This is one in a series of posts on the Sony alpha 7 R Mark IV (aka a7RIV). You should be able to find all the posts about that camera in the Category List on the right sidebar, below the Articles widget. There’s a drop-down menu there that you can use to get to all the posts in this series; just look for “A7RIV”.
In a previous post, I showed image of my bookcase made with the Sony a7RIII and a7RIV cameras an the Zeiss Batis 135 mm f/2.8 lens. These images used the Adobe Color Profile for both cameras and no sharpening or noise reduction. The images were made at the same exposure settings, all about 5 stops underexposed, made with uncompressed raw in single shot drive mode.
- ISO 100, f/5.6, 1/25 second
- ISO 200, f/5.6, 1/50 second
- ISO 400, f/5.6, 1/100 second
- ISO 800, f/5.6, 1/200 second
- ISO 1600, f/5.6, 1/400 second
- ISO 3200, f/5.6, 1/800 second
Here’s the overall scene:
Before I showed you the images with no sharpening or noise reduction. Now I’ll show you images processed with what I consider reasonable amounts of both. For same-sized prints, you can use more sharpening and more noise reduction on images from finer-pitch cameras. I took advantage of the tolerance of the a7RIV to more noise reduction before fuzziness sets on, but did not boost the sharpening.
Here are the settings for both cameras:
Here’s the region of the crops:
Here are the comparison images at each ISO setting:
As before, I note that the a7RIV image doesn’t appear to be focused as well.
As before, there is a green shadow shift with the a7RIV at high ISOs.
I’ve tested Adobe NR a lot on my A7RIV images at high iso . It creates strange colour shifts when you push to the aggressive numbers you’re using (making the green tint worse I imagine).
For ISO 3200 and 6400 I have found the following will bring you to a close match with the A7R3 at default. (use with sharpening DETAIL slider up a notch to taste)
Luminance 15
Detail 65
Contrast 0
Colour 25
Detail 55
Smoothness 50
At ISO 1600 <3200 and more detail to play with you can go with:
Luminance 25
Detail 75
Colour 20
No need to use any NR below 1600 in my opinion .
Either way, the A7RIV feels a stop worse than the A7R3 to me – I'll probably end up getting an A9II for high iso work – did you confirm if it also has an AA filter?
Green shift is result of lack information of red and green channel than the NR algorithm create false colors.
I don’t understand what you mean by “information”. In the Shannon sense? I think the color shift is caused by a black point error.