the last word

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

  • site home
  • blog home
  • galleries
  • contact
  • underwater
  • the bleeding edge
You are here: Home / GFX 100 / What pitch do you need to scan 6×6 TMax 100?

What pitch do you need to scan 6×6 TMax 100?

November 27, 2021 JimK 2 Comments

I’ve been scanning up a storm with my new home-brew GFX 100S scanner.

I’ve been getting what I consider to be good scans — certainly as good as I was able to get with my now abandoned-and-unsupported-by-the-factory Imacon Precision III. But I wondered if I could get better ones if I used the GFX 100S pixel shift feature.

I scanned this negative both ways:

The sampling pitch is 3.76 um on the image side with no pixel shifting, and 1.9um with pixel shifting. On the negative being scanned, that is about 7 um without pixel shifting, and 3.5 um with it. For those more comfortable with English units, the sampling resolution on the negative is 3600 samples per inch with no pixel shifting, and 7200 samples per inch with pixel shifting.

I processed both stacks (480 images for the pixel shifted version, 30 for the straight stack). I doubled the size of the non-shifted image in both directions in Photoshop using automatic interpolation.  Then I looked at an area with quite a bit of detail in the negative (shown here at 1:1 magnification):

200%

 

Pixel Shift

The shifted image is a bit smoother, but that may have more to do with processing differences than scan pitch.

Here’s an area where there’s a lot of visible film grain:

200%

 

Pixel Shift

 

There is more detail in the pixel shifted image. There’s more grain, too, and the grain appears to be lower in spatial frequency. That’s due to grain aliasing.

I was concerned that vibration would be an issue for the pixel shifted captures. It is not. I am using a vibration-isolation pad under the “scanner”.

Here’s a picture of the scanner where you can see it:

 

With such different workflows, it’s hard to get the processing close for these comparisons.

I’ll make some prints of these images to see whether the differences in the scans are significant in prints.

 

 

GFX 100, GFX 100S

← Poor man’s C1 Cube? What pitch do you need to scan 4×5 TMax 100? →

Comments

  1. Hatzipavlis Peter says

    January 18, 2023 at 4:34 am

    Hi,

    Could you tell me what vibration-isolation pad you are using please? I digitise film using a Sony A7r iv and am getting slightly softer images when shot with the 16 shot pixel shift process compared to the 4 shot and single shot.

    Cheers

    Peter

    Reply
    • JimK says

      January 18, 2023 at 6:07 am

      I think it’s this one.

      https://www.coleparmer.com/i/speirs-robertson-ams-40×50-ams-balance-platform-sorbothane-isolators-40×50-cm/1150005

      Reply

Leave a Reply Cancel reply

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

March 2023
S M T W T F S
 1234
567891011
12131415161718
19202122232425
262728293031  
« Jan    

Articles

  • About
    • Patents and papers about color
    • Who am I?
  • Good 35-70 MF lens
  • 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

  • JimK on Fujifilm GFX 100S pixel shift, visuals
  • Sarmed Mirza on Fujifilm GFX 100S pixel shift, visuals
  • lancej on Two ways to improve the Q2 handling
  • JimK on Sony 135 STF on GFX-50R, sharpness
  • K on Sony 135 STF on GFX-50R, sharpness
  • Mal Paso on Christmas tree light bokeh with the XCD 38V on the X2D
  • Sebastian on More on tilted adapters
  • JimK on On microlens size in the GFX 100 and GFX 50R/S
  • Kyle Krug on On microlens size in the GFX 100 and GFX 50R/S
  • JimK on Hasselblad X2D electronic shutter scan time

Archives

Copyright © 2023 · Daily Dish Pro On Genesis Framework · WordPress · Log in

Unless otherwise noted, all images copyright Jim Kasson.