• site home
  • blog home
  • galleries
  • contact
  • underwater
  • the bleeding edge

the last word

Photography meets digital computer technology. Photography wins -- most of the time.

You are here: Home / GFX 100S / Long exposure noise in X2D 100C, GFX 100x, part 3

Long exposure noise in X2D 100C, GFX 100x, part 3

November 14, 2022 JimK Leave a Comment

This is the 35th in a series of posts on the Hasselblad X2D 100C camera and the XCD lenses. You will be able to find all the posts in this series by looking at the righthand column on this page and finding the Category “X2D”.

In the previous post, when looking at 15 minute dark-field exposures made with the GFX 100S and Hasselblad X2D, it appeared that the noise spatial frequency distribution of the Fuji camera was biased towards lower frequency noise, making the noise more obtrusive, even though it was lower in amplitude with the GFX 100S.

In this post, I’ll look at that issue quantitatively.

We’ll be looking at raw plane spectra, so we’ll need to sort out which raw plane is which. The Fuji uses a GRBG Bayer pattern, and the Hasselblad uses a RGGB one, so:

  • Plane 1 on the X2D is red, and plane 1 on the GFX is green
  • Plane 2 on the X2D is green, and plane 2 on the GFX is red
  • Plane 3 on the X2D is green, and plane 3 on the GFX is blue
  • Plane 4 on the X2D is blue, and plane 4 on the GFX is green

The red planes:

I’ve had to use a different scale for the GFX vertical axis. You’ll see why in a minute.

The horizontal scale is frequency, normalized to the sampling frequency of the sensor. Everything but the vertical orientation in the X2D has about the same high frequency rolloff of roughly 2 stops from DC to half the sampling frequency.

The blue planes:

 

The GFX has substantially more rolloff. That is especially obvious near zero frequency, where there is a spike big enough that I couldn’t fit the curve on a graph with a plus and minus three stop range.

The first green channel for each camera:

 

The X2D is flat. The GFX is almost flat, but has a big spike near zero frequency.

The second green channel for each camera:

 

Both are pretty flat.

GFX 100S, X2D

← Long exposure noise in X2D 100C, GFX 100x, continued Long exposure noise in X2D 100C, GFX 100x, part 4 →

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

June 2025
S M T W T F S
1234567
891011121314
15161718192021
22232425262728
2930  
« May    

Articles

  • About
    • Patents and papers about color
    • Who am I?
  • How to…
    • Backing up photographic images
    • How to change email providers
    • How to shoot slanted edge images for me
  • Lens screening testing
    • Equipment and Software
    • Examples
      • Bad and OK 200-600 at 600
      • Excellent 180-400 zoom
      • Fair 14-30mm zoom
      • Good 100-200 mm MF zoom
      • Good 100-400 zoom
      • Good 100mm lens on P1 P45+
      • Good 120mm MF lens
      • Good 18mm FF lens
      • Good 24-105 mm FF lens
      • Good 24-70 FF zoom
      • Good 35 mm FF lens
      • Good 35-70 MF lens
      • Good 60 mm lens on IQ3-100
      • Good 63 mm MF lens
      • Good 65 mm FF lens
      • Good 85 mm FF lens
      • Good and bad 25mm FF lenses
      • Good zoom at 24 mm
      • Marginal 18mm lens
      • Marginal 35mm FF lens
      • Mildly problematic 55 mm FF lens
      • OK 16-35mm zoom
      • OK 60mm lens on P1 P45+
      • OK Sony 600mm f/4
      • Pretty good 16-35 FF zoom
      • Pretty good 90mm FF lens
      • Problematic 400 mm FF lens
      • Tilted 20 mm f/1.8 FF lens
      • Tilted 30 mm MF lens
      • Tilted 50 mm FF lens
      • Two 15mm FF lenses
    • Found a problem – now what?
    • Goals for this test
    • Minimum target distances
      • MFT
      • APS-C
      • Full frame
      • Small medium format
    • Printable Siemens Star targets
    • Target size on sensor
      • MFT
      • APS-C
      • Full frame
      • Small medium format
    • Test instructions — postproduction
    • Test instructions — reading the images
    • Test instructions – capture
    • Theory of the test
    • What’s wrong with conventional lens screening?
  • Previsualization heresy
  • Privacy Policy
  • Recommended photographic web sites
  • Using in-camera histograms for ETTR
    • Acknowledgments
    • Why ETTR?
    • Normal in-camera histograms
    • Image processing for in-camera histograms
    • Making the in-camera histogram closely represent the raw histogram
    • Shortcuts to UniWB
    • Preparing for monitor-based UniWB
    • A one-step UniWB procedure
    • The math behind the one-step method
    • Iteration using Newton’s Method

Category List

Recent Comments

  • Hakan Yesil on Fujifilm 20-35/4 GF distortion
  • JimK on More Than Exposure: Understanding Total Light on the Sensor
  • Brandon on Adobe Super Resolution
  • Brandon on A Modest Proposal
  • Jeffrey Horton on More Than Exposure: Understanding Total Light on the Sensor
  • JimK on A Modest Proposal
  • Brandon on A Modest Proposal
  • DC Wedding Photographer on Price and Performance: Hasselblad X vs. Fujifilm GFX
  • DC wedding photographer on A Modest Proposal
  • NiceDays on Do Raw Developers Use the Embedded JPEG as a Color Reference?

Archives

Copyright © 2025 · Daily Dish Pro On Genesis Framework · WordPress · Log in

Unless otherwise noted, all images copyright Jim Kasson.