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the last word

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

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Archives for April 2015

Sony a7II IBIS and sloppy technique

April 25, 2015 JimK 4 Comments

I tested the performance of the in-body image stabilization (IBIS; Sony calls it Steadyshot) on the Sony alpha 7 Mark II (a7II) with 16mm, 28mm, 55 mm, and 180mm lenses. The improvements over handholding without the IBIS turned on were impressive, both in reduction of the average amount of blur, and the tightening of the… [Read More]

The Last Word

Simulating Sony a7II camera motion blur

April 24, 2015 JimK 7 Comments

I few days ago, I posted the results of simulating camera motion blur in a Sony alpha 7R (a7R), showing how the modulation transfer function, as measured by MTF50, varied with camera motion blur measured in pixels, and also showing simulated photographs with their motion distances and MTF50 values, so that you could see what… [Read More]

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The visibility of a7R shutter shock

April 23, 2015 JimK 2 Comments

Ever since the Sony alpha 7R (let’s call it the a7R) came out in late 2013, a furor has raged about its shutter shock, or, more precisely, on whether it had any. One group of people — and that includes moi — were analyzing its effects and developing ways to ameliorate it. Another group vehemently… [Read More]

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Simulating motion blur: MTF50 and pictures

April 22, 2015 JimK 2 Comments

Yesterday, I reported on the results on simulations of a Zeiss Otus 55/1.4 at various f-stops, and showed how MTF-50 values translated into picture sharpness with simulated photographs. Today I’ll do something similar, but varying motion blur instead of f-stop. I set up the sim with the pixel pitch set to 4.88 um (same as a7R or… [Read More]

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What’s MTF50 = x look like: sim pix

April 21, 2015 JimK 6 Comments

Last week, I wrote this post on producing images that show visually the effect of image capture blur on Bayer-CFA cameras. I briefly discussed this simulation-based approach: Start out with a slanted edge. Dial in some diffraction, some motion blur, some defocusing, take the captured image, run it through a slanted edge analyzer, and get… [Read More]

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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

  • bob lozano on The 16-Bit Fallacy: Why More Isn’t Always Better in Medium Format Cameras
  • JimK on Goldilocks and the three flashes
  • DC Wedding Photographer on Goldilocks and the three flashes
  • Wedding Photographer in DC on The 16-Bit Fallacy: Why More Isn’t Always Better in Medium Format Cameras
  • JimK on Fujifilm GFX 100S II precision
  • Renjie Zhu on Fujifilm GFX 100S II precision
  • JimK on Fuji 20-35/4 landscape field curvature at 23mm vs 23/4 GF
  • Ivo de Man on Fuji 20-35/4 landscape field curvature at 23mm vs 23/4 GF
  • JimK on Fuji 20-35/4 landscape field curvature at 23mm vs 23/4 GF
  • JimK on Fuji 20-35/4 landscape field curvature at 23mm vs 23/4 GF

Archives

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Unless otherwise noted, all images copyright Jim Kasson.