Sigma 18-50mm f/2.8 DC Lens Review - page 2

Looking now at a better test of sharpness, I have the Sigma 18-50/2.8, Canon 24-70/2.8L, Canon 28/2.8, and Canon 50/1.4 at 28mm and 50mm.

Full View:

28mm, f/2.8:

Canon 28/2.8 @ 28mm, f/2.8

Sigma 18-50/2.8 @ 29mm, f/2.8

Canon 24-70/2.8L @ 27mm, f/2.8

28mm, f/4.0:

Canon 28/2.8 @ 28mm, f/4.0

Sigma 18-50/2.8 @ 29mm, f/4.0

Canon 24-70/2.8L @ 27mm, f/4.0

28mm, f/5.6:

Canon 28/2.8 @ 28mm, f/5.6

Sigma 18-50/2.8 @ 29mm, f/5.6

Canon 24-70/2.8L @ 27mm, f/5.6

28mm, f/8.0:

Canon 28/2.8 @ 28mm, f/8.0

Sigma 18-50/2.8 @ 29mm, f/8.0

Canon 24-70/2.8L @ 27mm, f/8.0

I'm not going to worry about the f/11 and f/16 crops because the sharpness is not improved at all.  The zoom is a little off but not enough to worry about. Here, 18-50 seems soft like a cheap zoom at f/2.8.  Although the detail is there, the contrast is not.  I wonder if it was a little backfocused in this case.  Regardless, it stopped down nicely and I would be happy to use the f/4.0 shot for a reasonably large print and consider f/5.6 to be critically sharp.  You cannot see here but in Capture One I could see the speckled texture on the chair at f/5.6 on the 18-50.  I wouldn't say the 24-70 resolved any more detail than the 18-50 except for the f/2.8 shot.

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