MP ? Sizes? help me out!

[Michael_B]

I am having a hard time understanding file sizes. I have a tightly zoomed clump of moss image, which is nearly 5.5 MB in size, but I have another image that has more in frame, albeit a blurry background, which is only 1 mb in size, I shoot in L mode and never change. Why the difference?

[k_wakasugi]

Some things of the top of my head... high ISO, or in camera noise reduction both would cause larger filesizes IIRC.

[tracknut]

With a more complex the image, the compression algorithms won't be able to work as well, leaving you with a bigger file. The two extremes might be a noisy image of that moss versus a photo of a plain blue sky.

Dave

[Michael_B]

In camera noise reduction is off..as that locks out continuous shooting. ISO was 100, or 200 on the moss. Reason I ask is for some reason FLICKR loves to upload 2.5 mb size images or less, the moss pic of 5+ mb, yeah it absolutely refuses it.

[Wilt]

If a photo has large areas of rather uniform color, compression works better at reducing file size. If the same photo is taken at high ISO, even with uniform color in the photos, compression is less efficient because of all the noise in the image!

[René Damkot]

You'll want to reduce the size for Flickr anyway. No need to put a 12Mp image online...

PS Tutorial - Resizing Images Using Save For Web (http://photography-on-the.net/forum/showthread.php?t=265690)

Similar can be done using other software.