PDA

View Full Version : question concerning megapixels



wantanewcamera
01-19-2008, 03:59 PM
Ok, I understand that "bigger is not always better" with regards to megapixels if the increase in megapixels is not accompanied with an increase in the size of the sensor, which results in noise

something like that at least..
it may be a silly question to some but how does taking a photograph at a lower picture size affect noise
for instance, what if instead of taking a photograph with a resolution of 3000x2000, I take a photograph with a resolution of 2600x2000?

DonSchap
01-19-2008, 04:37 PM
Ok, I understand that "bigger is not always better" with regards to megapixels if the increase in megapixels is not accompanied with an increase in the size of the sensor, which results in noise

something like that at least..
it may be a silly question to some but how does taking a photograph at a lower picture size affect noise
for instance, what if instead of taking a photograph with a resolution of 3000x2000, I take a photograph with a resolution of 2600x2000?

Well I cannot answer for all the cameras (just the SONY α700), as I have had no reason to use a lower resolution, but I can see no noise change between standard resolution and extra fine, even under crappy Tunsten lighting. The images are identical until you start blowing them way up, then it is the pixels that limit you ... not the noise.

So evidence shows that as far as resolution changing goes ... noise is probably the same in your images. ISO changes are usually where the noise starts creeping in.

griptape
01-19-2008, 04:55 PM
There won't be a difference in noise, because the camera still uses the entire sensor to take the picture, and simply reduces its size when it converts it to jpeg. So you would effectively be doing the exact same thing if you took the picture at full size and resized in in photoshop (or any other editing program).