Canon 24-70 f/4L IS sharpness

[jd7]

Hi all

I've started this thread as a result of a question Act444 asked in another thread:
http://www.canonrumors.com/forum/index.php?topic=24523.0
The other thread was about a review of Canon's new 24-105 non-L lens so it seemed better to start a new thread for this rather than further side-track the old thread.

I'm going to try posting some sample images (never posted images to CR before) to try to show something about the sharpness of my 24-70 f/4L IS towards the long end of its range and near MFD. Please note I only had a couple of minutes today to grab a few shots so these are all shot on a 6D, handheld at ISO 400, with IS on, using centre-point AF, with shutter speed in the 1/100 to 1/200 range. (Yes, it would have been better if I'd taken them with a tripod and using Live View!) Obviously, then, the testing methodology leaves something to be desired! In particular, movement by me when shooting or AF issues could be significant in making a shot seem soft.

 

[jd7]

Here are a series of crops from shots taken at 70mm, all at f/4, getting closer to the subject.
The last shot is definitely soft, but maybe I got inside the MFD ...? I also note the suggestion in the TDP review to shift into the macro mode rather than use it close to MFD at 70mm - see http://www.the-digital-picture.com/Reviews/Canon-EF-24-70mm-f-4-L-IS-USM-Lens-Review.aspx

I will have to find time to re-do the test at 70mm f/4 near MFD.

 

[jd7]

Here are a series of crops from shots at 50mm, f/4, getting closer to the target ...

 

[jd7]

For what it is worth, here are crops from two shots I took before I sent my 24-70 f/4 to Canon for calibration. One is at 50mm and the other 70mm, both at f/4. You will see how soft it was at 50mm. As with the tests above, the shots were taken handheld and using AF so that needs to be considered. However I did quite a number of tests before sending my lens back to Canon and the softness at 50mm was consistent. The lens was pretty good at 24mm and at 70mm, and a little soft at 35mm (although not as bad as at 50mm).

The lens may not be perfect now, but it's definitely a lot better - more consistent across the whole zoom range - since I got it calibrated.

 

[Deleted member 7828]

Thanks for posting those. From what I see, it looks to be consistent with what I'm seeing with mine - softer as you get closer to MFD, but it's difficult to be 100% sure.

Very insightful. So it's probably just the lens design in general as opposed to my copy.

Wow, that last shot at 50 almost looks misfocused. Mine was nothing like that (although I did get it refurbished so I'd think/hope that Canon tuned it up before reselling it)...

 

[Sporgon]

(although I did get it refurbished so I'd think/hope that Canon tuned it up before reselling it)...

Fat chance !

The amount of variability in the assembly of these lenses ( and indeed other L lenses) is alarming.

My 24-70 f4 now has a bad de-centring issue - it's very soft on the far right. Whether it was like this before or I've knocked it I don't know, but in future I'm going to perform the test that PBD demonstrated in a thread last year as soon as I get the lens.