A few things came to my mind:
- In most of the extreme wide shots, the center tends to be relatively sharp, but it falls off a lot on the sides. Is this just a quality of lens issue, or maybe because they're just extreme wide lenses in the first place?
- In some cases, there seems to be some sort of diffusion going on where a objects will have a slight halo or soft outline. One good example is during the "test" where Alex is on stage and they bring a nude woman out to see if his treatment has been successful. When the girl walks into the light, there's a rather large and noticeable halo effect on the (screen) left side of her.
- In the special features (and in fact, in a lot of the set photos in books like Michel Ciment's 'Kubrick' and Allison Castle's 'Archives') there are a lot of shots of Kubrick using a large blimped camera where the lens is inside, shooting through glass in the blimp itself. Might this account for soft/diffuse-looking stuff? I really don't believe Kubrick was much of a diffusion guy so I wonder if that may be causing the diffuse look.
- Throughout the entire film, there are a few shots that are quite sharp, but overall, things seem pretty soft. Probably not a transfer issue. Lenses? The blimp again?
- Minor criticism: There's a noticeable hair at one point on the bottom left corner of the screen, just as the nurse is prepping Alex for his first treatment. The film is presented at 1.66 on Blu-ray, the theatrical-release ratio according to IMDB, but I can't believe they wouldn't have fixed that before release