Beginner What is a T mount?

[Orangecroc]

I've seen a lens that has incredible zoom, but the description says that it needs a T-Mount adapter?

 

[mortimerhill]

It's an interchangeable mount so that one lens can be used a variety of cameras with the appropriate mounts. They are 1970s technology and not used very much now. It it's a T2 mount, there will be very limited functionality, i.e. no automatic aperture and no autofocus

 

[Major Eazy]

Lenses with a T-Mount or T2 Mount (or various names) would have a screw mount rather than the more common bayonet mount. And you screw those lens on a matching T-Mount camera.

However...

You could buy a T2 adaptor, which is more or less like a big oversized wedding ring (expect it's in black not gold). Usually the T2 adaptor needs to be correct for your camera's lens mount.

For example:

If you have a Nikon, then buy a T2 adaptor for F-Mount. If you have Canon, then buy a T2 adaptor for EF mount. etc.,

You screw the T2 adaptor on the T-mount lens.

Then you attach the lens to the camera (ie: T-Mount lens on a Nikon by using the T2 adaptor).

And Mortimerhill is correct, you lose or limit the functionality, mostly automatic aperture and autofocusing. Plus likely to need to give it an extra stop (ie: cut your shutter speed by one stop or open up your f-stop by one.)

By the way: T-Mount is not the same thing as a teleconverter, but if you are familiar with what a teleconverter look like, then image the T-Mount adaptor looking like a much more shorter teleconverter.

 

[Orangecroc]

OK cool. It's for a lens with 400-800 so wouldn't be moving around too much, so auto focus and aperture would not be a big deal as I would probably use it rested on beanbags targeting perches so would have time to set up.

 

[Major Eazy]

I have a 500mm mirror lens using a T-Mount, and I bought two T2 adaptors, one for the Minolta MD mount and the other for the Nikon F mount.

I can use the same 500mm mirror lens on my Minolta X-700 film camera or my Nikon D200 (at that time I used a D1) camera. I accept that I lose the AF when using the Nikon, but it don't bother me as I used it for shooting the moon, or days of using manual focusing cameras means I have experience in focusing the 500mm manually when using the Nikon.

 

[Retune]

You've probably come across something like this: http://www.thephotoforum.com/threads/prooptic-420mm-800mm-impressions-and-review.135930/ You shouldn't expect high quality results from this type of lens, but some people have fun with them.

 

[troutfisher]

The lens is probably on opteka or something similar,i got one in a bundle when i bought a cheap minolta film camera,that came with a T mount.
Dont bother!

 

[Orangecroc]

I can't afford hundreds or thousands for a long zoom though

 

[Retune]

What camera do you want to use it with? There may be other relatively inexpensive options (old manual focus zooms with adapters, kit zooms with teleconverters, mirror lenses, etc.) that could give you better results.

 

[Fuzzdog]

I can't afford hundreds or thousands for a long zoom though

You don't have to spend hundreds to beat the quality of most of those old T-mount lenses - believe me, I'm as cheap as they come and I already tried that route, it wasn't very satisfying.

I got far better (as in 'looked like a work of art in comparison') results heavily cropping images taken with a Canon 100-300 USM which cost me £20 from eBay. Not sure what camera you're using, but I'm sure there is a better solution for not much outlay.

 

[Orangecroc]

It was going to be for a Nikon d5300

 

[Retune]

At the budget end of the market, there are Sigma and Tamron 70-300 lenses that can be had new for under £100 (make sure you get the current versions with built-in AF motors rather than the older versions which rely on the camera having an AF motor, which the D5300 doesn't). You can find secondhand Tamron 500mm manual focus mirror lenses in Adaptall 2 mount (needs a Nikon adaptor, like a more sophisticated version of the T-mount) for around the same price.