This requires a very sturdy tripod as the weight of the lens makes the camera bounce when you hit the shutter. I had to buy a remote to eliminate blur.Pictures come out pretty good but not great.I purchased this lens as a potential low cost, lightweight option for eclipse photography. It arrived in perfect condition, along with a T-adapter, lens cleaning brush, microfiber cloth and storage bag.I decided first thing to test it at night imaging the full Moon. I used two different cameras: a Canon 60D with APS-C format sensor and a Canon EOS R with full frame sensor. As a baseline for the test I photographed the Moon with each of these cameras shooting through a 70 mm refractor telescope. I then compared these results with each camera shooting through the Jintu 500 mm telephoto mirror lens. I shot over a range of shutter speeds and ISO settings; representative results are shown in the photos included with this review. In all cases the camera/lens were securely mounted on a tripod, with focus carefully performed using 'live view' on a bright star. A self-timer was used to avoid camera shake during shutter release.Although it shouldn't be expected that the 500 mm mirror lens would achieve equivalent sharpness to a 70 mm refracting telescope, there clearly was a significant optical issue with the lens. Specifically, when paired with the full frame EOS R, there appears to be a double image - highlighted with a white arrow in the zoomed in photo. No amount of focus adjustment will make it go away. I am not an optical engineer, so I won't speculate on the cause, but this is clearly unacceptable for my application. I should note that the double image also appeared during daytime tests.Interestingly, the phenomenon did not appear when the lens was paired with the EOS 60D, and its APS-C sensor. Nevertheless, even with the smaller sensor, I didn't consider the focus performance adequate for my purposes.The lens appears to be mechanically well made, and its Catadioptric design is eye catching and cool, but performance is just not up to par. Sadly, it must go back.My expectations were not very high, but I just wanted to try it out. To my surprise, it works great!! Worth every dollar!for being a 500mm lens it's surprisingly small, the image quality is pretty good as well considering the price, the build quality is only really okay in my opinion with one big issue in my opinion. The issue is the lens isn't natively EF mount it comes with an adapter that you have to screw on however the thread mount is made of plastic and was shredding away a lot while I was screwing it on and honestly I could see this plastic thread being a big point of failure on the lens I honestly don't know why they didn't make it out aluminum or something that wouldn't strip as easily but honestly it feels like a big oversight in my opinion. However if you don't take the adapter off I don't see it being a huge issue other than the fact that it might loosen occasionally other than that, it's a nice lens for the price.Where to begin? There's a lot to be said for the convenience of a 500mm lens that will fit in a camera bag and doesn't require a separate tripod mounting collar. This lens is light enough to hand hold (but you quite literally cannot expect to hand hold a 500mm lens).So today the skies are overcast, and there isn't a whole lot of light to work with. I suppose you could say these are "torture test" conditions for a long focal length telephoto lens.This one has a fixed F6.3 aperture, which isn't too terrible on paper, but you will need to make some compromises in order to get the best from it, and even at its best, it's still not as sharp as other (albeit much more expensive) lenses in this focal range.So what's to like about it? It's the most convenient form factor and one of the lowest priced 500mm lenses available. It's a "T mount" lens, so you can use it with many different cameras just by swapping adapters. It's very lightweight and compact for a lens with this reach. And for many hobbyist photographers, it's going to be the only accessible option for a really long telephoto lens. It came with a lens cap, microfiber cloth and a lens cleaning brush, along with a drawstring storage pouch, and a T mount adapter. I would have liked to see a rear lens cap to use with the T mount adapter so you can leave it installed, but it's not a big deal, and they did include a rear cap for the T threads.On the other hand, there are the compromises. The aperture isn't terrible, but it's definitely dark enough to require ISO speeds that get up into "noisy" territory. It has an extremely shallow depth of field, so you will need to be very careful about focusing. You will do well to use live view and zoom all the way in to 10X while focusing.Almost any tripod, no matter how sturdy, will exhibit some shakes and vibrations while attempting to focus this lens. It's manual focus, so you have to touch it to focus it. This isn't easy because the very narrow depth of field makes it easy to miss your focus (see the chicken and tree spirit photos I attached, these were processed for color, contrast, sharpness and exposure).Contrast and saturation were very low. If you look at the two attached pictures of the rabbit brush, you can see the difference between the image straight out of the camera (with size reduction only) and the image with a lot of sharpening, noise reduction, added exposure level, contrast, saturation, etc. It takes a good bit of post processing to bring the images into a "shareable" condition.The resulting images aren't really great for enlargements. It's not going to be a great wildlife lens either, unless you get an animal to hold very still. Forget taking pics of birds in flight with this lens.Additionally, some people don't like the donut-shaped specular highlights (bokeh) produced by mirror lenses. But, this is a characteristic shared by all mirror lenses, not just this one.When using my Canon 80D, I found that the TV (time value) setting worked better with live view than the M (manual) setting, because it shows a better representation on the screen of the resulting exposure for the settings you choose.You will want to use a shutter speed of at least 1/500 on a full frame sensor or 1/800 for a crop sensor camera. This is going to force you to use higher ISO settings, which then forces you to deal with noise.In all fairness, many of these issues are common to all 500mm lenses no matter how expensive. You can't cheat physics. But there are other lenses that do a better job of sharpness, depth of field, contrast and color.If you are going to buy a 500mm lens and you don't already have a sturdy, heavy duty tripod, a remote shutter release, and good image processing software you will need to get these as well. Figure that into your cost.I don't really want to discourage people from getting this lens if they are aware of the compromises and are willing to work around them. But just know that it's not going to win any photo contests, and you will probably get better sharpness, saturation and contrast from a telephoto kit zoom with autofocus and image stabilization if you are able to get physically closer to your subject. This is a lens for situations where it is impossible to get closer.Build quality is satisfactory for a lens in this price class. Upon close examination, the rear threads and housing appear to be metal, not plastic. Focusing is smooth enough, but again, it's easy to focus right past the sharpest spot.I do believe with a lot of care and patience, I could squeeze a little better performance out of it than the attached test pictures. Naturally, the farther your subject is from the camera, the deeper the depth of field will be.I wish there was a 3.5 star option. I feel like it's better than 3 stars, but with all the compromises, 4 would be perhaps a bit too generous. I chose to go with 4 because this lens fills a necessary price and accessibility niche for amateur photographers who are just taking pictures for their own satisfaction.I’m not a pro photographer, but this lens gives me an image that is different than my stock lenses. It’s quite a bit larger in diameter than my others, which I gather is the point. Waiting for my son the pro to tell me how best to use it.