I am trying to take an aerial photo, so that when it prints, it will be in a typical engineering scale of 1:40, or 1-inch on the photo equals 40-feet in the real world.  This would also be synonymous with a 1":480" scale for the calculation below:

I know that the Mavic focal length = 28mm = 1.1-in.
I know the equation: S = f/H, where:


S= Scale,
f = Focal Length
H = Drone flight height above ground
And,
S = 1 / X, where 1/X is my 1:480 scale.


So if I know that 1/X = 1/480.  Then,
1/480 = 1.1-in. / H



H = 44-feet.  This is the altitude (AGL) I should take my photo from to create an aerial photo with a 1:40 engineering scale.


So I would love to get some help on two questions:
1.  Do my calculations look correct?  Is 44-feet the correct number?
2.  If my height calculation is correct, how should I print the image on 8.5x11 printer paper so I don't ruin my scale!?


Thanks,
TKane

Wouldn't it be simpler if you take the highest resolution photo possible, then scale your print? It doesn't matter what focal length you use, or how far you take the photo. You can even use a long focal length lens and stitch together your image for an even higher resolution image. You can then scale it down for your needs:

You know a 40-foot object should print out to 1 inch on paper. Assuming you are printing at 300 dpi, then you know you need to scale your image so this 40-foot object takes up exactly 300 pixels.

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Alex Jiang Photography

rent Posted at 2018-5-9 10:09
Wouldn't it be simpler if you take the highest resolution photo possible, then scale your print? It doesn't matter what focal length you use, or how far you take the photo. You can even use a long focal length lens and stitch together your image for an even higher resolution image. You can then scale it down for your needs:

You know a 40-foot object should print out to 1 inch on paper. Assuming you are printing at 300 dpi, then you know you need to scale your image so this 40-foot object takes up exactly 300 pixels.

You're the best - makes sense - Thanks! Tad