Although I suspect this will be of limited interest to most, I thought I'd share the results of a little test I performed this evening.
I've had a Sunpak 120J flash unit for some time and have come to love its power and bare bulb goodness. Finding a second one at a reasonable price has proven challenging. The 120J is a much sought after discontinued gem.
Anyway, in scrounging for another 120J, I discovered that used Quantum T2 flash units are fairly readily available on the used market and at prices often significantly lower than Sunpak 120J prices. Fancy features aside, the Quantum packs 150WS of stored energy while the Sunpak is rated at 115WS. On paper, that seems like a substantial difference. With its lower price and higher power, I recently decided to purchase a used Quantum T2.
The test:
This evening, I thought I'd see how the power of the T2 compares to the 120J. Note that both are similarly configured bare bulb type flash units that share a common accessory mount. The test setup had both flash units mounted to a Photoflex Quantum/Lumedyne speedring and firing into a Photoflex 24" x 32" white-lined softbox. A Minolta Flashmeter IV set to cordless mode and ISO 200 was positioned exactly 3' from the front baffle of the softbox. Power for the flash units was provided by a Quantum Turbo battery and the flashes were fired with Pocket Wizard triggers.
The setup:
The Sunpak 120J:
Fatboy (aka Quantum T2):
The Results:
I tested both units at full, half, and quarter power settings. Multiple pops at each. Here's what I found (numbers in columns 2 and 3 are f/stops):
Well, so much for the extra 35WS stored in the T2. The T2 is significantly bulkier and slower recycling (at least my copy) than my 120J while offering little in the way of useful additional output power. To be fair, the Quantum offers advanced capabilities that the 120J can only dream of. However, if the intent is to use either flash in manual mode only, in my opinion, the 120J floats like a butterfly and stings like a bee and is the better choice of the two. The icing on the cake is that the physical packaging of the Sunpak is much more bracket-friendly than the Quantum in that it can be positioned such that the flash tube fully enters an attached modifier. Here it is mounted on a Kacey bracket:
Fatboy's belly extends almost as far as the base of its flash tube so the tube cannot be fully inserted into a softbox or octa the way the Sunpak tube can.
Game, set, match Sunpak.
Now if only you could find clean 120Js at Quantum T2 prices ...
Dave F.
