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Old Feb 6, 2005, 8:43 AM   #1
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my dad has a panasonic lumux, and i know you can get televonverter lenses for it , but i cant find an explination of what they do. anyone got an explination for me?
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Old Feb 6, 2005, 4:20 PM   #2
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A teleconverter multiplies your cameras zoom by a fixed factor. My Oly 740 has a 10 X zoom, with the Oly TCON 1.7 I get 17 X ( 10 x 1.7 ).

For a Panasonic FZ, It would be 12 x 1.7, or 20.4 X.

If you had a Raynox DCR 2020 like my wife has on her FZ, it would be 12 x 2.2, or 26.4 X.

Usually teleconverters work only on the outer edge of the cameras zoom range, on the FZ, abour 6X out to max zoom.
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Old Feb 7, 2005, 12:15 AM   #3
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Sorry, but that isn't correct. A teleconverter doesn't extend the zoom range, it extends the focal length. A 7 - 20 mm lens with a 5x converter becomes 35 - 100 mm (even if only the tele end is usable). The zoom range doesn't change.

A teleconverter of the type that goes in front of the lensis similar to looking through binoculars.
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Old Feb 7, 2005, 10:21 AM   #4
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meow is right. the zoom capabilitystays the same, but the focal length is multiplied several times hence you have longer focal length. you may want to check another response from the other member of this forum, too.

http://www.stevesforums.com/forums/v...mp;forum_id=50


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Old Feb 7, 2005, 11:08 AM   #5
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Evilroy's answer makes more practical sense to the inexperienced in understandable terms than throwing focal length, which has no common reference. Sharpshooting semantics.
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Old Feb 7, 2005, 9:12 PM   #6
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Focal length, or better yet, field of view is much more usefull tha zoom factors for two reasons:

A number like "10x zoom" contains no photographically usefull information. It does not tell you if it is 28-280 or 40-400mm (equiv). The only use for zoom factor is selling cameras to the "Mine is BIGGER" crowd".

The other reason comes into play with teleconverters. In most/all cases, there will be vignetting if it is used at almost anything but the longest zoom. That means with an 1.7 multiplier on a 35-420mm zoom (not using the teleconverter), you will be able to shoot at 35-420 and at 714 (1.7*420)mm, but are very unlikely to be able to shoot at 500mm (equiv) without vignetting. So it makes no sense whatsoever to describe the effect of a teleconverter as multiplying the zoom factor - you cannot cover the entire range that is implied.

Zoom factor is a silly marketing number - ignore it. Look for the field of view numbers, almost always specified in terms of 35mm equiv focal length.
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Old Feb 8, 2005, 3:35 AM   #7
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Panzergnome, my English isn't native and maybe there is a "simpler" term than focal length that I don't know of. No offense, but letting "the inexperienced" stay misinformed makes no sense at all to me and it isn't doing them a favor either.

I seequestions like "How much zoom do I need for shooting birds?" all the time. Often the answer is something like"At least 5 times". That OP could soon become a very dissappointed camera buyer. And poor.

Sorry if you took my post the wrong way. :sad:
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Old Feb 8, 2005, 8:26 AM   #8
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Meow has it right: the simpler explanation is not always best. It might be simpler to describe the earth as being a flat disk on the back of a turtle with the sun being a burning chariot driven by some god than to describe it using the general theory of relativity, but very few people invoke turtles to describe the motion of the space laboratory. The use of zoom factor should be used about as frequently.
</rant>
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Old Feb 8, 2005, 10:09 AM   #9
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Even people who believed the world was flat could get a passerby to the next town without sending them to grouch college.



Focal lengths:

http://www.warehouseexpress.com/phot.../tamfocal.html


Oh, and, Zoomedy zoom zoom!
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Old Feb 8, 2005, 1:19 PM   #10
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Didn't mean to be a crank myself, it's just that saying 300mm or 31mm is completelymeaningless to most people. I know some of you have lived with this for years (appears some more years than others) and it's hard let inacccuracies slip by.

style="BACKGROUND-COLOR: #000000"Schmintan, hope you got an answer. I've got a Olympus TCON 1.7 and it works really well. I shot a few pics of the moon that impressed me. It is big, and yep, you can't zoom down much without the edges beginning to distort/blacken. Also no threads for a filter.

style="BACKGROUND-COLOR: #000000"I will say I don't use it near as much as a wide angle lens.
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