had been looking for an adapter for my old Praktikar lens for a long time, but either there was nothing on the market or the products had lousy reviews that made me worried about the lens. The shipping came from overseas and was estimated with significantly longer waiting time than it was in the end. The adapter was there within a week. It was packaged well and appears to be of good quality. I immediately put the adapter on my lens (a 50mm 1.8 Carl Zeiss Jena). When I put it on, I had to apply some pressure to push the leaf spring down. The lens then snapped into place reliably and could be placed on the body without any problems. It was also easy to remove, so that the lens can now be carried in the backpack as standard and I can use the slightly different bokeh for gimmicks :) UPDATE: From a purely mechanical point of view, a corresponding lens can be attached to the Canon 5D Mark 3 with the adapter, but the Spiegel offends, so that there is an error message in the body. Whether this applies to full format in general or whether it depends on the lens, I cannot say due to the lack of test objects. In any case, the adapter for my Carl Zeiss Jena 50mm 1.8 does not work on the 5DMIII... Too bad.

ordered the adapter to use a vintage Tamron mirror lens (5.6/350 mm) on my two Canon bodies EOS 5D mkIV and EOS 1Ds. Since both cameras are not listed in the compatibility list of the item description and one often hears (with other adapters) that the camera mirror can no longer move freely and therefore error messages or damage to the camera occur, I was curious whether that would also be the case my two cameras would work. It works out. The adapter is also seated without play, attaching and detaching is easy. It was clear to me beforehand that the focus and the time setting had to be made manually. Unfortunately, the invoice must first be requested from the seller, but it came within 24 hours as a PDF by email. However, it is an import invoice without deductible VAT and in the "worst case" the tax office will still have import sales tax when it is submitted. At the price of the adapter, however, that can probably be gotten over.

The adapter fits, so I can continue to use/reuse "old" lenses. Only getting the adapter off the lens is quite fiddly.

have an EOS 350D available on which I want to test the use of my Nikkor AI lenses. I received the adapter ring today and tried it out right away. The processing of the adapter ring is very good, the connection to the camera works perfectly. Since there is no description, you first have to think about the correct attachment to the lens (description below). When this is done, the ring can be put on and fastened (relatively stiff). Detaching the ring from the lens is also relatively difficult, not at all for me at first until I found the right procedure and "practiced". A point is deducted for the missing description. All in all, a recommendable adapter. It remains to be seen whether the problems identified so far with the EOS can be solved with connected AI lenses. Description of connection/dismantling of the adapter lens: Set the maximum f-number on the lens. Position the adapter with its red dot opposite the black dot on the lens. Fasten anti-clockwise (movable pin of the adapter goes into the U-groove of the bayonet ring). This also ensures that the lens is correctly aligned when the adapter is connected to the camera (aperture and distance settings visible from above). To disassemble the adapter, hold the aperture ring with one hand and use the index finger of the other hand to press down on the small release lever while turning the other fingers clockwise to release the adapter from the lens.

The M42 - EOS EF adapter does exactly what it should. It fits perfectly on my Jupiter-9 85/2 lens. Everything is tight and nothing wobbles. The packaging and processing of the adapter is excellent. For info. The standard M42 Russian lenses, which were copied from the 50s to the 90s, often have a back focus of 45.5mm. An EOS camera has a back focus of 44mm. The adapter has a thickness of 1.4mm (measured). That means I get a total distance of 45.4mm. Theoretically, 0.1mm is still missing, but with the focus in infinity it still works. Most old optics are used for portrait photography anyway.

Because the structure is tight, the body and the lens are firmly fixed.
The orientation of the lens also turned up the distance indicator.
If you dare to raise the point of concern or rather difficulty, the color is silver, so if the
body and lens are black, the silver of the mount adapter will stand out.
It might be more compatible with zebra lenses.

I bought the M42 lens to use with Canon EOS.
I could use it without any problems!

Tremendous product. I was using my usual, cheaper, adapter for a newly purchased Takumar 50mm/1.4 and it tightened the lens up to the point where it was impossible to reach infinity and still move the f-stop. This adapter resolved the issue immediately, it felt like a much better fit and a much more professional product. The lens now moves freely and works perfectly - think I'll probably upgrade all my M42 adapted lens to this stirling effort.

Thank you very much.

So I've bought a vivitar, a helios and a pentax and each of them had fit and felt secure in this adapter.
The build is simple, strong and secure! Very happy customer.