Teleconvertors

[dogyakker]

Simple question. Can you stack them?

Is there a massive drop in quality if you can? If you use the ones with the right compatabilty do you still get all the conectivity? And if you can would a 200mm lens with a teleconverter( =400mm) become an 800mm if I stacked another one on top?

If a f2.8 becomes a f5.6 does that mean it becomes a f11?

Just wondered as I am considering a x1.4 to go with my x2.

Thanks,
Chris

 

[happy haggis]

Yes you can, although there will be a loss of quality and the viewfinder will be quite dark.
2x + 1.4X would be 3 stops not 4.

 

[Joe T]

Some manufacturer TCs wont stack without modifaction. I'm not sure exactly which though!

Which ones have you got?

 

[dogyakker]

2x + 1.4X would be 3 stops not 4.

Yeah its OK - I did realise just using x2 to save me multiplying by 1.4!!

I've got the Sigma x2 at the moment, anyone know if Sigma allow you to stack with the x1.4??

Thanks,
Chris

 

[puddleduck]

This is going back to 2005, but when I had the 120-300 and 1.4x and 2.0x I tried this for a moon shot.

It did work, without any AF. IQ was awful.

 

[StewartR]

Can you stack them?

Yes, at least sometimes. But it depends on the details. For example a Canon 2x and a Canon 1.4x can only be stacked one way round.

Is there a massive drop in quality if you can?

Probably. Though if you start with a good lens that's designed to work with TCs (eg a 300mm f/2.8 or a 500mm f/4) then the results could still be OK.

If you use the ones with the right compatabilty do you still get all the conectivity?

Yes. But remember you'll lose the ability to autofocus at some point. Exactly which point depends on what kind of camera you have.

And if you can would a 200mm lens with a teleconverter( =400mm) become an 800mm if I stacked another one on top?

If a f2.8 becomes a f5.6 does that mean it becomes a f11?

Yes. A 200mm f/2.8 with a 2x TC becomes 400mm f/5.6. With a 2x TC and a 1.4x TC it becomes 560mm f/8. With two 2x TCs it becomes 800mm f/11.


You might be interested in my experience of garden birding fun at f=2000mm .....

 

[dogyakker]

Brilliant thanks guys,

Now all I need to do is borrow a x1.4 to check it works. Thanks again,
Chris

 

[neilyb]

Some people use 2x TCs on their 300 2.8 and love it. On a zoom the results are less satisfatory. I use my 1.4 kenko with the 500 f4.5 and find zero loss in IQ but on the 100-400 it is noticably different.