How to calculate PTZ optical zoom & field of view
We hope you enjoy Episode 1 of our “Back to the Basics” live show. Every week on Wednesday at 11AM PST, 2PM EST we will be hosting a Facebook Live event to review foundational knowledge about pan, tilt and zoom cameras. In this video, we review how to determine the proper amount of optical zoom for your video camera setup. PTZOptics offers a 12X and a 20X camera zoom lens option. To make it easy to calculate the horizontal and vertical image size that you will get of an object at various distances from the camera.

Field of View for camera based on distance and zoom
The field of view calculator above will help you determine the width in feet that your PTZOptics camera will capture at a given distance from the camera. The field of view (FOV) represents the viewing angle the camera will capture. The FOV will change as you zoom the camera in and the below charts will help us determine the wide and tele (fully zoomed in) distances.

PTZ Camera Optical Zoom
How to choose the right camera?
Choosing the right camera might be easier than you think. All we need to do is determine the furthest distance you will want to capture with your capture. For example if you would like to capture a “head and shoulders” picture zoomed into a subject 40 feet away, our charts will tell you that the 12X will capture a 4.9’ FOV and the 20X will capture a 2.8’ FOV. If you want to capture a “tight” view of your subject at 40’ away, the 20X will be the better option.

PTZOptics Zoom Capabilities Example
Maximum Usable Distance 12X:
Distance from Camera Lens (ft) | 10’ | 20’ | 30’ | 40’ | 50’ | 60’ | 70’ | 80’ | 90’ | 100’ |
12X Tele Angle | 1.2 | 2.4 | 3.7 | 4.9 | 6.1 | 7.3 | 8.6 | 9.8 | 11 | 12.2 |
12X Wide Angle | 14.3 | 28.5 | 42.8 | 57.1 | 71.3 | 85.6 | 99.9 | 114 | 128 | 142.7 |
Maximum Usable Distance 20X:
Distance from Camera Lens (ft) | 10’ | 20’ | 30’ | 40’ | 50’ | 60’ | 70’ | 80’ | 90’ | 100’ |
20X Tele Angle | 0.7 | 1.4 | 2.1 | 2.8 | 3.5 | 4.2 | 4.9 | 5.6 | 6.3 | 7 |
20X Wide Angle | 12 | 24 | 36.1 | 48.1 | 60.1 | 72.1 | 84.1 | 96.1 | 108.2 | 120.2 |
PTZ Camera Selection & Ideas
- How to calculate PTZ Camera Optical Zoom and Field of View here.
- How to access the On Screen Display Menu via IP web browser here.
Tutorial video transcript:
Paul Richards: Hello everybody! Welcome to Back to the Basics.
Tess Protesto: We haven’t said PTZOPTICS live.
Paul Richards: Yeah. This our new show and it’s actually on Facebook this time.
Tess Protesto: We figured we’d switch things up a little bit, trying new platform. And so, we’re pretty excited.
Paul Richards: Yes, so let’s get right into it. So one of the most popular questions we get all the time. And the cameras are ready. I’m going to grab the cameras.
Tess Protesto: Go ahead.
Paul Richards: Is 12x or 20x. And the reason why…Sorry.
Tess Protesto: I’m excited for this myself because I feel like I might learn some things that I don’t know yet because I’m still learning about our products.
Paul Richards: And so, the question becomes – how much optical zoom do I need and how do I determine. So they’re using the two lenses and you can see, hopefully you can see here, the 12x has a wider…
Tess Protesto: Do you mind I hold it up like your model?
Paul Richards: Sure. You can be the Vanna White. Tada! There’s a 12 and the 20 optical zoom. And if you have any questions, write here below. We’re pulling in all the comments directly from Facebook and display them here, which I probably might have to hide in a minute.
Tess Protesto: Yeah.
Paul Richards: So what we decided to do was to create an optical zoom calculator so that you guys can very easily determine exactly the video image that you’re going to get. This is available at ptzoptics.com/zoom.
Tess Protesto: I’ll put that in the chat.
Paul Richards: It’s super easy to get to and what it does is it basically allows you to go ahead and choose exactly how far you are going to be capturing an image away from your camera and then you can basically go ahead and grab exactly the data from either a 12x or a 20x lens. Let’s dig into this a little bit.
Tess Protesto: We’re going to have fun.
Paul Richards: Yeah. Make it easy. So if anyone out there, I would like us to use the information from your specific set-up. We can do that. And I’d be happy to make this a case study but let’s go ahead and try 10 feet. So the camera is 10 feet away from this object and what we’re looking at here is we’ve got a wide and a telephoto information here. And then horizontal and vertical information.
Horizontal and vertical is basically horizontal is the width of the image and vertical is the height of the image. Normally, it’s 16 by 9, which is an aspect ratio and then 1920 by 1080 is the pixel that usually people are streaming or capturing in. Some people actually do other resolutions such as on the bottom of the camera. We also support 720p and also 576i and 480i. Those are the resolutions on the bottom there of the camera.
Tess Protesto: Okay because I never see that before.
Paul Richards: Quick thing about the camera is at the back of the camera, there’s a little dial that you can go ahead and select exactly what resolution you want the camera to output but I think most people are doing 1080p.
Tess Protesto: 1080p. That’s ideal.
Paul Richards: High definition.
Tess Protesto: Gary says the 12x is wider.
Paul Richards: The 12x is wider and you can see here that…well, I guess really quickly, the 12x is 72 degrees field of view and the 20x is 60.7. So field of view is the width of the camera. So 72 degrees is wider than 61. And that is very important when we calculate how far it can zoom in because as you can see, the 20x here. Let’s just take this 100 foot example. And let’s just look at the horizontal because usually that’s what people really care about – how wide of an image am I going to capture.
Tess Protesto: Right.
Paul Richards: So if they’re 10 feet away, the horizontal is 9.5 feet, just about 9 and a half feet width you’re going to capture at 10 feet away from the camera and then on the 20x, you’re going to get 8.7. It’s roughly about the same, just about half of, about a foot difference.
Tess Protesto: Not too far off.
Paul Richards: Not much of a difference. But when we start zooming in from far distances, let’s say 50 feet, now let’s take a look at the telephoto. So we just look at the width, which is the horizontal width. Now, let’s look at the telephoto. What that stands for is the fully zoomed in.
Tess Protesto: Full zoomed.
Paul Richards: That’s the fully zoomed in one. So for example, on the 12x, when we’re fully zoomed in, an object 50 feet away, were going to get a 6 foot wide view. So when I think about that is if I get it to church and the camera is all the way in the back and there’s a pastor all the way at the front. With 12x zoom in all the way, the photos we can zoom in is going to be 6 feet wide.
Tess Protesto: Okay.
Paul Richards: So you’re not going to see the church pastor, head and shoulders fill up the whole thing. You can actually fit. In 6 feet, you can probably fit 3 people standing next to each other. But on the 20x, if you look at it, we can do 2.9 feet. So just 3 feet. So now, you’re getting closer to a head and shoulder shot that’s much more zoomed in.
Tess Protesto: Right. So Gary yes, a 12x would work better in a board room and the 20x would work better in an auditorium situation.
Paul Richards: That is a great way to look at it. Yes. So that is available at ptzoptics.com/zoom. And we actually…
Tess Protesto: The fun new little tool hasn’t been covered.
Paul Richards: It’s a great little tool.
Tess Protesto: Did you just make that?
Paul Richards: I just made it yesterday.
Tess Protesto: Every day I come in and he’s got something new he’s made.
Paul Richards: So it’s just been made and I just made this little document to go with it. It basically walks you through it and here’s the graph here that kind of explains it. Kind of boring data here but basically, as you can see, the fields of view on the fully zoomed in, that’s just the Tele Angle, which is, they call that telezoom. You can see here the much tighter angles. So you can zoom in much tighter field of view versus wide field of view.
How do you choose the right camera? Well, just really thinking about what is the farthest person away that you could possibly need to zoom in on and figure out, okay, well, if I need to zoom 50 feet, is a 12x okay? Do I just need 6 feet wide? Or is 2.8 going to be much nicer because I can zoom in father.
So that’s really how we capture everything and here is an example here. And I’ve got a couple example of videos I wanted to show. But you can see here that a 20x camera all the way zoomed out and all the way zoomed in, looks pretty good. And Tess, you got some great footage. So Tess last footage…Here it is. You got some really great footages from some of our customers.
Tess Protesto: Yes, I did.
Paul Richards: And I thought this one in particular really did the camera justice. I want to show this one. What is this Tess?
Tess Protesto: This is, I believe a high school age spring jazz festival. Though they seem pretty impressive. I mean, their production quality is really impressive. So it’s pretty cool
Paul Richards: Yes, it’s pretty cool. It is a two hour video but you could see in the beginning there, it was pretty far zoomed out. And in fact, there was another one that you sent me Tess. It was really good. But that’s fully zoomed out.
And then, you can see them fading in that minute 320x SDI cameras. You can see them fading into different shots where you can clearly see the people much better when it’s fully zoomed in. So that’s the reason why people use pan zoom in camera so much.
So that’s where we’re going to wrap up the show. These are super quick 10 minute, kind of quick videos. And then, we’re going to stick around and answer anymore question that you guys have.
So thank you so much for tuning in. We’re going to go ahead and roll the credits. We’ll stick around and answer all the questions and hang out and chat with you guys.