M42 = Auto Aperture?

[photophorous]

I currently have a Minolta manual focus SLR kit and I'm considering selling it all to buy into a different manual focus SLR kit. The M42 screw mount system seems neat because there are so many options for lenses, but this is one thing I can't seem to figure out. Do these M42 screw mount lenses have auto aperture, like the Minoltas, or is it all stop down metering?

The main reason I want to switch systems is so I can have old manual focus film lenses that I can use for film and also use them on my new Canon DSLR with an adapter. Others that I'm considering are Olympus, Nikon, and Contax. (I realize these will all be stop down metering on the DSLR.) If you have any opinions on these different systems, I'm all ears...er, eyes, in this case.

Thanks,
Paul

 

[sevo]

is it all stop down metering?

YMMV. There never was a common standard for aperture coupling and aperture control - each manufacturer had its own solution. Only the Chinon CE and its successors and its innumerable OEM versions (which however make up the majority of late M42 camera bodies at least in Western Europe) succeded in auto stop-down metering with only the stop down pin.

Sevo

 

[OldNick]

My M42 Takumars (Pentax) automatically stop down when used on my Pentax Spotmatic SP. When I use them on my Fujica ST705, I have to depress a front button in addition to the shutter release in order to get the meter to work. So, I guess there is no standard definition. On my Olympus E-510 with an adapter, I must use stopdown metering when I use these lenses.

Jim N.

 

[Melvin]

I use the Takumars on a Pentax ZX-M and they are totally manual, both for metering and exposure. Fortunately, they have an "auto/manual" switch. It's the same if you put them on a Pentax DSLR.

 

[rover]

M42 lenses will work in Av mode on your Canon DSLR. You would simply focus with the lens wide open, stop down the aperture and fire. I believe the camera will set the correct shutter speed for the aperture selected. This is also the operation on a Pentax DSLR.

 

[cmedin]

Do you get focus confirmation with the Canon bodies?

I really like using the preset lenses with my Pentax DSLR. One ring to set the aperture, then focus wide open, spin the second ring until it stops and shoot.

 

[photophorous]

Thank you all for helping explain that. I'm still not sure what I'm going to do. I think a family member might be giving me some old Nikon and Pentax (probably K mount) equipment, but she wasn't sure exactly what she had. I've been doing some reading on Nikon and that AIS 28mm f/2.8 sounds like a great lens. I guess I'll just wait and see what I get before deciding.

Thanks again.

Paul

 

[chambrenoire]

I bought a M42 lens yesterday to try on my 5D with an adapter - works like a charm. The lens has a manual/auto switch, which I use on manual, and with the Av-preset on the camera.

 

[titrisol]

Well, M42 can be autoaperture if you use Super-Multi-Coated Takumars on a Spotmatic F
In all DSLRS it'll be stop-down

I currently have a Minolta manual focus SLR kit and I'm considering selling it all to buy into a different manual focus SLR kit. The M42 screw mount system seems neat because there are so many options for lenses, but this is one thing I can't seem to figure out. Do these M42 screw mount lenses have auto aperture, like the Minoltas, or is it all stop down metering?

The main reason I want to switch systems is so I can have old manual focus film lenses that I can use for film and also use them on my new Canon DSLR with an adapter. Others that I'm considering are Olympus, Nikon, and Contax. (I realize these will all be stop down metering on the DSLR.) If you have any opinions on these different systems, I'm all ears...er, eyes, in this case.

Thanks,
Paul

 

[Tanneur]

Hello Paul,

there is a bit of confusion in this thread.
There are quite a lot M42 cameras with auto aperture and the standard for this is the same (the small pin at the back of the lens which closes the aperture by pressing the shutter). The Pentax Spotmatic or Practica MTL have a switch on the front which stops down the lens and switches on the meter. Focusing can be done with full aperture.

Open aperture metering is a different story. There is no common standard for this. You have to use dedicated lenses for full aperture metering or auto exposure.

If you want to go the M42 way the camera bodies are quite cheap but the lenses can get quiete expensive. Especially if you want to use wide angles since the choices are quite limited.