Again, there is NO difference in perspective between a 28mm lens on 24x36 and an 18mm lens on 16x24. Perspective is wholly dependent upon subject to camera distance. I don't have a 35mm camera to demonstrate this, but it's been shown in many many basic photography texts, including my copy of Focal Press "Basic Photography", 1968-1972 edition.
Field of View is what's different, and DoF, due to the smaller sensor format. As you can see from the following, the Field of View of a 28mm focal length on 24x36 format is matched by a lens right in between 18 and 19mm on the 16x24 format:
24x36mm format FoV (in degrees) f Hor Vert Diag 28 65.5 46.4 75.4
16x24mm format Width = 15.7 mm, Length = 23.5 mm, Diagonal = 28.262 mm f Hor Vert Diag 18 66.3 47.1 76.3 19 63.5 44.9 73.3
So if you take a photo with a 28mm lens on a 35mm film camera at 5 feet from a group of objects, then pick up a DS and fit an 18mm lens to photograph the same group of objects from the same distance, what you see will look exactly the same, plus or minus a little field of view.
Godfrey
On Mar 9, 2005, at 8:56 AM, Shel Belinkoff wrote:
Is the Pentax sensor 16x24? I thought it is smaller than that. I was
quite surprised at the difference in perspective between a 28mm lens on an
SLR and the 18mm on the istD.
Shel
[Original Message] From: Godfrey DiGiorgi
That's incorrect. Perspective is a function of the distance between the
subject and the camera. If you want the perspective you're used to with
a 28mm lens on 24x36mm film, you need to use an 18mm lens with 16x24mm
sensor. That's all.
