how much light is enough

I'm looking for some advise with flash equipment. I want to purchase

flash equipment and I am confused with just how much watt/seconds of

power I actually need. I am considering either the Sunpak 622 or one

of the Quantum heads. What I am trying to figure out is would 150 w/s

be enough or should I go with one of the 400 w/s heads. I photograph

mostly social events and a wedding once in a while. I am using film

and digital. The digital cameras I use are Kodak 14n and a Nikon D2H.

What I experience is that when I photograph large groups or large

areas the flash from my Nikon SB800 drops off beyond twenty something

feet resulting in a capture underexposed. Before I purchased the SB800

I was using a Sunpak 544 and never had this problem but that unit is

no longer working. Any info would be helpful.

I always take more power if I have the choice.

 

Why is your SB falling off so quickly? Do you have that factory diffuser mounted on it, Bob? It sets the zooming head at 14mm when it's placd on there. On the bottom of the SB head where this diffuser mounts you will notice a little lever that gets pushed in when the diffuser is mounted. Notch your diffuser so this lever does not get activated and then the only reason the head will zoom will be becasue of the focal lenghts you chose to use. There's something wrong if you're getting under exposed images at 20' with this unit even wih the custom job I just described.

Do you have something in the foreground that is upsetting the exposure reading? What f/stop are you using - you may have to open up. Lose the diffuser cap for anything beyond 10 feet. Bump the ISO to 400 - you'll still get good enough quality for most purposes.

 

An SB800 is a little wimpy for groups, but you can get by. A worse problem is shadows and red-eye. If you do groups, try to use available light with an optional (gelled) flash fill. Otherwise, get a monolight (500-1000 joules) and put it on a stand.

I was thinking of turning the sb800 into a backup flash. So I guess I have mostly the same question. Would you get a second sb800 or something differnt?

Whether 150 W/S is enough is dependent on the f stops you tend to use. Personally don't have too many situations where I wished I had a more powerful flash and my flash units are about that, with film or digital. When I do need more power, I get my off-camera Norman 200B out and use multiple flash.

 

It's always nice to have the power if you need it, but that is offset by weight and cost. Those Quantums are pricey. If you are feeling the lack of power only for large group shots, use a more powerful off-camera flash for those while keeping the shoemount on the camera, and use the shoemount by itself otherwise. I'm not necessarily recommending the 200B, but you can buy a used kit on e-bay for about $300--much cheaper than a new Quantum Q flash X kit.

I only use the diffuser for up close work. The camera is usually set in Progam mode and matrix metering and the flash set for TTL. Other than what I experience beyond twenty feet, the flash works great in this configuration. I will try notching the diffuser as Eric suggested.

 

I usually don't have anything between me and my subject to fool the camera. And as Edward suggested, I thought about a monolight but many of the events I cover I have to move around too much. That's why I was thinking of maybe purchasing one of the big dogs like the Sunpak.

 

But when a spec such as joules is listed, since joules is a measure of energy I don't know how to relate that to light in terms of distance/shutter-speed/f-stop. Some manufactures use the GN, some use w/s and then we have joules. I guess 400 w/s is a lot of light... Is this too much? Some photogs who own and use the Sunpak 622 tell me it's too powerful. I mean, lets face it, you gotta pay attention to what you're doing so my thinking would be to use the setup in manual and turn the power ratio down. That's what I did with the 544.

 

But I guess the only saving grace of having so much power is it gives one the option of employing some sort of diffusion device like a small soft box or bounce. Softboxes are a little bulky to lug around though.

Have you tried using a tripod first? If you set the camera to 1/15 second (or slower) and the group does not move, you should be able to light up a room with a single SB-type speedlight__using the 'S' mode in the camera to allow room light to be included in the 'flash' exposure. Try it and you may save $$$$s in buying equipment that is 'fun' to drag about on assignments.

wattsec and Joule is the same - depending where you look at it. It is more like "The Channel La Manche", and "The English Channel" - the same thing, depending on the point of observation.

 

These are measurements of the energy that a capacitor built in an electronic flash can hold.

 

There is no exact relation between wettsec and Guide Number, as it has more to do with the effeciency of the flash Xenon bulb, operating parameters, and the reflector properties. Certainly one would expect that more wattsec should yield larger Guide Number.

 

Studio strobes are usually rated in wattsecs, (Joules), and also sometimes a Guide Number is provided for a specific model and reflector, or perhaps without any reflector, and that changes when you apply a different reflector or a barn doors. Portable flashes are mostly expressed in Guide Numbers, and wattsec for them is usually not listed.

 

If you need to find the wattsec of your portable flash, that is if you have a screwdriver and possibly a hammer, you can get to the capacitor inside your flash (not recommended !), and read off the capacity and the working (or max) voltage of the unit. This will define the working (or max) wattsec value for the capacitor/flash, but will not tell you the Guide Number, as other elements of the flash influence the GN Value.

You use the camera in Program, but I would ask again--what f stops and ISOs are you/the camera using? And is it only for groups beyond 20 feet that you feel the lack of power? Have you tried using wider f stops, standing closer to your groups (within reason), and/or using a higher ISO with your current flash?

 

If you want to get a more powerful flash, compare them to each other by guide number and then minus a stop from each, since flash manufacturers over-rate their guide numbers. And why not just get a replacement Sunpak 544 if that served your needs?

Use http://www.processassociates.com/process/convert/cf_ene.htm to convert watt.s

into joules. Or just multiply by 1, whichever you find easiest.

 

Surely studio heads will always be rated in w.s as the GN depends on what you are

bouncing off, reflecting off, diffusing through etc. Why not hire a 400 w.s and 150 w.s

lamps from your local calumet hire store with a minolta or sekonic flashmeter for the w/e,

then do some set up's comparing your SB800 with both heads in a variety of situations...

family can be so understanding for this type of event, especially if you feed and water

them. You have digital so you also have instant feedback, think yourself lucky as others

have to wait a week to see the results.

 

TTFN... NB.

A used QUantum for about $250/350 ..should suffice any group shot @ 10-12 feet >>(250~ f8~ asa 100) situation lighting. We rarely need more than a single Quantum T4...the 400 w/s maybe warranted for larger groups >> indoors.

"If you set the camera to 1/15 second (or slower) and the group does not move", you might not need a strobe at all... right?<p>Get the X2 and use the (thyristor) auto mode. Add a remote sensor if you want to base your exposure off what the lens sees. I use the Lumedyne equivalent (sort of) with a 400ws pack and the sensor stays with the lighting unit (and measures output based on what light kicks back to the strobe). It works great... t<div></div>