-300 mm lens. completely manual. as I said, i have another comparable lens, a sigma 75-300 mm lens, exactly the same appearance, but the albinar is very dark and the sigma is normal. i can see the aperature adjust on the sigma but not the albinar.

i'll shoot a test roll today. Thanks!

trav--