Sigma 50 vs. Canon 50L Test Results

Photozone.de has full test results for both of these lenses (on 5D Mk. 2). It's evident from the resolution numbers that both lenses were optimized for center sharpness at large apertures. Neither one does particularly well in the border/corners, but I was surprised that the Sigmalux was able to edge out the 50L in resolution, vignetting at large apertures, and chromatic aberration (the latter by quite a bit).

I realize that there are many other factors that determine the ultimate image quality of a lens (for example, micro-contrast), so I'm not trying to start a flamewar by claiming that one lens is inherently better than the other. The Sigma's performance in the 3 areas below is definitely very impressive though, especially considering that you can buy one for 1/3 the price of a 50L.

Canon 50L on left, Sigma 50 on right:

Some important figures are never shown in such type of tests ... and they usually contribute to make outstanding lenses ..
-> colors depth
-> micro contrast
-> speed of incoming blur out of focus et smooth of the bokeh
-> etc etc etc ..
So sharpness, CA and vignetting are only a part of the qualities of a lens..

newworld666 wrote in post #11194714
Some important figures are never shown in such type of tests ... and they usually contribute to make outstanding lenses ..
-> colors depth
-> micro contrast
-> speed of incoming blur out of focus et smooth of the bokeh
-> etc etc etc ..
So sharpness, CA and vignetting are only a part of the qualities of a lens..

Definitely agree with you there. I'm not claiming that either one is the definite "better" lens. However, the 3 things I listed in my original post are undeniably important qualities of a lens, and the Sigma surprises me with its performance in those areas compared to the 50L.

One thing that can make all those charts more or less irrelevant in real use is focus accuracy - and even taking the 50L's focus shift into account I don't think the Sigma wins there.

Anders Östberg wrote in post #11194771
One thing that can make all those charts more or less irrelevant in real use is focus accuracy - and I don't think the Sigma wins there.

The 50L is no standout in focus accuracy either, though. Both lenses suffer from focus shifts as you stop down from maximum aperture. In fact, just as many people (if not more) complain about focusing issues with the 50L compared to the Sigma 50.

One factor that didn't surprise me was wide-aperture vignetting, as that's the reason the Sigma has an over-sized front element.

996gt2 wrote in post #11194781
The 50L is no standout in focus accuracy either, though. Both lenses suffer from focus shifts as you stop down from maximum aperture.

Is there a 50mm that doesn't have focus problems ?

I know people have different experience with the Sigmas, but my own is that even my 50/1.4 - bad as it is - is a better AF performer than my Sigma. If you have time to get it right it's great, but for some uses (moving targets) I prefer the Canon lens.

CountryBoy wrote in post #11194790
Is there a 50mm that doesn't have focus problems ?

The slower 50mm lenses are pretty good in terms of focus accuracy. The fast, well-corrected (aspherical) 50mm lenses all seem to have issues with autofocus.

Madweasel wrote in post #11194786
One factor that didn't surprise me was wide-aperture vignetting, as that's the reason the Sigma has an over-sized front element.

The 50L has a huge front element too though and still out vignettes the sigma at f2 vs 1.4?

These charts are definatly one point to take into consideration.

996gt2 wrote in post #11194800
The slower 50mm lenses are pretty good in terms of focus accuracy. The fast, well-corrected (aspherical) 50mm lenses all seem to have issues with autofocus.

I have the Sigma 50mm 2.8 macro which is slow but accurate . Someday I might pick up the Sigma 1.4 , with the idea i'll have to send it in .

I would still take the Canon. Charts are charts and if you stare at them long enough no lens sounds impressive. Photozone claims the 35L is not a great performer and I was absolutely blown away by that lens.

CountryBoy wrote in post #11194834
I have the Sigma 50mm 2.8 macro which is slow but accurate . Someday I might pick up the Sigma 1.4 , with the idea i'll have to send it in .

I sent my Sigma 50 in a few days after I got it and received it a week later. After calibration, it's generally very accurate in AF. It does have its bad days once in a while, but overall the AF accuracy is not considerably worse than my other lenses.

newworld666 wrote in post #11194714
Some important figures are never shown in such type of tests ... and they usually contribute to make outstanding lenses ..
-> colors depth
-> micro contrast
-> speed of incoming blur out of focus et smooth of the bokeh
-> etc etc etc ..
So sharpness, CA and vignetting are only a part of the qualities of a lens..

Tommydigi wrote in post #11194841
I would still take the Canon. Charts are charts and if you stare at them long enough no lens sounds impressive.

This, the theoretical performance of a lens doesn't mean that much to me. I'd much rather have a lens that produces images that look amazing, at which the 50L seems to be quite a bit better to be fair.

Rsyx wrote in post #11194854
This, the theoretical performance of a lens doesn't mean that much to me. I'd much rather have a lens that produces images that look amazing, at which the 50L seems to be quite a bit better to be fair.

The images from the Sigma also look amazing .