serene said:Hi,
From a greenbie understanding. Have you ever try to enlarge a projected image on the wall (for eg at a presentation) by moving the projector further away? By moving the projector further from the screen, we are increasing the focal length (ie, longer lens) and if we want a smaller image, we move the projector nearer to the screen. This is my intuitive understanding. Chancy, nightpiper and other experts, please correct me if I am wrong. Thanks
uginz said:ok thanks..
so am i correct to say that using a 4/3 camera would focus at the same distance and produce an image of the same size compared with a normal 35mm one.
and this is due the smaller size of the sensor hence being place abt half the distance from the lens to obtain the same image field of view compared to the 35mm one?
chancy said:... just to post a correction ... for the projector analogy, I meant moving the projector rather than the screen. The Contax AX example is analogous to moving the screen though. My apologies Serene.
uginz said:if both the film's and sensor were at the same distance, the 4/3 sensor will actually only capture half of what the film sees.
so, in order to make it such that both sensor and film will "see" the same image, the sensor as to move closer to the lens.
chancy said:Hello Serene,
If you take the projector analogy to a camera system, just bear the following in mind.
1) The projector's position is fixed.
2) The projected image to the projector must be fixed.
3) If you use a screen that captures the full slide image as denominator (eg 35mm system), then the 4/3 system would be equivalent switching to a screen that's half the size of the former. Yes the entire image will be still be projected, but the 4/3 screen will only take in the central half of that image.
Hope this finally addresses Uginz & your views on this thread.
Cheers,
chancy said:Hello Kah Heng & Uginz,
After checking out your references & subsequent comments, I must admit error of reasoning on my part by putting the imager & film in the same plane. Apologies for causing earlier confusion.
To clarify my thoughts further, can I say than the 4/3 standard uses the 25mm lens to base the imager to flange distance. And any FL greater or less than this normal FL uses lens designs to maintain this imager to flange distance ?
My second question concerns the image circle. Do 4/3 native lenses (ie. Digital Zuikos) project the entire subject image into the image circle and onto the sensor, or is does portion the picture spill to outside the image circle but is discarded.
Glad to have your views on this.
Thanks Uginz for locating the Olympus link, appreciated