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Image Size / JPEG Quality options


Standard Test Scene

The 6800Z offers eight different combinations of image size and JPEG quality, as we know the camera features Fujifilm's honeycomb layout SuperCCD sensor with 3.3 megapixels, Fujifilm are then processing this "honeycomb" of pixels to produce a maximum 6 megapixel (2832 x 2132) image. They also provide the option for a 3 megapixel (2048 x 1536), 1 megapixel (1280 x 960) and VGA (640 x 480) sized image. It's worth noting that the 3 megapixel image despite having a similar pixel count to that of the sensor can't be seen as a 1:1 representation of captured data as the captured pixels are in a 45-degree honeycomb pattern.

To provide an impression of the image quality at each image size / quality combination we've provided samples at all possible sizes and qualities (bpp = bits per pixel):

Size Pixel count Quality JPEG compression level
6M 2832 x 2132 Fine 3.2 bpp
6M 2832 x 2132 Normal 1.5 bpp
6M 2832 x 2132 Basic 0.6 bpp
3M 2048 x 1536 Fine 3.2 bpp
3M 2048 x 1536 Normal 1.5 bpp
1M 1280 x 960 Fine 4.0 bpp
1M 1280 x 960 Normal 2.0 bpp
VGA 640 x 480 Normal 2.0 bpp

Images below are cropped 240 x 100 area of the image magnified 200% (nearest neighbour).


 
2832 x 2132 (6M)
Fine
2,309 KB
Normal
1,063 KB
Basic
409 KB
 

 
2048 x 1536 (3M)
Fine
604 KB
Normal
276 KB
 

 
1280 x 960 (1M)
Fine
415 KB
Normal
262 KB
 

 
640 x 480 (VGA)
Normal
70 KB

It's interesting, Fujifilm have had to face the dilemma other manufacturers will be facing over the next 12 months, that is to provide a set of compression levels at very high pixel counts (6 megapixel) which strike a balance between file size and image quality.

There's no point having a six megapixel output if it's so heavily compressed that you lose much of its advantage. Kudos then to Fujifilm for just about achieving that, at full resolution and the highest quality (6M Fine) the images weigh in at about 2.2 MB and are artifact free, at the next compression level down (6M Normal) images are just over 1 MB and JPEG artifacts are starting to creep in, to my eye there was no need for 6M Basic as it's just too heavily compressed.

I'll not talk too much about actual pixel-by-pixel image quality at this stage, I'll discuss that later in the review.


ISO (Sensitivity) Adjustment

ISO equivalence on a digital camera is the ability to increase the sensitivity of the CCD to allow for faster shutter speeds and/or better performance in low light. The way this works in a digital camera is by "turning up the volume" on the CCD's signal amplifiers, nothing is without its price however and doing so also amplifies any noise that may be present and often affects colour saturation.

The 6800Z offers three different sensitivity settings of ISO 100, 200 and 400. Note that this makes the 6800Z the first SuperCCD to offer ISO 100, previously the lowest sensitivity was ISO 125 from the 4900Z. It's also interesting that on this higher pixel count SuperCCD Fujifilm appear to have dropped the ISO 800 sensitivity.

Images taken at 6M (2832 x 2132) Fine.

ISO 100, 1/69s, F2.8
ISO 200, 1/137s, F2.8
ISO 400, 1/274s, F2.8

And we can see why they dumped ISO 800, at ISO 400 noise is very obvious and worse of all it's mostly affecting the chroma channel (colour) and producing a random red/green/blue noise. ISO 200 isn't too bad and could probably be used in good light situations to increase shutter speed (though I wouldn't use it for longer exposures).

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