Tele-Conversion lenses

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Mr.Bolshoyhuy - 26 Aug 2006 05:18 GMT

I see 3x telephoto and wide angle Tele-Conversion lenses are cheap.
Why dont a lot of people use them?

How does their quality compare to real lenses?
If I get a Canon rebel XT($750) or Nikon D50($700) w/kit, and attach
a 3x Tele-Conversion lens to it, instead of buying a lens, I'd get
165mm. Which is more than the Olympus Evolt-500 w/150mm lens
kit($700).
If I get a 200mm lens, and use the 3x with it, why bother buying a
600mm? Likewise, why not use a 3x wide angle Tele-Conversion lens
instead of buying a real one?

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C J Southern - 26 Aug 2006 07:44 GMT

> I see 3x telephoto and wide angle Tele-Conversion lenses are cheap.
> Why dont a lot of people use them?
[quoted text clipped - 7 lines]
> 600mm? Likewise, why not use a 3x wide angle Tele-Conversion lens
> instead of buying a real one?

You need to remember the old saying: "If it seems too good to be true, then
it probably is".

The trade-off is image quality and loss of F-Stops. Most Canon cameras won't
autofocus when the effective max F-Stop drops below 5.6.

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mark.thomas.7@gmail.com - 26 Aug 2006 08:38 GMT

> "Mr.Bolshoyhuy" <bolshoyhuy@hotmail.com> wrote in message
> > I see 3x telephoto and wide angle Tele-Conversion lenses are cheap.
[quoted text clipped - 4 lines]
>
> The trade-off is image quality..

Exactly. The kit lenses are pretty awful anyway, and once you start
magnifying and adding more glass, of questionable optical quality..

> and loss of F-Stops. Most Canon cameras won't
> autofocus when the effective max F-Stop drops below 5.6.

Well, I think he is referring to front mounted add-ons. And that type
of lens will generally not lose you more than 0.5 of a stop, if that.
That's about their only redeeming feature...

But anyway, Mr BH, why not buy a set and find out for yourself? You
can always re-Ebay them..

It should be noted that there *are* a few *reasonably* good ones, for
example the Minolta ACT-100 (1.5x tele), and the Olympus WCON 08B (0.8x
wide). But note the rather meagre multiplication factors... And both
these lenses are huge, weigh a proverbial ton, and are fairly
expensive. (I should know, I own both of them!)

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Qbert - 26 Aug 2006 09:17 GMT

In the market there are front anf rear TC.
I saw several samples of rear TC, like Tamron and Kenko, and thay are quite
good (2x, at least). AF don't work over f5.6.
Front lens are very poor, but AF should work at all apertures.

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