Sorry to disagree but I think that this ought to say that is is "an internet promoted assertion that Canon wide-angle primes are not very good".
There's no smoke without fire. I think I've demonstrated that the 24TS with camera vertical can produce remarkably detailed images using shift for stitching purposes, way beyond what could be achieved with a single shot.
However, now that I've seen the results at the extreme edges, with camera horizontal (on the 5D), there's no way I'm going to bother using this lens in this way. If I need a stitched image with camera horizontal, I'll use my 20D with the 24TS.
I notice that Kirk Gittings has been very quiet on the issue of which camera he's using with his
What I'd like to see is a comparison between a P25 with Digitar 24mm ultra wide, and 2 stitched 24TS images with the 5D, camera vertical. The image size and aspect ratio should be almost identical in both cases, but I suspect the Digitar is a much
sharper lens than the 24TS, and of course it's a much more expensive lens.
Another issue that concerns me is the benefits of a centre filter. I notice that Schneider Optics offer a centre filter for their 24mm, that provides 2 stops variation between centre and edges. It seems to me that this is what's required for the Canon 24TS.
However, I don't think one can assume that raising the exposure at the edges will solve the resolution fall-off. It seems to me that some lenses have a vignetting problem at the edges as well as resolution fall-off. Other lenses, like the Digitar 24mm, might suffer from peripheral light fall-off but not peripheral resolution fall-off.
In my experience it is rare for an image to be unacceptable due to the lens being used - far more are unacceptable due to the photographer making unwise choices which may or may not include the choice of lens. Having sold many thousands of images I have NEVER lost an image sale due to the image quality provided by the lens I was using - and this includes Canon wides.
Well, of course, this gets us back to the very old issue, that's been debated many times on this forum, of whether it's the equipment or the photographer that 'makes' the picture.
The answer is quite clear. It's both. I've never yet come across an instance of a photographer who has been able to take a photo without using any equipment (good or bad), but I have come across instances of photos being taken by equipment without a photographer. The Mars Rover is an example .