Bunyip wrote in message ...
Angela, your a star, this is exactly what I was after.

Cheers.

Try this one:
http://www.photonhead.com/exposure/simcam.php

Angela is INDEED a star.

I too looked on the Internet for such a demonstration, but after a
quarter of an hour gave up. I am glad she found it.

For those who are interested in WET-PROCESS photography WITHOUT an
exposure meter, here is my usual trick;

Suppose you have 100 ASA film. Set the shutter to 1/100th or 1/125th.
(With 400 ASA, use 1/400 or 1/500 &c.)

GUESS the "day". For example, a "5.6 DAY". If the light is dimmer than
average, it will be a "4 DAY" or even "2.8 DAY" &c.

Now use that brilliant demonstration.

We have f/5.6 at 1/125.

Try one stop up (shutter), one down (aperture) &c.
f/8 at 1/60
f/11 at 1/30
f/16 at 1/15
f/22 at 1/8

Try one stop down (shutter), one up (aperture) &c.
f/4 at 1/250
f/2.8 at 1/500

That demonstration allows you to see the changing depth-of-field.

You can see how my method reduces the problem of exposure guessing to
a single standard guess - "guess the day". All the above exposures
give the same brightness of image, but with varying timing and depth
of field.

So you can now select from the list the properties you want - fast
shutter for sports, slow shutter for deep focus with static scenes.

DIGITAL cameras are not normally standardised in ASA, because of
automatic changes in the sensitivity. But with experience, one can
force the camera to behave as if it had a particular ASA-type of
gelatine film.

Charles Douglas Wehner