R.Jackson wrote:
>Interesting experiment, Moose. Here's something I don't understand,
>though.. .... it comes down to unmanageably large data
>streams. That's not really the case in still photography, though.
>Wouldn't a portrait photographer not care if he couldn't take another
>photo for 30 seconds as long as he could shoot at 14 or 16-bit
>latitudes?
>
As far as I know, all DSLRs and high end prosumer cameras capture at
least 12 bits per channel and some DSLRs capture 14 bits. So if one
shoots in RAW mode and converts to a format that supports 16 bits, like
TIFF, PSD, etc., all that latitude is there. Of course if you shoot
JPEGs, a format that only supports 8 bits, the camera has to compress
the brightness range before writing the data out. I believe the reason
nobody has gone to 16 bit yet in commercial consumer equipment is
technological limitations in the sensors and the signal handling
electronics. Another reason is that there aren't any common display
technologies that will display that range.
>I don't get why it's taking so long to get digital cameras
>with the same kind of latitude as negative films. Or am I missing some
>crucial point?
>
They are already well past reversal films. I suspect the 14 bit cameras
are already pretty close to color neg. Looked at one way, they are
already past neg film because the latitude of neg film is so
asymmetrical, with only about a stop advantage over slides on the
underexposure end for best results, and gobs on the overexposure end. If
you shoot neg film to have lots of underexposure latitude, you have to
derate the speed a couple of stops and the overall results on normal
exposures aren't as good as when exposed at the rated speed. If you
properly expose DCs "to the right", you maximize both ends of the
exposure range
<http://www.luminous-landscape.com/tutorials/expose-right.shtml>. Then
you have a usable latitude as great or greater than neg exposed at its
rated speed. It requires a different mind set when shooting, but gives
excellent usable latitude.
Moose
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