The m4/3 system got a significant boost when both Panasonic and Olympus adopted the Sony m4/3 sensor. With this move, Olympus and Panasonic finally has a sensor that can compete with the APS-C sized sensor mirrorless and dSLR cameras. The advantage of a smaller m4/3 sensor is best appreciated not just in a smaller and lighter camera body, but even more, in the smaller and lighter lenses. Nothing illustrates this better than comparing the length, width and weight of the Panasonic 35-100mm f/2.8 versus the Nikkor 70-200mm f/2.8.
The lack of dedicated DX lenses has essentially forced DX users to use FX lenses. While this may be a gain for Nikon, this has several drawbacks that has become apparent and clearer only now. The higher resolution and the resulting even tighter pixel density for the DX sensors means that even lenses that performs well on FX bodies will no longer fare as well with the new DX bodies. DX-specific lenses designed to work with higher pixel density will perform better than FX lenses designed to work sensors with lower pixel density. To appreciate this point, the current 24mp DX sensor in the D3200 and D5200 translate to a 54mp sensor in FX equivalent in terms of pixel density. Many of today's lenses will no longer work as well if Nikon releases a 54mp FX sensor body. Yet such is in fact already the situation now with 24mp DX cameras.
While not directly on tangent, one only needs to look at how the DX and FX lenses fare when mounted on the even smaller sensored Nikon V-1. The Nikon V1 is 10mp and has a 2.7 crop factor. This translates roughly to 73mp in FX equivalent. Photozone.de has reviewed two FX (28mm f/1.8G and 50mm f/1.8G) lenses and one DX lens (40mm f/2.8 macro) adapted for the Nikon V-1 via an FT-1. Looking at the results, one can already see the limitations of these FX and DX lenses when used on a camera with such high pixel density. Although still untested, I expect that a good number of FX lenses that used to work well with 12mp DX will be hard pressed when used with the 24mp DX bodies.
A dedicated DX lens will be smaller and lighter than an FX lens with a similar FOV. By limiting the choice of DX-specific lenses to a very few, Nikon is forcing its users to use FX lenses with its DX cameras. But FX means bigger and heavier and also more expensive. While this strategy may have worked when DX users did not have any serious alternative, that is no longer the situation now because of the m4/3 system. By sticking to its old strategy of making DX a poor cousin rather than a credible contender with its own merit, Nikon presents its DX users who want a lighter and/or less costly setup no alternative but to shift to the m4/3 systems that offers a plethora of small light lenses to use with a seriously capable camera body.
Previous to the E-M5 and GH3, I have not looked at the m4/3 system as a serious alternative for stills and have used the m4/3 GH2 primarily for video. But with the introduction of a GH3 that is also now a serious stills as well as video camera, the m4/3 system with its many prime lens choices plus its 12-25-100mm f/2.8 zoom lenses now offers a very good alternative to a DX system.
The DX system could have battled the m4/3 system specially if Nikon introduces very capable mirrorless DX cameras with smaller and lighter dedicated DX lenses. Instead, Nikon has chosen to continue neglecting the DX system. Nikon's neglect of the DX sector will come back to haunt it in the future unless it reverses course.
The D7000 is my sole DX camera. I likely will no longer get a new DX camera unless Nikon introduces extensive improvement in its new DX camera and support these with new DX-specific lenses. An increase from 16mp to 24mp in the D7000-successor will not make me upgrade my D7000.
Edited by Larry, 01 February 2013 - 16:03 .