[Hemi]

Originally Posted by JA

It's not a Barlow, but you can use a teleconverter (a telecentric amplifier ) which is like a powermate to increase the focal length, typically 1.4, 1.7 or 2 times, and even stack them if you REALLY must.

Best
JA

Thanks JA, just that he says, f4 x2 tele x3 Barlow to get to f24.

Cheers

H