I got my Sigma 70-300 DG Macro new online for $79, and I'm in love with it. But as I'm reading, I keep running into people saying that cheap lenses have things like Chromatic Aberration, Barrel Distortion and other poor qualities. Being new to photography, I've never used any expensive lenses, so I don't have a reference point for quality. In most of these shots, I'm zoomed all the way in to 300mm. Is there distortion that I'm not seeing? I was told one of my previous pictures had some distortion, but I couldn't see it. I'm hoping I got lucky and got a good lens. These are just test shots for illustration purposes. Thanks for the info.