 With so many beautiful deep sky objects out there, how do you pick which one to shoot? Well, with a fisheye lens, you don't have to pick because you will literally shoot the whole night sky in a single photo. Hello, this is Nico Carver. I'm a deep sky astrophotographer and in this video, I will be testing and reviewing five fisheye lens in terms of their night sky performance. You can find all of my test results and reviews for these lenses at astrolenses.com. I received no compensation to make this video. I rented the Sigma 15 and the Canon 8 to 15 from lensrentals.com. I already owned the Sigma 8 millimeter circular fisheye. I bought the Opteka from Amazon with proceeds from my Patreon and the TT Artisan lens was kindly loaned to me from the company for the purpose of this unbiased review. I tested these lenses on my Canon EOS RA camera I'm shooting on right now, which is a full frame camera with an extended HA response helpful for picking up nebulae. It's an RF mount camera, so the only lens that fit directly was the TT Artisan. The other lenses I adapted with a Canon EF II RF adapter. Okay, that's the disclosure and sort of the setup. Let's jump into the physical characteristics of these lenses. Okay, starting with the Teca 6.5 millimeter f3. This is a lens that comes in at $165. It's available on Canon EF and Nikon F mounts. It's designed for APS-C or crop sensors, but it will work still on full frame. You just have to remove the removable lens shade and you get a circular fisheye look on full frame and a diagonal fisheye look on crop sensors. The lens shade is easy to remove. You just press a button and twist. It has click stops for the aperture from f3 to f22. It's all manual, including the focus ring. Unfortunately, the manual focus ring on the copy I have doesn't work. It doesn't actually focus at all to infinity or anything. It just sort of stays the same. So this was something that I'll mention more when we get to the star test, and it was the biggest downside to this lens is that it wouldn't really focus. The Opteca with lens caps on measures 105 millimeters tall, 90 millimeters across, and with lens caps off, it's 85 millimeters tall. With lens caps off, it's 524 grams or one pound three ounces. With lens caps on, it's 580 grams or one pound five ounces. Okay, moving on to the TT Artisan 11 millimeter f2.8. This retails for about $215. It's available for all the different mirrorless mounts, including Canon RF, Nikon Z, L mount, M mount, and Sony E mount. It's all metal construction. It's very heavy for its size. All manual has a metal lens cap, a small metal lens shade that's not removable. It's a clickless aperture control. Goes from f2.8 to f16. Both the aperture control and the focus ring are very tight, which I like. They're sort of a little bit difficult to move. It measures 100 millimeters with caps on, 70 millimeters across, 82 millimeters with caps off. It weighs 502 grams with all caps off, one pound two ounces about. With the caps on, it's 546 grams or one pound three ounces. Okay, the Sigma 15 f2.8 diagonal fisheye. That would be a diagonal fisheye on full frame. It goes for $609. It's available on Canon EF, Nikon F, Sigma SA, and Pentax K mounts. It has a non-removable lens shade, has a mix of plastic and metal parts. It's very lightweight and small. It has both autofocus and manual focus with a switch on the side. The aperture control is controlled by the camera, and so it just has the focus ring for manual focusing. It measures 89 millimeters with caps on, 75 millimeters across the front cap, 68 millimeters long with caps off, 338 grams with caps off, 12 or 12 ounces, and 384 grams or 14 ounces with the caps on. Okay, next up we have the Sigma 8 millimeter f3.5 circular fisheye. Retails new for $899. It has autofocus or manual focus just like the last Sigma. It has a manual focusing ring. It measures 95 millimeters with caps on, 77 millimeters across, 66 millimeters from front element to flange, and 394 grams without caps or 14 ounces, and then 482 grams or one pound one ounce with caps on. Okay, last lens is the Canon 8-15 f4L zoom lens. This is the only zoom lens I tested. It's just something I've always wanted to try out. It is a circular fisheye at 8 millimeters on full frame or a diagonal fisheye at 15 millimeters. It has a removable lens shade that you would want to remove at 8 millimeters on full frame. The zoom ring is down here at the bottom of the lens, and the manual focus ring is more towards the top. It is 108 millimeters tall with caps on, set 90 millimeters across, 82 millimeters from flange to the front lens, 530 grams without caps or 1.3 ounces, 584 grams or one pound five ounces with caps on. Okay, next we're actually going to look at some star tests. Here are the details for how I conducted these star tests. You can pause the video and read through this, but the basic gist of it is they were all done with the same conditions on New Moon from a Portal 3 site with the same equipment. Okay, first up we have the Opteca. Like I mentioned, I was not able to properly focus this lens, so all the test results came out out of focus. It would not focus to infinity. It reminds me of an older lens I had called the Lens Baby Circular Fisheye that had sort of the same problem. And so you can't really tell much about the star distortion like coma or chromatic aberration when the stars are out of focus. That said, you know, if you don't zoom in, it looks fine, I think, because these shots, of course, are so wide field. So it's really up to you whether this focusing issue is a huge problem. And of course, you may get a copy and the focus might be okay. It might be a copy to copy variation thing. Okay, the next least expensive lens. Remember, this one is only $250, this TT Artisan 11 millimeters F 2.8. And at F 2.8, it looked pretty good. But then at F 3.5, it really sharpened up and looked great in all corners, edges, and center. So I would probably use it at F 3.5 because it didn't improve much from F 3.5 up to F 5.6. Okay, next up we have the Sigma 15 millimeter. This had some substantial vignetting and other issues, including pretty heavy coma even at F 5.6. Here's the Sigma 8 millimeter circular fish eye. This lens looked pretty good even at F 3.5, but it got a little bit better at F 4. And then it didn't improve much after F 4 looked pretty good from there on out. The Canon 8 to 15 F 4 L. This is at eight millimeters, so all the way out and you get the circular look at F 4 through F 5.6. It looked pretty much the same all throughout there with some coma and chromatic aberration. Same thing with at 15 millimeters, F 4, F 4.5 and F 5.6 all looked about the same in terms of the star quality. Okay, let's look at some head to head comparisons now. So these are center crops of just the circular fish eyes. And here it's really apparent how the opteca is suffering from that not being able to focus. And also here with the corner crops, we really can't tell much about the opteca's performance, like I said earlier, because those stars are out of focus. Well, we can see that both the Canon 8 to 15 and the Sigma 8 have, you know, a little bit of chromatic aberration and coma, but really not too bad. Could be a lot worse. And the coma is a little bit more exaggerated on the Canon compared to the Sigma. Now let's look at some center crops of the diagonal fish eyes. They all look really good. They're all pretty sharp. But when we look at the left edge, here you can see that the TT Artisan, the mirrorless lens, but also the cheapest lens of the three, I think really wins in this, in the edge test, has the least amount of star distortion and coma. Coma is that what gives stars instead of a circular shape more of a triangular shape. And when it's really exaggerated, like on the Sigma here on the right, it's sort of a triangular shape with wings. It sort of looks like a little bird in flight. The Canon was, again, did pretty well, but not as good, I think, as the TT Artisan, even though it did do a good job with contrast and sharpness. It did exhibit some coma and chromatic aberration as well. Okay, here are my final thoughts on all of this. I was really happily surprised by the TT Artisan at only $215. It really shows the promise of these mirrorless lens designs. You can't adapt a mirrorless lens to a DSLR, which is the big downside. So I think something like 90% of all camera, you know, advanced camera users are still using DSLRs and not mirrorless cameras. So it does limit the potential, but I think mirrorless is the future. So I'm really excited by how well that lens did for especially considering the price. Next up is the Sigma 8mm circular fisheye. This is a lens I already owned. I bought it used for about $500, and I was pleased by its performance. It's not perfect, but it's quite good for a circular fisheye lens and probably slightly better than the Canon in terms of performance on stars. After that, we have Upteka. This one was only $150, so I didn't expect much, but the frustrating thing is just like my lens baby that I used to have, which was like a $300 lens, it didn't focus properly to infinity. I was reading this article online about how to maybe fix this in these cheaper fisheye lenses, how to open them up and just change the focal distance yourself to try to fix the manual focus issue. And so I'm going to try that with this Upteka since I wanted to see if I can make it work to finish these star tests with it. Then we have the Sigma 15mm diagonal fisheye. I was a little bit disappointed with this one. It was nice and bright, but the star distortion, the coma especially towards the edges of the frame were really pretty bad when you get the sort of birds wing flaring on the stars. That's pretty bad coma. And then finally, the Canon 8-15mm. This is a f4 lens, a little bit slower. If you didn't have tracking, I probably wouldn't recommend this one because it's a little bit of a slower lens, and it's also very expensive. But it is cool that it combines, if you have a full-frame camera, a circular fisheye and a diagonal fisheye lens into one lens. So that sort of gives you more creative potential with it. And the performance was quite good, of course, but it was also a very expensive lens at $1300. Okay, so all these reviews are going to be available in text form on astrolenses.com. So you can head over there to download pictures or read about these, and you can also follow the links on that site to purchase them through my affiliate links. I'm just going to leave you with a processed photo since we've been looking at single exposures. This is a stack of a couple hours of exposures, just to show you the potential of a fisheye lens. And this was done with my Sigma 8mm and my Canon RA and some different filters. And lastly, I just want to thank all of my patrons over on Patreon. I couldn't have done this video without you because you're helping finance this channel and lets me do cool things like renting and buying equipment, in this case lenses to try out and review, which I'm really enjoying. So here's to all of my patrons, you're about to see all of their names in the credits right now. Until next time, this is Nico Carver from NebulaFotos.com.