Lens question

Discussion in 'Photography Equipment & Products' started by seemoo, Apr 23, 2007.

  1. seemoo

    seemoo TPF Noob!

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    I have Canon 20D and I'm looking for replacement of the 18-55mm kit lens.

    First off, does this kit lens already have the 1.6x scaling factor applied that results from the 20D sensor which would make it a 28-88mm lens? Or is it a true 18-55mm lens?

    I'm looking into the Canon EF 16-35mm f/2.8 L USM lens. I know I would have to apply the scaling factor of 1.6 to this one for using it on my 20D. Which would make it a 24-56mm.

    How do u see if a lens needs the 1.6x scaling factor applied to it or not?


    thanks a lot for you help

    simon
     
  2. Orgnoi1

    Orgnoi1 TPF Noob!

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    Well first off... ALL lenses are effected by the size of sensor... but not exactly how you stated it. It doesnt actually magnify a lens... but used less of the lenses overall width. A "crop sensor" is just that... a smaller sensor but the focal length doesnt change. What you get is the perception that the lens is longer due to it recording less image circle then a full frame or 35mm camera.

    Now more specifically... the kit lens is built to better work with the crop sensor because of the angles of glass... but it is still itself effected by the crops nature. You will still see the "effect" of a longer lens.

    I would suggest going to a shop that has the 16-35L and maybe a 17-40L and taking a look... if you dont do much darker light shooting or dont need the f/2.8's tighter DOF then I would suggest trying out the 17-40L... its a VERY decent lens and for a ton less cash. The only thing you lose out on is 1 f/stop. I use that lens on both my 1D Mark II and 5D and LOVE it...
     
  3. seemoo

    seemoo TPF Noob!

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    thanks a lot for that super quick reply. Very helpfull too!

    I also have the 10-22mm lens. And my understanding was, that this one doesn't fit on the full frame sensor cameras. So does that mean, that this lens doesn't show the "longer lens" effect and is in fact 10-22?

    I just checked out the 17-40 and it does look very cool... I will have to do some more research on the subject...

    thanks again for you help

    simon
     
  4. Orgnoi1

    Orgnoi1 TPF Noob!

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    The reason that the 10-22 doesnt fit actually is a mount issue. Canons EF-s mount is slightly different then the EF mount. It too though is effected... ALL lenses are actually. Comparable 3rd party lenses can be used on FF cameras (such as the 10-20 Sigma) but it will have a nasty vignetting (darkening of the corners)...

    Glad I could help out!
     
  5. Sw1tchFX

    Sw1tchFX TPF Noob!

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    17-55 f/2.8 IS?
     
  6. EOS_JD

    EOS_JD TPF Noob!

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    As stated above, the lenses are all affacted by the effect of the sensor crop.

    10-22f3.5-4.5 = 16mm - 35.2mm (equivalent)
    16-35 f2.8L = 25.6mm - 56mm (equivalent)
    17-55 f2.8 IS = 27.2mm - 88mm (equivalent)
    17-40 f4L = 27.2mm - 64mm (equivalent)
    18-50 f3.5-5.6 = 28.8mm - 80mm (equivalent)

    If you need speed I'd agree, look at the 17-55 IS. By all accounts a great lens and IS to boot!!
     
  7. seemoo

    seemoo TPF Noob!

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    thanks a for all your replys... They r very helpfull

    thanks
     
  8. Sw1tchFX

    Sw1tchFX TPF Noob!

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    I shoot with the Nikkor 17-55 f/2.8 DX and it's absolutly amazing at every aperture. It's sharper at f/2.8 than my 18-35 was at f/8! When I came back with my first images from it, i was glad I replaced my 18-35 with it because now I have compositional freedom with DOF. I didn't have that with the 18-35, it was f/8-f/11 or nothing. That's how soft it was.

    I don't know how sharp the Canon one is, but I'd expect nothing short of amazing from Canon with a lens that expensive. Not only that, but it has IS making it even more awesome. The focal range is just perfect with the cropped sensor too.
     

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