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Old 12th December 2016
Mark_R2 Mark_R2 is offline
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Re: Teleconverts again

Unfortunately, getting longer than 300mm with a native micro-4/3 lens is not going to be cheap. The Oly 75-300mm lens is a decent lens for the price but is not suitable to use with a teleconverter, even if one existed. At 300mm the lens needs to be stopped down to f8 or smaller aperture for decent results. With a 1.4x TC it will become f11 at best. The TC will introduce its own aberrations and so the lens should really be stopped down further to compensate. But then the resolution will be limited by diffraction instead of aberrations. Thus the combo will never be sharp, irrespective of aperture used.

The choices for going longer than 300mm are not legion. If you need AF, I think the only choices are:

Panasonic 100-400mm lens (native micro-4/3)
Olympus 300mm f4 Pro + 1.4 TC (native micro-4/3)
Sigma 50-500mm 4/3 lens with 4/3 to micro-4/3 adapter
Sigma 135-400mm 4/3 lens with 4/3 to micro-4/3 adapter
A Canon EOS-mount lens with the metabones smart adapter.

I suppose the 4/3 Oly 70-300mm lens could be used with the Oly 4/3 1.4x TC. I have now idea how well this would perform in AF terms, but the points I raised at the start will surely apply so I don’t think it will be optically a happy combination.

Some observations:
I have the Sigma 50-500mm and use it with my EM-1. It is quite decently sharp up to 400mm. AF is a bit twitchy even with the EM-1 (even with its phase contrast AF support). I can C-AF racing cars with it but not especially reliably. The lens is huge and heavy. I made an extra long hood for it and that improves contrast a lot. Even so, it is best to keep the sun behind you.

I have no experience of the Sigma 135-400mm lens but would expect the 50-500mm to outperform it in both resolution and AF.

I have the Metabones smart adapter for EOS to micro-4/3 and have used it with the Canon 100-400mm L lens (mark 1). AF performance with the EM-1 is TERRIBLE. Very slow and twitchy unless the focus is nearly correct. I consider it all but unusable. The Sigma 50-500mm 4/3 lens is better. The Metabones adapter gives MUCH better AF with Panasonic cameras. The adapter is not exactly cheap either, and then you have to get an EOS lens to use with it.

If you don’t need AF, there is a huge range of manual focus lenses that can be adapted to micro-4/3. But, to be honest, I have yet to find a 400mm MF lens that works really well with micro-4/3 (this could be my technique of course!!). Colour fringing is a common problem (though this can be corrected in post). Mirror lenses don’t suffer this way but are rarely sharp. I have a Rubinar 500mm f5.6 mirror lens and that does work well (NB this is the f5.6 not f8 lens, which is crap). This is a BIG lens and really hard to focus due to the thin DOF.

Mark
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