Although it is not very obvious in the photos, there is a place for the aperture pin in the m42 lenses and the images are very clear thanks to the matte interior. It arrived in about 2 weeks.

also works with the older Tamron zoom.

Betrayed by the age and weight of the bodies and lenses, I bought a lighter and more modern Sony body. The Canon 28-105 USM was a faithful companion, so I can keep it thanks to this adaptor ring.

Needed an adapter for my Helios so it could be used with my Sony A7III. The adapter wasn't aligned out the factory, causing the markings to show up on the side rather than on the top where they should be, but it was easy enough to correct with an allen wrench. Wish they did include an allen wrench in the kit though, it's not an unusual problem to run in to, regardless of the adapter brand

Works great with my sigma lens

I bought this adapter to mount it on a Sony case (the 6700) and use the Tokina lens (ATX I) in manual mode.

Got this for my Helios 44-2 to work with my a7IV, and while the adapter fits perfectly on the camera and looks amazing, the lens itself doesn’t screw on tightly to the adapter. It’s only a slight rattle, and I imagine you’d have to really shake it around and pry at it for it to come off, but my paranoia forces me to constantly hold the lens itself to just guarantee it won’t slip off somehow. Besides this, it does exactly what it needs to do

This adapter is really great in combination with M42 lenses on Sony cameras!

K&F has created a very high quality lens, the materials are very good and resistant. I have tested it by mounting a Sigma 18-35 on a Canon EOS R series and it works wonderfully.

M42 to SONY E-mount camera connection.
I have the purely manual adapter of the fourth generation. It also seems just as sophisticated.
Due to their design, older analogue and digital SLR cameras have a greater distance from the sensor or film to the flange focal distance of the lens coupling than modern mirrorless compact or even full-format cameras.
This adapter is therefore theoretically just a tube with the corresponding camera and lens connection to restore this distance. There is no mechanical or electronic transmission of lens data and no lenses whatsoever. On one side there is an M42 thread for holding the lenses, on the other the SONY E-mount bayonet connection for the camera. The length (the flange focal distance) is obviously perfectly adjusted, so that I have been able to use all lenses in the full focus range without any loss of sharpness. Internal reflections can be ruled out with this generation, as the matt black interior is very finely grooved.
The adapter from K&F Concept is made entirely of metal and is accordingly heavy. This also gives it a very high-quality and solid feel. The thread is very clean, burr-free, fits perfectly and is well made. There is no play or jamming here.
The orange-copper colored ring corresponds perfectly visually with the E-mount connection on SONY.
The E-mount connection also fits perfectly. It clicks into place well and then sits firmly and completely free of play.
The groove structure on the outside of the adapter makes it very easy to grip and can be connected very easily even under adverse conditions. The coating and even the labeling are very high quality and will certainly last a long time.
The adapter is very well packaged and even comes in a high-quality resealable plastic box. I made an insert out of dark foam so that I could also transport the adapter in the box. Unfortunately, only bubble wrap is included here. A small, sturdy fabric bag can be used in the camera backpack as an alternative. Perhaps an idea for “5 stars plus”.
I admit, I initially wanted to buy a simple adapter to test. Now I am glad I chose this one. At the same time, I have now favored the corresponding “K&F Concept” accessories.
Impeccable workmanship.
Highly recommended.
The trend is towards a second adapter.
This means I can leave the adapter permanently on frequently used M42 lenses.