1.4 tele converter

[powell7]

hi,
i need abit more length

iv got a 75-300mm lens but would like to get abit closer to my subjects-wildlife,airshows.
i was looking at a sigma 150-400 but cant afford that now as its jumped up £100.

how much difference would a 1.4 tele give to a 300mm lens ?
has anyone got the same shot taken with and without one fitted ??

also i`v been told a 2.0 x tele loses sharpness,is this true ?

thanks chris.

 

[artyman]

A 1.4 TC will make your 75-300 into 105-420 but you will lose 1 stop so if your lens is f5.6 it will be f8, which may mean having to resort to manual focus as many lower end cameras need f5.6 or better to AF

 

[HoppyUK]

All telecons lose sharpness - sometimes a lot, smoetimes not much, depending on the quality of the telecon and more importantly, hoiw much sharpness the mother lens has got when pushed to the limit.

As a very rough rule, you can often get away with 1.4x, but 2x is asking a lot even of the very best lenses.

On top of that, and this is usually the killer, you lose one stop or two stops respectively, and this often takes the lens higher than the f/5.6 threshold for the autofocus to function.

If your 75-300 is f/5.6 at the long end, then it will go to f/8 with a 1.4x, f/11 with a 2x. So you end up with a very high f/number, no AF, and soft images to boot. It's no free lunch.

 

[Greywolf]

A 1.4x converter converter on a 75 - 300 lens will turn it into 105 - 420mm zoom
(75 X 1.4) - (300 X 1.4)

Generally speaking tele-converters are best used on primes, best to buy the same make as your lens (not all lenses will accept them, especially zooms). Manufacturers will often show on their website which lenses will accept teleconverters.

As the teleconverter is mounted onto the lens there is often an extension that actually fits into the lens. If there is not enough clearance between this extension and the rear element, then as you turn the converter to lock it into position you may a very expensive grinding noise as you screw the converter into the rear lens element. Not to be recomended.

With a 1.4x converter you will lose 1 stop. with a 2x converter you will lose 2 stops.

Except with top quality lenses and converters, (eg canon 500mm f4 and canon 1.4x converter) most aspects of IQ will be compromised to some extent. The cheaper the lens/converter combination the more the likely degradtion.

There will be more degradation with a 2x than with a 1.4x

 

[Richard Peters]

You should probably check that a 1.4x will fit the lens, as with some lenses the rear element of the lens will strike the TC. 70-300 type lenses I didn't think were compatible with TCs...might be wrong but worth double checking before you buy.

EDIT: Oops, already covered above!

 

[acs]

Your chances of having a 1.4 work on a consumer zoom will depend on the make of body, lens, and TC -- but even if it works you'll not get the consistency or quality you see people getting with single focal length prime lenses.

You really need to see the results from someone with the same configuration you're considering and decide whether the results are good enough -- you may be better just cropping.

[Nikons handle this surprisingly well but need the Kenko or a modified Nikon TC... some brands won't even try to AF lenses over f/5.6]

The 1.4 TCs don't tend to sit deep in the lens like some 2x converters, but you still need to check clearance carefully.

Another option might be to try old MF lenses (maybe someone can comment on cost and compatibility) -- this might be a good option for wildlife, especially if there's a lot to distract an AF system.