ISO and storage capacity

[Bill Sheffield]

I placed a re-formatted 340mb Microdrive into D30 and checked capacity as 256 images. This was at Large/Large jpeg setting-ISO 200. My first use of camera at ISO 400 indicated 237 image capacity on Microdrive.

I began to shoot basketball game, set ISO at 800, and noticed that number of images was much lower.

Later before changing ISO back to 200, I noted the number of available images. After resetting to ISO 220 I checked capacity and noticed that more images were available. Out of curiosity, I changed ISO from 100 to 1600 and noticed that capacity decreased as ISO increased.

I do not consider this a problem, but an interesting observation. Same results with CF cards. I've used D1 and do not recall a change in capacity when changing ISO.

Anyone noticed this difference with your cards or Microdrives?

Bill Sheffield

[RichB]

I noticed this also. The file sizes are bigger as the ISO increases. If you test burst rates you get 17 in a burst at ISO 100 and 7 to 10 at 1600- the larger files fill up the buffer faster. This is the case with all Jpeg settings as well as RAW.

I know file size will vary from image content because of the way the jpeg compressor works. I don't know how or why ISO would impact on this.

I don't recall noticing D1's having this nature. I havenít thought to check one at work...

[Duane_Burleson]

The reason for this is that higher ISO images have more noise in them (jpeg sees this as more detail). And to preserve the detail there is less compression.

You can see this same relationship with scanned film. The higher ISO film scan will not compress as much using the same jpeg setting in Photoshop.

duane

[Uwe_Steinmueller]

actually that was my thought too. But is lloks as if the display also takes this into account. Also it might have less compression because with that noise the compression is more harmful.


Nice feature.

Uwe (Editor www.outbackphoto.com)

[RichB]

I checked a D1, the estimated remaining frames the camera displays does not change as ISO is changed, as it does on the D30. I know that file sizes will vary even at the same ISO depending on content.
The D30 re-estimating remaining frames as ISO changes says that compression routines may change as ISO is changed. If this is so it might be responsible for the D30's superior image quality (Less noise and more random) compared to the D1.

[Uwe_Steinmueller]

>If this is so it might be responsible for >the D30's superior image quality (Less >noise and more random) compared to the D1.

I am not sure whether the D30 has better color. Sometimes the D30 and D1 are close in color and sometimes not. This can be related to WB. The D30 has a bit better shadow detail and overall detail.

Overall it is difficult to compare. You have to use both cameras for some months or so.

I think the NEF/CRW conversion contest is a good way to start with your own comparison about photo quality.
http://www.outbackphoto.com/workshop...ersion_01.html

Uwe (Editor www.outbackphoto.com)

[RichB]

I use/used D1's quite a bit. IMHO the D30's image quality is a quantum leap ahead of the D1 even without aftermarket software. I was and continue to be disappointed with D1 image quality Raw or Jpeg.
I have been using a D30 for regular assignment work for 2 weeks now, for the first time I feel Digital, quality-wise, has arrived. I never felt thatway using a D1.