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Auto ISO

The DC280 has an interesting feature which enables the camera to switch automatically to a higher ISO when required (low light - ISO 200).

A quick note for those who don't understand how digital cameras "replicate ISO". When a manufacturer designs the camera they'll typically use a CCD which, combined with a signal amplifier produces a light sensitivity somewhere near ISO 100 (that is the same exposure value as ISO 100 film would require), to increase the ISO you simply "turn up the volume" on the signal amplifier.. The trade off is that you also amplify noise and can end up with a grainy image.

Measured light (using a flash meter) was 5.2EV, Center Weighted Metering. ISO values are according to EXIF headers.

Auto ISO: OFF (click for larger image) Auto ISO: ON (click for larger image)
ISO 100, 1/6s, F3.8

Auto ISO: ON
ISO 200, 1/8s, F3.8

Here you can see that the exposure was "pushed" from 1/6s to 1/8s but at the expense of added noise. That combined with the odd JPEG encoding errors from the DC280 makes very low light images pretty grainy.

JPEG Compression qualities

Here's a 200% blow-up of the same shot taken at differing JPEG qualities, you can start to see the JPEG artifacts creeping in at BETTER quality and they're easily visible at GOOD quality. The same image at STANDARD (896 x 592) resolution.

BEST: 577KB (click for larger image) BETTER: 373KB (click for larger image) GOOD: 195KB (click for larger image)
BEST 1760 x 1168
BETTER 1760 x 1168
GOOD 1760 x 1168

Overall I wasn't that happy with the JPEG compression in the DC280, I saw the same flat area artifacts which I found on the DC265 and I've seen in DC240 images, the obvious 8x8 blocking and "surrounding detail" artifacts can be found even in the BETTER quality images which is a pity because the camera can take really very nice shots.

Sharpening settings

The DC280 has the ability to control the internal sharpening on three levels, SOFT (some softening of image), NORMAL (no sharpening), SHARP (sharpening).

SOFT (click for larger image) NORMAL (click for larger image) SHARP (click for larger image)

As you can see not a huge difference between NORMAL and SHARP.

Internal Flash

Flash coverage test (click for larger image) Skin Tone test (click for larger image)
Flash Coverage: Fairly good, even flash from about 10ft from wall, very slight Cyan cast.

Skin Tone: Very good, and taken quite close to hand, no paleness or burn-out.

Macro Flash test (click for larger image)  
Macro Flash: Taken from about 20cm in macro mode, SLIGHT overexposure (could be compensated by exposure adjustment), otherwise good colour balance.

Exposure Lock

The DC280 has the ability to lock the exposure (aperture / shutter speed combination) from an initial shot for all subsequent shots. This feature is most useful when shooting panoramas where each image must have the same exposure (to get a seemless match at the edges of each photo). The image to the right of this text is stitched together using Enroute's Quickstitch and is a vertical combination of FIVE DC280 frames. The camera was set to Exposure Lock mode once this is done it prompts you to take the first shot, I took the middle one first, then two above and two below.

Because each frame is taken using the same exposure the images at the bottom came out slightly underexposed and the images backlit with the sky slightly overexposed, however the colour of all merging objects was the same for the whole vertical panorama, the images were then combined in Quickstitch and the result can be seen here.

Five image combined panorama (click for larger image)


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