Open full-size image in new tab. Same image at f/4 with 200% zoomed-in crop boxes showing star performance. Corner stars a bit sharper than at f/3.5. Still some chromatic abberation and coma, but not obtrusive. Open full-size image in new tab. 4 min. single exposure at f/4.5, ISO 1600, Canon EOS Ra, Bortle 3 sky. Open full-size image in new tab. Same image at f/2.8 with 200% zoomed-in crop boxes showing star performance. Significant coma and loss of sharpness in corners. Some chromatic abberation. Open full-size image in new tab. 2 min. single exposure at f/3.5, ISO 1600, Canon EOS Ra, Bortle 3 sky.

What confused me while I was browsing through the various discussions and articles is that while the manufacturer is stating that the lens is 11mm, which should be pretty ultra wide on a full-frame lens, that in reality it is more like 15.6mm, which suggests that it actually was meant for a DX/APS-C "crop factor" lens. If I were buying a lens that was supposed to be 11mm on full frame I would want it to be just that rather than 15.6mm. Then again I suppose when one gets into the wide angle realm it really doesn't make that much difference; I really don't know, as wide angle/ultrawide angle/fisheye has not been something I've explored much through the years. Even at longer distances loCA are hardly a problem, if you zoom in to 100% you can see a bit of color fringing but nothing that will ruin a shot. Alternatives Architecture was my next idea to shoot with the TTArtisan 11mm f/2.8 fisheye. I wanted to get a really bloody tall building entirely in frame from an unusually close distance. There’s a tall spire right near my work, so I made a beeline for it. In the end, I found that even as close as maybe 15-20m from the bottom I could get it all in, so I decided to frame in some tree to help draw the eye. I think it worked too. What’s interesting about this shot to me is that at f/5.6 you can see the effect of the softening down one side of the frame is no longer an issue. Vignetting: Definitely there and visible, but quite frankly far better than I expected (it's something around 1.5 stops wide open, and it's under a stop by f/4). As sometimes happens with really wide lenses on digital cameras, there's a very small amount of color shift in the extreme corners, as well, probably due to crossover pollution from the Bayer filtration when light hits at a non-telecentric angle.The sun stars created by this lens stopped down past f/8 almost look too good at times; you get 14 very distinct rays that are well disciplined. However, at lower aperture values, the stars can be a smear mess, and if you're diffracting the light source too much on an edge, things also get messy. With 11 Elements in 7 Groups optical structure, 11mm f2.8 has improved the problem of image edge defects. Great scenery and quality presentation will be presented under the ultra-wide viewing angle. The TTArtisan 11mm 2.8 Fisheye was kindly provided free of charge by TTArtisan for reviewing purpose for a few weeks. What is a fisheye lens? I have shortly been using this lens on my Nikon DSLRs and via adapter on a 24mp Sony camera. It is very good optically while also being very big and more expensive. As shown in the example above it is also possible to defish fisheye pictures. Defishing means removing the typical fisheye distortion in post. Here the image is stretched so much, the resulting image quality leaves a lot to be desired. If you want straight lines in your pictures better get a rectilinear ultra wide angle lens in the first place. Handling / Build Quality AstrHori 12mm 2.8 Fisheye

Flare: Decent if the light source is somewhat centrally located. Put the light source towards a corner, though, and things get really complex, with everything from prisming to colored ghosting occurring.

Open full-size image in new tab. Same image at f/4.5 with 200% zoomed-in crop boxes showing star performance. Not much improvement to stars over f/4. Open full-size image in new tab. 4 min. single exposure at f/5.6, ISO 1600, Canon EOS Ra, Bortle 3 sky.