How sharp should the 16-25mm L II be on a 6D body?

Hi folks,

I recently purchased a Canon 6D with a 16-35 mark 2 lens.  I previously owned a Canon 60D and a Sigma 10-20mm mark 1.

I'm not sure if my expectations were unrealistic, but having compared the 2 lenses on their respective bodies, there is virtually no difference in sharpness in the centre of the frame.

Both lenses seem equally sharp on the left hand side, and the Canon seems sharper on the right hand side.

So, my question is, should the Canon 16-35, which costs 3x as much, be producing significantly sharper images across the frame?  I would be particularly interested in hearing the opinion of those who have owned both lenses.

I have uploaded 2 full resolution files to my website of the same scene captured with each lens.  The same sharpening has been applied to each during RAW conversion in Lightroom.

Canon 16-35mm:

http://www.mountainsandwaves.com/files/20914/canon1635forcomparison.jpg

Sigma 10-20mm:

http://www.mountainsandwaves.com/files/20914/sigma1020forcomparison.jpg

Both shots were tripod mounted, taken within moments of each other, and were both shot at f11.

Thanks in advance your for your consideration and comments.

Stephen

Have you tried comparing images at maximum apertures rather than at f/11?

You're paying for more glass, two fold. To cover a larger sensor for one, then to give you more light with an aperture of 2.8 for two.

The sigma is a great lens, but I am surprised there isn't much difference.

If you don't need f2.8, why not just purchase a 17-40mm? Not a lot of difference with respect to sharpness. And it would save quite a bit of coin.

Your expectations are unrealistic.  High DOF photography benefits the least from larger sensor sizes.  This is why some people enjoy shooting landscape shooting even with MFT cameras.

This is because you are using apertures and shooting DOF for which smaller sensor camera's + smaller optics can do very much the same.  As such you should be shooting for dynamic range (for which most Canon's are similar and lagging behind competitors).  But yes that Sigma is holding up fairly well to the 16-35.  Although the 6D shot is more detailed and would hold up better to larger prints.

6D will probably be better with low-light photography or even long exposures, etc.  Also the 16mm seems wider than the Sigma APS-C equivalent.

It's been stated many times however that if you do not need large print sizes, larger sensor benefits are pretty marginal...

Both shots were tripod mounted, taken within moments of each other, and were both shot at f11.

Thanks in advance your for your consideration and comments.

I'm assuming you meant 16-35, not 16-25?

The Sigma image is clearly softer when viewed at 100%.  The Canon lens produced a noticably sharper image with bolder definition in the details.  But you shot these both at f/11 which means you are assessing the lenses at (probably) their sharpest.

Whist that's fine as a test, many lenses perform horribly at their widest and often the Canon lenses are far less prone to Chromatic Aberration and Purple Fringing than other brands. Perhaps you should try them at f/2.8?  Obviously, the Canon has a very good reputation with their 16-35L lens and many photographers from Reuters consider this to be the most commonly chosen lens for photojournalism ... hence I would choose it over the Sigma any day.

I've owned the EF 16-35mm f/2.8L II for about two years and it's only recently that I've come to appreciate just how sharp and reliable the optical array is on this lens.  On the 6D is should be superb.

at hi ISOs a FF sensor is vastly superior to 1.6 crop, and that has nothing to do with print size.

ed rader wrote:

at hi ISOs a FF sensor is vastly superior to 1.6 crop, and that has nothing to do with print size.

At narrow apertures, a smaller sensor can shoot equivalent DOF and FOV with wider apertures and there is no low light advantage.  Low light advantage comes with shooting at wider apertures where smaller sensors and optics can not compete.  6D is one Canon sensor with high efficiency, but there are other small sensors that are competitive if not still better in read noise and dynamic range at low ISO.  So again high DOF low ISO photography benefits the least as long as good optics are available at all formats.

you've lost me.

Examples of such small sensor cameras?

The 6D is insane good at high ISO, but you might be right. Canon's are a little lack luster in the DR department at lower ISO's...or so it's been reported by other users. I've never fussed about it however.

NomadMark wrote:

Examples of such small sensor cameras?

The 6D is insane good at high ISO, but you might be right. Canon's are a little lack luster in the DR department at lower ISO's...or so it's been reported by other users. I've never fussed about it however.

http://www.dpreview.com/forums/post/51531670

The latest Olympus PENS also have good sensors.  I'm just saying if you are shooting narrow aperture shots, smaller camera's can shoot equivalent pictures with wider apertures, etc.

Then it boils down to lens qualities.  IMO the #1 thing to me is having a good copy of whatever UWA lens you have!  For example my 24-105L is a bit soft at 24mm...but that is copy dependent.  This has a bigger factor than anything to me (i.e. making sure you weed out poor copies of lens, etc).

The 14mm Samyang I had was pretty incredible on FF and sharp edge to edge with very low CA!  Mustache distortion easily fixed in LR with downloaded lens profile.  But 14mm on a full frame exceeds my skills of composition at that point.  I would guess it would be fun however to do close-ups and play with the obscene optical distortions you'd get.

The 6D picture is much sharper... maybe not 3 times sharper, but hey, if you going for money vs price, why not just buy a s110 or something like that

Marco Nero wrote:

The Sigma image is clearly softer when viewed at 100%.  The Canon lens produced a noticably sharper image with bolder definition in the details.  But you shot these both at f/11 which means you are assessing the lenses at (probably) their sharpest.

f11 is well into pixel-level diffraction on recent Canon APS-C.  The Sigma would almost certainly be better served at f8 (or lower).  The 16-35LII only benefits from f11 in the extreme corners (and general DOF), but if overall sharpness is the objective, the lenses should be tested at their respective optimum apertures.  There are UWA alternatives to the 16-35LII on FF that will beat the Sigma on crop convincingly, but in general (and as others have pointed out) deep DOF photography is not the place to expect superiority from sensor size (with commensurate optics) alone.