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JPEG/TIFF Image Size & Quality

The 4900Z has nine different resolution / quality combinations. Remember that because the 4900Z utilises a 2.4 megapixel honeycomb CCD ("SuperCCD") none of these resolutions can be truly described as "native" (one CCD pixel for one image pixel). At the default resolution of 2400 x 1800 80% of the image data has been generated using Fujifilm's "processing algorithms" (they don't like me to call it interpolation). At the next resolution 1600 x 1200 there's a 12.5% "downsampling" of image data. Because the pixel layout of Fujifilm's SuperCCD isn't square there's no way to produce a pixel-for-pixel image on our square pixel output devices and image formats.

Standard Test Scene

To give an impression of what each combination of image size and quality produces the table below is a cross reference of image size against quality with an original image available for each, all images were shot within seconds of each other of the same subject. The TIFF file at 2400 x 1800 is a bandwidth crunching 12 MB and offers very little extra over the FINE JPEG (weighing in at about 1,600 KB). If you REALLY need the TIFF file then contact me.

Images below are 100% cropped 480 x 180 area of the image.
 


 
2400 x 1800
TIFF
(HI)

12,721 KB (not available for download)
FINE
JPEG

1,687 KB
NORM
JPEG

749 KB
BASIC
JPEG

307 KB
 

 
1600 x 1200
FINE
JPEG

781 KB
NORM
JPEG

323 KB
 

 
1280 x 960
FINE
JPEG

591 KB
NORM
JPEG

269 KB
 

 
640 x 480
NORM
JPEG

67 KB

Conclusions? Well, images at the 2400 x 1800 resolution always looked a bit soft to me, but that's to be expected as there are some "made up pixels" in there. Normal JPEG doesn't introduce much in the way of JPEG artifacts and looks like the best bet for every day shooting, Fine JPEG for those special occasions. The 4900Z really shines if you shoot lower than the default, at 1600 x 1200 images are crisp and clean and at about 800 KB per image at Fine JPEG you'll still get a good number of images on a 64 MB SmartMedia card.


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.

ISO 125, 1/2s, F7.0
ISO 200, 1/3s, F7.0
ISO 400, 1/6s, F7.0
ISO 800, 1/11s, F7.0

For my money the new ISO 125 (the 4900Z is the first SuperCCD digital camera with an ISO sensitivity setting lower than 200) doesn't offer any cleaner an image than ISO 200. There's a VERY SLIGHT difference but nothing like we were hoping, I think most people were hoping the new ISO 125 would be a new silky smooth noise free setting perfect for the compositions you have time to set up.

At higher ISO's the noise is more than apparent and seems to affect the entire dynamic range equally.


Sharpening

The 4900Z allows for control over the cameras internal sharpening algorithm with three different settings of Soft, Normal and Hard. I'd also like to have seen control over other internal algorithms such as contrast (tone) and colour saturation (as they've done for the S1 Pro).

Sharpening: Soft
Sharpening: Normal
Sharpening: Hard

Well, not a huge difference between Normal and Hard, I'm sure 90% of users will leave the sharpening setting at Normal.

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