Charlie wrote in post #16071056
not really, the 50D is a crop camera after all, not sure what type of sharpness you're expecting.
have you seen the 70-200 on a crop camera?
it's not super sharp either. There's only so much sharpness you can squeeze from a crop camera.
ekinnyc wrote in post #16071273
Please explain... i dont mean that in a challenging way, im juat trying to understand. A lens is a series of smaller lenses that ensure that an image is focused sharply on a perpendicular plane, so how does crop vs ff change how much sharpness we can expect from a given lens?
The only argument I can see being made for a lens seemingly performing worse on a crop sensor compared to a FF sensor of the same MP is that the sensors have different pixel densities, and so the crop sensor may reveal limitations in resolving power of the lens that are not seen in the FF sensor image.
But, since this lens is for crop only, it would make better sense to compare to another crop-only lens like the Canon 17-55 (or other brand).
One also needs to recognize that "wide-open" at f/1.8 is probably going to look softer than f/2.8...so perhaps an even better comparison would be the new Sigma 18-35 at 28mm vs the Canon 28mm f/1.8 mounted on a crop sensor (for the aforementioned reason), both at f/1.8. Looking at the image posted by ekinnyc vs the lens sample image for the Canon 28mm f/1.8 mounted on a 60D at the-digital-picture.com, the new Sigma appears to be pretty darned good - better than the Canon, based on what I can see.
Take it FWIW, YMMV, etc,