Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Is this lens for APS-C camera only? Or does it work for full frame cameras?
Document: I took a lot of pictures to test the quality of the lens and decided at least the one I got was fairly sharp. Be warned however, this is an APS-C size format and therefore not recommended for the Canon EF full frame models such as EOS-6D, EOS-7D, and Mark III. For the price, under $500, I really can't complain about the lens. Accuracy down to the pixel level seems strong.
I first ordered this lens for my 5D Mark II. I know that it is my fault that i didn't read it would't work well with full frame cameras. So i contacted Amazon to try to get the order cancelled, but they said it could not be cancelled because it was about to be shipped.
I needed an extra wide lens for my crop Canon 40D. I used it for outdoor shooting and quite satisfied with the result. Sharp image, nice color and contrast. I love this lens. Only bad thing is, it would not work in a full-frame camera.
Still, nice to have.There are a lot of good UWA lenses for APS-C mount cameras and everyone has their favorite, but to me it's tough to beat the Sigma for the price. For landscapes or anything outdoors really I think this and the Canon are probably the best; if you need a faster lens might want to go with the Tokina. Shooting at 10mm is a lot of fun, especially landscapes or architectural photography.
That's the tradeoff you get for a great price.It's nice to have a true wide-angle lens back in my arsenal, since the 28-70 combines with my 1.6x sensor size factor to become a 45-112, hardly wide.To anyone considering buying the lens, just be aware that it's not for full-frame cameras.
I hardly ever pick up my full frame cameras now unless I know its going to be an exploded image.
This is a great lens for Nikon DX format (digital). I didn't expect the sharpness of my nikon 20 mm, or even my nikon 18-35 (both FX full frame), in that case I better go the nikon way (expensive). The most important is that I get back the wide angle I used to have in my FX cameras. I use it with a D70 and pictures look good.
This lens has an EF mount, so it will work on other Canon film and full-frame bodies (with some heavy vignetting).All in all, a great value. I'm very happy with my copy (pay no attention to the pixel peepers).
there are currently 4 wide angle zoom choices available on the EF-S canon mount (d-rebel/xt/20d)  canon 10-22, Sigma 12-24, sigma 10-20, tokina 12-24. Of these, sigma 12-24 is the only one which is usuable on a full frame sensor (canon 1d, 5d, possible future cameras). There is sizable difference in field of view between the 10 mm, and 12 mm.
This is an amazing budget lens - great shots for an inexpensive pricetag. If you're like me and want to be able to capture full-frame pictures (such as close-up buildings or wider landscapes) this is the lens for you. I would highly recommend it to the casual photographer (I use it for European adventures) - it's one of the essential 3 lenses you need to turn your camera from 'alright' to 'amazing'.Lenses:1) 18-55mm lens for medium range shots.
Answer: Sigma DC lens are designed primarily for APS-C sensors (comparable to Canon's EF-S lens). They will work on full frame sensors but, as I understand it, the edges of the photo will be affected (darkened...) because the lens does not provide full coverage of the sensor.