Teleconverter Help!?!!!

Katsi · Feb 25, 2015

So, I have bought a mirror lens, have done a bit of reading and would like to get a 2x teleconverter to experiment with. I know I will lose a few stops of light with the converter. I have a m43 camera so I use adapter rings on most lenses. The mirror lens I have bought is a nikon mount, I have an adapter to m43 so I can use it normally but..... Do I buy a nikon fit teleconverter and the adapt the teleconverter to m43?? Or do I buy a m43 teleconverter and adapt the lens to fit the converter? Will that work? Any ideas?? Don't want to invest in the wrong thing.......

480sparky · Feb 25, 2015

The TC needs to be right behind the lens, so you'd need a Nikon F TC.

I'm guessing it's an f/8 lens, as that's most common. But even a 1.4 TC will make the lens f/11. That's very dark in any camera.

Derrel · Feb 25, 2015

A 2x TC on a mirror lens sounds like a nightmare. I'm going to suggest that it will better to shoot the lens straight, with no TC of any kind, and then simply crop.

Dave442 · Feb 25, 2015

I would use an TC with the Nikon F mount and then have the M43 adapter between that and the camera. However as noted by Derrel, the 2x or really any TC with a fixed f/stop mirror lens is going to be very difficult to use. I used a 500mm f/8 with a 2x TC with an old Pentax ME Super and it was almost black in the viewfinder and took quite a bit of time to focus. It would be interesting to find out if a M43 could focus with this combination (I'm expecting your screen is showing you the same image you would see after taking the shot). It will almost certainly have to be a static subject. I would not buy the TC unless you have a lens that you know you can use it with.

Katsi · Feb 26, 2015

Thanks for your responses. Yeah I was worried about the drop in light. You are correct it is an f8 lens and it sounds like a nightmare to me too, hence my question really. I have a metabones speed booster which will give me back 1 stop of light, I believe that I would normally loose 2 stops with a x2 TC. With the metabones I assume that at x2 I should therefore be working at f11 eventually? Well, I actually plan on only shooting the moon really.... So something that is pretty static. I am aware that focussing will be difficult but I right in thinking that I will get, focus permitting, a cleaner image with a TC than a digital crop??

Derrel · Feb 26, 2015

It's gonna be somewhat tricky...with an effective 1200mm lens at f/11 at 1/250 second or so, the moon might almost be a bit blurry from motion at that long length and at such a slow shutter speed...you'll probably end up needing an elevated ISO value of 400, 500, or 640 to get the sharpness you want...plus the added optics...I think it's a crapshoot on which will actually be better, the converter or just cropping...you might end up moving to 800 ISO in order to get a safe, good shutter speed.

Katsi · Feb 26, 2015

Thanks Derrel. I hear ya! Yeah, the need for elevated shutter speed was worrying me a bit, even with the slow movement of the moon I guess it will be enough to blur a bit. Especially at that effective focal length. Perhaps maybe cropping in will be enough.... I think the teleconverter people may have lost out here........

petrochemist · Feb 26, 2015

AFAIK it should work OK either way round, but there's only one micro 4/3 TC available and that's only recently released. Many more options with Nikon TCs.
Like most of the other replies though I don't think you'll find it worth the effort. Unless it's a top quality lens a digital crop will give much better results.