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Photography Question 
Raymond Rosch

What to look for in a Teleconverter

Hi All,
I am thinking of buying a Teleconverter for my FinePix S9500. I have noticed while looking that there are different numbers of lenses and groups. So other than the multiplying factor, what is the difference between 4 Elements, 4 Groups and 7 elements, 5 groups (Other than the numbers). I.e. What is better?

Thanks for your time.

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12/27/2006 4:19:39 PM

Bob Fately   Raymond, the elements/groups thing works like this: each individual optical glass in the unit is an element. Sometimes, in order to improve or counter certain distortion effects, two or more individual pieces lf glass are glued together - this then becomes a group.

Technically, each glass/air interface leads to a certain amount of light loss and potential abberation, so the idea is to have a few groups as possible. On the other hand, the additional elements in the 7/5 you mention are there to counter these distortions, and the 7/5 version is likely better than the 4/4 version. Of course, with more lens elements, the price will be higher as well.

That said, are you certain you will be able to use the teleconverter on your camera? Usually TCs are made for SLRs with removeable lenses - the 9500 seems to have a fixed lens. Or is this something more like a filter added to the front of the lens?

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12/27/2006 4:51:42 PM

Raymond Rosch   Hi Bob,
thanks for the quick response and easy to understand reply. Yes, the 7/5 (3x) is AU$100 more than the 4/4 (2.5x). (Both also come with a Wide angle lens as well)

From what I can ascertain, yes it is more like a filter that screws on the front of the lens.

Thanks again for your advice.

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12/27/2006 5:21:19 PM

Raymond Rosch   It also appears to be a physically larger lens.

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12/27/2006 5:25:42 PM

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