So I got me some Oakley photochromic glasses. Normally they work brilliantly, but the past couple of days, when the sun has been beating down here in London village, they’ve hardly darkened at all. Has it been really bright, but low UV? Is it a perception thing, they are darkening but not enough for the strong sunlight. Or is there some other reason? Bit perplexed…

They don’t work as well in the heat.

yeah i noticed the same thing today. optilabs here. didn’t know it was heat. that seems.. pretty retarded, since it’s when you want them to work 🙄

Ah ha. That will be it then. Pretty useless this time of year then…

Also works at opposite end of the spectrum – in extreme cold mine go very dark and don’t change back until they warm up (although that might also be the amount of UV bouncing off snow but I’m not convinced – seem much darker than even normal use)

As per beej – higher temperatures affects performance, from memory the performance drop off ramps up by temperature, bright cold conditions like sunny skiing/boarding situations are the ideal.

Also age affects performance, original plastic transition used to go a nice purple colour after a few years, newer versions are much better, but they don’t tell you these things on the adverts 🙂

I was always impressed with polarised lenses with the lighter grey tint and a mirror coat for bright hot conditions.

Could be perception. They generally set themselves lighter than normal dark lenses. I’ve used mine in heat and not had a problem.

If you want to see if they are working, cover one lens, or put some tape on part of one. You’ll see it work.

Incidentally my wife bought some tifosi shades for much less money. They go darker more readily, they go almost completely clear, and they work in a car too.

Hmm…