Sigma 12-24mm for Astrophotography

[andrew]

Well I'm finally about to bite the bullet and get a 5D mark ii for myself, which I have wanted for years (like many).

I primarily shoot wide field landscapes including huge star fields and I currently plan to purchase with a Sigma 12-24mm, I'm just wondering if anyone has any experience with this in regards to astrophotography.

Any help is much appreciated :)

[skysurfer]

This lens should have an exceptional quality. Virtually no (rectilinear) distortion at 12mm (unlinke other 16mm wideangles), but there is vignetting.
I have a Sigma 10-20 on a Canon 7d which makes excellent wide field sky pics.
Only one catch: as these wide angles are rectilinear, distortion can be a problem with astrophotos even when rectilinear distortion is low.
I made for example this image with the 10-20 @ 10 (equivalent with 16mm on FF):

http://sky.velp.info/skypics2/IMG_6204.JPG

At 12mm distortion can be even worse than 16mm.
Maybe a fisheye suits better if this distortion is a problem.

On the edges the constellations look larger.

Test reports on the 12-24:

http://www.the-digital-picture.com/Reviews/Sigma-12-24mm-f-4.5-5.6-EX-DG-HSM-Lens-Review.aspx

http://www.photozone.de/canon_eos_ff/676-sigma1224f4556iiff

[acropolite]

I tried 2 copies of the Sigma 12-24 on my 5DII, poor edge sharpness, the first copy could only be described as abysmal, the second better, but still not acceptable. Flare performance was poor.

I finally opted for a Canon 16-35. On my copy at least, edge sharpness is still not good enough for the asking price; edge softness is not an uncommon complaint with that lens. I guess the moral of the story is that none of the WA zooms available for FF Canons are up to the demands of the sensor and quality is quite variable even with Canon's L series glass.

The 15mm Canon fisheye suffers from severe abberations at the edges, bright stars or planets end up as noticeably larger triangles. I love mine but it's no Astro lens.

[gregbradley]

Probably a lot more expensive but the ultimate widefield lens is the legendary Nikon 14-24mm F2.8. You can get a Novoflex adapter to fit this lens on a Canon body.

I have that setup and it works well.

Greg.

[astroboy]

I would have to agree with Phil , the Sigma I tried was rubbish off axis just for regular photography let alone for astro.
I now have the Nikkor 14-24 with adapter for the 5D great lens ( even wide open ) as I keep telling people but then they go out and buy the Canon 16-35 and then complain about its performance .
If you stop the 16-35 down it should be ok , but be careful of the Sigma.
You get what you pay for I guess.

[acropolite]

The Nikon 14-24 was my first choice, I baulked at the price however. The Nikon 14-24, is widely used by (Canon) DSLR film makers, there's a wide range of adapters available (some of which don't support metering etc) so you need to do some research before buying. Lois (IIS member luigi) uses the Nikon 14-24 on his 5DII and has posted some of his work. Do a search for some of his work to get an idea of how the 14-24 performs.

To put the Canon 16-35 in perspective, mine at least is razor sharp at the centre but very soft over the last 10% at the edges, it doesn't improve much stopped down and never comes anywhere near the sharpness of my 24-105 wide open.

Many photographers aren't worried about the edge softness because the 16-35 is often used for portraiture, in that application edge softness isn't really an issue, speed is, so F2.8 aperture is attractive even at the expense of edge sharpness. Some users report good performance from the Canon 17-40 L but again you have to get a good copy.

[andrew]

First of all thanks for the replies and guidance, really appreciate it. I'm still quite undecided though, the Nikon 14-24 is unfortunately too pricey for me to even think about..

It seems as though the general consensus on the Sigma is the optical quality is not up there, but I don't really know what else to go with... maybe the 17-40 f/4L a better option? Certainly still within my budget.. but it does bother me that it isn't quite as wide as the Sigma.

It's a shame there seems to be a shortage of options for wide field FF lenses.. :shrug:

[astroboy]

What about the Samyang 14mm F2.8 they get good reviews , Luigi has one and the Nikkor 14-24 he maybe able to give some pointers