70-300 4-5.6 has soft flat images

Question

I have a 70-300 is USM 4-5.6 lens.  The lens take horribly soft, blown out and flat images... any known issues?

Answer 1

Is this your issue? Below is a review of the 70-300 f4-5.6 IS by the Digital-Picture.
"The Canon EF 70-300mm f/4-5.6 IS USM Lens has good center sharpness wide open at the wide end. Center sharpness decreases slightly as the focal length is increased to its weakest at 300mm. The lens becomes soft beyond 200mm. Stopping down improves sharpness somewhat but it is still weakest at 300mm.
Corners are soft at the ends of the focal length range and sharpen up noticeably as the aperture is stopped down. The long end of the focal length range continues to be the weakest performing over the range - especially in the vertical orientation. I don't make it a habit to formally test lenses in both vertical and horizontal orientations, but after hearing some reports of an anomaly I did some testing. Shots taken at the longer focal lengths are indeed sharper in horizontal orientation than in vertical orientation."
I don't have one so I can not comment further as to how sharp or soft they are but it seems by this reviewer that the lens does have some problems.
EOS 1Ds Mk III, EOS 1D Mk IV EF 50mm f1.2 L, EF 24-70mm f2.8 L,
EF 70-200mm f2.8 L IS II, Sigma 120-300mm f2.8 EX APO
Photoshop CS6, ACR 8.7, Lightroom 5.7