Field of view
- Thread starter igadget56
- Start date
I believe you mean Depth of Focus???? DOF is determined by focal length of the lens, distance from subject and f-stop. The higher the number, the larger the DOF, and more light or shutter is required. You can also increase the ISO to help. There are DOF calculators you can use. Just google it.
faithenfire
it's all IMO
i am going with you meaning dof. at least in nowadays terminology
yes, the bigger the number the more in focus things will be. the smaller the number the less things will be in focus in the background
wiki has a long and in depth article on it
depth of field
smaller depth of field
Exposure 0.008 sec (1/125)
Aperture f/6.3
Focal Length 85 mm
a bigger dof
Exposure 0.004 sec (1/250)
Aperture f/11.0
Focal Length 17 mm
yes, the bigger the number the more in focus things will be. the smaller the number the less things will be in focus in the background
wiki has a long and in depth article on it
depth of field
smaller depth of field
Exposure 0.008 sec (1/125)
Aperture f/6.3
Focal Length 85 mm
a bigger dof
Exposure 0.004 sec (1/250)
Aperture f/11.0
Focal Length 17 mm
Actually, I think the OP means exactly what he said. I beleive the f is focal length. . .and probably actual focal length for a small sensor and not the 35mm equivalent. If that's the case, then yes, a longer focal length would equate to less field of view. For example, when you "zoom" in on a camera, you're essentially increasing the focal length of the lens (or simulating an increased focal length), so you see a smaller section of what's in front of you.
Now, the big "F" is probably f-stop, which has a direct relationship (along with focal length) to the depth of focus that the previous posters are talking about.
Now, the big "F" is probably f-stop, which has a direct relationship (along with focal length) to the depth of focus that the previous posters are talking about.
igadget56
Member
Yes that is exactly what I meant. I am trying to figure what ip camera to get. Camera will be pretty far away from the tank.
I do understand the relationship between shutter speed and aperture. Faster shutter speed less focus. Slower shutter, bigger aperture the more of the subject will be in focus.
Thanks
Actually, if you're using a slower shutter speed, you make the aperture (i.e. size of the opening) is smaller. I think what you meant was larger f-number (i.e. focal length/aperture). Anyway, when talking about field of view, that can be tricky with the smaller cameras and camera phones, which I'm guessing is what you're looking at here. I tend to think in 35mm terms, but the focal lengths that I see advertized for point and shoot cameras doesn't seem to conform with what I'm used to from the 35mm world. For instance, if 3.9 - 39mm is indeed focal lenth, that's a practically impossible focal length on the short end for a 35mm, and still very wide on the long end. So, for me, anyway, those mean nothing in approximating the field of view.
Good way to put it Mike. I was trying to put that into words last night but it never sounded right. The other thing is, IP cams are even a little different. They normally have an auto iris to adjust lighting. I don't think you are going to get aperture adjustment or shutter adjustment. It will be more like a point and shoot on automatic, but the full image in the frame will be in focus as long as you're a certain distance from the tank. Three or four feet should be plenty.
Similar threads
