Vivitar VP-1 Varipower Module Manual pg. 2-3
Turns the trusty workhorse "283 into a useful strobist tool. The only downside is that since its just a potentiometer, there are no positive clicks for each setting, so you don't really know if that power level is what you're getting. But its pretty close. It also allows adjustment down to 1/64th power, better than the current 285 HV. "
- from an Amazon review. More 5-star reviews at B&H.
I got a 283 with AC adapter and the VP-1 module with some Canon film gear. Entire manual scanned here.
Vivitar VP-1 Varipower Module Manual pg. 2-3
Turns the trusty workhorse "283 into a useful strobist tool. The only downside is that since its just a potentiometer, there are no positive clicks for each setting, so you don't really know if that power level is what you're getting. But its pretty close. It also allows adjustment down to 1/64th power, better than the current 285 HV. "
- from an Amazon review. More 5-star reviews at B&H.
I got a 283 with AC adapter and the VP-1 module with some Canon film gear. Entire manual scanned here.