On 28/09/2015 12:42, whisky-dave wrote:
On Friday, 25 September 2015 22:49:23 UTC+1, NY wrote:
"dennis@home" wrote in message
eb.com...
On 25/09/2015 16:27, whisky-dave wrote:
Why call it a stop one have such strange stop
numbers....... why does f5.6 let in twice that of f8

f number is a measure of aperture *diameter* relative to lens focal length.



Its the same as a film camera, where do you think it differs?
Why do you even think it might differ?

My thoughts exactly. I can't work out whether he really doesn't know or is
winding us all up. Film and digital cameras have more in common that maybe
he realises.

They sure do, but there are some important differncies.

You still haven't said what they are, I don't think you know.


Yes if you set the camera on aperture priority and look at EXIF data of the
resulting photos taken in various lighting conditions, you'll see a variety
of unusual shutter speeds - whatever the meter judges is correct;

yes the meter is judging this isn't good if you're teaching the subject.

So you propose not using a light meter while teaching photography.


Why does the image on my LCD look the same irrespected of the
aperature and shutter speed I set.

Because you have a cr@p camera

wrong answer .

It was the polite one.


and can't set the image to look correct at
a guess. On mine if you stop down, the image darkens when you do DoF
preview just like an old fashioned camera.

does it still darken if you don't do a DoF. ?

Why should it, the diaphragm in the lens doesn't close unless you do a
DoF check, the same as on a film camera or are you proposing that only
manual lenses are allowed.


Seems you're getting corect exposure and DoF confused.

Seems you're getting photography confused.