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JPEG/TIFF Image Size & Quality

Thankfully Sony listened to our complaints about having one fixed JPEG mode and with the S75 have added a new "Standard" JPEG mode, this means you can now choose from a variety of image resolutions (2048 x 1536, 2048 x 1360 (3:2), 1600 x 1200, 1280 x 960 and 640 x 480) in combination with either JPEG FINE, JPEG STANDARD or TIFF image quality, a total of 15 different image size / quality combinations.


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:

  • 2048 x 1536 TIFF
  • 2048 x 1536 FINE JPEG
  • 2048 x 1536 STANDARD JPEG
  • 1600 x 1200 FINE JPEG
  • 1280 x 960 FINE JPEG
  • 640 x 480 FINE JPEG

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


 
2048 x 1536
TIFF
9,219 KB (Not available for download)
JPEG
FINE

1,360 KB
JPEG
STD

795 KB
 

 
1600 x 1200
JPEG
FINE

847 KB
 

 
1280 x 960
JPEG
FINE

593 KB
 

 
640 x 480
JPEG
FINE

152 KB

As you can see close-up there's very little difference between the TIFF and JPEG FINE, if anything the JPEG FINE image seems to look "cleaner" (weird). The overall feeling I'm getting for the S75's images at this stage is that they're slightly softer with less aggressive sharpening than we saw on the S70, I'm all in favour of cleaner sharpening as bad sharpening often introduces unwanted artifacts.


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 S75 now features three selectable ISO sensitivities of 100, 200 and 400 as well as the same Auto mode we saw on the S70 (varies sensitivity between ISO 100 and 300 automatically depending on available light). Our first set of test images were taken under normal light (our standard sensitivity test), however we were so impressed with how clean the higher ISO images were we shot again under dark conditions to push the camera's abilities.

ISO 100, 1.3 s, F5.0
ISO 200, 1/1.3 s, F5.0
ISO 400, 1/2 s, F5.0

As you can see high sensitivity noise is pretty much kept under control with the S75, at least it doesn't appear as we'd normally expect (monochromatic), rather it seems to mostly effect the hue / saturation channels of the image rather than luminance. All in all the S75 performs well at high sensitivities compared to other 3 megapixel digital cameras.


Picture Effects

Just as with the S70 (and most other Sony digital cameras) the S75 features four 'post processing' picture effects which can be used to stylise your images.

No picture effect Negative Art picture effect
Sepia picture effect Black & White picture effect
 
Solarize picture effect  

Note that as well as this you can use the "TEXT" mode to shoot black and white (2 colour) photocopy style GIF's (useful for copying text, although slow to process) and apply a date-stamp onto the image (same as S70).

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