Image size

R

RegG

Suspended / Banned
Messages
177
Name
Reg
Edit My Images
Yes
I know this may be a silly question but is one I can't seem to get my head around....:confused:

I have been trying out my new Canon 70D by taking a few still life photos in the house of ornaments etc (too wet and nasty to go out!). The camera is set to take large JPEGs but when I look at the pics on my laptop and view the data they are only coming out at around 5MB in size.

Could someone out there please explain the relationship between the number of pixels (the 70D has a 20 megapixel sensor) and the image size in MB?

Thanks

:canon:
 
RegG said:
I know this may be a silly question but is one I can't seem to get my head around....:confused:

I have been trying out my new Canon 70D by taking a few still life photos in the house of ornaments etc (too wet and nasty to go out!). The camera is set to take large JPEGs but when I look at the pics on my laptop and view the data they are only coming out at around 5MB in size.

Could someone out there please explain the relationship between the number of pixels (the 70D has a 20 megapixel sensor) and the image size in MB?

Thanks

:canon:
Click to expand...

There isn't a definitive one. Just more pixels of higher quality will generally result in a bigger file for a jpeg.

JPEG is a compressed file format so large areas of an even tone, like say a blue sky will result in a smaller file because the algorithms can compress further. An image with lots of tones in it, say a crowd of people for the sake of argument, will result in a bigger file. Noise, because its random will also increase file size. The higher the quality the less compression and the bigger the file as well
 
jpegs out of my 40D are about 2.5 mb , so that would make rough sense - your sensor is slightly more than twice the mega pixelage of mine and the files are twice the size.

if it bothers you my advice would be for general use shoot raw and convert to jpeg if you need to in lightoom or similar after you've post processed. That said my overarching advice would be not to worry about file sizes etc as 5MB will be fine for most everything you might want a jpeg for) and just concentrate on enjoying the camera and your photography
 
The file size of a discrete cosine transfer compression, e.g. JPEG, MPEG2, for a certain quality setting is dependent on the amount of detail in the image. It depends on what your camera is pointed at.

For uncompressed or raw, it's a relatively easy calculation.
 
I've just had a look at my 70D files and I've got Jegs going from just under 5Mb and up to over 10Mb depending on subject matter. Strangely, the files from my old 7D (18 Megapixel) seem to be slightly larger on average but the shots were taken in a different time of year in better light etc. The files from my 5D3 are only slightly larger than most of the 70D files as well although I do get the occasional shot up over 15Mb as well.
 
Thanks to all for the replies on this subject. As usual, you have explained things clearly and I now feel I understand how the image size can vary and why.

Thanks again. :ty: :canon:
 
You must log in or register to reply here.
Back
Top