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Is the Sony a7 ISOless?

February 19, 2014 By JimK 3 Comments

With the noise floor and self-heating testing out of the way, we’re ready to tackle the question, “Is the a7 ISOless?” If that question makes no sense to you, hang in there. Explanations follow. If you’ve read this or a similar explanation before, skip to the graphs. Let’s talk a bit about how your camera… [Read More]

Shutter slap simulation with ISO 12233, part 2

January 3, 2014 By JimK 2 Comments

I’ve done some more work with my camera simulator. I decided that doing the antialiasing filtering by allowing fill factors of greater than 100%, while programmatically convenient, is not always a good approximation to real AA filters. So I’ve added a separate AA operation that uses either rectangular averaging (box) filtering or circular averaging (pillbox)… [Read More]

Sony a7R noise floor

December 6, 2013 By JimK Leave a Comment

I am not completely happy with the preceding two posts. In order to do a better job of characterizing the vibration effects of the a7R’s shutter, I need to get further from the ‘scope, make the light path longer with mirrors (no smoke), or come up with a completely different way of making the measurement…. [Read More]

Sharpness testing, part 2

November 2, 2013 By JimK 4 Comments

I wrote a little Matlab program to generate the targets: And, yes, all you Matlab experts, I know it can be coded a lot more efficiently, even by me. I wrote it this way so that any Java or C programmer could figure it out. Here’s what a close up of the first four layers… [Read More]

Traveling with the Leica M240, part 6

October 20, 2013 By JimK Leave a Comment

Size and weight One eternal virtue for a travel camera is small size and light weight. The M240 is smallish by DSLR standards, and the lenses are much smaller than the best-performing DSLR lenses. Weight is not so clear-cut. An M240 with strap, battery, SD card, RRS grip and plate, 18mm Super-Elmar, hood, lens cap,… [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
  • 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 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

  • Robert Frangioso on Why so few posts?
  • Ken on Noise reduction and downsampling
  • Robert Kuechle on Chronography video up
  • JimK on Leica 90/2 Apo-Summicron ASPH-M on GFX 50S
  • DanB on Leica 90/2 Apo-Summicron ASPH-M on GFX 50S
  • gideon on How fast is the Sony a7RIV silent shutter?
  • JimK on How fast is the Sony a7RIV silent shutter?
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  • JimK on How fast is the Sony a7RIV silent shutter?
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Unless otherwise noted, all images copyright Jim Kasson.