PDA

View Full Version : Picture file sizes


Ellie
9th February 2008, 12:00 AM
Strange thing this.

I was talking to a friend about picture file sizes. Said I was going to abandon RAW for the time being, except for special occasions, because otherwise our new computer is going to fill up rather too quickly.

The RAW files for my camera are astonishingly big - 21mB. The SHQ JPEGs vary from about 6 to 8 mB.

According to the camera I can get 518 JPEG or 185 RAW on a freshly formatted 4 gB Sandisk card, which compared to my friend's camera isn't very many. The card is a genuine Sandisk one, came with a CaptureOne code that worked.

Any idea why the files are so huge?

Nick Temple-Fry
9th February 2008, 01:37 AM
Because they are RAW and totally uncompressed. Oly only introduced compression on RAW files for its latest cameras (the E-3 has it so a raw file is between 9-11).

I'd still shoot raw, you get so many more chances to work on the image (for example white point), and a 4gb card is little more than a couple would spend for one night in a pub with fish and chips after.

Nick

theMusicMan
9th February 2008, 06:30 AM
Hi Ellie

May I also add something here too please.

RAW files (in Olympus format are .ORF files) are just that... the RAW data - as is- that is captured from the camera. Not only do they contain the image levels for each pixel, but the file also contains meta data... and this might sound confusing, but this is data about the data.

So, in the RAW (ORF) file we also now have data about the sharpness, the white balance, the vibrance etc... not just the actual image. JPG files are what are termed lossy files meaning each time they are created some data is lost and there is a slight degradation in image quality. They are compressed image files containing a 'developed' version if you like of the RAW image.

Consider RAW files as the equivalent of 'negatives' - not quite the same thing in reality, but close enough to use as the analogy here. RAW files contain data that can be manipulated by the likes of applications such as Lightroom, Capture One 4, Olympus Camera Master etc. Not sure about the others as I use Lightroom, and if you use this try having a look at the settings that are available or greyed out when you load in a JPG compared to the settings available when you load in a RAW (ORF) file. When you load a JPG there are fewer attributes about the image that you can amend because the file has been compressed and this data is lost in that format.

Maybe it's too early in the morning I don't know... :) hope this post helps.

Ellie
10th February 2008, 12:06 AM
I understand why RAW files are so big, but I'm not altogether sure why the files from my camera seem so much bigger than RAW files from a different (make) camera. Is it because they're .ORF files?

How big are the RAW and JEPG files from your cameras?

Nick Temple-Fry
10th February 2008, 12:17 AM
Raw file size for E-500 13,797 constant as no compression
Raw file size foe E-3 8,642 - 11,645 variable as E-3 applies compression.

Surprised at E-400 shooting 24mb file size as I would have thought it was the same as E-500.

You are not shooting RAW+SHQ are you?

Nick

Ellie
11th February 2008, 12:55 PM
You are not shooting RAW+SHQ are you?
Nope I've checked, thanks. I'm glad you suggested this, because I could easily have pressed the wrong option. :o

I've checked the manual, never thought to because I'd lost it with a system crash. Downloaded a new one from Olympus.

The average RAW file for the E-400 is quoted as 22mB, it's on page 136. The average size of an SHQ JPEG 3648x2736 @ 1/2.7 compression is 7.9mB

HughofBardfield
11th February 2008, 06:48 PM
How odd! The E510 is roughly the same as the E3 - yesterday's batch of (fairly similar) images ranged from 8.9Mb to 10.4Mb. I have been trying to understand why the file sizes vary so much.

shenstone
11th February 2008, 08:22 PM
Strange thing this.

I was talking to a friend about picture file sizes. Said I was going to abandon RAW for the time being, except for special occasions, because otherwise our new computer is going to fill up rather too quickly.


Hmmm .. thanks for this thread I hadn't the file sizes were different I just bought more disk !

It's another justification for upgrading to the 510 though - I must tell the "boss" that it was a good use of money!

Regards
Andy