Lens infos for newbies

Discussion in 'Beyond the Basics' started by cryoglobe, Oct 18, 2005.

  1. cryoglobe

    cryoglobe TPF Noob!

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    Hello

    I'm new in photography...

    I have problems about all those number etc for lens...

    Who could help me understanding EF , IS , USM , 3.6-4.5 , , etc stuffs ?

    Thanks
     
  2. cbay

    cbay TPF Noob!

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    EF is a new technology that canon have created. IS stands for Image Stabalising which helps within fast capture imaging but comes at an expensive price, 3.6-4.5 is the reccommended F-Stops related to the Aperature.

    This thread may help you:
    http://www.thephotoforum.com/forum/showthread.php?t=3028

    What is the "etc" you would like to know?
     
  3. Christie Photo

    Christie Photo No longer a newbie, moving up!

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    USM brags about how quite the auto focus is.
     
  4. cryoglobe

    cryoglobe TPF Noob!

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    Thanks for the reply

    I did some search on the forum before creating this thread...
    Seems that I did not perform the good search :(

    Sorry
     
  5. cbay

    cbay TPF Noob!

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    Dont worry about it, everyone makes mistakes and has to learn somewhere.
     
  6. Unimaxium

    Unimaxium TPF Noob!

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    That's wrong.
    The f/3.6-4.5 on your lens refers to the maximum -- or widest -- apertures that your lens can use. On a fixed lens that doesn't zoom, there will only be one of these numbers, like f/3.6. If it's a zoom lens (which is the case here), there may be a range of aperture sizes, refering to the widest aperture available at the widest zoom setting and the widest aperture available at the longest (most zoomed in) setting. The lower number (in this case 3.6) is the widest aperture you can use when your lens is zoomed all the way out, and the higher (4.5) refers to when it's zoomed all the way in. For more information on what the lens aperture and how it works, try searching on google. There's a lot of good information on this kind of stuff out there.
     
  7. Unimaxium

    Unimaxium TPF Noob!

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    EF is just a name Canon gives to their line of SLR lenses. It's not really important to know what it stands for (I don't even know). But is is useful to know that EF-S lenses will only work on some of Canon's digital SLR cameras (e.g. Digital Rebel, 20D, 1DMkIIn). So watch out for that when you're buying a lens for either a film camera or a digital one with a full 35mm-sized iamge sensor (e.g. 5D, 1DsMkII).

    IS as someone already mentioned is an image stabilization system. It helps reduce camera shake when using a long telephoto lens, making it easier to make nice and crisp photos.

    USM is an autofocusing mechanism in some of Canon's lenses. It uses a different kind of motor to focus than you find in most other lenses.

    And 3.6-4.5 I described in my post above.
     
  8. cumi

    cumi TPF Noob!

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    Let me use this thread for my question about lenses:

    There is a parameter for lenses like:

    Camera A (Canon G6):
    7,2 - 28,8mm (35 - 140 equivalent)

    Camera B (Powershot A520):
    5,8 - 23,2mm (35 - 140 equivalent)

    Which one is better? How can I see it / calculate it?
     
  9. Unimaxium

    Unimaxium TPF Noob!

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    These lenses actually have the exact same zoom range. The G6 has a 7.2-28.8mm lens, but has a larger sensor than the A520. The A520 has a 5.8-23.2mm lens, but because its sensor is smaller, its field of view (f.o.v) range is the same as the G6's. That's what the "equivalent" number is for. The fact that both lenses are 35-140mm equivalent means that they both have the same f.o.v. range as a 35-140mm lens would on a 35mm film camera (which shoots negatives that are 24x36mm in size)

    As for other factors that influence the overall quality of the lens (e.g. maximum aperture size, general glass quality, etc.), there's no way to calculate that from the information here, so it's impossible to say which one is better.
     
  10. cbay

    cbay TPF Noob!

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    Sorry, Unimaxium i tried my best. I am new to the whole SLR thing so im still learning myself.
     
  11. cumi

    cumi TPF Noob!

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    From which attribute can you see this?
     
  12. Meysha

    Meysha still being picky Vicky

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    You can tell by the difference between it's mentioned zoom and it's real (equivalent) zoom. If the difference between these two is small then it means it has a large sensor.
    So the first lens you mentioned, 28.8 -> 140mm is a smaller difference than 23.2 -> 140mm. So this first lens has a larger sensor than the second one.

    When buying a digital camera, make sure you look at the size of the sensor. Bigger = better!
     

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