Jump to content

Monochrom high iso test


Jay B

Recommended Posts

Advertisement (gone after registration)

I am more apt to take the camera and just go out and shoot, but enough interest has been raised here for me to undertake this absolutely non-scientific test.

There has been some chatter about deliberately underexposing the M9 at a lower iso and then pushing the exposure in post to get better noise results, and questions have been asked, since the Monochrom shares the same base sensor as the M9, if that would work with it.

 

The answer is yes and no.

It is doable, but (to my eye), with the Monochrom, there is no appreciable reason to do it. The underexposed image has a slight (approx. 1/4 stop) gain in the highlight side of the histogram, but the overall noise is the same, and when fully processed, no real differences are apparent.

It does demonstrate how much detail is available in the Monochrom shadows; a 5 stop push on the underexposed image was just fine.

 

#2171: iso 10000, -.3 stop exposure compensation, no other Lightroom adjustments.

#2172: iso 1250, -.3 stop exposure compensation, + 3 stops exposure added in Lightroom.

 

#2171A: Additional post processing in Lightroom to look correct (in my opinion).

#2172A: Additional post processing in Lightroom to look correct (in my opinion).

 

The images are here:

 

http://jayburleson.com/leica/misc_images/mm_iso_test/

Link to post
Share on other sites

#2171: iso 10000, -.3 stop exposure compensation, no other Lightroom adjustments.

#2172: iso 1250, -.3 stop exposure compensation, + 3 stops exposure added in Lightroom.

 

Jay Burleson

 

Jay, thanks for posting these. I didn't look at the images with the additional post processing, but I have some comments on the two "unprocessed" ones.

 

1) They both appear to have been sharpened, and fairly aggressively so, as evidenced by the white halos around black objects, like the coax in the middle upper left. The less processing, the easier it would be to evaluate the images.

 

2) The size of the images at 1350x898, is but a fraction of the resolution of the MM. The aspect ratio is the same, though, which leads me to believe that these are not crops, but resampled images. Is that right? Resampling makes it really hard -- actually, nearly impossible -- to evaluate the noise in the original high-res images. If they are resampled, what was the interpolation algorithm? Some interpolation algorithms incorporate sharpening in their design, which could explain the first point.

 

3) The images have been subjected to lossy, discrete cosine transform, JPEG compression. This type of compression partially removes, by design, high-spatial frequency information, like photon noise, which is what I'd like to look at.

 

If you could post links to crops at the original resolution in uncompressed files (TIFF would be fine), I might be able to make a worthwhile comment. As it is, I'd just be guessing. By the way, monochromatic files are one-third the size of the RGB files you're posting, and contain the same information.

 

Thanks again, Jay.

 

Jim

Link to post
Share on other sites

This test was non-scientific, using the standard methodology that "I" use for creating web-based images, and the original response was to show that iso 10k with the MM was very useable compared to the M9 despite the two sharing the same base sensor architecture.

 

DNG processed in Lightroom 5.3, with default import sharpening.

Uncropped image exported from LR as jpeg 100 quality / sRGB with default web output sharpening. (Lightroom does not have a grayscale option.)

 

My intent was to see if while photographing it was worthwhile to take the extra time & effort to calculate / adjust the camera to do a severe underexposure for better noise response. I typically have auto shutter set to minimum 1/125 and auto iso set to 10000 max and adjust the aperture to achieve the look I want, and work pretty fast getting images, so time is important.

 

In my opinion, looking at the both dng images noise and histograms, it is not a noticeable difference.

Perhaps if one was using a tripod and taking the time to set up a shot, my opinion would be different; I hardly ever work that way.

 

Perhaps someone who has a more scientific method approach to life can do a proper test.

Link to post
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...