Originally posted by yeatzee Someone try it out and shoot a ruler
Your right.
If you put a 50mm lens on a 50mm tube you get 1:1
You simply divide the lens with the tube ( or the other way around perhaps) so in that case:
50/50=1
The 1 is what you put after of the "1:" so that would make Mag ratio 1:1
Using a 28mm lens on a 50 tube seems to give about 2:1 ( twice life size)
update: Im slightly confused at the moment. I had to give you something shot from a macrolens so here's a ruler shot with a Tokina 90mm f2.5 at f2.5 + a 50mm tube handheld in bad light and I cant wuite get this math working.
90/50=1.8 so that should be mag ratio 1:1.8 ? That doesnt really make sense but it does sort of match the shot.
1.8 inches wide even though the shot looks more like 1.6 inches.
Help!