Macro Focus

Optimum macro performance for the DSC-R1 was found at full telephoto with a subject distance of 35 cm from the focal plane (sensor) or 25 cm from the front lens element (this is the same as the Sony specified minimum focus distance). At this combination of focal length and subject distance we measured a frame coverage of 97 x 64 mm which produces just over 1000 pix/inch at the ten megapixel setting.

Wide macro - 315 x 234 mm coverage
11 px/mm (281 px/in)
Distortion: High
Corner softness: Low (with slight CA)
Equiv. focal length: 24 mm		 Mid-zoom macro - 97 x 64 mm coverage
40 px/mm (1014 px/in)
Distortion: None
Corner softness: Low (with virtually no CA)
Equiv. focal length: 120 mm

Barrel and Pincushion Distortion

Kudos to Sony's lens designer (or should we thank Carl Zeiss?), at 24 mm (equiv.) wide angle the DSC-R1 only produced 1.1% barrel distortion which we would consider below average for a 'normal' zoom lens at around 35 mm equiv. It's highly unlikely that you'll see this amount of distortion in everyday shots unless you framed a line in the scene very near to the frame edge. At telephoto we could measure no distortion at all. (Apologies for the poor white balance in these images, thumbnails have been desaturated).

Wide angle - 1.1% Barrel distortion
Equiv. focal length: 24 mm		 Telephoto - 0% Pincushion Distortion
Equiv. focal length: 120 mm

Purple Fringing (Chromatic Aberrations)

For anyone concerned that the DSC-R1 would be an F828 Mark II, fear not, the DSC-R1's lens / sensor combination performs far better and exhibits only slight purple fringing at the extreme combination of maximum wide angle plus maximum aperture.

Thumbnail 100% Crop
24 mm equiv, F2.8 (max aperture)
24 mm equiv., F2.8 (max aperture)

Vignetting & Light Falloff

Where relevant we now included a measured falloff test in our reviews, the DSC-R1 is relevant because it has a fixed lens designed specifically for its sensor and hence will produce an imaging circle just large enough, this could well lead to some falloff at large apertures.

Testing


Measurement Areas
We aim the camera at a white wall (about 0.5 m away) which is evenly lit by two soft boxes (producing about 10 EV across the entire wall), the lens is manually focused to be about 1m out of focus (to avoid picking up texture detail from the wall). A sequence of shots are now taken at every aperture from maximum to F11 (beyond this there's only a very slow roll-off from the lens & camera combinations we tested), for zoom lenses at both wide angle and telephoto.

These images are then processed by our own analysis software which derives an average luminance (Lum) for the four corners of the frame (5% each) as well as the center (10%), the corners are averaged and the difference between this and the center of the frame is recorded. This value can then be plotted (see graphs below) as a representation of the approximate amount of falloff (as negative percentage).

Range of falloff

The chart below demonstrates the difference that these figures above can make, we took the blank wall luminance value of 75 (about 190,190,190 RGB) as our normal level. Remember that these patches are solid and the actual effect of shading is a softer gradual roll-off which would not necessarily be so obvious.

Compared

As you can see the DSC-R1 performs very well, its maximum falloff of 16% at wide angle and maximum aperture (F2.8) is well below our 'noticeable' threshold of 20%. Compare that to the EOS 20D with its 'digital' EF-S 17-85 mm lens (price $599), it exhibits potentially noticeable falloff at wide angle up to F5.6. Note that we have used the EOS 20D in this comparison, results with the EOS 350D (Digital Rebel XT) would be identical.

Sony DSC-R1 vs. Canon EOS 20D (with EF-S 17-85 mm lens)

The images below were produced from our test shots, they have been deliberately 'posterized' to indicate different levels of falloff. Each band represents a 10% drop in luminance. As you can see the DSC-R1 performs very well, considerably better than the EOS 20D with its 'digital' EF-S lens. At maximum aperture you are unlikely to see any falloff on the DSC-R1, however on the EOS 20D (with this EF-S lens) you may see some falloff at F4.0 (maximum aperture) and possibly also at F5.6. At telephoto neither camera / lens combination produced enough falloff to be of concern.

 
Sony DSC-R1

24 mm equiv.
Canon EOS 20D
EF-S 17-85 mm lens
27 mm equiv.
F2.8 n/a
F4.0
F5.6
F8.0
F11