manual pre-set lens

I have been playing a little with a Orestor 2.8/135 in M42 mount. Allthough the lens needs cleaning on the inside (I have to find a company who does that here in the Netherlands) it works very nice.

The beauty of this lens is that it is a pre-set lens, so there is no coupling between the body and the lens for the aperture (I suppose the use of a M42 lens on a K-mount will allways have this effect). This way you can directly see what the DOF is without having to operate the DOF button on the camera.

This lens allso has no fixed steps for the aperture so you can set it exactly where you want it and the huge number of aperture blades (15) makes the aperture allmost a perfect circle.

After I have been playing with this piece for a few hours I get the hang of the manual lens and I must say in some ways it is easier to use that the modern lenses.

The stop down metering of the DS (the AE-L button in Manual mode) works very good in this setup.

Are there any pre-set lenses from Pentax or Takumar out there?

Just about all lenses in M42 work (or can work) this way.

The more advanced ones had a stop down pin to allow them to work with cameras which could do automatic stop down. This actually works to our advantage.

These lenses have a switch on the barrel marked "M" and "A". When set to M turning the aperture ring immediately stops the lens down. A was supposed to be used with auto stop down cameras, since the DSLRs have no M42 stop down pin it instead keeps the lens locked wide open.

With my M42 Zeiss Flektogon 35mm, I set the lens to A to focus, then set to M to stop down and shoot. It works wonders.

Sorry to highjack this thread, but can someone tell me what is so special about the Carl Zeiss 35mm F/2.5 Flektogon? They are going for crazy money on the bay... are they THAT good or is it only the name that draws people to them?

they have a bit of a cult following, which is largely justified, at least if you get a good one. At reasonable working distances my Flek 35 resolves more detail than the 6MP sensor on my *istDL2 can pick up, even wide open. The K10D can discern some benefit from stopping down.

The lens is also able to focus down to 20cm, pretty close for a non-macro 35mm.

It's just a lovely standard lens on a *ist series or K100, the exposure problems with the K10D mar it a little bit, but it's still my standard prime of choice.


Now I'm not convinced they are really worth the money they fetch on ebay, the cult following and the adaptability of the M42 mount means that just about everyone is after one. I found mine hiding in a charity shop with a stuck aperture and a box of assorted goodies. I gave them £20 for the box as I recall, then spent several hours taking it to pieces, cleaning it and putting it back together again. It was worth it.