Chuck,
Thanks for this very clear and simple explanation. It now makes
sense to me.
Don
--- Chuck Norcutt <chucknorcutt@xxxxxxxxxxx> wrote:
> Perspective is controlled by the distance between camera and
> subject.
> If 100mm gave you your desired perspective on 35mm film then 50mm
> will
> give you the same perspective on a 4/3's frame.
>
> If you use the 100mm on the 4/3's camera you will have to stand
> twice as
> far away in order to frame the subject the same way as with a 35mm
> camera. That change of distance is what will change the
> perspective.
> If you use a 50mm lens you can still frame the subject the same way
> at
> the same distance you used with the 100mm lens on the 35mm camera.
> Preserving the distance to the subject preserves the perspective.
>
> To make this a little more visual, imagine a post sticking out of
> the
> ground at the very edge of the frame half way between you and the
> subject. If you have to back up to maintain the same angle of view
> of
> the subject, the position of that post will move inward on the
> frame as
> you back up. That's perspective change.
>
> The bottom line is; to preserve the same perspective abide by the
> "crop
> factor". The same rule pertains to the difference in film sizes
> between
> 35mm and medium format and between medium format and large format.
> A
> "normal" lens for any given format is approximated by the diagonal
> of
> the film frame. Adhering to that rule will define focal lengths
> for
> each format having the same perspective since it allows shooting
> the
> same angle of view from the same distance. The rule is only
> approximate
> since using the diagonal of the film alters relationships between
> image
> sizes because of the varying aspect ratios between film/sensor
> sizes.
>
> Chuck Norcutt
>
>
> Don Shedrick wrote:
>
> > I have not yet made the digital SLR switch, although I am getting
> > closer. With 35mm film cameras, a good focal length for
> portraits is
> > generally thought to be in the 75 - 150mm range. (I really like
> my
> > Zuiko 135 f2.8) My question is, with the 4/3 system with the 2X
> crop
> > magnification, is the same 75 - 150mm still the best for portrait
> > work, or would 1/2 of that focal length be best to use, with the
> > resulting image with the 2X factor being the same size image. My
> > thought is that the angle of view and perspective with the
> 75-150mm
> > range is the same with the 4/3 even though the image size is
> greater
> > due to the 2X factor, so the ideal portrait lense would still be
> the
> > 75 - 150mm. This means one would have to stand about twice as
> far
> > from the subject to get the same size image unsing a 4/3 camera.
> > Any thoughts or experience from others?
>
>
>
> ==============================================
> List usage info: http://www.zuikoholic.com
> List nannies: olympusadmin@xxxxxxxxxx
> ==============================================
>
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
==============================================
List usage info: http://www.zuikoholic.com
List nannies: olympusadmin@xxxxxxxxxx
==============================================
|