I have this sunpak 444d flash that I picked up along with a bunch of camera equipment I picked up on Craigslist. Do you know anything about this Flash? I am not going to lie, I am totally confused by the whole GN thing. You say that the sb-800 has a GN of 125 in one post and nikon advertises at 56. the 444d is rated at 50 GN but on sunpaks site it says something about 120-170 GN. I am totally confused. Perhaps you could explain it to us/me. I think that us new kids on the blocks have been spoiled by our run-and-gun i-ttl flashes, and have not learned what all the numbers mean. I'd like to learn, because i am sick of my camera being the alpha dog in our relationship.

I just checked the vivitar 285 and it has a GN of 37. Should i keep the 444d and use it as my lightstand/off camera flash once i pick up some PW's since it has a GN of 50? questions questions questions.

Thanks.

Hey John

a couple things, first off stated GN and actual are very very Different things. They always list them as more powerful that they actually are, kinda like horsepower for cars.

you can test the GN yourself, its easier with a flash meter but can be done with your dslr. measure off 10' from a subject, place the flash there, shoot till you get a proper exposure (with a high shutter speed around your max sync speed so ambient light doesn't interfere, shooting at night or in a dark room is best). Whatever aperture you get that gives you a proper exposure, multiply by 10 and you get the GN. So if its f/5.6 thats a GN of 56.

As for how its stated, its a GN at a certain iso, like GN 56 at iso 100. at iso 200 it becomes GN 80, it works just like the aperture scale, and the higher the iso, the more powerful the flash.
Many cheep flashes are rated at a higher GN and in the fine prints it say iso 400 or something. Some also do it in feet, others in Meters. There really isn't a standard unfortunetly.

Dude, I tell you the truth, GN values are of very little importance to me. When I am comparing flashes I know that the GN is similar to "horsepower" in cars as stated above. One flash has 120 horsepower and another has 140 horsepower so I know the second flash has a bit more power than the first.

When I'm shooting pictures I think about the GN of the flash about 0% of the time. What I need to know is done in testing. Can this flash over power the sun at 2pm? If it can, under what conditions and with what modifiers and at what distance?



I also think you may be seeing GN values in feet and/or meters. 50x3=150... Could this be what the difference in numbers are? Flashes have guides on them in feet and meters.

Cheers,
Zack