Pentax-K to EOS adapter alignment

8310 · Joined: 05 Jun 2010 Posts: 123

Hey everyone,

All the PK-EOS-adapters I know of (actually, they are one the same type) mount the lens in a way that the top of the lens sits somewhere around one o'clock on the camera.
As far as I understand, that is for being able to mount unmodified lenses on most of Canon's crop cameras. It is pretty much nonsense for FF though.

Does anyone know of adapters that align the lenses the way they are supposed to be, at 12 o'clock?

8310 · Joined: 05 Jun 2010 Posts: 123

Thanks for the enthusiastic help, everyone! Very Happy

Just kidding.

Anyways, I managed to find some adapters that seem to align the lenses at 12 o'clock and I thought I might post them here in case someone else is looking for them, too.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110535711345&ssPageName=STRK:MEWAX:IT
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=370430302905&ssPageName=STRK:MEWAX:IT
Imho the second one looks particularly tasty as it seems to lock the lenses with a screw instead of those wobbly spring thingies.
Not exactly cheap but I think I will give it a shot.

calvin83 · Joined: 12 Apr 2009 Posts: 7554 Location: Hong Kong

One of the best PK to EOS adapters is the Kipon/Kinda brand. These cheap PK to EOS adapters cannot lock the lens firmly.

Share with us if you get the second adaptor. Smile

8310 · Joined: 05 Jun 2010 Posts: 123

Okay then, here is a small review about the Phototools24 adapters. The only other Pentax-EOS adapters I have are the cheap chinese brass ones, so those are the ones to compare to. Apologies for the crappy pictures, I was a bit in a hurry when taking them.

The Phototools24 adapters are quite a bit lighter than the brass ones since they are made from aluminium. Nevertheless, they feel sturdy and well made.
They come in two parts, the adapter and the locking screw. Getting the tiny screw into the drilling hole can be a bit fiddly at first, but it has to be done only once. When removing/putting the adapter from/onto a lens (small screwdriver needed!), the locking screw does not have to be removed completely but can be left attached to the adapter. The difference between being able to move the adapter and removing the screw is not very big though, so one has to be careful not to accidently remove (and then lose) the screw.

Due to the spring-like mount thread wings (do these thingies have a name?) which are only fixed at one end (see third picture above, on the left inner side), lenses fit very tightly, they also do not have any radial play inside the adapter. Once the lens is locked with the little screw, there is also not the tiniest bit of circular movement possible between the lens and the adapter.
Unfortunately, the locking screw tends to punctuate some of the lenses a little, especially some 3rd party lenses that have a mount made from softer material than the genuine Pentax ones. Imho not a big deal if the screw is being locked at the same place every time, but still...

Put onto a camera, there is no radial play here either. When using some force, there is a small amount of circular play possible though (about the same amount as with the brass adapters), so the lenses do not sit as snuggly as they would on a Pentax camera. As the adapters sits pretty tightly, I could not notice anything of that when shooting, but it might be an annoyance when using very heavy lenses or lenses that have a very tight focusing ring.

The adapter aligns the lens slightly off 12 o'clock, but the discrepancy differs from lens to lens. It is also possible to lock the lens with the locking screw before the adapter stops it, so most of the offset can be compensated if necessary.

I cannot make a final comment on focusing beyond infinity yet. The adapter seems to be a tiny bit thicker than the brass ones that allow me to focus noticeably beyond infinity. When taking pictures of a subject at about 200 meters distance, I had to focus slightly closer than infinity with a 85mm and 135mm lens to get it perfectly sharp. However, 200 meters are not really infinity yet, so I might have to wait until I can take some pictures of the moon.

The adapter does not actuate the lens ID lever of the 1Dx and analogue EOS series.

On a sidenote, I appreciate the black finish which is supposed to prevent internal reflections. Other than that, it simply looks better Cool

Compared to my cheap brass adapters, which have radial play and, depending on the lens and the locking spring, circular play between them and the lens, they seem to be a much better choice in my eyes at about two to three times the price.
I would love to compare them to a Kipon/Kindai one, but since those seem to be about five times more expensive (and I need more than one adapter for quick lens swapping), they are simply out of reach for me.

calvin83 · Joined: 12 Apr 2009 Posts: 7554 Location: Hong Kong

Thank you for your detailed review. Adaptor is not recommand for heavy lenses or lenses or lens with tight focusing ring.

The Kipon brand adaptor use a similar locking mechanism as most CY to EOS adaptor. It should work well if the lens is not so heavy.

8310 · Joined: 05 Jun 2010 Posts: 123

So how tight does the Kipon adapter sit on the lens? Apart from better built and tighter tolerances (I guess), how does it differ from the brass adapters?

From my experience with the cheap brass adapters which, as far as I can see, use the same locking mechanism I can tell that this spring lever works fine on some lenses but on some it does not. For some lenses the spring is not long enough so the adapter is wobbly, for some it is too long so it cannot lock, and in some cases the lever is even being pushed outside again because there is no proper hard-edged notch on the lens mount. Apparently there are big tolerances when it comes to the exact shape of the lens mount parts that those levers attach to (especially among 3rd party lenses, once again).

calvin83 · Joined: 12 Apr 2009 Posts: 7554 Location: Hong Kong

PK to EOS adaptor is no found on the official kindai site. The product information on the other xx to EOS adaptor never mentioned any third party lens. I guess the adaptor will works best with the Pentax made lens.