Canon 30D questions

I feel confused and I need some clarification.

I just recently realized, when shooting at JPEG (Highest resolution setting), my files are no bigger than 3MP but the size is showing 3504 X 2336.

I’ve always shot JPEG before and the MP was always 7MP or higher based on shutter speed and so on, but recent photos I’ve taken even at the highest JPEG setting on my 30D only shows 3MP and smaller files.

Is this normal?

I assume you are concerned because you have heard (or believe from experience with film scanning) that file size = image quality. This is not really the case. Pixel dimensions rather than file size are a better indicator of how much information your chip is capturing.

That said, JPEG is a compressed file format that will produce radically different file sizes based for the most part on the repetition of identical color values (so product shots on seemless or a cyc will probably be smaller than a landscape). However once the image is open the file is now "uncompressed" and shows its true size. Photoshop will indicate this size at the bottom-left of the image window. If I recall the first file size shown is the file size as most recently saved and the second number is the file size of the current edit. I might have those switched or have it completely wrong but it is something like that. Layers especially will increase the "uncompressed" file size. It is basically an indicator of how much space the scratch disk is using for this image.

If you open a JPEG and re-save it as a TIFF you can see its true uncompressed file size (this is also just a good workflow considering JPEG is a lossy quality – every time you re-save a JPEG you worsen image quality – TIFF and PSD are lossless).

don't confuse image resolution with file size in megabytes -- MB. 3MB is a common size for out of camera 8MP jpgs.

Could it be that you are mistakenly reading the megabyte value for megapixels?

The picture size 3504x2336 is OK and it amounts to a total of 8.19 megapixels (MP).

The .JPG file size of about 3 megabytes (MB) is right too. Only the .JPG file size will increase with the amount of picture detail, higher ISO and strong sharpening. I have never had it reach even close to 7 megabytes, though.

Take a picture with alot of trees and see how big the file is. It depends of the subject matter also.

7 megs is about what the average RAW file is out of my 30D. Sure you're not confusing the JPEG size with the RAW size?

when you shot RAW and then DPP the file ...you should get 0ver 8MB JPG image .

That is normal if you just shot jpg .