[Laser] focal length question

[George Vastianos]

hello everybody

iam new to laser coms and while i was searching in the net for fresnel lenses i found lenses for 17.99$ that have maximum dimensions: 15.5x15.5 inches (~390x390 mm)
and are available in two versions:
a) 330mm focal length
b) 220mm focal length

What version is better for laser receivers???? Is it better to have the short focal length or it doesnt matter since the max dimentions in both versions are the same?????

mny 73 de George Vastianos SV8GXC