1D camera file size question

I just noticed that my 1D jpg file size under fine L is only about 2.0 - 2.4 MB. Is this correct? I thought it was supposed to be about 4MB?

Jpg compression (and filesize) is influenced by a few things:

First (obviously) the size (in pixels) of the file
second: The amount of detail in the image: More detail = less compression = bigger filesize (in Mb). (This also means a high ISO jpg will be bigger generally)

I think you are confusing Mb with Mp (mega pixels) though: the 1D "classic" is about 4.1 Mp.

A 3.58MB tiff converts to a 2.88MB jpg straight from the camera to DPP. Thats about a 20 percent compression.

I think what Rene said here

René Damkot wrote in post #5483600
I think you are confusing Mb with Mp (mega pixels) though: the 1D "classic" is about 4.1 Mp.

is indeed where most get mixed up. 1 pixel != 1 byte. A pixel records data at x bit depth and there are 8 bits in a byte. That has to be accounted for and then you have to account for actual file overhead as well. And that's just for RAW (which may actually also have proprietary compression applied).

As has also been mentioned, JPG goes through a lossy compression algorithm and so will be alot smaller on top of that.

LotsToLearn wrote in post #5483848
I think what Rene said here



is indeed where most get mixed up. 1 pixel != 1 byte. A pixel records data at x bit depth and there are 8 bits in a byte. That has to be accounted for and then you have to account for actual file overhead as well. And that's just for RAW (which may actually also have proprietary compression applied).

As has also been mentioned, JPG goes through a lossy compression algorithm and so will be alot smaller on top of that.

To expound on this further, a pixel of a JPEG image has a bit depth of 8 bits/color. Since a color image has three colors per pixel (Red, Green and Blue), that's a total of 24 bits or 3 bytes per pixel. So, the uncompressed image file from a 4.1 MP camera would be 4.1 X 3 = 12.3 MB in size. A lot of compression went into getting that 12.3 MB file down to a 2.4 MB file!

mastertech01 wrote in post #5483754
A 3.58MB tiff converts to a 2.88MB jpg straight from the camera to DPP. Thats about a 20 percent compression.

If that's the raw TIFF from the camera you're talking about, the compression is actually much higher because each pixel in the RAW file only represents one color. When the raw image is converted, each pixel ends up with 3 colors so the image size becomes 3 times the raw image size (assuming the raw TIFF file was not compressed when written out).

Oh yeah. Um, don't know how I got MP and MB mixed up in my head!