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 / Technical / Antialiasing, part 3

Antialiasing, part 3

January 3, 2011 JimK Leave a Comment

Sunlit wet asphalt aside, most pictures I make with cameras lacking antialiasing filters look just fine with no special post processing. That doesn’t mean that there’s no aliasing going on; it just means that the artifacts thus produced look fairly realistic and aren’t objectionable.

There are two eminently defensible but mutually exclusive perspectives on whether to use an antialiasing filter at capture time.

  1. You’ve got to use an antialiasing filter, because once the aliased information is captured, no post processing in the world can sort out what’s aliased and what’s not, and thus the image can never be corrected.
  2. You don’t want an antialiasing filter, because it costs you sharpness. If you get visible aliasing, you can make the image look good with a little post processing.

The counterarguments are as follows:

  1. We’re not doing forensics here. It’s not important that the image be a mathematically accurate view of the world; the main thing is that it looks realistic.
  2. The algorithms that reduce aliasing artifacts blur detail and desaturate fine structures; you can’t just apply them to every part of every image. I don’t have the time or energy to go through every photograph looking for artifacts and fixing them; let the camera get rid of them.

There’s a British expression “horses for courses” that translates to something like “what’s best depends on the situation.” That applies here. If you’re a journalist, or a wedding photographer, or anyone else producing pictures in bulk with little or no editing, you want the antialiasing filter. If you’re an artist looking for one or two great images a month, or a commercial photographer looking for one or two great images a day, and are willing to spend the time going over your work with a fine-tooth comb finding and fixing artifacts, then you’re probably better off without it.

If you buy that line of reasoning, then maybe you’ll like my speculation as to why most 35mm-sized DSLRs have antialiasing filters and most medium format DSLRs don’t: most of the people buying the bigger cameras are using them in situations where they are producing a few very high-quality images, and they’re willing to suffer the pain of finding and correcting the artifacts.

Note that I keep emphasizing finding the artifacts. If you’re going for the very best quality and treating every picture like it’s precious, you’ve raised the stakes. You sure don’t want to be standing in a gallery with your pictures on the wall and have someone spot something that’s just not right, or turn in the double page spread for which you’re charging many thousands, and have the art director see a problem.

Next time: what the future might hold.

Technical

← Antialiasing, part 2 Antialiasing, part 4: the future →

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.