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Thread: multipier effect on zoom and aperture

  1. #1
    velve
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    Default multipier effect on zoom and aperture

    hi all out there,

    i am looking at purchasing a DSLR and am waiting for the D100, but i just discovered that it's X1.5 mulitpier effect appies for the aperture of the lens too.

    So to my understanding, if i got a 28-70mm lens with F2.8, under the D100, my zoom increases to roughly, 45-105mm, with F4.2? is that so?

    if that is the case, wouldn't it be really drastic on the control i can have on my camera, as i would be losing so many 'stops' on the aperture, just becos of the multiplier effect!

    pls clarify, (for those who know, and who can spare the time to reply)

    thanks again to all, who spend the time to read, or reply.

  2. #2

    Default

    On most digital SLRs (other than the upcoming one from Contax), the sensor is smaller than the 35mm film. Normal lenses are made to project an image the size of 35mm film, so what happens is that the sensor on the DSLR only captures part of the image. Note that the aperture,depth of field and perspective, etc does not change.

    This cropping produces an image that appears the same size as an image taken on 35mm film with a focal length set at 1.x times. But it is not an equivalent image, since the few params I mentioned didn't change.


    So to my understanding, if i got a 28-70mm lens with F2.8, under the D100, my zoom increases to roughly, 45-105mm, with F4.2? is that so?
    So the answer is, you get the zoom effect of roughly 45-105mm F2.8, but its not exactly the same as having a 45-105mm lens.
    Last edited by reflecx; 27th April 2002 at 01:53 PM.

  3. #3
    velve
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    Default

    sorry, so u mean that my aperture would not change rite, just the zoom length,

    cos, i read in dpreview, some guy's post, where he stated that the aperture would increase with multiplier effect, and thus, made me reconsider abt the DSLR till it's full frame.

    so in short, 28-70mm F2.8 would convert to roughly 42 - 105mm meanwhile aperture stays constant F2.8.

    another qn, what is the biggest output i could get from the canon G2, A3?

    and the canon D60, A0 size?

  4. #4
    Senior Member
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    Default

    No the aperture doesn't change. Neither does the available DOF (so you have effectively more DOF at any given focal length).

  5. #5
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    Default

    Originally posted by velve
    cos, i read in dpreview, some guy's post, where he stated that the aperture would increase with multiplier effect, and thus, made me reconsider abt the DSLR till it's full frame.
    Maybe he's refering to teleconverters?

  6. #6
    Senior Member
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    Singapore, Singapore, Singapor
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    Default

    Originally posted by velve
    sorry, so u mean that my aperture would not change rite, just the zoom length,

    cos, i read in dpreview, some guy's post, where he stated that the aperture would increase with multiplier effect, and thus, made me reconsider abt the DSLR till it's full frame.

    so in short, 28-70mm F2.8 would convert to roughly 42 - 105mm meanwhile aperture stays constant F2.8.

    another qn, what is the biggest output i could get from the canon G2, A3?

    and the canon D60, A0 size?
    The multiplier of DSLRs does not multiply the aperture.

    As to how large a given image can be printed to, it all depends on the subject matter and how clean the image is. No absolute number for this. I've seen 10x15" D30 images, 20 x 30" Fuji S1 Pro images, 8x10 Coolpix 950 (2mp) images, etc.

    Regards
    CK

  7. #7
    velve
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    Default thanks for updated replies

    hey, guys, to all that read, thanks for showing interest to my threads,

    to all those who replied, THANKS alot too.
    well, now i understand that the d100 does not compromise the aperture, great, so i will continue to save money for the one,
    well, to the people who replied, thanks, u saved me from a G2 powershot, as i was abt to buy that!

    pls explore this website which provides GREAT photojournalist links, www.learphoto.com

    hope those who are learning photo taking as learn from his site, as i feel i had, thanks to ALL again!

    the friendliness of free-forum, and the speed of the net saved the day

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