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Question: Will it turn a 50mm FD lens into a macro? I've read about this issue with other adapters.
Document: I was hoping to get some use out of my old FD lenses, so I tried this adapter. The problem with FD lenses on EOS cameras is that in order to use an adapter there has to be glass in it if it is going to focus to infinity (adapters without glass cannot focus to infinity and can only be used for macro shots). This has a slight magnification factor, which makes the 1.6 crop factor on my Canon 40D even tighter, which is not what I was looking for.
I bought a 50mm 1.8 canon FD lens at the pawn shop for 20 bucks, used this to hook it to my old rebel xt and wow. Really just gorgeous pictures. I also feel a little more like a photographer again using manual focus and framing my shots, adjusting shutter speed.. back to the roots with an amazing feel in image quality.
Purchased this mount to use an old 50mm FD f/1.8 on my 5D MK3 and it's been a joy to use.-Locks in without worry of my lens randomly falling off-Overall has solid build and image quality for the price-Lets you use your daddy's old school FD lens for funCan't really think of any negatives so have at it. 5/5 great purchase, very glad I did it
Like any teleconverter, a tradeoff is the loss of an f-stop -- which is not a big deal with the FD 100mm f/2.8 or the FD 200mm f/4 -- but with this adapter everything pretty much needs a tripod. Manual focus is no big deal when using a tripod mounted tele lens, but I did discover that I needed to adjust the auto exposure settings; the Rebel's meter didn't accurately read for the 1-f/stop loss.
This Opteka adapter is typical of the version with glass. There are also clones of the version without glass that serve well for FD macro lenses, when you probably don't need to focus to infinity. If you are using a full frame sensor camera with a long lens, it will probably vignette badly using the version with optics.
This adapter is a great solution to bring life to your old FD lenses. It's not the perfect answer but it works great. The inner element allows for focus to infinity and is removable to take macro shots. It does reduce the quality of the lens a bit and has a unique dreamy effect on pictures which can be nice for portraits. It works great when shooting video too. This is a cool and fun adapter to have as a part of your camera equipment!
It took a lot of fiddling to figure out that the internal glass was threaded too deeply, not allowing for infinity focus. After tweaking the alignment, it works reasonably well. Resolution tests prove the two elements of glass really kills the contrast and the resolution of the FD lenses. I've got 15 good to great FD pieces I really wanted to use again. After testing, the loss of sharpness was a disappointment. Stopping down helps, but it's nowhere near what an EOS lens creates.
1. As you can see if you read all the reviews, you definitely loose some of the quality when you hook it up to the EOS body using this adapter.2. And yes, the adapter can be pretty tricky to figure out how to put on the lens and body the first couple times you do it.
Adapter works adequately, but pictures won't be suitable for National Geographic. I had stalled for a long time on getting an FD -> EOS adapter and am glad I ordered the Opteka. I have a whole case of elderly FD lenses with great optics that hadn't been used since I "went digital." The adapter fits these lenses securely to my Rebel body and does provide focusing to infinity (which not all adapters do).
All in all, this adapter is not going to keep you from investing in some good EOS lenses but will let you get some mileage out of those trusty old FD lenses in special circumstances. I haven't pulled out the optics to use as a macro tube yet, but I like having that option with the Opteka.
Answer: No, it will turn your 50mm lens into a longer focal length, slower max aperture lens, and cost some image quality loss.  But at least you can have the feeling of using your old favorite lens on your new favorite camera.