Kenko extension tubes.

[Jose Luis Silva]

That's quite a terrific lesson that I have here!

Many thanks to you by helping me !

[Taliesin]

You are right. That means you get a 280mm 8.0 in the end if you start with ANON 70-200mm F/4-5.6 L USM. Now that is practically useless.

Well that depends. I do a lot of inflight spotting and often use shutter speeds well over 1/1000th of a second at F6,3 (F6,3 because I find sharpness increases a bit with an added one third aperture, although I might be fooling myself here), so F8 might still be usable for inflight spotting or normal spotting. Airplanes have the advantage of very slick surfaces that reflect light a lot, but F8 certainly is a "sunshine-lens" for everything else. Maybe you can talk to your local shop and ask if you could borrow the piece for a day, most shops are ok with that. See if you get decent pictures with decent speeds and consider then.
You can also try to set your lens to F8 manually and see if you are ok with the light, although you would test it without the added focal length, which would add more motion blurr if you take pictures by hand and not with a tripod.

[seahawk]

But consider the price, the converter still costs nearly 50% of a decent Canon 70-300 5.6 (no idea which version is best as I am using the other brand).

[Taliesin]

For a 200mm lens, it would certainly be less than ideal, when you can get the same focal length and a lot more light with a 300mm standard lens.
Olympus doesnt offer more focal length than 300mm, so Id have to look into Sigma or an extender, so for me and my 300mm lens it would be worth it. Olympus extenders are very expensive though, Id be using 350 dollars worth of extender on a 250 dollar lens.
I may just buy a telescope instead of the extender one day, at the same price.

[B7772ADL]

Hello,

Does someone here use the "KENKO" extension tubes and can give your opinion about them, concerning image quality, for a Canon user like me?

Thanks in advance!
José Luis

Kenko Extension Tubes are for macro work, not a tele-extender/convertor.

http://www.warehouseexpress.com/product/default.aspx?sku=1005553

So do you mean those, or are you looking for a tele-converter to extend your zoom range?

[Jose Luis Silva]

Kenko Extension Tubes are for macro work, not a tele-extender/convertor.

http://www.warehouseexpress.com/product/default.aspx?sku=1005553

So do you mean those, or are you looking for a tele-converter to extend your zoom range?

Hi James,

Thanks for your reply. I'm looking for extend the zoom range.

Thanks

[B7772ADL]

Hi James,

Thanks for your reply. I'm looking for extend the zoom range.

Thanks

Lol, well don't buy extension tubes then as you migbht be a bit disappointed . What you need is a tele-converter/extender.

[Taliesin]

Lol, well don't buy extension tubes then as you migbht be a bit disappointed . What you need is a tele-converter/extender.

I thought that was a different word to mean the same thing, heh.
Well, what I said is still correct, if you scratch extender and replace it by teleconverter

[B7772ADL]

I thought that was a different word to mean the same thing, heh.

They are different things...Extension tubes create a magnification effect on an existing lens so it can be used for macro work, where-as an extender extends the zoom range.