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Invicta
9th December 2007, 11:07 AM
Hi

I am puzzled :rolleyes: by the raw file size on my E3. 10 mega pixel sensor, manual states on page 141 raw file size approx 11 MB which is what I would expect.

However, the size of the raw files I get are approx 8.7MB. Anybody else get raw files in this size range or understands why they are smaller than expected?

Thanks

emirpprime
9th December 2007, 11:39 AM
The compression and noise relationship creates a variance in file size. You will find the los ISO images will be smaller than stated, and the very high ISO images can be bigger. So in the manual they just give an 'average' type value. You're not loosing data!
All the best,
Phil

Invicta
9th December 2007, 11:49 AM
The compression and noise relationship creates a variance in file size. You will find the los ISO images will be smaller than stated, and the very high ISO images can be bigger. So in the manual they just give an 'average' type value. You're not loosing data!
All the best,
Phil

Interesting, many thanks. I just upped the ISO and the file size increased. I had wrongly assumed raw was just a straight copy of the unprocessed sensor data.

ianc
9th December 2007, 12:23 PM
I just did a test on the E3. Using a 2Gb Sandisk Extreme III card the camera says I should get 118 RAW shots, I thought this was a bit low at 11Mb I should get around 180. I set the camera to 100 iso and fired off shots until the card was full. The subject was mostly grey sky so very little detail. I got just over 240 shots. I'm amazed as the most I have ever got from the E1 was just under 200. 20% more shots while doubling the number of pixels! Olympus have obviously made huge advances in RAW compression. I did think I would have to buy more memory when I bought the E3 but now I doubt I'll need it.
Ian C.

Invicta
9th December 2007, 01:02 PM
A similiar observation is what confused me originally :rolleyes:

With my old E300 8 Mega pixels each raw file was about 13 MB. Hence I was really puzzled to see the 9 MB files on my E3 10 Mega pixel camera.

Oly obviously doing so good work in the background with this. Means less space on the PC too which is great.

Ian
9th December 2007, 02:11 PM
Interesting, many thanks. I just upped the ISO and the file size increased. I had wrongly assumed raw was just a straight copy of the unprocessed sensor data.

The E-1 RAW format was uncompressed so the file size was always 10MB, but E-3 RAW files are losslessly compressed resulting in different sizes according to the complexity of the image data - more complex = less effective compression and so larger files.

Ian