16-35mm f/2.8L II possible lens blur problem

Landscapeforfun wrote:

Almost certainly an element out of alignment.

IMO if your primary interest is milkyway/nightscape photos I would call the lens a total loss and upgrade to something much better. The left side of your lens is sharper, but the coma is pretty terrible, and the corners are mostly mush even on the good side.

The Rokinon 14mm f/2.8 is a good cheap alternative. Fully manual, but wider, and less coma than the canon. Sharper in the corners but a little less sharp in the center.

The Nikon 14-24 f/2.8 would also be fully manual but it is significantly sharper in all parts of the frame, wider, and almost no coma.

The new Tamron 15-30 f/2.8 VC is about on par with the Nikon, except you gain VC, AF, a native canon mount, but lose 1mm (still a 1mm gain over the canon).

You also lose screw on filters with all of these lenses which may or may not be a deal breaker for you.

The final option is the canon 16-35 f/4. You lose a stop, but the corners are significantly sharper and you maintain the use of filters. Also gain IS on this one.

Just something to consider if you are going to end up with a $300 repair bill just to get the lens to subpar compared to newer lenses.

Thanks so it does look like there'll need to be a trip back to Canon then. I've really liked the lens though, and I'm the kind of person who tends to stick to the original manufacturer products. Manual wouldn't be ideal either. Tamron looks good on paper. Don't think i would consider an f/4 if I do focus on the night sky since fast shutter speed is quite key and IS is useless on a tripod. I do take it on travel too, when IS may become useful (especially in churches) but I found the lens to be sharp over past use - if it went back to its good old days then I'd be happy.