Film speed on digital cameras? What's it all about?

[Janos]

What does film speed mean in digital terms?

I've got me an Oly 5060, and I'm wondering what film speed to set it at. I had a play with it in the pool last week, and a lot of the photos came out under-exposed (if I used manual settings) or severly blurred as I really needed a shutter speed of 1/2 a second or so. This is with the aperature as wide as it can be (f3.2 or something like that).

Then I realised that it was set to ISO 80.

If I crank it up to ISO 400, then presumably I can have a quicker shutter speed, but does this have any implications for picture quality. I think I know what it means in film terms (but I'm by no means an expert - so please correct me if I'm wrong). But what is film speed in digital terms?

Help me YD!

Janos

PS - Off down the pool again tonight so will have plenty of time to practice.

[John N]

Check this out:

http://www.dpreview.com/learn/?/Glos...itivity_01.htm

[turbanator]

Originally Posted by Janos

What does film speed mean in digital terms?

I've got me an Oly 5060, and I'm wondering what film speed to set it at. I had a play with it in the pool last week, and a lot of the photos came out under-exposed (if I used manual settings) or severly blurred as I really needed a shutter speed of 1/2 a second or so. This is with the aperature as wide as it can be (f3.2 or something like that).

Then I realised that it was set to ISO 80.

If I crank it up to ISO 400, then presumably I can have a quicker shutter speed, but does this have any implications for picture quality. I think I know what it means in film terms (but I'm by no means an expert - so please correct me if I'm wrong). But what is film speed in digital terms?

Help me YD!

Janos

PS - Off down the pool again tonight so will have plenty of time to practice.

You're right, it will act as if you'd got a faster film in.
I think what it really does is electronically amplify what the CCD see's, but will amplify any 'artifacts' as well.

I *think* there's a fuller expanation in the CD-based manual than there is on the printed one that you get with the camera.

R
Paul

[Getafix]

One of the biggest things is "noise" especially in the blacks.They will appear "spotty",and quite often the picture will appear less contrasty,without a decent black being produced.

Experiment and see what happens.

Alan

[recurve]

Hi Janos, much as the others have suggested, when you dial in a higher ISO/DIN film speed, you are simply turning up the gain on the CCD. This is much like turning up the volume on an amplifier (not precisely, but it will do as an analogy), so along with increasing the volume of what you want (sound in the case of the amplifier, brightness in the case of the CCD), you also increase the 'volume' of what you DON'T want. In both of these cases the unwanted 'stuff' is noise. With an amplifier it is noise you can hear, and with a digital camera it is noise you can see, usually maifesting as a speckled grainy like appearence to the picture, not dissimilar to the inreased grain you get with high speed photographic film.

I did a previous explanation a little while ago about how you don't get something for nothing in photography. If I can find it in archives I will post the link.

HTH Phil

http://www.yorkshire-divers.co.uk/fo...ad.php?t=22920

there

[vid]

Originally Posted by recurve

I did a previous explanation a little while ago about how you don't get something for nothing in photography. If I can find it in archives I will post the link

Janos - I've got a paper (? old habit) print out of this (but it's filed at home, so you can't have it today)

there's also some info on http://www.yorkshire-divers.co.uk/fo...highlight=5050

from this, the best explanation (IMO) was on
http://www.splashdowndivers.com/phot...phy/index.html

vid