Teleconverters?

[Markw]

I have the Nikon D90. I was looking to buy a teleconverter for it. Say I wanted to buy the Sigma 70-300mm lens for it instead of the Nikon 70-300mm. What teleconverter would I need? Would I need a Sigma with a Nikon mount or a Nikon teleconverter? What terms should I lok for to make sure the camera still autofocuses with the TC on it? This confuses me terribly. Any help and/or links would be greatly appreciated. Thanks in advance.

Mark

 

[chrisburke]

i'm thinking you've mixed up your deffination of what a teleconverter is.. its not for mounting other lens on your nikon body.. Its job is to enlarge the central part of an image obtained by the objective lens. For example a 2× teleconverter enlarges the central 12×18 mm part of an image to the size of 24×36 mm.

but to let you know how to go about a sigma lens on a nikon body.. you order the one with the nikon mounts... sigma makes lens that will fit on nikons, canons etc.. you just get the one made for the nikon

 

[Markw]

I know all of this. What Im saying is, I know both sigma and Nikon make Teleconverters. If I have the Nikon body, but the Sigma lens, which brand would I use? Since the Sigma lens has a Nikon mount, I would need a Nikon Teleconverter, correct? Or do other brands make teleconverters that would fit both the Nikon lenses and bodies?

Mark

 

[chris miss]

You might want to contact customer service at Sigma. I have the 70-300 lens for a Canon and was thinking of doing the same thing. They told me that the 70-300 lens isn't compatible with a teleconverter. Maybe someone else knows something different, but that's what they told me.

 

[davebmck]

You can buy a third party teleconverter for your Nikon, just get one with the mount for your camera. There have been many threads here on teleconverters. You should do a search and read these, because there are many issues with using teleconverters, such as losing autofocus and incompatibility with certain lenses.

 

[Dao]

If I am not mistaken, the 70-300mm lens from both Nikon and Sigma will not work with the TC.

You need a lens that has a Max Aperture of F/2.8 or larger in order to use it. And in general, the 2x TC lose 2 stops of light and 1.4x TC will lose 1 stop.

So a 70-200mm F/2.8 will work and it behave as a 140mm-400mm F/5.6 lens with a 2x TC

 

[Overread]

there are several types of teleconverter on the market:

1.4 teleconverter - increases focal length of the lens by 1.4times and reduces max aperture of the lens by one stop; thus can be used on an f4 lens - moving it to an f5.6 which is the AF limit on Canon cameras and is petty much a limit on Nikon as well (unless you buy the top range flagship camera bodies). Note that whilst Nikon has no AF limit after f5.6 accuracy and speed take a noticable hit especailly in less than very bright conditions.
A 1.4TC generally will give you very little to no (when combined with pro end lenses) loss of image quality and is about the best TC for your money.

1.7TC - nikon make one and it takes away 1.5stops of light and also reduces quality further than a 1.4TC. I have not used one myself (canon user only) but to all extents I belive its a good choice for combining with a good lens (probably limited to primes only and the very top range of zooms)

2TC - doubles your focal lenght, but also robs you of 2 stop of light - so its f2.8 lenses only or else your onto manual focusing. It also gives you a very noticable drop in image quality. This TC is best reserved only for the top lenses where a drop in quality will not be too damaging on the final image.

As for the lenses you are thinking of - the 70-300mm zooms - I don't think any TC would be of use on them - even the 1.4s. The quality of the 70-300mm is just not high enough (in general) to be able to take a TC and still produce acceptable results - though of course acceptable is a personal standard. Also I don'y think there are any TCs that will actually fit a 70-300mm - certainly my Canon and Sigma TCs will not fit my 70-300mm sigma. Further after seeing the TCs in action and also my experiences of my sigma lens I think and boost in focal length gained would be offset by a larger loss of quality - cropping from a 300mm shot without TC would probably produce a better or equal quality image as one taken with a 1.4 TC and zoomed in closer