New Canon EF 70-200mm f/4 L USM Lens - But what's with the CRAZY flashing from my camera?

[neuroanatomist]

So, consensus is that it's probably the AF assist required in low light - which, for the T2i is a 4-5 strobe burst of the pop-up flash. An f/4 lens is not especially fast (wide aperture) so when used indoors, your camera may not have enough light to achieve focus.


I'll add that for your next purchase as part of your "foray into 'proper' digital photogrpahy" you might consider an external Speedlite flash (430EX II or 580EX II). In addition to the ability to bounce a flash off the ceiling and thus avoid both red-eye and the 'deer in headlights' look of subjects, one of the features I like best about the Speedlites is that they provide a different kind of AF assist - a red/infrared pattern of lines that's much less annoying. (Side note: I don't recommend the cheaper 270EX flash - even though that can bounce, it has no AF assist lamp so it's AF assist is still just a series of strobes.)

[Globespy]

ok cool. another purchase for using this lens indoors at night. maybe i will check out these lightds to avoid blinding the next group of 4 year olds at a birthday party, or stick wuth my prime. ok cool