Fotodiox x Novoflex x Voigtlander: M-mount adapter cagematch

Started Nov 19, 2013 | Discussions thread
GXRuser
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Re: Fotodiox x Novoflex x Voigtlander: M-mount adapter cagematch
In reply to Tom Caldwell, Nov 21, 2013

Tom Caldwell wrote:

Letsgokoulos wrote:

turnstyle wrote:

Sorry, I'm losing track -- the Fotodiox properly hits infinity?

Even the high quality adaptors will not guarantee accurate infinity on the lens hard stop. They need to have a tolerance, for mechanical reasons and because each lens may have slightly different settings. Any good quality adapter will make sure that you can go past infinity, so if you want infinity you have to manually adjust before the infinity mark.

You may be lucky and have the adaptor providing infinity with a lens, but it most likely will not work 100% with other lenses in the same mount.

If you want an accurate hard stop on infinity, the only solution is shimming the adaptor. I have made the choice of cheaper adaptors so I could purchase one per lens and then shim it accurately. Since it is dedicated to a specific lens, it never is dissassembled and therefore does not deteriorate.

Marc

I agree Marc and note that all the very expensive Canon EF telephoto lenses (at least) are deliberately made to focus past infnity to take into account the effect of heat. Canon make no bones about this and note it readily. I imagine that smaller lense less affected by heat may also have some smaller tolerance built in. Besides lenses potentially have a lot more mechanical tolerence discrepancy in construction than those of adapters. Older lenses at least needed a final focus adjustment at final assembly.

And so the debate over perfect infinity focus has many caveats. Obviously your solution to shim adapter/lens combinations to perfection is a good one. But might even then vary very slightly in extremes of weather. On smaller lenses it would probably take a focus genius to perceive.

However making an issue out of focus before infinity is one of the lesser problems presuming that the "operator" (photographer) has checked focus as part of a normal shooting routine. It might be a nuisance - but photography is a discipline as much as any other craft and not "painting by numbers". With AF lenses of course the user would certainly never know.

However while I admit to a small focus beyond infinity as an "acceptable problem" a substantial focus beyond infinity is not.

The other thing that never gets discussed is the effect of hyper-focal distance when shooting infinity. This has never before crossed my mind. If a lens can focus past infinity and at the infinity stop is out of focus - does part of the dof always be oof as long as the hyper-focal area exists? Or is there some sort of auto-adjust to only focus on the focused part of the hyper-focal? This might be the real problem (if true) of a lens/adapter focusing beyond infinity. But then of course all Canon EF telephotos would have an instant problem unless the temperature was "just right" (quite hot I would think).

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Tom Caldwell

One of the issues that really bug me is that I can not assume that if I set a lens to infinity, it will focus to infinity.

I have noticed that most of my legacy lenses show this problem, independent of adapter.

I used to own a nice selection OM lenses. I noted that with the GXR and the M Module, some of the lenses would focus way past infinity. My RJ adapters and the fotodiox adapters were the most out of spec. The Kipon OM to LM adapter was just off, but usable. If I stopped the lens down to f8, infinity would still be in focus if the lens was turned to infinity where wide open it would be out of focus. I eventually tried Rayqual adapters and they were exactly on spec when the lens was wide open and set to infinity. (I never thought this was an issue with the OM1 and the split image focusing screen or microprism focus screen.)

I had no infinity focus issues with Leica M mount lenses on the GXR with M Module.

With my original Panasonic G1, I used both the Voigtlander and the Panasonic Leica M to micro-4/3 adapter with great success. With both the M-Rokkor 90mm and 40mm, infinity focus was perfect wide open.

So I expected the same when I got my NEX-6. I have a Voigtlander Leica M to E-mount adapter. I note that the M-Rokkor 90mm and 40mm lenses will focus at infinity just before the infinity stop. By stopping down to f4, infinity is now in focus. Depth of Field is your friend. I then proved this with the Voigtlander 25mm f4 Snapshot Skopar and Voigtlander 21mm f4 Color Skopar where they both focused at infinity with no issues. Both of those lenses have superb depth of field.

I then tried a Rayqual Pentax DA to E-mount adapter as well as a Novoflex Pentax DA to E-mount adapter. With a SMC M 100mm f2.8 I found the lens to focus at infinity before the infinity stop. I then tested the same lens with a Kipon Pentax DA to Leica M adapter with the GXR and it also focused before infinity. I also tested a Pentax DA 70mm and it had the same behavior of infinity focus before the infinity focus stop.

It is quite disheartening.

My conclusions:

1) Infinity focus calibration seems to be both lens and adapter specific.

2) Adapters seem to perform better with wide angle lenses or with cameras with smaller sensors as a function of depth of field.

3) If infinity focus is critical, native lenses with AF work better than scale focusing to infinity with adapted lenses.

3) Adapters work superbly with manual focus lenses if one needs to focus closer than infinity using live view.

Note: Snap focus function implemented by Ricoh (GR, GRD4, or GXR with S10, P10, A16, or the A12 lens units) allow one to set infinity focus. This is best solution I have found for infinity focus.

It would be wonderful if Sony could implement a snap focus function as a option for E-mount lenses.

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