JPEG/TIFF Image Size & Quality
The DC4800 offers six different image size / quality combinations. Refered to on the selection menu by their megapixel size they relate to:
|Name||Image Quality||Image Size|
|3.1MP Uncompr.||TIFF Uncompressed||2160 x 1440|
|3.1MP||JPEG 5:1||2160 x 1440|
|3.1MP High Comp.||JPEG 10:1||2160 x 1440|
|2.2MP||JPEG 5:1||1800 x 1200|
|1.6MP||JPEG 5:1||1536 x 1024|
|0.8MP||JPEG 5:1||1080 x 720|
|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. Please only
download the TIFF image if you feel you really have to, otherwise you're
wasting yours and our bandwidth.
Images below are 200% cropped 240 x 120 area of the image.
|2160 x 1440 (3.1MP)|
|1800 x 1200 (2.2MP)|
|1536 x 1024 (1.6MP)|
|1080 x 720 (0.8MP)|
The CFA and noise artifacts visible in these images are here and plain to see even in the TIFF image, it's difficult to justify wasting storage space on a 9 MB image when it's no better than its 705 KB JPEG equivalent. A relatively good selection of resolution modes which would be easy to understand for a beginner.
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 DC4800 offers an Auto mode which will select an ISO sensitivity depending on the available light (tends towards ISO 200 most of the time), you can also manually select ISO 100, 200 or 400 equivalent sensitivity. Crops below are magnified 200%.
|ISO 100, 1/13s, F5.6|
|ISO 200, 1/25s, F5.6|
|ISO 400, 1/50s, F5.6|
A fairly good performance, with the DC4800 there's some visible noise even at ISO 100, this increases (as we'd expect) with each hike in sensitivity, ISO 200 seems usable for small prints or web sized reductions, ISO 400 could be used at a push.
|Thunderheads With Egret by Buzz Lightyear|
|Double Rainbow; Abiquiu, NM, USA. by abiquiuense|
from After the Rain