Transitions are good. I kinda like it, although I dont like the look of it.
In warmer temperatures, it seems... it is less active. But good enough to take the glare away at the beach or taking photos under the sun.
In cold climates... it goes bonkers! I went to tokyo disney land and it turns dark very very quickly under moderate lighting. Standing in the sun in the queue makes it super dark, and it does not clear at all when u go in for the ride indoors. This has led me to keep my glasses in the pocket when I'm queueing.
Due to my serious myophia, I was quoted like almost $300 for a pair of Essilor Photochromatic Lenses (or 'Transitions') at Paris Miki Liang Court.
It depends on ur myophia 'degree' in a way. Naturally, logic goes: Thicker lens, more expensive.
They've got their own in-house Photochromatics as well which is slightly cheaper and work just as well IMO. But something to take note abt Photochromatics:
1) They 'transit' faster in colder weather. It may be a property of the coating. Which is why, even on a glaringly hot day in Singapore, it may not work as well due to the weather & humidity conditions.
2) Photochromatics have a lifespan where they would not change colours as well, not as fast or not at all, even under optimal conditions. When this lifespan had been reached, it will leave a sort of a minor tint on the lenses. This is a natural property of all photochromatic lenses.
Finally, it doesn't affect viewing thru the viewfinder even after turning dark. ;p
Compared to my older specs, I tend to squint less under bright sunlight. See things somewhat clearer now.
Got my pair in Guangzhou last year... paid 160RMB for them, High index plastic, multicoat, transitions.. but dunno wad brand, it works like a charm... but does not really turn that dark... however it does help alot in bright sunlight... will know better when use them in cold weather later this year... anyway, its a good investment, and as jsbn said... shooting outdoors is still the same. does not affect one bit...