This is a totally unscientific test I performed today. Keep that in mind.
If you have any suggestions to make this test better/more trustworthy, just tell me and I'll try to do it.
Keep in mind also that results like these are VERY subjective, so, where I see a big difference, some people will see none, and the other way around. Just let's remember this is NOT a place to argue, so please, be polite. If you don't trust/don't like the results, you're welcome to complain but let's keep a friendly discussion, OK?
Converted using DPP, default settings (the same) for every picture, with only +3 sharpness added straight out of the camera. No other corrections done. Converted to JPEG at the highest quality and resided to 1024 by DPP. I'd expect some quality loss from Flickr, but that would apply to all the pictures, so...
400 L 5.6 prime - 3 shots: f/5.6 (wide open), f/6.3 and f/8.0
Sigma 150-500mm @ 400mm - 2 shots: f/6.3 (wide open) and f/8.0 (sweet spot of my copy)
Canon 7D, M mode, 10s timer, 10x Live View. Each photo shown is the best of 5 taken.
Very steady tripod. No winds.
Subject is the roof of a church, with some screws and cables showing. It is around 50 meters away.
Cloudy day at 11 AM. Light is not exactly the best, but is pretty OK.
So, let's go to some pictures.
First set: 400L @ 5.6, 6.3 and 8.0 respectively:
Sigma 150-500 @ 400mm, f/6.3 and f/8.0 respectively. OS off.
(100% crops on next post due to the limitation of quantity of images)
The Canon is sharper wide open but very, very slightly sharper only @ f/8.0.
The OS on the Sigma IMHO compensates for the sharpness difference, not to speak about the versatility of the zoom.
On the edges of the frame, the Canon is noticeably sharper at any given aperture.
AF on the Canon SMOKES the Sigma. No comparison at all.
Canon is lighter (way more), and can be used @ f/5.6 with optimal results. It has a more solid barrel as well and "feels" more solid and robust.
If I'd need:
- VERY fast and accurate AF (tough not tested here, since it was MF)
- Lighter, smaller lens
- f/5.6 with great sharpness
I'd get the Canon.
On the other hand, if I'd need:
- Optical stabilization
- Can sacrifice 1 stop of light for it
- Don't care about the weight
- Versatility of a zoom
I'd get the Sigma.
Anyways I got both..
Now, your opinions?