[f/8] This lens isn't a substitute for a giant wildlife lens--it is a completely different thing, a way to get tight shots of wildlife without carrying a lot of kit that requires patience, a bit of skill, and good weather. Results are softer than a non-reflex 400mm, particularly noticeable for closer shots. It is manual focus so you need a camera with a decent viewfinder, either a good mirrorless or a DSLR. It is fixed at F8, and I keep the shutter speed at 1/500 to avoid motion blur, which means ISO is pretty high, 3200 even in sunlight (I am using an SL3 on shutter-speed priority mode). Within those limitations, it is a lot of fun to use, and good results if you're not looking for a publishable nature shot. It could be used for sports or similar also, but I haven't tried that.

[1.59 lb] This lens packs a wallop for the dwarf size it is, I find it has a lot of character giving my images a nice tonality. The focus ring is very easy to use and the lens hood helps a lot for cleaner picture quality. The body of the lens is a metal construction with a rubber focus ring it feels very nice and has a strict quality feel. I highly recommend this to those who want a longer focal range and don’t want to compromise between backpack space and camera weight!

[f/8] This lens is simply amazing. I bought it almost last notice before the eclipse and used it on my Sony A7II camera for the eclipse.

Call it user error but if a lens can produce this type of shot from me not using a tripod and fumbling around with ISO and shutter speed settings, just imagine the pictures when you do incorporate those tools.

[Manual Focus] First, this is a full-frame lens. On Micro 4/3, 400mm f/8 turns into 800mm f/16, which needs a very bright conditions to shoot at shutter speeds higher than 1/160 (at 800mm handheld this speed is already crazy, but compensated very well by IBIS - I get shots with no motion blur).

Second, speed booster is a must (from full-frame EF to M4/3). Just forget about sharp photos at 400mm (800mm FF equiv) on M4/3. On the magnification that high you'll see a lot of distortion effects like atmospheric dribble, haze, loss of contrast even from the small amount of directed light. Your photos really start depending on the air temperature. 800mm focal length is near useless during the hot summer regardless of the lens. With a speed booster (x0.71) it turns into the light compact 300mm 5.6 with acceptable sharpness, which has a nice build and joy to handle.


Thirdly, at 800mm, which you get on M4/3, the focus shifts substantially even from the slight touch (literally, just from touching the focus ring). The significant amount of focus ring rotation interval is devoted to close distances from 3 to 15 meters. You get practically millimeters and fractions of millimeters left to focus on distant objects.

Overall, this is an excellent lens with a nice build, impressive resolution and joyful handling. Just not on Micro 4/3.
At least, not without a speed booster.

[Sony E] When your professional Baseball team's ballpark limits you to a less than 6 lens length and you want to check the brand of your players shoe laces, this lens is the solution. Easy to handhold when leaning on guard rail.

[Manual Focus] I got this lens to pair with my Nikon Z50. Knowing it is a FX lens on a DX body, the 1.5x crop factor on this 400 mm lens gives it incredible reach, although I am hesitant to call it 'effectively 600 mm'. I have taken rather sharp shots with a tripod of subjects ~2 miles away, and can resolve the basic skyline ~5 miles away at night with long exposures. Indeed there is 0 chromatic aberration, and I've counted ~4 rings in the point spread function from a bright light source at effective infinite distance, which is very impressive given it's a $250 lens. The bokeh is really something special, and I sometimes find myself taking shots intentionally out of focus for the artistic appeal which as far as I know, is not easy to recreate digitally. The lens is a bit heavier than I expected, but I'm OK with it given the metal construction - it feels solidly built. My one gripe is that the macro quality is OK, but not amazing. I thought I could get away with not purchasing extension tubes and just using this for macro photography, but something which I haven't precisely identified yet gives the photos a surprising amount of softness. Possibly, this could be from the fact that its a manual focus lens and I'm just not nailing it every time, which, although it is my problem, will likely be your problem too! I enjoy the 270 degree throw for focusing, but because it is so sensitive, it still takes some getting used to.

[Full-Frame] Years ago I had a Sigma 600mm f8 in the camo green color with a canon T70 and found it a bit large and wieldy. This version is super light and about half the size if not smaller and takes a bit of practice to get the best out of it. Tripod important and I also use a minimum of a 2 second timer on the shutter to ensure no movement when pressing for the picture. Using a Canon EOS T6s APS-C so actually getting about 800mm in 35mm format conversion. Also found that the sharpness is better without a UV or similar filter on the front. Possibly a more expensive filter would not degrade the result however I keep the filter on for protection and take it off for shooting. It helps to have the back display screen used to help focus the image and when you enlarge the image you can much easier set the proper focus as the long telephoto is inherintly sensitive. It's taken a bit of time to get used to using a mirror lens again and I'm looking forward to many more good shots. Some recent outings catching the moon at near full have created some excellent results.
.
Cheers all!!

[Manual Focus] I purchased this Tokina SZX 400mm F/8 Reflex MF lens for fun and it's great! It takes some time getting used to because it's a manual focus, but focus peaking can help a lot. A tripod is obligatory. Images are soft and not sharp, but with the a bit of editing you can make them look sharp. This lens is great if you have a lot of time on your hand and gives a different perspective and opens a new door to get creative. I am using this on my Canon R7 which gives me a 640mm focal length.

[Full-Frame] The Tokina SZ 500mm f/8 is a reflex lens. Reflex lenses use mirrors to reflect light back and forth in the lens barrel rather than using multiple elements as traditional lenses do. This makes the lens much lighter and much shorter. This lens is a fixed aperture at f/8 and is a prime lens fixed at 500mm. The lens is a manual focus lens and needs lots of light to use handheld. The bokeh has circular patterns to it due to the nature of the reflex lens. The lens is sharp edge to edge with no degradation from center to edge. However, the sharpness is notably less than a traditional lens with multiple elements. The lens is well built and feels precise when focusing. It is solid and comes with a metal screw in lens hood instead of teh industry standard plastic hood. For the price, this is a great lens. It is not going to get your wildlife photo on the cover of National Geographic, but if you understand the limitations of the lens and work with its strong points, you will get great results.

[1.59 lb] I'm an amateur photographer, growing into my Nikon Z5 and the mirrorless world. I wanted a telephoto with decent enough reach and performance for me to capture the birds and wildlife in my backyard and on nature hikes. This fits the bill! It doesn't weigh a lot as I walk in the field. The depth of field performance actually helps me focus on the wildlife with some nice bokeh. I don't need the highest-quality sharpness or for everything to be automatic at this stage of my hobby life, and my budget is limited. In short, I've taken some good photos with this lens for my birding record and artistic use with this affordable option. I'm extremely pleased.