Can UV haze and high-contrast sunlight affect the appearance of bokeh?

Question

A post on dpreview makes the claim:

UV haze and high contrasts in sunny days will make any good lens a poor bokeh performer and bokeh will likely be fuzzy and chaotic. Bokehs [sic] look best in controlled, subdued light [...].

Now, I can buy the argument about high-contrast sunlight. This seems likely to bring emphasize harsh bokeh — although, a question remains: would it make nice bokeh worse?

But, I'm unclear about the "haze" point — no pun intended. Wouldn't any atmospheric haze have the opposite effect?

Answer 1

Well given that focus and detail are closely related to (local) contrast, higher contrast light ought to give you more apparent detail, while haze, by definition, is going to give you reduced contrast and less apparent detail.

I would say subjectively that a low contrast, out of focus background might produce what we would call a "creamy" bokeh more than a high contrast one. But I've seen gorgeous bokeh, from a 85mm f/1.4 for example, in quite high contrast backgrounds.

I don't agree that it would make a good lens a poor bokeh performer. It might really accentuate poor bokeh, for example in a mirror lens (which you've pointed out in your question I see).

And I agree that haze ought to have the opposite effect to that suggested by the dpreview post.