Lens Tests

On fixed-lens compacts like the Coolpix A, the lens is right at the heart of the imaging system, and ultimately just as important as the sensor and processor in determining the image quality. Fortunately the Nikkor 18.5mm 1:2.8 is really rather good: its only flaw is relatively strong vignetting that persists on stopping down. However the Ricoh GR's lens is just as good, while exhibiting less vignetting: click here to compare the two in our lens data widget.

Note: it's not possible to determine the T-stop for a fixed lens camera, so this number is not displayed.

Sharpness Sharpness results are impressive. The centre of the frame is very good even wide open, although the corners lag behind a bit. Optimum results are obtained from F4 - F8, beyond which diffraction starts to have a clear softening effect. We'd probably steer clear of F22 (the smallest available setting) in normal use.
Chromatic Aberration Lateral chromatic aberration is very low, to the extent that you'll rarely see it in practice. But for the record you may see a little blue/yellow fringing at the extreme corners of the frame in uncorrected raw conversions (the camera's JPEG processing will remove it automatically).
Vignetting The lens's one weakness is vignetting - it measures 1.7 stops wide open, and drops only slightly to 1.5 stops at F4. But from then on it persists at all apertures, right down to F22.
Distortion The Coolpix A shows a little barrel distortion with recorrection towards the corners, but it's sufficiently low that you'll rarely see it in real-world shooting.

Macro Focus

The Coolpix A has a quoted minimum working distance of 10cm and it's actually more effective than this in real-world use. Our unit would happily focus down as close as 9.4cm, giving a magnification of 0.2x - a perfectly reasonable result for a camera with a 28mm equivalent lens.

Macro - approx 118 x 78mm coverage
Measured magnification: 0.2x
Distortion: negligible

Minimum focus distance*: ~14cm
Working distance**: 9.4 cm
Focal length: 18.5mm (28mm equiv)
* Minimum focus is defined as the distance from the camera's sensor to the subject - the position of the Nikon's sensor is not marked, so this figure is approximate.
** Working distance is measured from the front of the lens to the subject

What's rather less impressive is the image quality when working this close-up: all the lens' slight weaknesses are exaggerated when focused this closely. The slight curvature-of-field we saw when shooting our new test scene is much more pronounced, here, with image sharpness dropping away as soon as you move away from the center of the image. The camera's tendency towards vignetting is also amplified, with this back-lit scene exagegerating the effect to almost Instagram levels of corner shading.

The corners sharpen-up slightly as you stop down but are still rather smeared, even at F8 and the vignetting never goes away.

The lens test data in this review is produced in collaboration with DxOMark. Click here for the full test data and DxOMark's own review of the Coolpix A's lens, over on dxomark.com