Use of teleconverter

I think I have managed a sneaky.

I have discovered that the Sigma 1.4 teleconverter on the Nikon D300 will also work using a Nikon 70-300mm VR lens. In effect giving me a lens with a max of 420mm with VR. Ok it aperture gets thrown out a bit and its more trial and error to correct.

There is enough distance , infact double the Sigma 70-200mm F2.8 lens, between the rear lens and the converter lens so there is no chance of it hitting. Auto focus works and so does the VR so it looks as if the contacts are compatable.

have I discovered a cheats way of getting a +400mm lens with VR at a fraction of a normal 400mm lens I wonder?

Bazza

It certainly a cheaper option than buying a longer lens but remember that your lens becomes a 'slower' lens.

A 200mm F2.8 lens for example with a 2X teleconverter becomes a 400mm F5.6 lens

A 400mm F2.8 lens would be far more expensive but twice as fast.

I have a Kenko 1.4x teleconvertor which also works on
the Nikkor 70-300mm and the 18-200mm with full AF.

Nice one - lets see some demo shots

thought I'd just add this bit of info as it's often a grey area as to whether a lens will 'auto focus' once it has a teleconverter added.

Most non-professional cameras will read the maximum aperture as f8 and then won’t even try to autofocus. Most professional grade cameras can focus at f8, but usually only at the center point.

With that f8 in mind - the handy maths for working out if you are still going to be able to autofocus.......

A 2x teleconverter can be used on lenses with aperture at least f2.8 (becoming f.5.6)
A 1.4X teleconverter (and usually a 1.7X) can be used on a lens with an aperture of at least f4, (becoming f5.6 or f6.8)
lenses with maximum aperture of f5.6 might not autofocus with teleconverters much more than 1.4X

That said - a lot depends on the light.

The big advantage I can see, taking everything into consideration, is I now have a lens capable of 420mm with VR at a fraction of the cost of a prime 400mm lens.





Just a very quick shot at about 60ft away totally unedited, apart from removing number plate I.D, using Nikon D300 + Nikon70-300mm lens+Sigma teleconverter.

Not come out too bad but could be improved had I spent a little more time taking it. Note Exif files will only show the lens at 300mm with converter added. Even so it still came out pretty sharp.

Bazza

that's interesting info considering the 70-300 VR actually says in the instructions not to be used with a teleconvertor.

I think they are referring to the Nikon teleconverter JR not to other 3rd party makes. As you can see this combo works. Nikosnop concurs with his Kenco version of the same converter.

My 2x Nikon converter wouldn't work with it because the opening on the rear of the lens was designed not to fit with it, hence I sold it. One manufacturer isn't going to promote another company make.

Nikosnap
Hope you are liking it here and already you are giving us the benefit of your very wide experience which is most welcome

PS the car is seldom that clean, you can actually see the fence in the reflection to the right of the number plate

Bazza

Looks good Bazza

Here's what my 2X teleconverter comes out like.....

Standard lens



Then a 300mm lens with 2X teleconverter so it's shooting at 600mm
If you take the 1.6X crop sensor into account it's like a 480mm shooting at 960mm

I would havethought you'd need to be careful not to damage the VR that way - a lot of reading I did with regards to the extensions said to turn off VR if it was available, and if possible only manual focus. I imagine this is because the 'information' so to speak, has further to travel. I do notice AF is slow and clunky with the tubes on, the more tubes, the worse it is. I wouldn't advise using VR on this combo if you can turn it off.

xx