Previous page Next page

Post-capture Exposure Compensation

Probably one of the single biggest strengths of the Kodak DCS digital SLR's is their huge dynamic range. Load an image into Photo Desk, knock the exposure compensation down half a stop (-0.5 EV) and you'll see detail leap out of what previously appeared to be completely lost overexposed areas. It's almost as though every shot is deliberately captured under the selected exposure to leave some headroom in the RAW file for downward compensation.

The example below shows an image which ended up with portions of the scene overexposed, I simply dialled in -1.0 EV compensation and detail which appeared to have been lost suddenly appeared. Very impressive. All images were processed as TIFF and converted to JPEG later.

As shot, the white brickwork on Tower Bridge is clearly overexposed
1,975 KB JPEG
Not a problem, just set exposure compensation to -1.0 EV and the detail is there
1,538 KB

This is something I've tried with D1/D1x images in Nikon Capture and haven't so far been able to pull out even half as much detail from overexposed highlights.

'Look' (contrast)

Kodak's acquire module has always had this concept of 'Look', this has migrated to Photo Desk and is essentially a way to control image contrast. A setting of 'Product' produces a normally balanced image where black is almost black. A setting of 'Portrait' pushes the black end of the grayscale upwards (and flattens it a little) to produce more visible shadow detail (clearly this compresses the middle of the grayscale). It's a handy way to produce a 'lighter' image without changing exposure compensation. All images were processed as TIFF and converted to JPEG later.

Look: Product / 1,248 KB JPEG
Look: Portrait / 1,376 KB JPEG

Color (RGB / Gray)

Lastly, you can choose to save the image as full colour or 'gray'. Useful if you wish to shoot grayscale or are looking for the cameras optimum image resolution.

Color: RGB / 1,989 KB JPEG Color: Gray / 1,570 KB JPEG

Footnote: the need for high quality lenses

Something which I hadn't considered was the DCS 760's need for high quality lenses. It's obvious of course that a six megapixel sensor requires a lens which can generate very good resolution, but with the DCS 760 it's a bit more complicated than that...

Using lenses on the Nikon D1x we're capturing the center 66% of the frame for the final image (1.5x focal length multiplier because of the size of the sensor in proportion to a 35 mm negative), this means you can get away with using average lenses and still get very good results (the 28-105 mm F3.4 - 5.6 D is a good example).

However, the DCS 760 has a larger sensor with just a 1.3x focal length multiplier, this means that it captures the center 76% of the frame for the final image, this requires the lens to be that much sharper to the edges. Something which became quite apparent looking up near the edges of some of my shots taken with the 28-105 mm F3.4 - 5.6 D).

And here we are all begging for full frame sensors...

Previous page Next page
I own it
I want it
I had it
Discuss in the forums