Extender- is it for zoom lens only

[Asish]

Hi, I am Asish and have a few silly questions and I hope I shall get very valuable information.
1. If I use a extender with specifications EFS 60 mm f/2.8 Macro with a USM EF 2 X III extender, shall I get the Macro lens would serve as EF 120 mm Macro (100 mm). You know, the price difference between 50 mm and 100 mm Macro is massive and with that difference I could purchase an Extender that could be used with other zoom lenses as well.

2. What is the differences between Entender EF 2 X II and EF 2 X III?

3. How is Extender related to Autofocusing of lens (it was written that autofocusing shall not be possible in lens slower than......)

Cheers
Asish




4. I am new and I have a lens 18-200 mm (Canon). Is it a fast or slow (I guess this term exists) lens?

[Black Pearl]

Canon extenders (like their Nikon counterparts) could be more accurately described as Matched Multipliers in that they only work with certain 'matched' lenses. They will only fit on long, pro (L series) lenses as the extender ...err extends....inside the rear of the lens and very few lenses have the recess necessary. It won't fit on your EF-S 60mm nor will it fit your zoom - in fact I think the only zoom they will fit is the 100-400mm L lens (go on someone prove me wrong) and even there you lose the AF.

The difference between the MkII and MkIII is quality and unfortunately price - both being higher.

[Geoff F]

You are definitely wrong, Robin; what about the 70-200 L series.

But everything else is correct.

Asish, you don't say what you intend to photograph, which may have a bearing on the recommendations.

The III version is simply a newer and slightly improved II model. But whether you could use one satisfactorily is open to debate. A 1.4x extender usually works fairly well with good quality, and suitable, lenses but the 2x can cause more problems.

Some people use x2 extenders satisfactorily but you can encounter difficulties when shooting in poor light, etc. And the more the magnification the more you risk having quality problems.

Incidentally, I have used a Canon 1.4x with my Sigma 180 macro lens. The trick is to insert a 12 mm extension tube between the extender and the lens. It works for close shots but the lens will not focus at infinity.

[Black Pearl]

Bah!

[Asish]

Thanks guys

[Colin Southern]

Couple of notes ...

- Mostly the extenders are designed for Canon L-Series zoom lenses, but they can also be used with the EF135mm F/2.0L USM

- The 2.0x mark II converter works a treat with the new EF 70-200mm F2.8L IS USM II

- AF is retained so long as the new max aperture is F5.6 or wider for non-1 series bodies, and F8 or wider for 1 series bodies

- You can get a good result with the 2.0x II extender on older zooms, but one has to be careful about sharpening -- usually slightly more agressive capture sharpening is needed.