Re: About CCD response

From: Roger Hamlett (rogerspamignored_at_ttelmah.demon.co.uk)
Date: 06/18/04 

Date: Fri, 18 Jun 2004 16:24:54 +0100

"Paco Rosso" <pacorosso@ono.com> wrote in message
news:1kDAc.21472$kn2.344947@news.ono.com...
>
> > The dynamic range available from CCD's, especially, if the chips are
cooled
> > to reduce the thermal noise, is _massively_ higher than achieved by any
> > film.
>
> This is not what I see every day. I see dinamix range of CCD cameras
> more lower than black and white film.
> Not theorical values, but "visual input", I am electronic engineer and
> photographer.
I suspect you are not seeing true 'dynamic range'. The key is that film, has
a compression effect, tending to clip bright objects at the top of the
scale. It also tends to 'lose' dark objects at the bottom of the scale
(reciprocity failure). If you expose film to avoid these sections, the
useable range is small. Film, behaves rather like a CCD, with an anti
blooming gate, being able to shoot in bright conditions, and return data in
the darker parts of the image, with little sign that the data has been lost
at the top end of the image scale (but it has). Visually the effect is
smooth, making it possible to effectively be significantly overexposing.
Also remember that most commercial cameras, are using relatively lower
accuracy AD converters. If you look at industrial CCD systems, using 16bit,
or in some cases 18bit AD converters, the dynamic range is truly massive
compared to film.

Best Wishes

Relevant Pages

  • Re: DSLR vs P&S a replay of Film vs Digital?
    ... looking at the curves given on Norman Koren's webpage, ... the film was capable of recording. ... That is the actual dynamic range of the captured image ... If you set your exposure meter to 400, ...
    (rec.photo.digital)
  • Re: How far...
    ... especially DSLRs have higher dynamic range than film. ... Dynamic Range and Transfer Functions of Digital Images ... means you didn't meter and expose correctly. ... With a digital camera you expose to not blow any highlight you don't want blown, then you generally have the signal to noise to pull the image from the shadows. ...
    (rec.photo.digital)
  • Re: How far...
    ... especially DSLRs have higher dynamic range than film. ... Telling me the cameras would help. ... just like photographers have to learn to expose slide ...
    (rec.photo.digital)
  • Re: DSLR vs P&S a replay of Film vs Digital?
    ... In theory a 12-bit digital camera can have a 72 dB ... The graphs for film that we've looked at in this thread ... Even the Kodak curves for Tri-X don't ... 3.0, or roughly about 631:1, for 56 dB of dynamic range. ...
    (rec.photo.digital)
  • Re: high dynamic range in P&S ??
    ... highlights and amplifying mid and low range signals. ... None of that will increase "apparent dynamic range". ... misunderstanding of exposure technical details. ... It works for both digital and film, ...
    (rec.photo.digital)