It's for my 5D. Should I just get a cheap one from one of the HK ebay dealers or are there certain ones to avoid due to infinity focus issues? I much prefer the focus-assist adapters if possible.

My 40mm pancake should arrive next week

Thanks....

I would avoid the Hartblei, I had two copies that would not mount to my 200mm f/4 macro lens.
Dan

I have a couple of the Chinese ones. They work pretty well, but they are all a little thin.

Dan - How are you liking the Pentax 200/4?

I have one from the ebay store Roxsen. It seems to be of a pretty good quality. Cost: 10 GBP including postage.

Some info, quoting from photobits42 who seems to sell the same adapter (also with af-confirm):

The lens is mounted offset by about 30 degrees to keep the protruding guard of the aperture lever of the lens away from the reflex mirror of your camera. Even so, the reflex mirror of film cameras and full format Digital (1d and 5d) is likely to hit the protruding guard of the aperture lever of the lens. This is a "feature" affecting all PK adapters on the market. If you want to use a PK lens on a full format (35mm) camera the only solution is to trim a few millimetres off the guard with a hacksaw so that it does not extend behind the adapter. The lever can be left intact (on most lenses) or trimmed as you wish.

The 30 degree mount offset is actually convenient, because the builtin flash (on 40D) doesn't block your view of the aperture scale.

On my 40D, the aperture lever of my Vivitar 28mm/2.0 Close Focus still hits the mirror box, because of which the lens can't be stopped down further than 3.5. So I will need to make a small mod on the lever...

The Hartblei is quite a bit thicker than a cheap aluminum one that I have. I was able to mount the Hartblei but only after some surgery.
The 200mm macro is very sharp. I've had it about a year now but I need to use it more.
Dan
danbrownphotography.com

I just ordered one from photobits42 since he had a better rating than Roxsen. Thanks.

Haha, good luck! I ordered from him on 24th of May. My adapter arrived today.
It had a drop of epoxy on the mount, which I had to scrape off before I was able to mount it. Sloppy.

The adapter also has lots of play when I mount my PK lens. The same adapter that I got from Roxsen mounts perfectly solid without play. I might be able to fix this by opening those 'things' that press against the PK lens mount, by putting a small screwdriver in those slits and rotating it slightly. I had to do the opposite to a cheap OM-EOS adapter that wouldn't mount until I pressed those things together (mount was too tight).

Edit: Well, that didn't work. There is still some play in the adapter. It's probably just the bad error tolerations in these cheap adapters. Lesson to be learned: it's always good to buy cheap adapters from a few different sources. More chance that you will get a proper one. And on ebay, the rating doesn't say much about the quality of one of many items of a seller. Pictures and elaborate descriptions actually tell more, if they are good.

I don't think it matters much where you get your cheap chinese made adapter. I've ordered many of the same OM-EOS from different vendors and they all seem to be identical, except some are a little tight, while others can be loose. It's likely that most come from the same source, with sloppy manufacturing tolerances.

I guess worst comes to worst as long as the adapter lets the lens focus to infinity I can just drill a couple of little holes and bolt the adapter to the lens or use the screw to put enough tension on the lens to keep it in place. I have to cut the lever off the back of the lens anyways to mount it on the 5D. So it will lose its resale value right after the surgery.

I guess that when you get the same adapter from different sources, you'll probably be getting ones from different batches, so to say. My two PK-EOS adapters prove that - they look identical, but one is basically perfect while the other probably can't be fixed because it's just too loose.

Sorry to bring this thread back to life, but did any of these adapters have a focus confirmation chip? Did it work well?

my adapter makes the lens sit on its side like perfectly center like my OM adapter and contax. Is all PK adapters like this?

What does PK stand for, ive never heard this term?

pentax K mount...

The Big-Is adaptors have a groove in the thread that can be expanded for a tight fit. With some tweaking you can get it just right, not too tight not too loose. The tolerances might be a little generous, but at their price they are a bargain. The AF-confirmation works like a charm.

I might be willing to buy an expensive adaptor for an expensive alternative lens, but not up to the price levels where I have been looking. Anyway, I just buy an adaptor for each lens, make it fit well and just leave it on.

Ruy