[Tig] Is there anybody out there

[Adrian Thomas]

Film only has a wider NON-LINEAR dynamic range. When I was at  
university, we generally only measured contrast, dynamic range et al  
from the straight portion of the HD curve. If one does that, film  
seems quite poor compared to a typical CCD. Some CCD designs attempt  
to mimic the highlight handling abilities of film, with impressive  
results:-

http://www.dpreview.com/reviews/fujifilms3pro/

and here's another eye-opener:-

http://www.clarkvision.com/imagedetail/dynamicrange/index.html

and another:-

http://www.clarkvision.com/imagedetail/digital.signal.to.noise/ 
index.html

--
Adrian Thomas
Automatic Television
35 Bedfordbury
London WC2N 4DU
www.autotv.co.uk
--


On 2 Aug 2006, at 03:02, Bob Friesenhahn wrote:

>
> It seems to me that the mean reason why film is still considered  
> "better" than electronic capture is due to the wider dynamic range  
> of film.  But high end electronic capture provides sufficient  
> dynamic range and usually looks cleaner than film originated  
> material.  "HD" usually signifies Rec.709 colorspace which implies  
> a specifically limited gamut most suitable for unaltered  
> reproduction and not for substantial post-production.
>
> Another issue is that electronic capture based on a Bayer pattern  
> may not provide as much actual resolution as a film transfer since  
> RGB values are computed from a dithered spacial matrix.  The real  
> resolution obtained from a Bayer sensor depends quite a bit on the  
> honesty of the camera vendor.
>
> The nyquist sampling theorem (http://en.wikipedia.org/wiki/Nyquist- 
> Shannon_sampling_theorem) which is often used to explain sampling  
> resolution actually only applies to *sine* waves so if the image  
> data (or harmonic thereof) does not perfectly fit a sine wave of  
> 1/2 the sampling frequency, then the actual supported resolution  
> must be lower.  According to fourier analysis, any waveform may be  
> recreated using sine waves of particular frequency and amplitude.   
> In order to be able to replicate the original, one must be able to  
> replicate the sine waves.  The output replicated from the samples  
> must be perfectly low-pass filtered to allow only sine waves up to  
> 1/2 the sampling frequency to be passed. Film is reputed to support  
> as much as 6K resolution in 35mm (evaluated by projecting in  
> "analog" form on a screen) so it has a spectral advantage over "HD".
>
> One last issue is that most HD capture sensors are smaller than  
> 35mm so it is more difficult to produce the high Modulation  
> Transfer Function (MTF) lenses (back to fourier theory!) required  
> to apply the same resolution image on these smaller sensors.
>
> BRRE. QED.
>
> Bob
> ======================================
> Bob Friesenhahn
> bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/ 
> bfriesen/
> GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/
>
> _______________________________________________
> Tig mailing list
> Tig at tig.colorist.org
> http://tig.colorist.org/mailman/listinfo/tig