5dMKIII.....taking the picture....Post Processing.....PRINT

[jrw]

Silly questions for the day.

1) When comparing camera noise levels why are both not shown at native resolution? Upsizing and downsizing is known to affect apparent noise. Even though it is nice to bring both to same size for easier direct detail capture comparison, why can't we also get the originals for both to assess whether resizing software has also changed the noise levels?

2) Much is made of the Nikon blacks and how they can be pushed up to such high levels. It is also known that Nikon clips the blacks in the camera. Is it possible to determine the levels in the blacks to see at what level they have been clipped in the Nikon shots and compare that to the Canon shots to see if that is one possible source of the noise? So many people go on about the need for the same treatment of the files, but if it is to be done should not the differences of in-camera processing be adjusted for as well?

Not trying to fan any flames here, just hoping to increase my understanding.

[Daniel Browning]

1) When comparing camera noise levels why are both not shown at native resolution?

Because that's not how the images are used in real life. If I was trying to decide between two cameras and I was comparing noise, I would print out images at the same size. Increasing magnification on just one of the cameras wouldn't provide an equal footing.

Upsizing and downsizing is known to affect apparent noise.

Quite right. While you should always apply resizing in order to get realistic results, different programs do resizing very differently. That's why I prefer to get the raw files and do the conversion and resizing myself, so I can see how they perform with my particular set of software and methods.

Even though it is nice to bring both to same size for easier direct detail capture comparison, why can't we also get the originals for both to assess whether resizing software has also changed the noise levels?

I don't know why. Usually when I post comparisons, I also post the raw files.

Is it possible to determine the levels in the blacks to see at what level they have been clipped in the Nikon shots and compare that to the Canon shots to see if that is one possible source of the noise?

Yes, it's possible to determine the black levels. It's always at or very near to the read noise floor. It's about the place where most Canon raw converters will clip blacks -- and in fact most of them do it before any other processing, so you get the exact same result as if it was done in camera. (A few converters, such as RawTherapee, don't clip it right away though, which is smart.)

And no, that is definitely not the source of the noise difference. Nikon clips the blacks way, way below the level at which Canon becomes unusable.

So many people go on about the need for the same treatment of the files, but if it is to be done should not the differences of in-camera processing be adjusted for as well?

Yes. That is always a good point to remember.