Sigma 50mm 1.4 EX HSM @F1.4 Camera EOS 5DA few weeks ago I noticed that my faithful Canon 50mm 1.4 was becoming reluctant to autofocus. I decided to get a replacement and hunted the internet for the information on what to get in its place. Studying user reviews on the internet you'd believe that about half the products on sale are some way defective, and almost every lens I looked at had disatisfied customers beliving they had a bad copy of the lens or a lens that needed recalibrating to focus on their camera.
I have to admit I've never worried much about lens calibration. When I started shooting seriously it was all film and looking at the kind of 100% close ups that we now take for granted was not easy. You'd either use a loupe on a light table or a grain focusser in the darkroom neither of which were as good or as easy as the simple magnify tool in photoshop. Generally speaking I'd buy the best lens I could afford and would judge it by how good a big print looked I didn't nit pick down to the finest detail. Now you hear countless stories of forum addicts who'd have to send back 5 lenses before they got a good one. The only real issue with sharpness I had came when I had to adjust the rangefinder in a Bessa R before but generally I'd always thought that any softness in a lens would most likely be down to me, and I'd either adjust my camera settings or work on my focusing technique if I suspected it'd got slightly sloppy. Sometimes I'd go and have a sight test, just to be sure.
Then I bought a 5d mark to with its lens micro adjustment feature. Now I can put a lens and camera on a tripod point it at a suitable target and do some simple tests to work out whether I have a good or bad copy of a lens. I did this with my new Sigma 50mm and found it needed an adjustment of -10 which I thought quite big. I test it against my previous Canon 50mm and found to my horror that this lens came out as a +10. So now I discovered why that lens was no good wide open and risky at F2! I'd just put it down to the fact that I always handhold cameras and I shoot mainly portraits so the subject moved or I moved. I also tend to focus on the bridge of the nose when shooting portraits so I'd unconsciously adjusted my focusing for the back focusing Canon.
On top of this I found the Sigma would occasionally dial in huge focusing errors (gross back or front focusing which seemed totally inconsistent. I was faced with two issues, the micro adjustment (Which although I could perform on the 5d mark two I couldn't on my back up classic 5d so I had a lens that was good only on one camera) and the occasional 'freak' errors. I weighed up the pros and cons and decided that instead of returning the lens for another I'd send it with the 5d to Sigma for calibration. It made no sense to me to get a new lens which could be no better than the one I had, although this seems to be the kneejerk reaction of most enthusiasts. I felt that it was always possible that my cameras were out and swapping lenses with abandon would get me nowhere unless I got a lens with the same error. Best I thought to get the camera and lens matched together, eventhough it would mean doing without a camera and lens for an unspecified amount of time. I packaged up the lens and camera and sent it to Sigma Service in Welwyn Garden City.
On receiving the lens they said it could take 2-3 weeks to fix, which seemed a bit long for professional service but in the end I was without camera and lens for a week and got it back just in time to shoot a wedding assignment, which meant I had all my back ups for that job which was a great relief. When I got the lens back it went from 'maybe' being a bit better than Canon's 50 1.4 to being a lot better especially wide open and at moderate distance. Bokeh is certainly streets ahead of the canon as is vignette control, the Sigma is much brighter in the corners than the Canon, as well as being sharper. So all in I may well start calibrating all my equipment either as I get it or when it's due for service. Next is the Canon 50 1.4, which has a failing autofocus mechanism after a few years heavy use. We'll see if it gets closer in quality to the Sigma.
