Archived posting to the Leica Users Group, 2004/09/08

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Subject: [Leica] The Ted Grant Discovery.
From: henningw at (Henning Wulff)
Date: Wed Sep 8 21:29:51 2004
References: <> <>

At 8:11 PM -0500 9/8/04, Clive Moss wrote:
>While on my last driving trip I whiled away the hours trying to figure
>out what my next digital camera, smaller than a Nikon  D100 but faster
>than a Canon G3, would be. Mentally reviewing the bids, I realized
>that the Digilux 2 is unique in one way -- it is the only 5MP camera
>with a 2/3" sensor. The other cameras with a 2/3" sensor are 8MP, and
>the other 5MP cameras have smaller sensors. Thus, the D2 has larger
>pixel receptors, and thus should show less noise, than other non DSLR
>digital cameras (if my memory and mental math served me well.
>This could explain the effect or not, but at least it gives a
>rationale that may fly with SWMBO.

There are a number of 5MP cameras with 2/3" sensors; most are the 
antecedents of the 8MP cameras, such as the Nikon 5000, the Sony 717 
and the Minolta A1. I'm sure there are others.

This sort of procedure has been discussed at various times on digital 
camera forums, and it comes down to: many digital camera sensors have 
fairly good low light sensitivity, and if you boost a significantly 
underexposed photo, you can get a lot of information out of it. You 
risk increasing the noise to unacceptable levels, and you risk 
posterization if shooting in 8bit modes. Changing to B&W tends to 
reduce the detrimental effects in most cases, and can make the photo 
eminently acceptable.

Having a larger sensor helps, but even 1/1.8" sensor cameras can 
benefit from this trick, especially if you're trying to get the most 
from your digicam in low light. The difference between 1/1.8" and 
2/3" sensors is slight as far as noise is concerned. This method 
works especially well with DSLR's, as you can shoot in RAW and 
convert to 16bit, which will never introduce the posterization.

I was shooting in very low light levels last week, to document an 
accident scene for a law case. EV levels at ISO 100 were at and below 
-4 (as low as my Profisix SBC, my most sensitive meter, can read) and 
yet I was able to capture photos with my Canon D60 that could be 
boosted in Photoshop to give reasonable photos, even though they were 
severely underexposed (up to 4 or 5 stops) at ISO 1000, f/2.8 and 
30sec. These were light levels such that you had trouble making out 
door frames on a wall, let alone doorknobs. The D60 is hardly state 
of the art, yet it was able to produce photos in extremely poor 
conditions. The photos, BTW, were shot in jpeg so that processing 
wasn't necessary to view them for the legal use.

    *            Henning J. Wulff
   /|\      Wulff Photography & Design
  |[ ]|

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