K&F ConceptM42 to NEX Lens Mount Adapter, for M42 Screw Mount Lens and Compatible with Sony Alpha E-Mount Cameras

Good

I had previously purchased several Canon EF lenses for my old and heavy EOS 5D mark ii. Having sold the 5D a decided to take a gamble and buy this converter. All my Canon lenses can now be attached to the Sony and the results are extremely good. Auto focus is fast, though it can struggle a little in low contrast situations. In such a situation it is easy to set to Manual focus. I've tested the following Canon lenses with great success.EF 100mm f/2.8 macroEF 50mm f/1.8 a cheap lens but really sharp resultsEF 28-105mm f/3.5-4.5EF 17-40mm f/4 L seriesEF 24-105mm f/4 L seriesCanon Extension Tube EF25 ii works too!The only other slight negative is that the lens image stabilizer doesn't seem to work on those lenses that have it.The other advantage is that there are lots of Canon lenses available in the second hand market. Why buy a new Sony lens when you can get good second hand Canon ones!The picture was taken using the Canon 100mm macro lens hand held.

Good quality item, fit perfectly

The quality of these adapters are unreal. This will be my second m42 adapter from K&F and both are exceptional quality, and accommodate the small aperture pin on these lenses.My only feedback would be ideally if the adapters were a bit lighter, especially as m42 lenses themself tend to be on the heavier side so the weight does become a little much but not enough for me to not use them by any means.

It's got a decent clicked ring to adjust the aperture on G type lenses without their own aperture rings. I also like using it on older lenses too, as I can pre-set aperture on the lens, open it up to focus with the adapter, then quickly close down for the shot.

K&F market themselves as decent quality but then don't have someone check if a lens even fits on the mount before it leaves the factory. I had the same non-fitting problem with one of their PK to NEX adapters and another of theirs leaked light. Fortunately with free returns its not such a big problem but a waste of money and reputation for K&F, i've ordered another in the hope the next one works, if it doesn't i'll never bother trying K&F again. Get your act together K&F - UPDATE: received the second one and it also doesn't allow a lens to be fitted.

The manufacturing quality of this mount is very, very good. I bought it for its built-in removable tripod mount, but I don't own any G lenses (yet) so can't comment on the aperture control. Having used it once in the field, I can say that the design of the tripod mount is flawed, because it allows minor movement between the adapter and its tripod foot. It's enough to be quite annoying and it introduces vibration when shooting. As a result of this movement, the screw can also loosen....not the extent it will fall of the tripod, but definitely to the extent that you need to continually keep tightening it up.I didn't send it back, because I'm really pleased with the quality of the adapter and my workaround solution is to fit a metal pin between the tripod foot and the adapter. The end in the tripod foot will be securely glued in, the other end will be removable.

A very well made and very solid adapter which does the job perfectly.