Sneak Peak - The IPVM Camera Calculator

Next week, we are formally announcing our new software tool - a lens / camera / ppf calculator.

[UPDATE - The calculator has been formally launched.]

This discussion is a sneak peak and is not being promoted / emailed out.

There are 5 modes - 4 of them are for specific tasks and the last, 'Advanced', is a full calculator that allows entering any input and seeing fov and ppf previews.

Let us know what you think. If there is anything confusing or missing, feel free to suggest.

neato. are there other tools somewhere on the site (besides camera chooser) or coming soon?

Other tools like?

i thought i remember a vms recommender tool or at storage calculator tool? i might be confused...

Seeing as height affects camera performance, would you consider adding it as a variable?

Ari, height is an interesting idea. Are you thinking about us simulating in the FoV preview or?

I would say it would be more useful in the PPF simulator, but the FoV simulator would be helpful to show customers who want the camera mounted higher than the integrator would be inclined to.

We could potentially do another mode / tool that shows camera height positioning effects. I am not sure we can do it on the current one but we'll think more about this.

Btw, another calculator I've been considering adding is F stop comparison, something that surveillance people often have troubles assessing (e.g., what's the difference between a camera/lens with f1.2 versus one with f/2.4).

Also, would you consider creating a mobile app? I'd pay a small but reasonable fee to get this on my phone.

We have not thought much about a mobile app. I am not against it, it's just 80% of our visitors come from PCs so it's something we'll consider after we roll out a complete web client.

That's because this site is more useful on a PC. That isn't necesssarily true of a calculator.

Works better with more options than any of the ones I've used. Good job!

One question: Maybe I'm overlooking how to do it exactly, but let's say you have a problem like the seminal 'View a Face at 3000M'. One where there is no target horizontal FOV but only a ppf requirement ~50 (?) and a distance to target. And for greater applicability let's assume only 100ft , not 3000M, for distance to target. What's the best way to find out what your choices are among the multiple solutions in three unknowns (FL,SS,RES). Just start plugin' each one and stop when your out of range?

@Ari, not quite the same as a mobile app, but the calculator seems to work fine in safari on ios, so iphone will work, of course its kinda small. :(

We have 4 basic scenarios that let you work with simpler, more common scenarios:

For example, how far can this camera see takes in camera resolution, ppf desired and angle of view, returning distance.

As for your specific example, the closest mode we have is 'how wide an area can I cover?' Speaking of which, I think that's broken. Will review tonight.

Interesting that small pixel size is not all bad; starting with the default values in advanced mode and changing the resolution to 1080P, and then alternating between 1/1.8" and 1/4" sensor size doubles the ppf, at the expense, of course of FOV width.

I imagine you will point out that this is backwards and not that useful because we have less choice over imager size, than say lens or camera placement, since it is tied to the camera, and we are choosing cameras based on a multitude of other factors. I know that, but still its interesting to note.

'how wide an area can I cover?' Speaking of which, I think that's broken.

Modes both Far and Wide are broken.

"I imagine you will point out that this is backwards and not that useful because we have less choice over imager size"

Yes, than you for anticipating my response. Not only do you have less choice, the practical range is far less than what you tried. Most surveillance camera imagers today are between between 1/2.5" and 1/3" (including Full HD cameras).

We in the civilised world use the metric system. I only have 2 feet and I'm sure my collegues have different sized feet. Sounds like quite an inaccurate system of meassurring.

Oh, and praised be the gods. A calculator which has 1/2.7" CMOS size!

Well at least 5 of them can be easily remembered metric-ally by this peculiar pattern...

  • 1/8" = 2mm
  • 1/6" = 3mm
  • 1/4" = 4mm
  • 1/3" = 6mm
  • 1/2" = 8mm

Rogier, we have plans to allow toggling between imperial and metric units. In surveillance, ppf seems to be widely used even outside the US, so that's why we started with that. Will add the toggle in August. Thanks.

We have enhanced the calculator with improved daytime PPF previews and new night time / low light ones. Check it out - lower right hand corner of the calculator.

Two questions:

Could you add the capability to enter Distance to Object and Horizontal FoV and have it calculate Angle of View and Focal Length?That would be more useful for my purposes.

Also, will the calculator be something I can share with my team?

By the way, one calculator I would like to see is something that shows what you can see from certain angles and distances. For instance, if we want to see the faces of slot machine(s), I typically use my arm or a stick which I sight along to determine the correct mounting location for a camera.

Through trial and error, I've found that 45 degrees +/- ~10 degrees from the face of slots gives adequate coverage but it's tough to pass that trick along. Most people can't picture the results in their heads. A graphic would be ideal and I suppose I could take a bunch of pictures from various angles to show a comparison but....

A good part of the consideration includes obstruction of the face by objects and people: too high an angle and you lose the ability to see the display. Too low and the display can be blocked by the customer. Other considerations are focus variance. Too large a lens-to-object distance variation between machines and you can't get them all in focus simultaneously.

Carl, for the angle / distance issue, see Testing Camera Height vs Image Quality. We could turn these type of images into a tool in the future.

We have made a number of major improvements to the calculator:

  • Directly edit PPF and HFoV as well as AoV, Distance to Object, resolution, etc. This provides great flexibility in trying out different combinations.
  • The controls have been moved up top, which makes the calculator more compact and quicker to change settings.
  • Added PPF preview for night time which shows the contrast between day and night image quality.
  • Added convenience controls to adjust distance / PPF from inside the PPF preview so its easier to try different settings out.

We won't officially promote it until next week but you can try the improved calculator here.

Looking forward to more feedback.

Like the always on advanced what-if mode...

What's the best way to change the focal length and have it only recalculate the ppf leaving everything else alone? And vice versa?

I see that you have an upper limit on focal length in-place. I've heard there is some limitation with these linear calculators and long-lens lengths, but I've never learned the details. Is this why the 500mm cap exists, and if so can you explain what causes the problem?

What's the best way to change the focal length and have it only recalculate the ppf leaving everything else alone? And vice versa?

The focal length, by definition, changes the AoV, so I don't understand why it would make sense to only recalculate the ppf. Am I missing something?

The 500mm cap is the Rukmini feature :) We simply don't have enough experience testing super long lenses and worry that other issues (atmospheric conditions, depth of field problems, etc.) will make the PPF previews images inaccurate. it's an edge case, and if there is a lot of demand for 500mm+, we can always review, do testing, update appropriately.

Btw, the calculator is now embedded above.

One to consider when you run out of other enhancements: Ability enter two focal lengths to simulate the range of a vari-focal lens. Then automatically zoom, or drag, between the two to show corresponding fov and ppf changes.

The 500mm cap is the Rukmini feature :

Suggested feature rename: Rukmaxi

Regarding the two focal lengths / vari-focal lens idea, I agree.

We are actually going to implement this when we add in camera models. There will be a dropdown list of models. Let's say the user picks an Axis P3364-V. We'll know it's a 1MP with a range of 49-109° AoV. We'll then lock in the calculator so it only shows that AoV range and no more than the camera's max resolution.


Focal length appears to override everything in Advanced. For instance, when I enter distance as 15' and try to enter a horizontal field of view of 6', it keeps changing distance to 3' while keeping the lens 2mm.


When you change the HFoV, there are 2 things that can potentially change as a result:

  • The AoV may change to accomodate the new HFoV entered, distance stays the same
  • The distance to subject may change to accomodate the new HFoV entered, AoV stays the same

We had to pick one of the two as the default, as either could realistically change.

If enough people feel keeping distance constant is better than AoV constant, we could easily change the function.

Or we could add in more advanced controls someplace else...

OK, well I have pretty much always used lens calculators by plugging in distance and desired HFoV and calculating lens focal length. Guess I'll stick with my handy dandy widget, though it is optimized for 4:3 and only covers 1/4", 1/3" and 1/2":

I have one of these. Makes me feel like a Hollywood director.

Carl, always with the passive aggressive response. I told you we can easily do this in software. We need to figure out how to design it in as there are many options to consider.

Hah! Every disagreement can be construed that way. Seriously, the issues I have with my "widget" are that it doesn't account for 16:9, only covers 1/4", 1/3" and 1/2" imagers and it automatically compensates for 10% CRT overscan.

Ari, I have one of those too but it is older and only has 1/3" to 1" graduations and doesn't go "wide" enough for many of our applications.


Here is passive aggressive:

"Guess I'll stick with my handy dandy widget, though it is optimized for 4:3 and only covers 1/4", 1/3" and 1/2":"

Here is direct:

"Please add a mode on the IPVM tool where I can do this, plus get different aspect ratios and various imager sizes. It will be a great help to me and others."

Funny, that's what I asked for five days ago.

In the last 5 days, we have added in both the ability to edit / change HFoV and PPF. We can still add other things, like outputing angle of view.

This is similar to my question regarding PPF,  i.e. what part of the wheel moves, and your answer would be the same I believe. (polynomials with two unknowns)

Or we could add in more advanced controls someplace else...

But I like the layout and the simplicity of the interface the way it stands, and think you could accommodate full freewheeling 'what-if-ness' by adding a lock or unlock icon (smaller than shown) next to the edit boxes to constrain the values:  

The lock is an interesting approach. Thanks. We'll definitely consider it. Right now, we are trying to figure out a bunch of enhancements / changes.

Btw, one thing we have queued up is to click and drag the AoV / FoV lines on the graph to make it easier to try out different HFoVs.

Hi John

Not sure if it's easy but, as you already have a database of tested cameras, i guess you could have one pick his camera to fill in the imager size, resolution and angle limits.

Or the other way around, after selecting the parameters you could get a list of cameras which fit in , by form-factor , and with links to your tests.

Just some ideas.

Very nice. Well thought out.

The calculator will be formally released on Monday.

We made 2 major changes to it this week that I think you will really like:

  • You can now control AoV by dragging the AoV lines on the graph
  • You can no control distance to target by dragging the camera icon on the graph up and down.

Now that we have these 2, I use them constantly to fine tune / experiment / refine calculations.