Optimum Noise Reduction when down sizing high ISO A7RII files
A7RII raw files, especially the uncompressed version I have my camera set to save, are big. The native pixel size is 7952 by 5304. That’s a 26 inch print at 300 pixels per inch. The pixel count also means a really big file on disk. When I’m sending JPGs to the studio I downsize the files to 3600 pixels on the long size. That still means 12 inches on the long side and could be 18 inches at 200 pixels per inch. Rarely does a file need to be larger.
The next question is what are the best noise reduction settings for the 3600 pixel images? The A7RII delivers good high ISO performance, especially when the file is downsized and some noise reduction is applied. So I created virtual copies of two images in Lightroom one shot at ISO 3200, the other at ISO6400. I applied a series of noise reduction setting to the images, beginning with no noise reduction. Second 25/50/0, 25/50/50. Third 40/50/0, 10/50/50. Fourth 50/50/0, 50/50/50.
What follows are 100% crops of each image.
ISO 6400 No noise reduction applied:
ISO 6400 Luminance: 25/50/0, Color: 25/50/50 noise reduction applied:
ISO 6400 Luminance: 40/50/0, Color: 10/50/50 noise reduction applied:
ISO 6400 Luminance: 50/50/0, Color: 50/50/50 noise reduction applied:
ISO 3200 No noise reduction applied:
ISO 3200 Luminance: 25/50/0, Color: 25/50/50 noise reduction applied:
ISO 3200 Luminance: 40/50/0, Color: 10/50/50 noise reduction applied:
ISO 3200 Luminance: 50/50/0, Color: 50/50/50 noise reduction applied:
Everyone will have a personal opinion about which looks best. Keeping in mind that these crops represent what an 8×12 print might look like. Its also worth noting that looking at 100% crops on a monitor offers more visual acceptance than a print is like to have when held at normal viewing distance.
When I was a young photographer I wanted my high ISO B&W prints to have sharp grain. Recognizing that the grain was part of the image. Personally, some noise in a high ISO image doesn’t bother me.
Here is the ISO 6400 image with no luminance noise reduction, 50/50/50 Color noise reduction, then adding 10/10/50 grain.
Here a crop of the image that is more than 2000 pixels on a side. Reduced here to 900 pixels, to illustrate how high ISO, color noise reduction and grain work together.
It was a great party. It was a local band concert.