Calculating Distance from Model Rocket Photo

[KevinMWHM]

Launched a model rocket with my 5 & 3 year old, have a photo of the rocket straight overhead at the approx peak. Can I figure out the distance? I know the length, and the magnification. What would the formula be?

 

[NobodySpecial]

Depends what you mean by the magnification.

But if you photograph the same object a known distance away and note how many pixels it is on the image then you can work out the distance to the rocket by just comparing the number of pixel on your photo.

So distance rocket = known distance * unknown size/known size