Simple question about lenses

Discussion in 'Beyond the Basics' started by Lanimilbus, Jun 21, 2005.

  1. Lanimilbus

    Lanimilbus TPF Noob!

    Jun 9, 2005
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    Hello, I have a fairly simple question regarding three lenses that I am looking at buying. I’m not sure if any of these three lenses increases my zoom capability, which is what I’m looking for, so if anyone could tell me if they would in fact do that, it would be greatly appreciated. I’m looking for a lens that will magnify/multiply my zoom, or in other words, a telephoto lens. The first lens that I’m looking at is this one:

    This lens says in the details that its magnification is “3x.” But does that refer to macro or close-up photography? Again, what I’m looking for is to increase my optical zoom (which is 12x) so that if I were to be say across a field from a subject I wanted to photograph, I would want to attach that lens and have my optical zoom increased by 3x, in other words, I would want my optical zoom to be 36x. Would this lens do that?

    This lens says that its magnification is 2.5x…again, does that mean that it would multiply my 12x optical zoom by 2.5, making it 30?

    This lens says that its magnification is 4x…and again, what does that refer to? Would this lens make my optical zoom 48x?

    Thanks in advance for any help regarding these questions,

  2. Rob

    Rob TPF Noob!

    Jan 29, 2005
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    Hi Alec and welcome to the forum.

    You've got two different types of product there - macro and tele conververs. A macro converter will enlarge close-up things and a tele will enlarge far-away things. From what you've said, you want a teleconverter, which are normally prefixed or suffixed with the letters TC.

    The concept of 12x zoom is quite a tricky one with a digital compact camera as there are a number of technical things to bear in mind. I'll have a crack at explaining it from the point of view of an Olympus C5060 (if that's what you have):

    1x zoom is approximately what the human eye sees and is equivilent to 50mm on a normal film camera.

    Digital compact cameras have a much smaller sensor than a normal film camera has film area, so the length in mm doesn't need to be as long to achieve the 1x zoom.

    With one of the baby Olympuses, 10mm optical length is about the same as 50mm optical length on film. When the camera is zoomed out, it's max length of 23mm is about the same as 110mm on film or 2x zoom to the human eye.

    So far I've only been talking about the glass optics. Digital cameras often have the ability to enlarge a sub-part of the image to create a virtual zoom. The small Olympuses have about a 4x digital zoom, so you can multiply the two together to get an effective length of something like 8x or 400mm on a normal film camera.

    A 3x teleconverter will simply multiply what you have by three and lose you quite a bit of light. If you have a 400mm equivilent lens (about 8x zoom) on your camera, it will give you 1200mm equivilent (24x zoom). Or if you have 12x, then it'll give you a massive 36x or 1800mm equivilent.

    My personal opinion is that you won't be able to hand-hold this, and you probably won't get enough light to take a decent picture under any normal circumstances. That is, however, just my opinion, you may be able to use it.

    Bear in mind that these kind of after-thought accessories weren't within the original design specifications of the camera and you may find that image quality is drastically lowered as a result.

    Good luck with your quest.


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simple question on lenses