Instruction: Answer the given question by extracting information from the supporting document.

Input:
Question: Will this mount a Canon FD 50mm to my Canon T1i?
Document: The adapter works perfectly to mount my 50 year old M42 Super Takumar 50mm/1.4 and 135mm/3.5 on my Canon T2i. No grinding, no binding; just smooth rotation into the confirmation "click." People complain that the focus/aperture ring/distance meter is relocated 90 degrees from top dead center. Well, that's exactly where it should be. If it was at top center, the on-camera flash protrusion of the T2i will block my view of the numbers.
I use this to mount a 55mm f1.8 Super Takumar to an EOS T1i. Focus confirmation chip works brilliantly, which is especially nice because modern cameras don't come with the prism viewfinder anymore. This mount will suffice for your M42 to EOS needs.
This was a little piece of equipment that I didn't know existed until about two weeks ago. I ordered it and now I can use my Takumar lenses from 1966. They have been sitting for years in the camera case I used in Germany. Had given up on using these great lenses. I had a 28mm. 50mm, 105. 200mm, and a 500mm. This little device put new life into my old lenses. They all fit and work with my Canon 7D.
I own two Canon digital cameras (an old XT and a Canon 5D), and a decent collection of Pentax lenses, so I've been using Fotodiox adapters for some time. Years ago I purchased two of their basic adapters without the chips. Those adapters allowed me to use all of my lenses on the Rebel (small sensor) but I could not focus on infinity with the 5D (full-frame sensor) with my 3 widest lenses (24mm, 35mm, 50mm).
This adapter fit perfectly on my Pentax screw mount threaded 50 mm lens, and enabled me to use it on my Canon camera. For the price, it was worth the try to resurrect my old lens.
I was looking for something to mount my Helios 44-2 onto my Canon T4i, and I decided to pick this unit because of the Dandelion AF confirm. I just received it today (after over a month wait, which is another story, but I'll keep this review focused on the product itself), and I'm very happy to report that the AF confirm works great with my T4i.
New to this world of photography.Received a Canon Rebel AE-1 as a gift along with various lenses for which I thought I understood this Fotodiox Lens Mount Adapter would make the adjustment to my new Canon 60D. The Ad stated it would cover so many camera lenses - 60D being one and it does fit the 60D lens house but none of the lenses; they are all to small for the adapter.
The adapter allows me to use my old Takumar (Pentax) lens collection on a Rebel T2i. The adapter's fit and finish is excellent and the focus confirmation chip is nice. If you are wondering how 40 year-old glass compares to modern lens I can tell you it's definitely worth $29 bucks for the adapter! The Takumar 50mm F1.4 rocks in low light and all the old lens have a superior focus ring. Fotodiox has outstanding customer service should you need it.
This adapter works well with my M42 lenses. They line up the way they should when attached to the adapter and camera. (markings on lens point up) The only small issue I had was, when I first tried to attach the adapter to my camera the EOS mount caught at the point it should have clicked to lock. Cautious I turned the adapter back off and looked at the camera and lens, all looked good. So I tried again. It caught right before the click again.
The adapter adapts an M42 mount to an EOS mount pretty well, though not rock solidly, and on my lens at least, the infinity marking on the lens is PAST infinity, suggesting the adapter isn't quite thick enough. To be clear the lens will focus at infinity, but that point of focus is just before the actual infinity stop on the lens which is frustrating.Furthermore the documentation available for programming the dandelion chip, the focus confirmation section in particular, is abysmal at best.
Answer: NO NO NO! this is a M42 (thread Screw) to EF adapter. You need the FD to EF adapter.Good luck!