Confusion-Advice Needed

sandychiansandychian Registered Users Posts: 7 Beginner grinner
edited March 9, 2006 in Wildlife
Hi,
I a newby to the forum. Need some advice on the ongoing discussion about 4/3rd system by Olympus. Zuiko digital lens is said to have equivalence to 2x in 35mm format, i.e. 300mm F2.8 is equivalent to 600mm F2.8 in 35mm format. What does this mean? If I take a picture using Zuiko 300mmF2.8 on Olympus E500 and compare with say Canon 300mm lens on Canon 20D, will both pictures be equivalent size and magnification?

I am an Olympus user thinking of acquiring the Zuiko 300mm F2.8 lens for bird photography.

Appreciate advice,
sandy

Comments

  • wxwaxwxwax Registered Users Posts: 15,471 Major grins
    edited March 9, 2006
    Do you a link to the thread you're talking about?

    Sounds like what they're talking about is something called the Crop Factor. Look for it in the definitions I linked you to.
    Sid.
    Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam
    http://www.mcneel.com/users/jb/foghorn/ill_shut_up.au
  • jwearjwear Registered Users Posts: 8,013 Major grins
    edited March 9, 2006
    think confused is a another word for photography :D if you do a search this has been talked about a bit and you should find some helpthumb.gif
    Jeff W

    “PHOTOGRAPHY IS THE ‘JAZZ’ FOR THE EYES…”

    http://jwear.smugmug.com/
  • RohirrimRohirrim Registered Users Posts: 1,889 Major grins
    edited March 9, 2006
    sandychian wrote:
    Hi,
    I a newby to the forum. Need some advice on the ongoing discussion about 4/3rd system by Olympus. Zuiko digital lens is said to have equivalence to 2x in 35mm format, i.e. 300mm F2.8 is equivalent to 600mm F2.8 in 35mm format. What does this mean? If I take a picture using Zuiko 300mmF2.8 on Olympus E500 and compare with say Canon 300mm lens on Canon 20D, will both pictures be equivalent size and magnification?

    I am an Olympus user thinking of acquiring the Zuiko 300mm F2.8 lens for bird photography.

    Appreciate advice,
    sandy

    You're not the only one confused by the crop factor deal. I know that I don't totally understand the whole thing. If I understand this correctly the basic deal is that the Sensor in digital cameras gives you a smaller end result image than a standard 35 mm camera. The image hasn't truly been magnified it has been cropped to appear that way. This is an oversimplification. The 20D has a 1.6x crop factor. For more detailed info check out this link http://www.the-digital-picture.com/Canon-Lenses/Field-of-View-Crop-Factor.aspx

    There are also lots of other discussions that you might try reading by doing a search for Crop Factor
  • wxwaxwxwax Registered Users Posts: 15,471 Major grins
    edited March 9, 2006
    To me the simplest way to think of crop factor is this...

    Light is coming through your lens. Take the end of your lens that goes into your camera. Hold it close to a wall. Your lens is throwing a round circle of light on the wall. The wall is the biggest possible sensor - it captures everything, the entire circle of light coming through your lens.

    Now draw a big rectangle inside that round image. That rectangle is your actual sensor. As soon as you draw a rectangle, you're cutting off some of the original image - it's round, and your sensor is a rectangle. You're cropping out part of the circle of light coming through your lens.

    Now, draw a smaller rectangle inside the big rectangle. This smaller rectangle captures even less of the original, big round image than the big rectangle.

    These rectangles are your different sensor sizes. As you can see, they're simply cropping the round circle of light coming through your lens. That's why a smaller sensor is said to have a "crop factor." It's not zooming in. It's simply capturing less of what your lens is putting out.

    Make sense?
    Sid.
    Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam
    http://www.mcneel.com/users/jb/foghorn/ill_shut_up.au
  • wholenewlightwholenewlight Registered Users Posts: 1,529 Major grins
    edited March 9, 2006
    sandychian wrote:
    Hi,
    I a newby to the forum. Need some advice on the ongoing discussion about 4/3rd system by Olympus. Zuiko digital lens is said to have equivalence to 2x in 35mm format, i.e. 300mm F2.8 is equivalent to 600mm F2.8 in 35mm format. What does this mean? If I take a picture using Zuiko 300mmF2.8 on Olympus E500 and compare with say Canon 300mm lens on Canon 20D, will both pictures be equivalent size and magnification?

    I am an Olympus user thinking of acquiring the Zuiko 300mm F2.8 lens for bird photography.

    Appreciate advice,
    sandy

    It's crazy because everything goes back to the standards set for 35mm film cameras (actual the numbers refer to focal length but that's a more involved subject). But here's a fairly simple way to understand what the result of all the milimeter numbers mean.

    50mm lens on a conventional 35mm film camera = approx what our eyes see in magnification - things don't look closer or farther away.

    300mm lens on a conventional 35mm film camera = things look 6 times closer than what our eyes see - like a pair of 6X binoculars (sporting goods store can help)

    300mm lens on a Canon 20D = same as a 480mm lens on a conventional 35mm film camera - things will look 9.6 times closer than the human eye sees.

    300mm lens on an Olympus 4/3 camera = same as a 600mm lens on a conventional 35mm film camera - things will look 12 times closer than the human eye sees.

    Does that help?

    Olympus' 2X crop factor works well for bird photographers (related to magnification, anyway). The birds will look closer in the shots because the smaller sensor crops a little more (as wxwax identified). Some may question if a smaller sensor can deliver the same resolution but that's another subject.

    Hopefully this is not too simple - I'm pretty simple minded . . .biggrinbounce2.gif
    john w

    I knew, of course, that trees and plants had roots, stems, bark, branches and foliage that reached up toward the light. But I was coming to realize that the real magician was light itself.
    Edward Steichen


  • sandychiansandychian Registered Users Posts: 7 Beginner grinner
    edited March 9, 2006
    Simple but Clear :)
    Thank you John and to all that replied to my question. The analogy of how close the image is being dependent on the focal length of the lens is an effective one. I am no longer confused now. Looks like the 4/3 system with a 2x multiplication factor is a good thing for bird photography.

    Appreciated,
    sandyclap.gif
  • CookieSCookieS Registered Users Posts: 854 Major grins
    edited March 9, 2006
    OK I have to play devils advocate here....just because i am that way "saucy of me I know" Buut I have been told that the Crop factor is Just that a crop factor. the image/subject will LOOK the same size as IF taken with a lens of that lenghth. but the Subject will Not really be any CLoSER . to the lenghth of the lens. .....so the bird at 300 mm lens is stilll the same size whether the 1x6 crop factor is there. It may FILL up more of the frame, but it will be the same distance away.

    Is this correct?
  • wholenewlightwholenewlight Registered Users Posts: 1,529 Major grins
    edited March 9, 2006
    CookieS wrote:
    It may FILL up more of the frame, but it will be the same distance away.

    Is this correct?


    But if it fills up more of the frame (or viewfinder) it appears closer.

    here's a quote from kenrockwell.com (yeah, I know that some people dislike him but the quote works)
    [FONT=Georgia, Times New Roman, Times, serif]The CCD is smaller than film, so your image from any lens is the same as cropping out from the middle of a film frame.[/FONT]
    [FONT=Georgia, Times New Roman, Times, serif]A more complex way to imagine this change in field of view is to play a game and imagine that your lens changed focal length. Typically this factor is 1.5, meaning a 50mm lens used on a typical digital SLR will give the same angle of view as a 75mm lens on a film camera[/FONT]

    If the angle of view appears smaller, the object photographed appears bigger or more magnified - right?
    john w

    I knew, of course, that trees and plants had roots, stems, bark, branches and foliage that reached up toward the light. But I was coming to realize that the real magician was light itself.
    Edward Steichen


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