Rudeofus said:
StudentOfLight said:
Rudeofus said:
mdflare said:
A bold claim without hard measurements to back it up. And it even fitted an image stabilising unit in there too ???
As Kevin/LSXPhotog has already stated, the review even did not point out a single problem with the lens. Suspicious too.
I found it particularly amusing, how the review raved about corner to corner sharpness of these lenses, even on a full frame high megapixel 5Ds.
This recent post shows MTF data, which tells a very different story, especially for the new 35mm lens.
Define acceptable sharpness
A severe falloff of the MTF@10lpmm curve tow thirds towards the corner may be acceptable to many including myself, but I would definitely not call this corner to corner sharpness on a 5Ds. The lens may be ok, but the review sounds bogus, unless the author received a spectacular sample that outperformed the posted MTF curve by a wide margin.
Here is an article on Field Curvature:
http://www.lensrentals.com/blog/2014/09/field-curvature-and-stopping-down
By comparing the Tamron and Sigma...
If you look at the yellow background flowers in the top right corner you'll see the Tamron is sharper than the Sigma (both being shot at the f/1.8 setting). If you look at the wood grain on the table towards the corners the sigma appears to have sharper foreground. The Sigma's sharper foreground and more blurred background points to field curvature towards the foreground. But from Lensrental measurements we know that the Sigma has incredible flatness of field. So isn't the logical conclusion then that the Tamron has strong field curvature towards the background like the current Canon 35mm f/1.4L?
My guess is that field curvature is what makes the chart look worse than the lens feels to perform in practice. Test charts are flat, the real world has depth and from looking at the photographer's portfolio, he shoots anything but flat subjects