Teleconverter

alexkara

Hi,
i have a D5200 and a Tamron (SP 70-300mm F4-5.6 Di VC USD).
I want a teleconverter. Is there anyone who can help me ?????

bruto

Though it is often possible to use a teleconverter, remember that with a lens that's fairly slow already, the teleconverter may make AF either poor or nonexistent. Unless you are planning both to extend and to crop, you might do better to use the image you have and crop it.

Once upon a time, on film, it was the rule of thumb that the loss from cropping would be greater than the loss from using a good TC (and of course you can't readily crop slides anyway). Nowadays with dense sensors, the gap has pretty much disappeared, and you may do better with cropping. This is especially true if the TC's loss of aperture requires you to boost the ISO, and also if the lack of good AF makes it harder to nail the focus. There are a lot of variables here, but you need to think about what conditions will prevail when you're using that lens with a TC, because a 2X TC will rob you of two or three stops of exposure.

I have not used the lens in question, or a modern TC. A while back I experimented with the D3200 and a 40/5.6 AI lens and a matching Nikon 1.4X teleconverter, which I had used extensively on film with good results. The lens in question has a reputation of being one of the sharpest lenses Nikon ever made, and the TC is comparably good. This rig neither autofocused nor metered with the 3200, but I tested it on a tripod, and found that in this case, there was no appreciable difference between the sharpness with the TC and a crop without it. A 24 megapixel sensor has a lot of room for cropping, and the biggest enemy of sharpness here is edge deterioration from high ISO.

For compatibility, you should probably start your looking with Tamron AF. B&H has some converters, and if you have doubts about compatibility you can ask on the web page and often get a good answer.

You might also look at Kenko brand teleconverters. They have a very good reputation, and for some time were preferred by Nikon users when Nikon was quite lax in updating their design to work with newer lenses.