Rudolf Leadpaws
Purchased this item believing it would reduce effective focal length by .43x, turning a 50mm lens into something like 21.5mm (nominal focal lengths are often not precise and change with focus breathing so there really isnt enough precision there to justify the use of decimals, but I digress) Upon using it I noticed it has considerably less effect than a .42x fisheye adapter acquired some time in the early 2000s, so I did a few tests. Comparing the field of view of a 50mm lens equipped with this adapter to a 28mm lens, I found the 28mm lens was actually wider. That should not be so! I then compared 50mm + adapter setup to a 35mm lens, and the field of view just about perfectly matched. To convert 50mm to 35mm you need a .7x adapter, which is what this falsely advertised product is. Multiplying by .7 can also be approximated by dividing by 1.43, which is where I think they mightve screwed up and gotten the 0.43 from-- they could have accidentally subtracted 1 from 1.43 instead of dividing 1 by 1.43 to convert the divisor to a multiplication factor. Or they could be lying outright and guessing nobody would catch that big an error, but this is the difference between being *barely* wide angle at 35mm and ultrawide at around 22mm and has a *huge* impact on the appearance of photos and video. All this said, the quality of this product seems fairly decent. It threads in smoothly, is built of solid metal, and has very little chromatic aberration. I even tested it on a telephoto zoom lens for fun, just to see if I could detect any significant chromatic problems that would be hard to spot on a normal length lens, but none could be seen before the image became too soft to be usable-- and in spite of claims people make about products like this being "zoom through" for camcorder use, its not advisable to use anything like this for anything on either side of a "normal" focal length. Too wide and youll see the edges creep into the frame (about 35mm full frame equivalent is where you can see black spots in the corners, and it gets worse from there) and any longer than 50mm equivalent you start to defeat the purpose of a wide angle adapter. (So any of the reviews mentioning black corners are already using a wider angle than can be achieved by putting this on a normal focal length lens-- not its intended use, and not a flaw with the product.) However, in spite of being actually fairly usable, I cannot recommend purchasing any product that misrepresents itself. Anything of this nature that advertises itself as "HD," "digital," or "professional," tries to mimic the appearance of Canon or Nikon optics by including a red or gold colored ring, or mentions autofocus is throwing up some HUGE red flags that its intentionally deceptive. I had hoped itd still work for my purposes, but it definitely will not.