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Color reproduction

Color reproduction is a new addition to our in-depth reviews and provides a quick overview of the general look of images from the camera as well as an ability to compare this to other cameras. Here you can see a generated GretagMacbeth ColorChecker chart, place your mouse over any of the labels below it to see the color reproduction in that mode. Select a camera/setting combination from the 'Compared to' drop-down to comparative boxes inside each patch.

If you compare the DSLR-A100's color reproduction to the Canon EOS 30D (Standard) you'll see that they're remarkably similar, the A100's colors perhaps a little stronger. In comparison with the DSC-R1 the A100's colors appear to have the same hue but are less saturated (probably not a bad thing).

Sony DSLR-A100 Compare to:  
      
      
      
      
StandardVividPortraitLandscape
SunsetNight viewB&WAdobe RGB

Artificial light White Balance

No real surprises here although we were disappointed (once again) to see yet another digital SLR which can't handle automatic white balance in incandescent light. The Incandescent preset on the A100 proved to be pretty good if a little too far to blue for our lighting setup (would it be possible to use the preset as a 'baseline' and then apply some automatic adjustment?). As usual the best results were in fluorescent light where the A100 scored two Excellent's both in automatic mode and using the preset.

Incandescent - Auto WB
Red: 8.5%, Blue: -11.3%, Average
Incandescent - Incandescent preset WB
Red: -0.2%, Blue: 2.5%, Good
Fluorescent - Auto WB
Red: 0.4%, Blue: -0.3%, Excellent
Fluorescent - Fluorescent preset WB
Red: -0.2%, Blue: -0.6%, Excellent

Long Exposure noise reduction / Night shots

As per most recent digital SLR's the A100 provides a 'dark frame subtraction' noise reduction option for long exposures. When enabled this extends the exposure time and uses a 'dark frame' taken after the main exposure to remove hot pixel noise. The A100's noise reduction however appears to go further than this and left the image (in my opinion) looking worse when enabled than when switched off. Artifacts introduced were; 'black pitting' (hot pixels removed but replaced with black pixels rather than the average of surrounding pixels), posterization of gradations (see below) and softening of detail. With NR switched off we counted approximately five or six hot pixels (on a warm evening).

Noise reduction Off Noise reduction On
ISO 100, 30 sec, F9 ISO 100, 30 sec, F9

Noise Reduction Posterization

As noted above one side-effect of enabling long exposure noise reduction appears as the introduction of banding from some kind of posterization, this can be seen fairly clearly on the reduced (and brightened) crops below. My advice would be to avoid the long exposure noise reduction and simply touch-up any hot pixels in post-processing.

Noise reduction Off (brightened, click here for original crop)
Noise reduction On (brightened, click here for original crop)

Flash

The A100's built-in flash and flash metering proved to produce good results even with fairly challenging shots such as our two test shots below (white background often fools flash meters). Color balance was very good with no hint of color cast or incorrect white balance.

Built-in flash Built-in flash

Overall Image Quality / Specifics

Overall results from the Alpha DSLR-A100 were very good, resolution produced by the ten megapixel sensor was as high as we expected, essentially the same as the D200 (we understand that while based on similar designs the D200's sensor is wired differently). Color response was good with very similar hues as the DSC-R1 although perhaps slightly more conservative in saturation, the Landscape setting guarantees brighter more appealing foliage greens and sky blues. Sharpening is conservative, but the detail is there, even sharper crisper images are available if you shoot RAW and convert using Adobe Camera RAW.

Issues? Firstly there's noise at ISO 800 and 1600, while on par with some other models is still about a stop worse than Canon's CMOS sensor, it tends to have a chroma (color) appearance rather than film-like luminance noise (it's a pity nobody else has realize that Nikon's approach of reducing chroma noise but leaving the luminance information alone produces a much more appealing, natural looking image). Second comes an odd multi-segment metering problem that I experienced with all three DSLR-A100's we tested (see below).

Multi-segment metering under-exposure

This rather strange issue reminded me of a similar problem we had with the Olympus E-300, that in certain circumstances, mostly where a small percentage of the scene is much brighter than the rest (although not exclusively), the camera's metering system appears to 'panic' (or simply make a poor decision) which results in image which is under-exposed. This seemed to affect between 5 and 10% of my everyday shots (obviously it depends what you shoot) and was quite easy to 'catch' because the image review would appear quite dark (adding some positive exposure compensation fixed it).

I was also able to reproduce this mounting the camera on a tripod and aiming it at the edge of strong contrast (such as a window frame) and note that even before taking the shot the metered exposure could jump up or down by as much as two stops. As the sub-title hints this problem only affected multi-segment metering mode. (This problem has been discussed privately, at length with Sony who feel that it may simply be something which only affected the cameras I had for review).

Thumbnail Exposure / Luminosity histogram
ISO 800, 1/80 sec, F8, 0.0 EV comp.

ISO 400, 1/250 sec, F13

ISO 400, 1/100 sec, F10, +1.0 EV comp.

ISO 100, 1/160 sec, F11, +0.3 EV comp.

ISO 100, 1/320 sec, F11, 0.0 EV comp.

ISO 100, 1/320 sec, F13, 0.0 EV comp.

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