What is the difference in a 8x10 picture from 5.0mp to 7.1 mp? by %?

Answer 1

I'm not sure if this is exactly what you want or not, but here's my logic...

I've looked up a couple of camera's in the 5.0 and 7.1 MP categories to see what the image dimensions are. I chose the Canon Powershot A530 (5.0) and SD800IS (7.1), just because I know what their resolution is and I didn't have to hunt around.

The maximum image size on the 5.0 MP camera is 2592x1944 pixels, but if you wanted to get the maximum possible 8x10 out of this image, the dimensions would be 2430x1944.

The maximum image size on the 7.1 MP camera is 3072x2304 pixels, but if you wanted to get the maximum possible 8x10 out of this image, the dimensions would be 2880x2304.

This means the maximum pixels in an 8x10 from the 5.0 MP camera would be 4,723,920 pixels and the maximum pixels in an 8x10 from the 7.1 MP camera would be 6,635,520 pixels.

This means that the 8x10 from the 5.0 MP camera has 71.2% of the pixels from a 7.1 MP camera.

Moreover, the resolution from 5.0 MP camera would be 243 pixels per inch and resolution from 7.1 MP camera would be 288 pixels per inch.

Am I on the right track?

Answer 2

Adding a bit more 'realness' to this, in all cameras with 5MP or greater, well lit pictures will look tremendous when enlarged to 8x10. That's about the break point for 5PM. Well Lit means that the picture a shot in a well lighted area, light a sunny outdoors scene. This is important since the camera's compression circuits will have to work pretty hard in low contrast shots, and the GRAIN will become much more evident. 8x10 is the limit for a 5MP, whereas the 7MP or higher can actually be puched a little larger and still look good.

Don't fret if you just got a 5MP camera for xmas. It will produce GREAT 8x10s when well composed. Lighting is an evil for ALL digital cameras... you are not alone.