I read a comment or a post recently which inferred that a 7D II file shot as a jpg at one of the smaller sizes was inherently cleaner than a larger file at similar settings (ISO etc).
Is there any truth to that statement? If this is crazy talk just say so.
I bring this up because I own a 7D and if someone can tell me that a Medium Jpg is 10x cleaner than a Large or Raw ... I'm locking those settings in today. Moreover, is that the case with all cameras? Is this phenomenon a jpg exclusive or is it the same with Raw? I mean, I have printed like 40 files of size 8x10 and nothing bigger. So if I can get cleaner images that will print at that size amazing ... Awesome..
Why isn't this 'feature' advertised?
I think that saying "smaller files
" is the reason the images are better is wrong and misleading. The size of the file really has nothing to do with it. JPEG files are smaller than RAW files, even at full size image dimensions, however RAW files are generally superior, often far superior, in terms of IQ.
It isn't the file size that matters. It is the image dimensions, and more specifically the relative image dimensions
, that matters. By relative, I mean in relation to the original image size. A smaller image, in terms of dimensions, generated from the same sensor, means that a greater quantity of information was "oversampled" to produce a lesser quantity of better quality information.
When you take a large image, say a 20mp image, an downsample it, you are taking a lot of original source data, averaging it together and packing it into a smaller spatial area. Averaging many pixels into fewer pixels reduces noise, by the square root of the number of pixels averaged. Downsample an image to 1/4 the original area, and you reduce noise by a factor of two (2x2 pixels averaged into one pixel, SQRT(4) = 2.) Downsampling also has the effect of improving acutance, which improves sharpness, which is a big factor in terms of what we perceive as image quality.
So, no, smaller files does not mean better IQ. Smaller images, in terms of spatial area, often DOES mean better IQ. You can achieve smaller images in a few ways. Obviously you can downsample larger images. You could take a RAW image, process it to optimum quality, then export it as a downsampled JPEG. The results are likely to be superior to a small-sized OOC JPEG every time. You can also use a lower resolution sensor with bigger pixels, however depending on exactly how the sensor is designed, that may or may not actually improve IQ as much as downsampling a higher resolution image (i.e. use and strength of AA filter, or lack of an AA filter entirely, could dictate whether a lower resolution sensor is better than downsampling images from a higher resolution sensor.)