ISO and File Size Question

"JeffS" wrote in message
...
[]
I'm curious about why this happens. I was thinking that the exact
opposite should occur. Could someone please explain to me what is
happening such that a shot taken at ISO 1600 takes more storage than one
taken at ISO 100? Any information is appreciated!

Thank you,

Jeff

Perhaps they allow for greater noise in the 1600 shot, which will result
in a larger JPEG file.... (because noise does not compress as well as
images).

Cheers,
David

I tend to ignore that number as to the number of shots left. It is just an
estimation and changes based upon any number of settings.

Alan D.


"JeffS" wrote in message
...
Hi,
I have a Canon 300D and use 512 MB compactflash cards. When the cards
are empty, the camera indicates 157 shots at ISO 100. If I increase the
ISO to 200 it drops to 154 shots. ISO 400 takes it down to 142 shots
down to 121 shots at ISO 1600.

I'm curious about why this happens. I was thinking that the exact
opposite should occur. Could someone please explain to me what is
happening such that a shot taken at ISO 1600 takes more storage than one
taken at ISO 100? Any information is appreciated!

Thank you,

Jeff
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JeffS wrote:

Hi,
I have a Canon 300D and use 512 MB compactflash cards. When the cards
are empty, the camera indicates 157 shots at ISO 100. If I increase the
ISO to 200 it drops to 154 shots. ISO 400 takes it down to 142 shots
down to 121 shots at ISO 1600.

I'm curious about why this happens. I was thinking that the exact
opposite should occur. Could someone please explain to me what is
happening such that a shot taken at ISO 1600 takes more storage than one
taken at ISO 100? Any information is appreciated!

Assuming you are storing in JPG. Higher ISO means more
noise/less smooth transitions. The more detail change in the
image the less effective the encoding algorithm is at storing it,
so larger files.

Given the changes you indicate above, no big deal really. Memory
is cheap, esp. when re-used as on a digital camera.

Cheers,
Alan


--
-- rec.photo.equipment.35mm user resource:
-- http://www.aliasimages.com/rpe35mmur.htm
-- e-meil: there's no such thing as a FreeLunch.--

"David J Taylor"
wrote in message ...
"JeffS" wrote in message
...
[]
I'm curious about why this happens. I was thinking that the exact
opposite should occur. Could someone please explain to me what is
happening such that a shot taken at ISO 1600 takes more storage than one
taken at ISO 100? Any information is appreciated!

Thank you,

Jeff

Perhaps they allow for greater noise in the 1600 shot, which will result
in a larger JPEG file.... (because noise does not compress as well as
images).

Yes exactly, you can only estimate the number of images left because it will
vary depending on what you shoot. In general an image shot with higher
noise will produce a bigger JPEG file, it needs more space to represent the
noise compared to a smooth image.

"JeffS" wrote in message
...
Hi,
I have a Canon 300D and use 512 MB compactflash cards. When the cards
are empty, the camera indicates 157 shots at ISO 100. If I increase the
ISO to 200 it drops to 154 shots. ISO 400 takes it down to 142 shots
down to 121 shots at ISO 1600.

I'm curious about why this happens.
SNIP

Images that are more noisy, can be compressed less.

Bart

JeffS writes:

I have a Canon 300D and use 512 MB compactflash cards. When the cards
are empty, the camera indicates 157 shots at ISO 100. If I increase the
ISO to 200 it drops to 154 shots. ISO 400 takes it down to 142 shots
down to 121 shots at ISO 1600.

I'm curious about why this happens. I was thinking that the exact
opposite should occur. Could someone please explain to me what is
happening such that a shot taken at ISO 1600 takes more storage than one
taken at ISO 100? Any information is appreciated!

Don't know "for real" how the camera makes that decision, but the
obvious explanation is that it takes more space to store the extra
noise at higher ISOs. Really.
--
David Dyer-Bennet, , http://www.dd-b.net/dd-b/
RKBA: http://noguns-nomoney.com/ http://www.dd-b.net/carry/
Pics: http://dd-b.lighthunters.net/ http://www.dd-b.net/dd-b/SnapshotAlbum/
Dragaera/Steven Brust: http://dragaera.info/

In message ,
Alan Browne wrote:

Assuming you are storing in JPG. Higher ISO means more
noise/less smooth transitions.

That's true for losslessly compressed RAW files as well.
--


John P Sheehy

In message ,
Alan Browne wrote:

Assuming you are storing in JPG. Higher ISO means more
noise/less smooth transitions.

That's true for losslessly compressed RAW files as well.
--


John P Sheehy