Tring to understand "Linear" - terminology quest

Martin2111

• 24. Mai 2006 13:57

This has been vexing me for a while now but I have thought generally, that I don't really need to know and left it at that. You see, up until I came to digital photography, \"linear\" always meant in a straight line or along a line. Digital imaging/processing seems to have taken the term and somehow, made it mean something else.

In the processing options (I generally use film standard or extra shadow) there is a linear option and I am not sure what the linear bit is? Would I be correct in assuming that it means the absence of a curve? i.e. the other options all apply a predetermined curve adjustment but Linear processes \"as is?\"

Just thinkin' out loud here but any contribution to my own non-linear learning curve would be greatly appreciated! 😕

Regards

Martin

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  Gunner B

  • 28. Juli 2006 21:59

  Hi Martcol,
  
  I think you've pretty much worked it out. Digital sensors are described as "linear" - that is, they have a linear (ie straight line) response to changes in light levels. If you double the amount of light hitting the sensor, the output will also double.
  
  Here's a very good article explaining sensor linearity far better than I can:
  
  http://www.dpreview.com/learn/?/key=sensor+linearity
  
  This is very different to the non linear (or "curved") response of film, or of the human eye, both of which deal with highlights and shadows much better than a digital sensor can. (As well they should, given the amount of R&D and evolution they have between them!)
  
  Which is where the concept of "custom curves" comes from. Digital cameras, or RAW conversion software such as C1, apply curves to the raw sensor output, to better manage highlights, shadows and contrast. I'm a relative newbie to C1, (and to digital photography in general), but I'm a great fan of its "film" curves, which give me the same great "look" I get with film. The "linear" menu option (I'm guessing here) is what you get when you don't apply those custom curves to the raw(-ish) sensor output. And pretty dull it is, too. (To me, anyway.)
  
  Yes, you can play around with curves manually in post processing, but for me, the view (as they say) is not worth the climb. As with the film manufacturers, the folks at Phase One have been doing this stuff for years, and they know how to get the best out of my Nikon D200 RAW files, so I leave things in their capable hands. I get consistently good (and indeed, consistent) results, and all I need to do (if I shot it right in the first place) is make minor adjustments to exposure, white balance, etc.
  
  And no, I'm not on commission! 😊 I'm just very impressed with C1. It beats any other RAW converter I've tried, hands down. It saves me a huge amount of time in post processing, which suits my shooting style. I'm a keen amateur photographer - keen enough to shoot RAW - but I'm no digital imaging expert. So I leave that part to those who are.
  
  Regards,
  
  Simon.

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  Martin2111

  • 29. Juli 2006 08:07

  Thanks for taking the time Simon,
  
  I've been thinking about this for about four years now so it's pretty gratifying to think that I might have learned something.
  
  Regards
  
  Martin

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