Review on Opteka 6.5mm f/3.5 Professional Ultra Wide Angle Aspherical Fisheye Lens for Canon EF-Mount Cameras: EOS 90D, 80D, 77D, 70D, 60D, 50D, 7D, Rebel T8i, T7i, T7s, T6s, T6i, T6, T5i, T5, T4i, T3i, T3, T2i and SL3 by Wayne Gilbert

As you may know, a Korean company makes this lens as well as several other lenses from different brands, all of which are identical. (Other brands include Rokinon, Pro-Optic, and Vivitar.) Other brands claim different focal lengths from 6.5mm to 8mm, but it's actually the same lens and I believe testing shows that the actual focal length and distance be approximately 7.4. mm. Don't let that bother you: these multiple but identical products actually offer a notable advantage as you can shop around to find the best deal of the moment. That's what I did when I bought this lens as part of the one-day pre-Christmas sale at a whopping 45% off its already modest price. It's important to remember that you will only be focusing manually. But as you know, your depth of field is much greater than the shorter focal length, so finding the right focus won't be much of a problem. If your camera has a live view mode, use it and magnify the screen by 10x, manually focus on it, and then periodically return to recording. If you still have trouble focusing, the manufacturer recommends shooting at 5.6 or even 8.0, but I haven't had such problems. Please note that in addition to manual focusing, you will need to manually adjust the aperture settings on the lens itself. Here's the good news for Canon users: If you set the dial to P, you can set the desired ISO in the camera, set the aperture and focus on the lens and it works as usual. You can even trigger bursts in bracketed mode. I've found it helpful to reduce the exposure by 2/3 or even a point to include the flares on my particular example, but your lens may not require this and I'm sure you're looking for things like this when shooting anyway . with any lens. I've read that some people have had quality control issues with this lens, but mine is crystal clear. I'd say the only caveat is that it's not a true 180 degree fisheye. That means you won't get a true fisheye effect unless you carefully consider when to use it. Otherwise you'll just end up with a distorted wide angle that looks too distorted for a wide angle and too undistorted for a fisheye. So the day I arrived I went to Rockefeller Center. I figured if I could get an entire city block, including the ice rink, as well as the sides with lights, full height 30 Rock, and pull it as far as possible, even with a 180-degree lens, it wouldn't quite be it's still possible to get a nice "curve" of buildings on the left and right of the block, which would accentuate the fisheye feel. It turned out very well as you can see in the attached photo. Note, however, that the "bottom" of the photo has only a slight curvature compared to a real 180 degree fisheye. Be careful with him. Finally, it comes with a five-year warranty! Aside from Tamron's historic six-year warranty they offer on all their products, this is the longest warranty I've ever received. I'm not sure if other brand lenses but identical lenses offer the same warranty, so check before you buy. I am very happy with this purchase, especially with my significant discount. I can only recommend this lens due to the small flaws.