The saga started when I decided to sell my EF 24-70mm f/2.8L lens, intending to then purchase an EF-S 17-55mm f/2.8 IS lens to replace it and pocket the difference. As it happened, the person to whom I was selling the 24-70mm lens happened to have the 17-55mm lens on his camera and I was able to play with it a bit. I did not like the build quality at all and decided that I really didn't want to buy one of those lenses.
So, I remembered someone local was selling an older Canon EF 17-35mm f/2.8L lens on craigslist and was able to arrange a deal, pocketing some of the money from the sale of the 24-70. This lens design dates back to 1996 and was discontinued in 2001. While I knew that the edges of this lens are extremely soft on a full frame camera, I was counting on the fact that the 7D would only be using the middle portion of the lens' image circle.
I don't know if this was a particularly bad copy of this lens or if the design is so outdated that it simply doesn't work well with modern digital cameras but the results were really not useable. And since Canon no longer supports the repair of this lens there wasn't really a way for me to find out. I was able to sell the lens for much less than I paid for it but only after I made sure that I would be getting enough to replace it with something I hoped I would like.
Enter the Sigma 30mm f/1.4 EX DC HSM lens which I bought on eBay for less that what I received for the 17-35. The EX version of this Sigma lens was replaced in 2013 by one of what Sigma calls their "Art" line of lenses. Most reviews of the newer lens mention a superior build quality over the EX version but as my Sigma fisheye is an EX lens I wasn't really concerned about build quality as that lens is quite solid. Luckily, I was right as the two EX lenses are very similar and I have no complaints.
A 30mm lens has the field of view of a 48mm lens on a full frame camera. Image quality with the Sigma 30mm is far better than the old Canon 17-35mm zoom lens. Right after picking it up at the post office I stopped at one of the Waterford locks for a test. I was quite happy when I examined the images. This JPG has no correction for chromatic aberration and only standard adjustments for contrast and sharpness.
|Canon 7D, Sigma 30mm f/1.4 EX DC, f/8, 1/350 sec., ISO 100|
So, in addition to my Canon EF 70-200mm f/2.8L IS II lens, I am now using only the Sigma 10mm fisheye and 30mm lenses and the Canon EF-S 60mm macro lens with my two 7D bodies. Here are shots, made from the same spot, showing the field of view of each of the three prime lenses.
|Sigma 10mm f/2.8 EX DC HSM Fisheye|
|Sigma 30mm f/1.4 EX DC HSM|
|Canon EF-S 60mm f/2.8 Macro|