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the last word

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

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Archives for May 2025

Input-referred read noise spectra in the CFV-100C

May 28, 2025 JimK Leave a Comment

In my last post, I showed graphs of the input-referred read noise spectra at several ISO settings for the GFX 100 II. Spikes were visible which I attributed to the PDAF pixels. I ran a similar test with the Hasselblad CFV100C, and there are no such spikes.              

X2D

Looking at input-referred read noise spectra across ISO ranges

May 26, 2025 JimK Leave a Comment

I’ve added code to see how input-referred read noise from dark field images varies as the ISO setting of the camera is changed. For the GFX 100II, with 600×600 pixel crops away from the center of the sensor:                 You can see the following things: Decrease in input-referred… [Read More]

The Last Word

Another way to look at read noise spectra

May 24, 2025 JimK Leave a Comment

I’ve been looking for a better way to present read noise spectra, and I think I’ve found one. These graphs present the average horizontal spectra of each of the four raw channels, one ISO setting per eight-panel plot set. The reference level is preserved across the graphs, so that you can see the ensemble increase… [Read More]

The Last Word

Why it’s so hard to forecast camera production (and no, it’s not a conspiracy)

May 20, 2025 JimK Leave a Comment

Every time a hot new camera is released, and the new Fujifilm GFX 100RF certainly qualifies, there’s a flurry of speculation online. Why is it in such short supply? Did Fujifilm intentionally limit production to create artificial scarcity? Are they playing games with the market? I don’t think so. What’s more likely is something far… [Read More]

The Last Word

The Last Word in a generative pre-trained transformer

May 18, 2025 JimK Leave a Comment

If you wish to access the text content of The Last Word, you can do it here: https://chatgpt.com/share/682a0e4a-6714-800b-8b88-48b07545dc67   Limitations: Users must be ChatGPT Plus subscribers ($20/mo). Custom GPTs have no persistent memory per user. Each session is stateless unless the user keeps the window open and continues the same thread. Files users upload are… [Read More]

The Last Word

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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

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