Wednesday, November 5, 2008

Part 4: Canon 50D sRAW Noise and High ISO test

This sRAW thing is fascinating.

I can't reproduce sRAW results from full RAW files. Not even close. I wish I could though.

On the left is a 50D RAW file at ISO 1600, 200mm f/2.8.
On the right is a 50D sRAW2 file at ISO 3200, 400mm f/5.6 (200mm @ f/2.8 + EF-2x)
Both were cropped to the middle 600 pixels with no resizing necessary.

I thought the higher ISO and EF-2x should have ruined the one on the right, but sRAW overcame that. I'll have to try that test again with smaller apertures to be sure.

It seems to me that sRAW should be valuable to bird photographers who can't get very close to small birds in low light and wonder if they should crop a raw file or use an extender and trade the stop or two of light for higher ISOs. And indoor or night sports photographers where high ISOs and fast shutter speeds are necessary and will either crop use the extenders and don't need huge prints anyway.

sRAW is NOT for saving space on a memory card. The files are extremely bloated for their small resolution. And they don't relieve the buffer much at all. Probably because sRAW is generated from the RAW file, but that would slow the camera down (and it doesn't)?

I now tend to use sRAW1 when at ISO 6400 and sRAW2 when at ISO 12800.

Here's an example of an indoor low light sports photo. sRAW2, ISO 12800, 1/1000, f/2.5, 85mm, cropped not resized. Exposed to the right, corrected and heavily processed in Lightroom.

1 comment:

Harald Hoyer said...

Hmm, changing focal length and aperture does not help comparing.. now it's like apple and oranges..