kipon eos->nex aperture adapter vignettes

[docmaas]

I bought one of these so that I could try out some canon lenses now in preparation for my upcoming move to the Sigma SD1. Unfortunately when I tried it with a Tokina 11-16 zoom is vignettes at f2.8. In fact as far as I can tell the moveable aperture has no effect until it is past the adjustment range designated by the adjustment numbers engraved on the ring. I managed to get it to f8 just well past the engraved numbers and just short of the full throw of the ring. At that point it is no longer vignetting but full blockage of the image with only a central circular portion showing through.

The placed the diaphragm as close to the lens as possible but the throat of the adapter behind the diaphragm is as narrow as the diaphragm itself. Making it larger might help.

I'll be reurning mine unless someone else wants to buy it to try it out on some other lens. The tokina is the only canon mount lens I have.

Mike

 

[Tesselator]

No thinks. I'll pass. Whoever designed that thing is either a retard, doesn't understand the elementary basics of lens design, or is trying to pull a fast one (gimmick) on unsuspecting people who don't know any better - and that's the majority of users - I'm pretty sure.

Again I'll say, it just can't be that hard to create a battery operated adapter that can control an EF lens's aperture - really! Until one comes along I'm afraid we're stuck using EF lenses wide open or not at all.

Poor us!

 

[agoglanian]

They said specifically it won't work with EF-S lenses. The Tokina 11-16mm is a crop sensor (EF-S) lens.

 

[docmaas]

They said specifically it won't work with EF-S lenses. The Tokina 11-16mm is a crop sensor (EF-S) lens.

An EF-S lens is a canon lens with a different mount than an EF lens.

I specificall asked them if all APS C lenses were considered to be the same as the EF-S and they didn't think so. Keep in mind I'm dealing with the seller not the mfr.

In any case I have another ff lens on the way for further testing.

Mike

 

[Amatieris]

Of the three adapters for NEX I have Kipon is the best, the other two I bought cheap both have issues (returning one already). I think in your case it is a simple misunderstanding.

 

[docmaas]

I got a 14mm Rokinon FF canon mount lens and tried it with the adapter. Again I found that I had to turn the aperture adjustment fully to the minimum to get f8 and again there is vignetting although it is not as bad as it was on the tokina. I didn't try corner fix on it but I will when I have the time. Regardless, it is impossible to use an aperture smaller than f8 on this particular lens. I don't know how other lenses will perform.

Mike

 

[Diane B]

Here is a link to a test done with a variety of EF lenses
http://vimeo.com/17821964

 

[docmaas]

Thanks Diane. The tests were oriented to movie making rather than stills. I suspect the adapter will be somewhat more suitable for that kind of work. The tests themselves say nothing about the fstop or tstop where vignetting begins, only what the indicated degree is on the adjustment dial on the adapter which will relate to stop differently from lens to lens.

Mike

 

[conurus]

We are working on an electronic adapter so that you just dial in the aperture on the NEX body, and the EOS lens stops down at the time of exposure (or during movie capture). The Canon lens gets its power from the Sony NEX camera body. Our adapter translates between the two communication protocols. You also get basic EXIF information in the image files.

We have already a first prototype. Find out more by searching for Conurus on Youtube, Twitter or Google.