I might even suggest 2000 lumens calibrated so that you could have about 25 ftL at first, which could be reduced with an ND2 until the light output drops naturally to around 12-15 ftL. Of course, this is based on unity gain, and I suppose at that size, you would at least be considering a gain screen.
Come to think of it, with a real-world 2.0 gain screen, you may be very happy with the HD81 just as it is. That would give you about 22 ftL to start if the HD81 calibrates to 900 as TzungILin suggests in an earlier post. You would finally settle at 10-12 ftL after aging, which would be very watchable, I think.
Come to think of it, with a real-world 2.0 gain screen, you may be very happy with the HD81 just as it is. That would give you about 22 ftL to start if the HD81 calibrates to 900 as TzungILin suggests in an earlier post. You would finally settle at 10-12 ftL after aging, which would be very watchable, I think.




















