Photoscan : Impact of different focal length

I oftenly read that you must take every shot with the same focal length
Since I got my canon 1100D with a 18-55mm so let’s make an experiment.

I’m going to make 2 scan of Adriano, one where the focal length will be fixed at 18mm and one where I will be changing the focal for each shot.
The point here is not to get a good scan but to see if there is an alteration of the shape, so I won’t take a lot of pics and the lighting will be crappy

Pictures parameters :
Tv speed : 1/2, Av speed : F11, ISO speed : 100
Tripod used, no image stabilisation, mirror lock, 2 sec timer

18 mm pics :

Variable Focal length pics :

Results :

Pretty similar, let’s get a closer look :

For me there is no difference, we can see some small discrepency but this is probably due to the scaling/alignment process which was done quite quickly.