ecobin Loc: Paoli, PA

I agree. For astrophotography you need a wide angle fast lens and the Rokinon 14mm has gotten high marks for its price (around $500). The only negative that I've read about it some vignetting but it's sharp and fast at f/2.8.

Beercat Loc: Central Coast of California

The secret of using the 10 - 18mm EF-s is to stay as close as possible to 14mm. At 14mm there is no distortion. I always find something in the frame to make sure my vertical lines are correct. When I keep these two things in check this lens rocks on a cropped Canon.

mjmoore17 Loc: Philadelphia, PA area

I agree. I have the Canon 16-35 2.8 L and love it for landscapes but for night photography of the stars, I use the Rokinon 14mm. It is highly recommended for astrophotographers ( but remember it is manual). For all other uses, it is difficult to do better than the 16-35 Canon.

M

amfoto1 Loc: San Jose, Calif. USA

The widest non-fisheye zoom available for your full frame camera is Canon EF 11-24/4L... which is a truly amazing and well corrected piece of glass that costs about $3000.

Sigma makes a 12-24mm that's full frame capable, a lot less expensive but still not cheap ($950) and has some pretty heavy distortions (largely correctable in post-processing).

Canon EF 14/2.8L II is another superwide with premium image quality... and pricing ($2100).

If you don't mind manual focus - which isn't very difficult with an ultrawide - there also is the Samyang/Rokinon 14/2.8. It's also a manual aperture lens, so will a bit slower to shoot with, though that might not be any problem for night photography. It's not nearly as well corrected or well built as the Canon 14mm, but a whole heck of a lot cheaper: about $300 to $350 usually. This lens also sells under Bower, ProOptic, Vivitar (who call it a 13mm) and other brand names. It's the same lens, regardless. There seems some quality variation copy-to-copy, most especially check any for de-centered element problems that will show up as softness on one side or the other of the image. But "good copies" do seem quite good for the money, according to user reports.

If their tendency to strongly bend straight lines aren't a problem, there also are a number of possible full frame capable fisheye lenses, including the Canon EF 8-15mm f4L zoom (about $1200) and now discontinued EF 15/2.8 (used only). Sigma still offers a 15/2.8, too. And there is a Samyang/Rokinon 12mm F.E. (manual focus and aperture). Actually, if you don't mind manual focus and aperture, there are many vintage fisheye that might be bought used and easily adapted for use on Canon EOS.

All the above use protruding, convex front elements that preclude using standard filters on them. In some cases there are accessory filter holders available (not cheap) or that can be homemade, to accommodate 100mm square and rectangular filters. Some lenses have a few, common types of filters built-in, that can be "dialed" into place.... Some others offer a rear element mount for gel filters.

Canon 16-35/4L IS USM is relatively new and given very high marks for image quality, but only very slightly wider than the lens you already have. The Canon 16-35/2.8L (both original and current II) offers larger aperture, but at some cost to image quality at its biggest apertures, particularly in the corners... as well as larger size and more weight. Still, for night photography, astrophotography, f2.8 is often wanted. The f4 lens uses standard 77mm filters, while the f2.8 II requires more expensive 82mm.

It's not a full frame lens, but the Tokina AT-X Pro 11-16mm f2.8 DX actually can be used on FF at its 16mm setting, is quite sharp and popular for astrophotography. It does have a bit of a tendency to flare in other situations, though. This lens was recently supseded by a new 11-20mm f2.8... which I am not yet very familiar with. Not a lot of difference between 16mm and your current zoom, though.

I used a 17-35/2.8L myself, back when I was shooting film. I found it quite good when stopped down, but tended to have some chromatic aberrations and a bit softer at or near wide open apertures (where astrophotographers are likely to want to shoot). It was fine for landscape shots and other purposes, though I ended up selling and replacing it with a wider crop-only lens eventually (Tokina AT-X Pro 12-24/4, which looks and feels very similar, can be partially used on FF to about 17 or 18mm, but isn't quite as sharp as the Toki 11-16mm and also has a bit of CA in the corners at larger apertures).

The Canon EF-S lenses mentioned in several response cannot even be mounted on a full frame Canon camera. They use a variation of the EF bayonet mount that's designed specifically to prevent that. Even if you could mount them (the 10-22mm's mount is easily modified), they have to be used very carefully. Besides image vignetting that is bound to occur at their wider settings, they also are retro-focus designs that protrude into the camera more or less depending upon the zoom and focus settings, which can physically interfere with and might damage the FF camera's larger mirror mechanism.

Have fun shopping!

Blurryeyed Loc: NC Mountains.

I originally purchased the Canon 17-40 for my 6D and was totally unimpressed with its IQ, I then purchased another expensive lens and although it was better than the Canon it is not a great lens for night skies as it is not fast enough, I finally broke down and purchased a Tokina 16-28 f/2.8 and have been totally impressed by its image quality, it is excellent in every respect.

Unless you are willing to get the Canon 11-24 or the Sigma 12-24 DG II you will not get any zoom shorter than 15mm that is compatible with your 5D.

I highly recommend the Tokina, I bought mine used on ebay for about $400 and it arrived in like new condition... the image quality is similar to that of the Canon 16-35 f/4 and better than the 16-35 f/2.8L II..

Grandpa Pete Loc: Western Finger Lakes (NY)

I've had good luck with Tokina 12-24 now also available in 12-28.

bwana Loc: Bergen, Alberta, Canada

I have and like the Samyang 14mm f/2.8 (manual, full frame); my goto lens for Aurora's, wide-angle Milky Way shots and meteor showers.

One of many albums:
Full Sky Aurora Borealis - April 10, 2015 (Samyang 14mm, f/4, Sony A7S, tripod)
(https://goo.gl/photos/WJ5Y3kJsJGqEoWAi7)

Enjoy!

bwa

wattsimages

I have a little experience with a couple open wide lenses. Using a 5DIII we found the Sigma 12 - 24 good for interior architectural shots. There is distortion, however if you are careful it can be dealt with. Currently we're selling this lens because our Canon shooter upgraded to the 5DSr. The main reason for upgrading is Clients wanted very large prints. The combination of printing large, and the additional resolution of the 5DSr showed some softness, and lack of contrast that we hadn't really noticed before. now he is using the Canon 11 - 24 and that lens is very good.

If your main goal is night photography? I would recommend a 14mm 2.8, or maybe the new Sigma 20mm 1.4. the extra light that these lenses let in will help you keep your exposures short enough to stop start movement.

James R. Kyle Loc: Saint Louis, Missouri (A Suburb of Ferguson)

===============

Thank you for this advice.

Saves me a step in post-process - with the lens correction thing in CS-5.

:-)

PixelStan77 Loc: Vermont/Chicago

Save money and use what you have.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

The Samyang/Bower/Rokinon 14mm - F2.8. It's manual focus, but you won't have an issue given your intended use. there are two compelling reasons to get one - the image quality is great (it does have complex distortion but it is easily corrected in LR, PS or using PT/Lens or DXO) and the price - $289

http://www.bhphotovideo.com/c/product/859167-REG/Samyang_SY14M_C_14mm_f_2_8_Super_Wide.html

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Great lens. It's not 10-14mm.

wotsmith Loc: Nashville TN

I have both the 16 - 35 f2.8 Canon L lens and the 11 - 24 f4 Canon L rectilinear lens; I highly recommend either. I have some great night shots from the 16 - 35 f2.8 that were 20 sec and wonderful images of the night sky and the milky way.

wotsmith Loc: Nashville TN

I have both the 16 - 35 f2.8 Canon L lens and the 11 - 24 f4 Canon L rectilinear lens; I highly recommend either. I have some great night shots from the 16 - 35 f2.8 that were 20 sec and wonderful images of the night sky and the milky way. The 11-24 is fairly new and no night shot experience with it. I am shooting with Canon 5Dmk3 or 1DX both FF; I also have gotten some great shots of the sky with the Canon 85mm f1.2

imagemeister Loc: mid east Florida

Yes, I know - but it is much faster than any 10-14 and will do what he wants ....