Nikon 40mm f/2.8G AF-S DX Micro - £235/$280
The most compact lens in the group, the Nikon 40mm is even smaller and lighter than the Nikon 18-55mm VR supplied with cameras such as the Nikon D3100. Conveniently for kit lens owners, it also has the same 52mm filter thread, as does the Nikon 85mm f/3.5G AF-S DX ED VR Micro.
The front element doesn't rotate during focusing with the 40mm, which it does on the 18-55mm, although it still extends as you focus from infinity down to the minimum focus distance.
When you're close-focusing, the lens extension is a problem - at its closest setting, the front of the lens is a mere 3.5cm from the subject. This will often cast whatever you're shooting into shadow unless the main light source is at the side or you're using ring flash.
Autofocus isn't particularly fast for a ring-type ultrasonic system, but is aided by a focus limit switch that can lock the range at 0.2m to infinity. Due partly to the compactness of the lens, the manual focus ring is small, and it lacks smoothness both in autofocus override and full manual mode. On the plus side, sharpness, contrast and image quality are very good.
From f/2.8 to f/11, sharpness edges ahead of even the Sigma 105mm, and is still excellent at f/16.
Sharpness at f/2.8: 2471
Sharpness at f/8: 2559
Sharpness at f/16: 2025
Fringing is slightly higher than average for a macro prime lens, but only towards the corners of the frame.
Fringing at f/2.8: 0.33
Fringing at f/8: 0.45
Fringing at f/16: 0.57
There's very marginal pin-cushion distortion, but it's barely noticeable in images and not really an issue.
Image quality verdict
The baby Nikon delivers excellent image quality, but the short focal length of 40mm makes it impractical for many common macro scenarios.