UCLA Develops World's Fastest Camera To Hunt Down Cancer In Real Time

I can tell. The lens and F stop have nothing to do with speed, the shutter does. Of course with fast shutter speed you need fast film (is there still any around?) and a larger aperture (F-stop).

The lens has nothing to do with a camera's speed.

And you're speaking nonsense.

First, there are three variables at play when taking a photo. The shutter speed, the aperture size (usually expressed as a fraction of focal length, f), and the "film" speed (sensitivity).

A properly exposed photo (usually desired in most cases excepting artistic composition) is where sufficient photons hit the light-sensitive medium to generate a usable image. With 3 variables to play with, there is a whole range of settings that will generate an image.

Hence the concepts of stuff like "stops" - where you can halve the shutter speed (1/30th from 1/60th, say), but also close down the aperture (by half) and still end up with a good exposure. Or decrease the media's sensitivity.

What you use depends on the situation and artistic effects you want to put on it - larger apertures reduce depth of field, faster shutters "freeze" fast motion, more sensitive recording media generally are noisier/grainier, etc.

A "fast" lens is called that because it has a very wide aperture that can let in lots of light, meaning you can get very nicely exposed photos at very high shutter speeds, thus capturing faster motion. A "slow" lens means the aperture is smaller and thus requires a longer exposure time (slower shutter speed).

Remember, it's all about getting the proper exposure, and playing with the three variables will generate many configurations of apeture/shutter/sensitivity that will work. The one you use depends on the situation.

Source: http://rss.slashdot.org/~r/Slashdot/slashdotScience/~3/_BnoBwt_NOI/ucla-develops-worlds-fastest-camera-to-hunt-down-cancer-in-real-time

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