Originally posted by MarkJerling Would you care to provide your maths for that? I'd venture that the resulting error would be much smaller than that.
The classical thin lens function:
(1/f) = (1/v) + 1/u)
units [mm]
where f : focal length = 50mm for example
u = distance from n2 to film plane
v = distance from n2 to the subject being photographed
Case 1 : Adaptor Error = zero,
subject : 100 metre = 100000 mm
(1/50) = (1/100000) + 1/u) >
u=50.025mm
Case 2 : u = 50.025 mm from case 1. Adaptor Error = 0.2mm, subject : to be calculated as v
(1/50) = (1/v) + 1/50.025) >
v = 11161 mm; v= 11.161 metre`