[meteorite-list] Meteorite Photography

[Matson, Robert D.]

Hi Eric, Al, Erik,

> Erik is right, The higher f-stop of 22 will increase depth of field
...

Yes.

> ... not sharpness of focus.

Unless you have a very good lens, it will ALSO increase sharpness of
focus for stationary objects.

> This is why sports photographers use a low/large f-stop lens like
> f2.8 lenses.

(f/2.8 is actually not that fast a lens for a professional. f/1.4 is
a fast lens.)

> The reason is simple, the smaller aperture only allow focus on a
> small area of the subject, blurs out the background and has a
> very shallow DOF ...

All of these points are true, but that's not the main reason sports
photographers use low f/#. In sports photography, short exposure times
are crucial so that action isn't blurred. This cannot be achieved at
high f/# because the stopped-down lens doesn't let in enough light
for a properly exposed image. That said, professional photographers
usually do NOT use the fastest f-stop of a lens since the lens
periphery has the maximum optical aberrations. An image (of a still
object like a meteorite) taken at f/1.4 using an f/1.4 lens will
rarely be as crisp as an image taken with the same lens at f/2.

Best,
Rob