![]() ![]() A 40cm focal length for the C160 makes no sense, especially when the C310 has a mere 4.4mm focal length. Given the specs of the two web cams you linked, I think there is very likely some typos or just sloppy data entry work. A wide sensor will have a larger FoV, where as a square sensor with the same area will have a smaller FoV (again, assuming a horizontal angular measure). Sensor area may even remain constant, however if the shape of the sensor changes, that too will change the field of view. Assuming a 4.4mm focal length, a larger sensor is going to support a wider field of view, where as a smaller sensor will constrict the field of view. Sensor shape and size can affect the angle. It should also be noted that the Field of View is not purely determined by the lens' focal is also affected by the sensor. In a general sense, most people think of the FoV in terms of the horizontal, but that is not necessarily what is actually measured for a given product like a web cam. It can be measured horizontally, vertically, or diagonally. The angle for a given field of view can be determined a few ways. This is always the case for electronic stabilization and most often used for multi-shot techniques like Multi-Frame Noise-Reduction, and HDR plus geometric corrections such as distortion correction,įield of View refers to the breadth of the field (the region of a real-world scene that is "visible" by the imaging medium. Certain features reduce the displayed aspect-ratio to save some boundary pixels used in their computation. Digital processing reduces aspect-ratio.A common example is switching between SD (4:3) and HD (16:9) video but the same thing applies with image-formats (3:2, 4:3, 1:1, etc). Only a few makers special field-of-view by aspect-ratio. On cameras that shoot with different aspect-ratio, a reduced field-of-field is possibly shown. Actually, even the focal-length changes when away from infinity! Unfortunately, there is no formula for what happens to field-of-view as focus is changed because it depends on the particular optical design of the lens. Most field-of-view numbers are stated with the lens focused at infinity. As a lens focuses, there is often change in its field-of-view, particularly when close-focusing. ![]() If you have to guess, it is usually the diagonal field-of-view. Those numbers are not the same but some manufacturer only quote one of them and do not say which one. Field-of-view can be measured vertically, horizontally and diagonally.While this sounds like numbers could be compared, there several reasons why not: This is very reasonable since the lens is fixed and cannot server on something else. For fixed-lens cameras, and all web-cams that I know of, the field-of-view is normally stated relative to sensor-size. This makes no sense to me, can someone clarify what "field of view" actually means?įield-of-view is the angular extent shown through the lens. To see the marks for the C160 in the C310 I have to move the C310 further away by a full 3 cm. I found that in the C160 (field of view = 50°) I can see 21.6 cm of the paper and in the C310 (field of view = 60°) I can see only 19.2 cm. Then I looked at the picture from the webcam and marked the edges of the image with a pen on the paper (click for original resolution). I set both cameras next to each other facing a sheet of graph paper. Since this is contrary to what I had said from gut feeling, I did a little experiment. I found that the C160 has a field of view of 50° while the C310 has 60°, so one would think that the C310 shows a bigger area of the wall behind me. To verify this, I looked up the specs of the Logitech C160 and C310 which I both own. I was under the impression that a greater number as the FOV angle means that one can see more. I was looking for a webcam that shows a wide area left and right of me, so I compared the field of view of several webcams. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |