 | | Math/Optics Problem
|
|
So. Let's assume I have a photograph of Bob standing in front of his house. Knowing Bob the way I do, I know that Bob is 6 feet tall. And asking him later, I know that his house is 30 feet tall. Now I want to find out how far in front of his house (...) (23 years ago, 13-Aug-01, to lugnet.off-topic.geek)
|
| |
| | Re: Math/Optics Problem
|
|
David: (...) No. (...) No. (...) Yes: Focus (I think). (...) dist. from camera = (fisheye const.)*(actual height)/(photo height) + (small obscure camera dependent constant) Since you only ask about the relative distance, the "small doesn't matter. (...) (23 years ago, 14-Aug-01, to lugnet.off-topic.geek)
|
| |
| | Re: Math/Optics Problem
|
|
(...) Hmm... So both the zoom and the focus affect the fisheye constant? How exactly does the focus change it? I guess I'm imagining the same actual image in and out of focus and not seeing actual change in the image's shapes & relative sizes... (...) (23 years ago, 14-Aug-01, to lugnet.off-topic.geek)
|
| |
| | Re: Math/Optics Problem
|
|
David: (...) <activate brain/> Hmmm... Maybe not. The focus is probably rather affecting the "small obscure" supposedly only "camera dependent" supposedly "constant". (...) I think I have to open a camera (or an optics textbook) and have a look. (...) (23 years ago, 14-Aug-01, to lugnet.off-topic.geek)
|
| |
| | Re: Math/Optics Problem
|
|
(...) Alrighty. Since I have been studying this stuff for the past month and am supposed to pass a test about it, let's see what I can do. (...) Depends. Does it "focus"? The "fisheye" constant you're referring to is, in technical terms, called the (...) (23 years ago, 14-Aug-01, to lugnet.off-topic.geek)
|
| |
| | Re: Math/Optics Problem
|
|
(...) Really? I woulda thought it had more to do with the zoom rather than the focus. But then again, I'm really not sure how the lenses in cameras work. I guess my assumption (based on nothing at all I think) is: {A}--------B--------...E)--F--[G] (...) (23 years ago, 14-Aug-01, to lugnet.off-topic.geek)
|
| |
| | Re: Math/Optics Problem
|
|
It's amazing how much physics and math I have forgotten, so let me simply note that the focus of the camera isn't going to change the proportions of the objects. The focal length will. The perspective will change as your lens measurement changes (in (...) (23 years ago, 14-Aug-01, to lugnet.off-topic.geek)
|
| |
| | Re: Math/Optics Problem
|
|
(...) Ahhh-- so perhaps I've been getting stuck on photography terminology. I had assumed the "focus" in Shiri's response to relate to the fuzziness of the resulting image, not the "focal length" which affects the zoom level. That makes just about (...) (23 years ago, 15-Aug-01, to lugnet.off-topic.geek)
|
