Summary: Overall this is a very impressive and inexpensive lens that should bring true macro photography within the grasp of most DX-format camera users. There are a few minor weaknesses, the most obvious of which is relatively sluggish focusing in AF mode, but there is nothing serious to dislike about this lens.
Excerpt: The AF-S DX Micro-Nikkor 40mm f/2.8G is the most affordable macro lens for Nikon's range of DX format DSLRs, and as an AF-S model, it'll autofocus on any Nikon body. Yes you read this right: it's even cheaper than any lens capable of 1:1 magnification from Sigma or Tamron. If you think that doesn't bode well for the performance of this little lens read on: there's a pleasant surprise waiting for you!
Excerpt: Nikon has brought the macro lens goodness (btw: Nikon calls macro, Micro) for DX-format shooters with the new, portable Nikon AF-S DX Micro-NIKKOR 40mm f/2.8G ($279) . For less than $300, this lens is a steal and a must-have for anyone within the Nikon D40 to D7000 range. Delivering high-resolution, contrast-filled photos with gobs of background blur, this lightweight 40mm lens will shoot anything from infinity to life-size (1x).
Excerpt: In both capability and cost, this close-up lens is a gift to DX-format (APS-C-sensor) Nikon shooters. A full-frame equivalent of 60mm, it delivers a lot for its meager $280 street price: 1:1 macro shooting, a fast f/2.8 aperture, metal lensmount, and great optics. The closest Nikkor with 1:1 subject magnification, the full-frame 60mm f/2.8, costs nearly twice as much.
Summary: Although the AF-S DX Micro Nikkor 40mm f/2.8G has obvious limitations when it comes to macro photography, the pros it offers to entry-level and enthusiast photographers outweigh the cons. The lens is sharp, resolving a great deal of detail, while the multicoated optics produce a good level of contrast and colour.
There are distortions, but these are minimal and easily removed in editing software, or in-camera if you are shooting JPEGs.
Summary: The relatively low price tag makes this lens an attractive proposition for cash-strapped enthusiasts who want a lightweight and relatively compact macro lens. But, being designed specifically for DX cameras, it won't suit photographers with Nikon's 'full frame (FX) camera bodies. Its light weight will suit travellers, while near-silent operation will make this lens attractive for photographers who want to create movies of small subjects.
Micro Nikkor AF-S DX 40mm f/2.8 G (CX) - Review / Test Report
24 January 2013
Conclusion: The Nikon AF-S DX 40mm f/2.8 G offers excellent resolution in the image center straight from the maximum aperture. The borders and corners struggle a bit at large aperture settings, but stopped down reach very good resolution.
Excerpt: In July 2011 the Nikon company quite unexpectedly presented a new lens - the Nikkor AF-S DX Micro 40 mm f/2.8G. It is a macro instrument, with the 1:1 reproduction ratio, designed to cooperate with reflex cameras featuring DX sensor format. It gives the same angle of view as a 60 mm device on full frame (so 39 degrees).
Cons: the build quality could have been at least a tad better,, noticeable astigmatism,, slow autofocus,, huge vignetting at the maximum relative aperture,, too weak work against bright light.