Sony DSC-P5 Review
Overall Image Quality
The DSC-P5 produces well metered images which have good colour. This little camera clearly has very similar image processing algorithms as are used in the DSC-S75, the primary difference between the two is the lens. The DSC-S75's 'Carl Zeiss' designed lens is much sharper and less prone to distortion / corner softness than the P5's small, compact Sony lens.
Indeed, my primary gripe was the very soft edges to images shot at telephoto focal lengths with a wide open (maximum) aperture. Like most compact digital cameras the P5 only has two apertures; F2.8 or F5.6 at wide angle and F5.6 or F10 at telephoto. These apertures are not manually selectable and so for telephoto shots it would be down to the brightness of the scene as to whether the image came out looking soft (depending on whether the exposure system decided to stop down or not). The DSC-P1 did not seem to suffer from this problem (this years lens is new). I've given some examples of this below.
Purple Fringing (Chromatic Aberrations)
As we'd expected chromatic aberrations are very similar to what we saw on the original DSC-P1. While not as strong as we've seen on some 3 megapixels it's definetly there and more so when the lens is at the full wide angle setting. Also noted is a certain amount of blooming.
|Visible chromatic aberrations in an "every day shot"|
|Our now standard chromatic aberration test shot|
Soft images (at maximum aperture)
Most zoom lenses work better at wide angle to mid-zoom positions and better with at an aperture one or two stops down from maximum (normal SLR rule is two stops, but for digital cameras one stop is usually better).
The DSC-P5, just like the P1 and many other compact digital cameras only has only two apertures which are normally 2 EV's (2 stops) apart; F2.8 or F5.6 at wide angle and F5.6 or F10 at telephoto. This is typically because the aperture diaphragm and shutter are one component.
The camera uses these apertures in combination with shutter speed to get the correct exposure. Cameras with more apertures will tend to stop down at least one or two stops to ensure the sharpest possible image, compacts don't have this luxury.
The DSC-P5 exhibited quite noticable image softness with a combination of maximum aperture and telephoto zoom. Looking through the selection of images we had taken it was easy to isolate those which 'may be soft' simply by looking for any image shot with a telephoto focal length at maximum aperture* (F5.6). It's interesting to note that going back through my DSC-P1 samples I didn't observe the same behaviour.
* When we talk about apertures in relation to zoom lenses the maximum means the largest aperture (smallest F number) possible at a particular focal length.
|39 mm equiv. (wide), F2.8, 1/500 sec
Wide angle, maximum aperture and image is acceptably sharp
|117 mm equiv. (tele), F5.6,
Telephoto, maximum aperture image is noticeably soft
Barrel and Pincushion Distortion
Almost no pincushion distortion at full telephoto and about what was expected at wide angle (1.1% barrel distortion). This is pretty much in line with what we've seen from other ultra-compact (and indeed compact) digital cameras.
|Barrel Distortion, 1.1% @ Wide Angle||Pincushion Distortion, ~0% @ Full Tele|
Unfortunately Sony haven't updated the P5's white balance options, it still has the now dated 'Hold' white balance instead of newer manual preset white balance which would have been far more useful. This means that you only have the option of Auto, Indoor or Outdoor as white balance options (Hold simply freezes the current Auto white balance). Auto white balance did a fairly good job, though better (without any colour cast) under natural or fluorescent light.
|Outdoors, Auto||Outdoors, Outdoor|
|Incandescent, Auto||Incandescent, Indoor|
|Fluorescent, Auto||Fluorescent, Indoor|