new lenses to play with!

[azmyth]

Get ready for some flowers and children! I picked up a few vintage pentax spotmatic lenses to try on my t2i.

[drapeama]

Get ready for some flowers and children! I picked up a few vintage pentax spotmatic lenses to try on my t2i.

Don't forget the little cats!!

[azmyth]

maybe its just me.. but I had this same issue with my GH1 and could never figure it out. This lens I am playing with has a focus ring, and aperture ring. However, when I try to adjust it with the ring it doesn't seem to do anything.. its like "wide open" and I can't figure out how to change it..

[paperkut12]

You checked if you had your exposure set to manual in the camera? I don't know if that has anything to do with it.

[drapeama]

This lens I am playing with has a focus ring, and aperture ring. However, when I try to adjust it with the ring it doesn't seem to do anything.. its like "wide open" and I can't figure out how to change it..

It's an old lens? So it's not on "auto" like the kit lens on the T2i. Maybe the lens is broken, my 28mm Hoya does the same: the Iris stays wide open all the time. Not bad as I usually use it at night but on a bright sunny day, you must use some ND filters to stop some light, otherwise you end up using 1/2000 shutter speed with ISO100 and it's still overexposed...

You checked if you had your exposure set to manual in the camera? I don't know if that has anything to do with it.

I think it's more the lens that's the problem. Otherwise he would notice a change in the picture (more grainy). If the iris on the lens doesn't change/move, then it's the lens that's the problem.

[azmyth]

Yeah, the ebay auction I got it from stated that it was supposed to function, unless its the adapter I bought thats the problem. Like you said, at night its not a big deal since you pretty much shoot wide open anyway, but outside.. its a killer.

[Janke]

Note that some old lenses DO stay open despite the setting of the f-stop. It needs a mechanical stop-down linkage to the camera to go to the actual, set f-stop. M42 and Nikon lenses come to mind. Some adaptors may do this, others may not. An M42 lens needs to have the aperture pin pressed in to stop down.

[drapeama]

Note that some old lenses DO stay open despite the setting of the f-stop. [...] M42 and Nikon lenses come to mind.

Well, I've said that mainly because all the lens (all Nikon) I have, aperture on it can be set manually except the one that's broken (on the body or apart, the iris doesn't close at all)

[azmyth]

Yep its an M42 mount lens. Is there a way to change it before you put it on the adapter? or does the adapter open it all the way up? I wonder if I can get an adapter that will help me change it.. hmm..

[Dr. Benway]

Note that some old lenses DO stay open despite the setting of the f-stop...

Yeah, older lenses will stay at maximum aperture (e.g. f1.8) until the shutter is fired. This helps the photog view the image through the... viewfinder.

[Bif]

Azmyth: The M42 (thread mount) Takumars and other brands made in that thread mount have a "pin" that sticks out the back end of the lens mount. Something must push this pin "in" to cause the iris diaphragm to close to the aperture selected on the aperture ring.

I would think that as you thread the adapter on the back of the lens, the adapter "face" would push this pin in. The Chinese are "churning" these adapters out as fast as they can and little if any attention is being paid to proper fit and function. I had to go through 4 Nikon to EOS adapters before I got one that really fit and worked.

Bruce Foreman

[KingDucky]

when I try to adjust it with the ring it doesn't seem to do anything

I had this problem. It might only be on FD lenses, but couldn't hurt to try this:

http://blog.jag35.com/2009/07/toothpick-trick.html

[AJUK]

Not all m42 adaptors have the pin plate, I have several.
Take the lens off the camera and look at the back, inside the threads, you will probably see the pin sticking out.
If so, then you need to get a different adaptor, some of them are marketed on ebay as being 'auto' compatible, meaning they have the extra back plate needed to push the pin in. That's the type you want.
However, if you don't see a pin then you already have an auto adaptor and your lens is probably broken

[mkkid28]

I have this issue with a vintage lens (I think it's a K Mount) so it needs to have this little tab cut/removed before you can change the aperture otherwise it's fully open.

[azmyth]

its not a game breaker. I shot some footage last night with it that looked good, I wouldn't use it for anything but low light stuff anyway because its a 1.7 lens.. so everything I shot with it was wide open.

[homestar_kevin]

Definitely check the pin, that's the most likely cause


I doubt the lens is broken.