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Nick Temple-Fry
18th February 2008, 01:41 AM
With a Sandisk Ultra II 4Gb CF card my E-3 (updated to current firmware) shows a capacity of 236 pictures when shooting RAW. Today I pulled 355 RAW files off it and it still claimed to have room for 16 more.

Now I'm happy that it is a bit pessimistic in its expectations, but this seems unnecessarily extreme.

Is this a general experience, or just a feature of my camera/card combination. I admit that I have not formatted this card in this camera (it was formatted in the e-500) but?

Nick

ukanalyst
18th February 2008, 07:52 AM
My Sandisk Extreme III and Extreme IV 4GB cards both show capacity @ 236 RAW shots IIRC even when formatted in my E3 although I haven't tested this out yet ... does seem odd the camera will allow so many more shots to be taken on it. What happens when you reach 0 ... does it stay there and allow you to keep on shooting or go into minus figures or does it re-calculate capacity before that?

Dave

Edit: Been looking at Wrotniak's technical review (http://www.wrotniak.net/photo/oly-e/e3-rev.html) and he has this to say:


Starting from the E-410/E-510, ORF (Olympus Raw Format) files are compressed using a lossless compression scheme. This allows for smaller raw file sizes. The manual says ORF files are, on average, 11 MB large; my own experience shows sizes ranging from 9.4 MB to 9.5 MB (except at ISO 3200, when 11 GB seems to be the norm). This means that a card 1 GB in size will store about 100 raw images.


Which is interesting ... if infact the file sizes are 11Mb each (I'm at work so can't test right now) then taking 4GB to be 4,000 MB (which is technically incorrect but something that Sandisk and most other card manufacturers seem to do) this should fit (not taking formatting space into account) around 363 images on (so 355 probably not too far out with formatting space). So why on earth would Olympus put that in their manual and then tell the camera to estimate for the card based on nearly 15MB per RAW file?!?

emirpprime
18th February 2008, 08:01 AM
AFAIK it is a result of the varying file sizes of the photos. Mainly due to noise levels. So the number you see is based on an "average" file size that Oly determined. It keeps recalculating the number that will fit in the space on the card using this file size.
Hope that makes sense.
Phil

Dick Bowman
18th February 2008, 08:04 AM
The number shown is something like a worst-case estimate because the E-3 RAW format is compressed. I find that file sizes average out at around 10MB, the camera starts out with an estimate of around 20MB. Not quite sure exactly how it refines its estimate.

There are other cameras with similar estimation systems - use the camera for a while and you'll get a feel for it. The displyed number always seems to be pessimistic, which is better than the other way round. Exact figures might be useful in some situations, I suppose.

The E-1 RAW format was uncompressed, which made the calculation a good deal simpler.

Nick Temple-Fry
18th February 2008, 04:07 PM
Thanks All

It just seemed odd at the time to keep shooting and see the space left apparently go up.

I still think the Oly algolrithm is unnecessarily pessimistic.

Nick

DerekW
18th February 2008, 06:12 PM
It is no different to the Distance to Empty calculation on the car - drive steady after a period of stop start driving and the DTE can increase dramatically.