Still camera - pic storage requirements?

AndrewT · 13th September 2006, 10:03 AM

Hi all,
how do you get from image mega pixels to number of pics stored on a card?

Say 1Gb card and 8Mp image with no compression, how many pics?

And with lossless compression, how many extra pics can be squeezed onto the card?

I am not interested in lossy compression.

clem_o · 13th September 2006, 10:22 AM

Hi Andrew

Figure on 24 bits per pixel, so 3 bytes per pixel. 8MPx3 give you 24MB to store 1 pic without compression.

But, it that number certainly looks wrong. My RebelXT is an 8MP unit, shooting in raw gives about 6 to 8MB per pic. So I guess, RAW mode already contains some form of lossless compression.

Shooting JPEG 'fine' mode gives about 2.5 to 3MB per pic.

1GB = 1000MB. Figure from there..

Cheers!

Clem

AndrewT · 13th September 2006, 10:36 AM

Hi,
that 24Mb estimate matches up with Olympus TIFF storage of 23.3MB per pic.

But they also quote RAW @ 13.5MB/.

What is Jpeg? are these lossy compression or lossless?
Jpeg gives 1.9MB/, 4.3MB/ and 6.1MB/

So TIFF gets 42pics onto 1GB
and RAW gets 74pics onto 1GB without any loss. Is that right?

clem_o · 13th September 2006, 11:10 AM

Hi,

I'd expect RAW to actually vary dependent on lighting etc, dependent on how redundant the data is.

JPEG is definitely lossy. It's the compression used on most of the images you see on the web, now that GIF has copyright etc.

Yep, 42 and about 74 or 75 pics for tiff and raw, in your case...

Cheers!

davidsrsb · 14th September 2006, 08:10 AM

RAW is not compressed at all.
The camera makers play games by counting each colour pixel transistor individually - which they are really, while we think of the RGB triplet as a single pixel.

kvholio · 14th September 2006, 10:39 PM

a RAW-file is, technically speaking, not even an image.
It's the raw data taken from the camera-ccd, before internal camera post-processing takes place.
This means you have to take care of the post-processing yourself.
In your digital dark-room, using specific software to read the raw data.

Some links regarding raw versus jpeg:
http://www.kenrockwell.com/tech/raw.htm
http://www.prime-junta.net/pont/How_...ow.html?page=5

With kind regards,

Klaas

AKN · 14th September 2006, 11:21 PM

Hi!

One more link:

http://www.dpreview.com/learn/?/Glos...gital_Imaging/

dpreview has in my opinion very comprehensive camera reviews.

clem_o · 15th September 2006, 12:00 AM

Thanks for the corrections re raw. No wonder irfanview takes so long to generate images...

Cheers!

kvholio · 15th September 2006, 12:17 AM

Personally i don't bother with raw nor tiff;
my 4 mpixel camera can take upto 3 shots per second using jpeg,
it takes 2-3 seconds for one shot when i use tiff.

When editing, i always save "inbetween edits"using a lossless format, bmp or tiff.
Every time you save, depending on the editing you did, there is a potential loss using jpeg.
This also depends on the jpeg-quality settings in your editing-software.
When i need the final result f.i. for web use, i convert to jpg.

Also i ALWAYS keep the original jpg.

Klaas

kvholio · 15th September 2006, 03:46 PM

Another link, this one explains the internal workflow of a digital camera and the size-difference between raw/tiff:

http://photo.net/learn/raw/

With kind regards,

Klaas

13th September 2006, 10:03 AM	#1
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Still camera - pic storage requirements? Hi all, how do you get from image mega pixels to number of pics stored on a card? Say 1Gb card and 8Mp image with no compression, how many pics? And with lossless compression, how many extra pics can be squeezed onto the card? I am not interested in lossy compression.

14th September 2006, 11:21 PM	#7
AKN No snake oil diyAudio Member Join Date: Aug 2005 Location: In the middle of Sweden	Hi! One more link: http://www.dpreview.com/learn/?/Glos...gital_Imaging/ dpreview has in my opinion very comprehensive camera reviews. __________________ / Anders

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13th September 2006, 10:22 AM	#2
clem_o diyAudio Member Join Date: Jun 2005 Location: Manila	Hi Andrew Figure on 24 bits per pixel, so 3 bytes per pixel. 8MPx3 give you 24MB to store 1 pic without compression. But, it that number certainly looks wrong. My RebelXT is an 8MP unit, shooting in raw gives about 6 to 8MB per pic. So I guess, RAW mode already contains some form of lossless compression. Shooting JPEG 'fine' mode gives about 2.5 to 3MB per pic. 1GB = 1000MB. Figure from there.. Cheers! Clem

13th September 2006, 10:36 AM	#3
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, that 24Mb estimate matches up with Olympus TIFF storage of 23.3MB per pic. But they also quote RAW @ 13.5MB/. What is Jpeg? are these lossy compression or lossless? Jpeg gives 1.9MB/, 4.3MB/ and 6.1MB/ So TIFF gets 42pics onto 1GB and RAW gets 74pics onto 1GB without any loss. Is that right?

13th September 2006, 11:10 AM	#4
clem_o diyAudio Member Join Date: Jun 2005 Location: Manila	Hi, I'd expect RAW to actually vary dependent on lighting etc, dependent on how redundant the data is. JPEG is definitely lossy. It's the compression used on most of the images you see on the web, now that GIF has copyright etc. Yep, 42 and about 74 or 75 pics for tiff and raw, in your case... Cheers!

14th September 2006, 08:10 AM	#5
davidsrsb diyAudio Member Join Date: Dec 2005 Location: Kuala Lumpur	RAW is not compressed at all. The camera makers play games by counting each colour pixel transistor individually - which they are really, while we think of the RGB triplet as a single pixel.

14th September 2006, 10:39 PM	#6
kvholio diyAudio Member Join Date: Jul 2005 Location: leeuwarden	a RAW-file is, technically speaking, not even an image. It's the raw data taken from the camera-ccd, before internal camera post-processing takes place. This means you have to take care of the post-processing yourself. In your digital dark-room, using specific software to read the raw data. Some links regarding raw versus jpeg: http://www.kenrockwell.com/tech/raw.htm http://www.prime-junta.net/pont/How_...ow.html?page=5 With kind regards, Klaas

15th September 2006, 12:00 AM	#8
clem_o diyAudio Member Join Date: Jun 2005 Location: Manila	Thanks for the corrections re raw. No wonder irfanview takes so long to generate images... Cheers!

15th September 2006, 12:17 AM	#9
kvholio diyAudio Member Join Date: Jul 2005 Location: leeuwarden	Personally i don't bother with raw nor tiff; my 4 mpixel camera can take upto 3 shots per second using jpeg, it takes 2-3 seconds for one shot when i use tiff. When editing, i always save "inbetween edits"using a lossless format, bmp or tiff. Every time you save, depending on the editing you did, there is a potential loss using jpeg. This also depends on the jpeg-quality settings in your editing-software. When i need the final result f.i. for web use, i convert to jpg. Also i ALWAYS keep the original jpg. Klaas

15th September 2006, 03:46 PM	#10
kvholio diyAudio Member Join Date: Jul 2005 Location: leeuwarden	Another link, this one explains the internal workflow of a digital camera and the size-difference between raw/tiff: http://photo.net/learn/raw/ With kind regards, Klaas