High-Power 500mm/1000mm f/8 Manual Telephoto Lens for Canon EOS 80D, 90D, Rebel T3, T3i, T5, T5i, T6i, T6s, T7, T7I, T8I, SL3, 60D, 70D, 5D, EOS5D IV, 6D II, 7D II SLR Cameras

Can’t believe that I almost returned this.
Not sure exactly what I was expecting…something between a useless toy and cheap-n-good. Mostly, something to get a better idea of how long a lens I’ll want when it comes time to buy a ‘real’ supertelephoto (I.E.: mortgage my life for a Canon “L”). I’ve been shooting with SLRs and now DSLRs for a half-century, but somehow I’ve never used anything longer than 200mm. I figured that 500mm would be another world–and it is.None of the review examples posted here gave me more than hint at what this lens would do, but I bought one anyway. Mine came branded Vivitar, but that doesn’t mean much of anything these days. It’s reasonably pretty and the T-mount-to-EF adapter mated nicely. It focuses past infinity. Focus is smooth if a bit stiff, and the f-stop detents are positive. The stop-down ring is much too stiff for my taste. I have no interest in the 2x teleconverter.It has a minimally effective AR coating, but I wasn’t expecting any. I thought that it might be a simple telescope at this price. But being physically shorter than it’s effective focal length, it is a real telephoto lens.After a much less than successful attempt at taking shots of the moon, I was convinced that I wouldn’t learn much from it. So I requested a return.The night that I was packing it up to ship back, I decided to give it another chance. Just an informal quickie. Printed up part of the standard ISO 12233 target and taped it to a toolbox 3 rooms with open doors away, for about 32 feet. An ancient Canon 1D MkII N was all that was handy, but it’s 8.2M pixels were fine for this test. (APS-H sensor, so 500mm x 1.3 = 650mm equivalent.)f/16 (two stops down) for more sharpness and depth of field, indoors at 1/5 second and ISO100. The three pix I’ve posted are the same photo, full frame resized to the maximum width of a review photo, plus two crops at 100% (400×420). Otherwise, straight from the camera. As printed, the finest pitch of the lines on the target measured 1/32″.So this lens is resolving a surprising 32 lines per inch at 32 feet, with decent contrast and only moderate chromatic aberration. If you’ve stared at many resolution targets, you’ll appreciate at how good that is for any lens in this price range. (Check out reviews of the Canon EF 500mm f/4L IS II USM to see how much sharpness $9k will buy,)Now, cheap lenses like this generally have a lot of unit-to-unit variation in quality, and I wasn’t getting that kind of resolution throughout the frame (at least partly because the paper target wasn’t lying completely flat). YMMV.Some other caveats: There aren’t many tripods that are solid enough (mine wasn’t) for a resolution test at this slow shutter speed and I was in too much of a hurry to figure out how to lock up the mirror. Plus, this lens is physically very light adding little mass for stability. So I put the camera on a heavy table, shimmed the lens up to a useful angle, and used the self-timer.The rule-of-thumb for hand held without image stabilization is a maximum exposure time that is the reciprocal of the focal length. So 1/500 second for a 500mm lens. But that’s the maximum for reasonable sharpness with a reasonably stead hand. To show off this lens’ sharpness, maybe an extra stop or two faster shutter when out and about. Sunny16 would suggest full daylight at f/16, 1/1000 second and ISO1000.At f/8 wide open, this is a mighty slow (dim) lens. I wasn’t able to get an accurate focus indoors without a 2.5x viewfinder attachment, and even that was a challenge with 20-20 and OK night vision.Conclusions? 500mm is probably somewhat more than I want on a full-frame body and about half what I’d like from a telescope. I really will need to rent an expensive lens before popping the cash to purchase, but this gives me a rough starting point.All said and done, I’m glad that I bought it, and will definitely keep it to fool around with.

Absolute terrible
I am new to photography… BUT….I attached the lens and started taking pictures. Everything was fine. until I moved the camera on my tripod a bit. The ring that attached from the connector on the lens to the camera came loose and I was not able to attach it tightly. Mind you, it requires an extreme small screw driver to fit into the openings to tighten 3 screws up. I had no tools that would fit with me at the state park, so a bust for this shoot.Came home and had to purchase something that would fit into the opening for the screw to reach the screw. Tightened the screws down and it seemed fixed and fine.Went to the park again today and moved the camera just a bit and the lens was loose again. 3 minutes of use. I had the ball head loose so I can move the camera and not put any pressure when moving the camera itself, and had to re-tighten the screws. Happened two more times during my 30 minutes of “fun”.Based on this, its a one star. Not sure if it was faulty or if it is always this bad, but I would not buy anything from that brand again. Since I can tighten the screws and it is fine but has to get re-tightened right away I would think it is simply a junk product.My suggestion, stay away and spend more money on a better lens….