Jpeg & Raw File Megapixel Size Difference - Why?

snoop69

snoop69

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Paul
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I took a few pics today in Raw & L using my 450d.

I have noticed that the Jpeg files are 12mp + (3-5mb) whereas the Raw (CR2) files
are smaller & average 3mp (12mb+).

I would have thought that a 12mp camera would take 12mp pictures if
set to Raw.
 
How are you determining the number of megapixels of the raw files?
 
There's no way a RAW file can be less in Mb than the sensor size in Mp....ie, your 12Mp sensor is going to produce files of 12Mb or larger (typically 15Mb+).

Some higher spec bodies have an sRAW facility which is a lower resolution pick off the sensor but it's not an option on the 450D.

Bob
 
I think you may be looking at the resolution rather than the file size? If so then you may be comparing the full size jpeg to the medium size jpeg preview which is embedded in to the raw file. How are you viewing the Raw file?
 
Mark.A said:
How are you viewing the Raw file?
Click to expand...

Im using Faststone Viewer to view RAW files as they wont open up in CS3.

I have one image that Faststone display as 1504 x 2256 = 3.39MP ,11944kb

The same picture saved as a JPG is 4272x2848 = 12.17MP ,3238kb
 
I know Adobe's raw editor gives you the option of what size you want to output, which ultimately dictates how many MP the image gets outputted as - maybe it's the same on your software and you have the options set to the lowest output setting? Just a thought....
 
Have you got the camera set to sRAW rather than RAW by any chance? sRAW gives a much smaller, roughly 4mp file I think
 
snoop69 said:
I took a few pics today in Raw & L using my 450d.

I have noticed that the Jpeg files are 12mp + (3-5mb) whereas the Raw (CR2) files
are smaller & average 3mp (12mb+).

I would have thought that a 12mp camera would take 12mp pictures if
set to Raw.
Click to expand...

You are mixing things up The 12 Mg is resolution IE the number of pixel not the file size The file size will change for every photo you take It all about how much data is in the shot some will be much bigger then others.
 
I suspect faststone is showing the size of the jpeg preview embedded in the raw file. Try opening the raw file in Canon's DPP and exporting it from there to find out what size it really is.
 
snoop69 said:
Im using Faststone Viewer to view RAW files as they wont open up in CS3.

I have one image that Faststone display as 1504 x 2256 = 3.39MP ,11944kb

The same picture saved as a JPG is 4272x2848 = 12.17MP ,3238kb
Click to expand...
The same viewer I use, great program. Go look in the settings, in the Raw tab there's a bit at the top that says 'View Raw files in: Embedded preview image (Fast)'. You can change that to 'Actual size (Slow)'. Of course the images won't display quite as quickly with that setting but you will get the full size image.

The jpeg preview image that is embedded within the Raw files is only medium size, which is what you are currently seeing.
 
pxl8 said:
I suspect faststone is showing the size of the jpeg preview embedded in the raw file.
Click to expand...
Mark.A said:
The same viewer I use, great program. Go look in the settings, in the Raw tab there's a bit at the top that says 'View Raw files in: Embedded preview image (Fast)'. You can change that to 'Actual size (Slow)'. Of course the images won't display quite as quickly with that setting but you will get the full size image.

The jpeg preview image that is embedded within the Raw files is only medium size, which is what you are currently seeing.
Click to expand...

Correct - settings altered & im now getting the correct info.

Thanks a bunch for all your help :clap: :thumbs:
 
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