ARS wrote:
If I mount a 50mm Nikon ais lens to a m4/3 body with an adapter, will it be a 100mm equivalent or stay at 50mm.
Arnold
The LENS is always going to remain 50mm. The 2X magnification factor of m43 will give it the field of view similar to a 100mm lens used on a full frame body.
Using Nikon full frame lenses on my Lumix GH4 has been mostly annoying. I have 24, 35, 55, and 135mm Nikkors I can adapt to m43, but:
> The 24mm f/2.8 is one of the worst Nikon lenses I ever owned. Only the 43-86mm zoom from the 1960s was worse. Using it as a 48mm equivalent field of view optic on m43 just magnifies the coma, astigmatism, and other issues of the 24.
> The 35mm f/2.0 was my favorite film lens. But it is mediocre on m43. Contrast is low, oddly, it is prone to flare, and as an unstabilized 70mm equivalent field of view, it is unsteady.
> The 55mm f/3.5 "Micro Nikkor" has a 110mm field of view equivalence on m43, useful for video interviews, macro work and portraits. But its lack of modern coatings leaves it prone to flare.
> The 135mm f/2.8 has a 270mm field of view equivalence on m43, but since it is a manual focus lens and has no stabilization, it is hard to control.
My twins use these lenses on occasion for filmmaking. But we find them all annoying. The adapter is just a mount adapter. There is no automatic diaphragm, no meter coupling, no autofocus, and no lens compensation data to be passed to the firmware, so you're essentially dumped back into the 1950s and the very early days of Exakta SLRs! Plus, they're double the size and weight they need to be for m43 coverage.
I have a 12-35mm f/2.8 II Lumix G X-Vario zoom, a 30mm f/2.8 Lumix Macro lens, a 42.5mm f/1.7 Lumix prime, and a 35-100mm f/2.8 Lumix G X-Vario zoom. All of these have image stabilization (my GH4 does not have IBIS). They also have autofocus, auto diaphragm, and transmit lens aberration and other data to the camera's JPEG engine firmware and to Lightroom Classic for raw file processing. These lenses make very sharp images with lots of contrast.
I highly recommend buying used lenses from KEH, MPB, UsedPhotoPro.com, Adorama, or B&H. Micro 4/3 lenses are a much better match for Micro 4/3 cameras.