Teleconverter query.

[Mike Kennedy]

I just received a 2 times Vivitar teleconverter for my Nikon mf system. Will I loose 2 stops or more?
Before anyone mentions just how cruddy teleconverters are I needed one to lighten my field kit.

Thanks Much,
Mike

 

[Marco Gilardetti]

Yes, it's generally 2 stops. Converters are not always THAT bad. Just try it.

 

[David A. Goldfarb]

Generally, look for a 7-element converter. They are usually better than the 4-element types. You might find that you lose a little more than two stops with most 2x converters due to transmissive loss. It's not a big deal if you use TTL metering, but if you use a handheld meter, your exposures might be up to a half stop under.

Quality depends a great deal on the prime lens. With long lenses look for color fringing in contrasty areas to see if they'll stand up to being used with a doubler.

 

[Christopher Walrath]

As a matter of fact, I just did a lens/light test with my XG-M and my lenses. I found that my fixed focal length lenses and my zooms were pretty much dead on as to exposure settings compared against each other. But with a teleconverter, attached to either the zooms or the FFL's I had a three stop decrease in light metered with my TTL meter. At both f5.6 and at f16. Best thing to do is set up a test like that which I did.
28mm 28mm ffl and 28-70 zoom set at 28
50mm 50mm ffl and 28-70 zoom set at 50 and 28mm w/ 2x tele
70mm 28-70 zoom at 70 and 70-210 zoom at 70
100mm 50mm ffl w/ 2x tele and 70-210 zoom at 100 and 28-70 zoom w/ 2x tele at 50
140mm 28-70 zoom w/ 2x tele at 70 and 70-210 zoom at 140

At all focal lengths and aperture settings, the 2x tele setups reduced light by 3 stops.

 

[glbeas]

Cheap teleconverters are nice, you can unscrew the glass from them and use them for coupled extension tubes, usually around 25mm extension. I used to use a set for my old Minolta rig, with the extension stacked under a good teleconverter I got a 7/8th inch field of view and the results were pretty sharp.

 

[Dave Parker]

Mike,

In the wildlife photography I do, a convertor is mandantory, I use a 7 element 2X and a 5 element 1.4, if you get a good quality model, the loss of quality, is really not that bad, back when I still had good eyes and shot manual focus gear, I always found the Vivitar to be very good, what you need to do, is take some test shots at various apertures and see what the sweet spot of the combos you are shooting are.

Yes, as an average, you will loose 2 stops on 2x and 1 stop on a 1.4

Dave

 

[Christopher Walrath]

Same here. I still get good quality images w/ my teleconverters but they do rob alot of light and somewhat reduce your options.

 

[MattKing]

I have a really neat Vivitar 1.4 teleconverter, that is only for close focus work with my Olympus OM cameras. It allows me to use standard or moderate telephoto lenses (particularly my 85mm f/2.0) and adjust the magnification between about 1/10 life size and 1/2 life size (IIRC). If I use it with one of my automatic exposure OTF models (OM2 etc) it handles the exposure question effortlessly. It is only slightly bigger than a couple of extension tubes, and gives me results that I am very happy with.

Just an example of a relatively unknown item, that works really well.

I bought it used, and very cheap.

 

[Dave Parker]

Hey Matt,

I have one of those as well, for a screw mount system, it is a neat little convertor, that has the pin for the exposure and stop down system on the screw mounts.

Dave

 

[Claire Senft]

2 Stops is the correct adjustment. How good the results are depends upon the optical relationships for this marriage. They can certainly be dreadful. On the other hand when the items are well made and specifically designed for use with each other the combination can be extremely good. A TC with a new MRP of $25 being mated to a new $100 zoom lens with a 5x ratio or more
may have you wishng that you brought your Holga Lubitel along for entertainment. A TC that comes with a new 300 mm 2.8 Zeiss sport pack for a Hasselblad at $25 grand may be so good that you have forgotten your first love, Holga Lubitel, stole your purity.

It is unlikely in the ultra extreme that the TC and lens together will out perform the lens by itself.

 

[Lee Shively]

I'm going to throw a kink into this discussion. I have two old Canon A2E (AKA EOS 5) cameras and the Canon 1.4x and 2x extenders. With some of the Canon lenses, the exposure compensation with the extenders is not the standard stop/2 stop.

There's a compensation table for the extenders when used with certain lenses on the A2E bodies. I've also used them on a Rebel body and there is no compensation necessary. It's an odd little glitch that would mean nothing to you unless you're using A2E/EOS 5 cameras.