RE: Presentation

[George L Smyth <glsmyth@xxxxxxxxx>]

--- Belén Martínez <belenmartinez@xxxxxxxxxxxx> wrote:
> Hello Russ:
> 
> Why is lower then summer the film ISO in winter?

In the summer the angle the earth is at with respect to the sun allows for a
greater amount of infrared radiation to fall on the earth.  Therefore, you can
generally shoot faster in the summer than in the winter.

> And about focus, if I choose f/8 or smaller, that means focus increase
> togheter the depth of field, but, how can I know if the focus is exactly?

This is due to the Depth of Field.  The more you stop down your aperture, the
greater your apparent focus.  I generally tend to select f8 or greater with
shorter focal lengths, but go to f11 or f16 with greater focal length lenses.

If you wish to shoot at a wider aperture,  you can correct for focus by
advancing your lens 1/4% of the lens' focal length.

Cheers -

george

=====
Handmade Photographic Images
http://members.home.net/hmpi/

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