Am I Understanding Lenses Correctly?

Discussion in 'Photography Beginners' Forum' started by Glasticart, Mar 10, 2010.

  1. Glasticart

    Glasticart TPF Noob!

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    I've done quite allot of research on SLR camera lenses and there functions over the past week. Please correct me if i'm wrong, and tell me am I understanding SLR lenses correctly.

    The normal lens kit you usually get with the camera body is suitable for shooting just about everything but when purchasing new lenses for shooting a particular subject that you want to capture in outstanding quality you must purchase the correct one.Fixed focal length lenses include Wide angle lenses, for shooting wide images (example: a large group of people) therefore they can all fit into the one photo etc.. Zoom lenses do not have a fixed focal length and therefore you can adjust the focal length to see closer up images. Macro lenses are for shooting close up macro images, these lenses capture more detail than the eye can see. Image stabilization lenses are to stabilize the camera, usually when shooting images with long shutter speeds.

    Am I correct ?
    What is the difference between a Telephoto lens and a zoom lens?
    Are different lense usually only used by professional photographers ?
    what does EF/TS etc.. Mean ?
    Can I use a EF-S 18-55mm f/3.5-5.6 lens to shoot everything ?


    Thank You
     
  2. Overread

    Overread has a hat around here somewhere Staff Member Supporting Member

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    Telephoto is a refrence to the focal length of the lens and (from what I gather) on a 1.6 crop sensor camera or a 35mm fullframe camera its around 100mm or longer.

    Zoom is when you have a lens which can zoom - like the kit lens - and has a range of focal lengths. A zoom lens can be a telephotozoom if it can reach the longer distances as part of its range.

    Prime or fixed/single focal length lenses can also be telephotos with just that single range - eg 100mm, 200mm, 300mm etc....

    EF/TS I assume referse to an EF mount canon lens with a tilt shift setup. That means you can adjust the plane of focus to be at an angle rather than a flat line. Imagin the focus like a sheet of paper - the lens default is a flat sheet perpendicular to the front of the lens - with a tilt shift you can angle that paper backwards and forwards - a good example would be taking a photo of a building close up - if you use a regular lens the bottom of the building might be in focus, but the top out of focus - because you have to aim upwards to get the whole building in focus - a tilt shift could shift the paper/plane of focus and thus let you get bottom and top in focus.
     
  3. Dwig

    Dwig TPF Noob!

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    A zoom lens is a lens that can change focal length of a continuous range. Technically, a true zoom will not shift focus (the distance at which the subject is in sharp focus) when zoomed. If the focus changes as you zoom, the proper term for the lens is "varifocal" (as in VARiable FOCAL length). A zoom lens can be any mix of wide-ange, normal, and/or telephoto.

    In common parlance, "telephoto" means a lens that is significantly longer than a "normal" lens, although the classic proper term is "long focus", a normal" lens being one with a focal length equal to the diagonal measure of the film/sensor image, ~43mm for 35mm full frame and ~28mm on the common "crop sensor" DSLRs.

    There is also a different technical definition for "telephoto" that applies only when discussing details of the internal optical design. Almost all lenses that have true telephoto optical designs are also long focus lenses, hence the common substitution of "telephoto" for "long focus". There have been some normal lenses used in compact cameras (e.g. the old Olympus XA) that were technically telephoto optical designs. There have also been some long focus lenses that were not actually telephoto designs (e.g. the classic Micro-Nikkor 105mm f/4.0).
     
  4. KmH

    KmH Helping photographers learn to fish Supporting Member

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    Yes. But. Everything would have to be pretty close.

    At about 35 mm the field of view of the lens, on most of todays dSLR's, would be about the same size as we see with our naked eye.
     

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