Originally posted by UncleVanya Not only sharpness - but there are those who claim color differences are a problem for them - some prefer Sigma others Pentax, but it's hard to see that kind of difference at work here. I'm going to admit up front I have not shot the Sigma's - any of them - and my curiosity is at work here mostly. I hoped to see meaningful differences and didn't. But I don't know if that's because the original files are masked by the limitations of JPG uploads here or if there are other factors or non-factors at work.
Maybe in response someone could post shots that DO show these differences - in a similar method?
I'd be interested in that too... As I say ad infinitum, we have sold multiple 30x20 canvases from our 10 MP Option 80W pointed shoot. Our conclusion is, there's more to IQ than resolution.
The problem being most of us have a lens we like and shoot with it all the time. It gives us confidence and that's a wonderful thing. My Sigma 70-300 is reported to be a complete dog at the long end. If you shoot more images with a given lens, you probably also get more keepers with the same lens. A sort of self fulfilling evaluation that makes it hard to guess if it's the lens, or other circumstances.
Here's an example...Sigma 70-300
Heres the DA*60-250
If you're close enough even your "dog" takes a good picture, if you're too far away even a sharp lens may be less than perfect.
My guess is a poor lens at 15 feet easily out resolves a great lens at 40 feet on a test subject.
In the above images, I have no doubt is the subject were further away and I had to crop, the DA*60-250 and K-3 would give me a better image. But for the images presented I kind of like the Sigma, between these tow. The feathers look a little bit soft, and there's a part of me that thinks , well that's because feathers are soft.