D800 E - strange math

I've just gotten my D800E. I'm learning all the controls and settings.

I've set RAW files to be saved as 14 bit-lossless compressed, no JPEG. There's one card in the camera, an 8 Gigabyte SanDisk Extreme Pro SD. The camera indicates for these settings, it has room on the card for 99 images.

When I bring the files over to my Mac, they measure 39-41 megabytes. I figure at 40 megabytes average size, the 8Gig SD card should hold roughly 200 RAW lossless compressed images, not 99.

Where is the math going wrong?

BTW, the camera is fantastic. And compared to my previous equipment, write speed to the SD card is for all intent and purpose, instantaneous.

More later.

Rich

125 should be about right for that size card.

Make that 100.

So the 32 gb should hold about 400 raw pictures?
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Jay

400 is what shows in my viewfinder using lossless compressed 14 bit on a 32GB card. 12 bit gets you 519. Divide by four for 8 gig?

Reilly Diefenbach said:

Make that 100.

Click to expand...

OK, but 8Gb divided by 40 Mb = 200.

How do you get 100?

The number of images has never been accurate with Nikon dSLRs unless shot in uncompressed format. This is because some scenes compress better than others. In other words Nikon cannot know in advance how big the files you take will be after lossless compression. There is nothing that Nikon can do about this. So choices have to be made on how to estimate the number of remaining frames on the card.

The traditional approach which Nikon has taken is to be on the conservative side: to calculate the number of remaining images the camera divides the remaining space on the card by a size assuming that all of the remaining images will not compress well. In other words it uses a worse scenario estimate.

The net result is that the counter is always under estimating the number of remaining frames on the card. Another approach would be to divide the free space by an average size of a compressed file. This would give you a more realistic number. But the caveat is that you could end up with less images available than what the camera tells you if the scene does not compress well (i.e. lots of fine details). Nikon has picked the other approach instead (I personally agree with this choice).

As stated before it's always been that way with my past Nikon's. I didn't check again with the D800 but chances are high that this is exactly what you observe.
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Thierry

TOF Guy,

OK. Thanks

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Mike M. (emem)
http://www.veritasmea.com

In 14-bit lossless-compressed NEF only, I got close to 340 images on a 16 Gb card and 170 on 8 Gb.
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Jur

To legally protect themselves I expect, if they said 150 shots and it turned out to be 100 there would be complaints, if they said 100 and it managed 150 lots there would be lots of happy faces !

I set the D800 to uncompressed 16 bit nef files and a 16Gb CF card has a capacity of 200 images, must me me but I never thought to check the maths, I am a very trusting long term Nikon user

...it's an estimate. If you're shooting compressed NEF, the size of the file depends on the subject matter and how well it compresses. Nikon has no way of knowing what you're going to shoot, so the display indicates how many uncompressed files will fit on the remaining space -- the worst case scenario.

If you find this unacceptable, shoot uncompressed -- you'll get exactly what the display tells you.

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Rick

Gosman said:

So the 32 gb should hold about 400 raw pictures?
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Jay

Click to expand...

i get about 370 images on a 16 gig card. consistently.

Strange things may happen if you change cards
http://forums.dpreview.com/forums/read.asp?forum=1021&message=42618580

It seems from another post you've made in the thread you point to that this was just a little confusion from your part (don't we all do this more than we care to admit !)

http://forums.dpreview.com/forums/read.asp?forum=1021&message=42630404

What's the final word?
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Thierry

Lossless compression comes down to finding patterns which repeat themselves, then reducing file size by replacing the patterns with a token which is smaller in size.

Compression will not have an impact on file size if the image has no repetitive pattern whatsoever at the pixel level. Seems highly unlikely in real life (and with 36 MP it should compress even better!) but technically possible.

The 50% is welcome. You want to have a good guess about how many images you really have on the card? Just multiply by 2 the number shown by the camera. That makes it easy. Easy is good

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Thierry