When I was painting from a photograph, I used to draw the composition on the painting surface as best I could to try and get the perspective and proportions right. That was until Pam bought me a digital projector one Christmas.
Now, I connect the projector to my iPad and use that to make an accurate drawing ready for painting. Some may say it is cheating but is it?
David Hockney postulates in his book, "Secrets of the Old Masters" that artists going back to the 14th century made use of lenses and mirrors to create accurate drawings. Not all of course but many did and the evidence for his argument is entirely convincing.
Where an artist has drawn without such aids, there is usually evidence of a searching to get the form right. In drawings using optical devices, there is no such evidence.