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Image Size / File Quality Options

The DSC-F828 provides a total of five image sizes, each is labelled with an approximate megapixel value, these are: 3264 x 2448 (8M), 2592 x 1944 (5M), 2048 x 1536 (3M), 1280 x 960 (1M), 640 x 480 (VGA). In addition there is also a 3:2 size which records a 3264 x 2176 image, essentially the standard 8M image vertically cropped. All image sizes can be output as JPEG Fine, JPEG Standard and TIFF. In addition the DSC-F828 becomes the first Sony Cybershot to provide a RAW image format, it writes these files with the .SRF file extension. Sony's RAW images are a little larger than we would expect (8 million x 14 bits = approx. 14 MB). It looks to me as though Sony's engineers simply pack out each pixel to a 16 bit value, which is wasteful to the tune of 2 MB per image.

The RAW image shot below was converted to TIFF using the supplied Image Data Converter 1.0.


Standard Test Scene

To give an impression of what some of the combinations of image size and quality produce the table below is a cross reference of some of them:

  • 3264 x 2448 (8M) RAW
  • 3264 x 2448 (8M) TIFF
  • 3264 x 2448 (8M) JPEG Fine
  • 3264 x 2448 (8M) JPEG Standard
  • 2592 x 1944 (5M) JPEG Fine
  • 2048 x 1536 (3M) JPEG Fine
  • 1280 x 960 (1M) JPEG Fine

Crops below are of the same 240 x 100 area of each image nearest neighbour magnified 200%.


 
8M: 3264 x 2448
RAW
16,986 KB .SRF + 3,799 KB JPEG (not for download), VGA crop - 541 KB .TIF
TIFF
23,413 KB .TIF + 3,792 KB JPEG (not for download), VGA crop - 587 KB .TIF
JPEG
Fine

3,804 KB
JPEG
Std.

2,018 KB
   

 
5M: 2592 x 1944
JPEG
Fine

2,245 KB
JPEG
Std.

1,272 KB
   

 
3M: 2048 x 1536
JPEG
Fine

1,410 KB
   

 
1M: 1280 x 960
JPEG
Fine

558 KB

To my eye at least there is virtually no difference between the output of Image Data Converter converted RAW's and TIFF/JPEG images straight from the camera. The difference of course is that Image Data Converter provides a certain amount of adjustment to the images before they are converted to the final format. Otherwise quality is as we expect, some JPEG artifacts appearing in the higher compression images, some slight sharpening 'halo' artifacts around dark detail.

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