Most of my shots are of my 2 yr old son playing around.I bought the canon 600d last year and wanted more so I got the 18-55mm STM kit lens along with the 70D. And I upgraded to 24-105mm f4 L and canon 50mm f1.4 USM(no efs lens to make future proof in case i upgrade to full frame). Mostly I use the 24-105 for my shots.But I find the image quality to be not much greater than the kit lens and the images are soft with less detail for my taste even at f8. Its a 1000 dollar lens and i expected much more than that.I went to flickr and saw the efs 17-50mm f2.8 of sigma and 15-85mm canon USM has better image quality on the 70d .I am thinking now maybe I should sell my EF lens and get an EFS lens because maybe the EF lenses does not perform well on the 70d as the efs lenses would have.Maybe i made a mistake.Maybe the 15-85 mm USM lens would have been better for my camera.Is it so ? or any zoom lens within that price with that reach gives me the same image quality on 70D ?I am confused.Please help me out