Strobe Flash wattage ?? and a few other ??

[WayneF]

A watt is 1 joule of energy emitted over a period of 1 second.

Yes.

Unfortunately a watt-second technically also means 1 joule of energy emitted over 1 second.

No, a watt second means 1 joule, period. Read your own link. Unfortunately you added too many per seconds.


But the point to be considered in a lighting forum is that a continuous light array (lets say several CFL bulbs, since they have similar efficiency as flash)...
of say 500 watts power, used with a 1/100 second exposure,

is 500 watts x 1/100 second = 5 watt seconds (available behind the shutter)

Which is nothing compared to a 75 watt second speedlight, or a 300 watt second studio light.

 

[Village Idiot]

Read:
Strobist: Lighting 101

Strobist: A Guide to Choosing Photo and Lighting Gear

And it really depends on what you're shooting. A 300w/s may even be too much in doors or in low light condition where you just may need a tiny bit of light, but on the other hand, 300w/s is not enough when you're shooting outside, with modifiers, trying to under expose a bright day, and you're light can't be right up on your subject. I use 800w/s Dynalite packs and Canon speedlights depending on what I shoot. Speed lights have their place and are great when I need to be light and portable or just don't need all that light where as the packs come out when I'm trying to get just a little bit of light.

 

[KmH]

A watt is 1 joule of energy emitted over a period of 1 second. . .
. . . Unfortunately a watt-second technically also means 1 joule of energy emitted over 1 second.

Read your own link.

I did.

From the watt-second link.

The watt-second is the energy equivalent to the power of one watt sustained for one second.

 

[WayneF]

[/quote
I did.

From the watt-second link.

The watt-second is the energy equivalent to the power of one watt sustained for one second.

1 watt = 1 joule per second.

Sorry, no, guess again. You are not reading it right (and the sin is trying to explain more stuff you don't know).

It does say a watt second is one watt over one second.

It does NOT say a watt second is the same as a watt. You made that part up. You said:

A watt is 1 joule of energy emitted over a period of 1 second.
Unfortunately a watt-second technically also means 1 joule of energy emitted over 1 second.

Which is simply confused and wrong.
The definition of the joule is: 1 amp through 1 ohm for 1 second (which is 1 watt second).

Your link says: watt second (joule) = watts x seconds

Rearranging with algebra: watts = watt second / seconds, i.e., watts = watts

The Wikipedia that you linked says EQUIVALENT THREE TIMES in three consecutive sentences!

A watt second (also watt-second, symbol W s or W·s) is a derived unit of energy equivalent to the joule. NOTE THE PERIOD HERE after the equivalent statement - seems very clear. (Taylor & Thompson 2008, pp. 39–40, 53) The watt-second is the energy equivalent to the power of one watt sustained for one second. NOTE THE PERIOD HERE. While the watt-second is equivalent to the joule in both units and meaning SEE? Seems exceptionally clear. there are some contexts in which the watt-second is used instead of joule. BECAUSE THEY ARE INTERCHANGEABLE UNITS

 

[dannylightning]

All the technical talk is cool and all but I have one more questions. why do people not like constant lightning, it seems simple and looks to do a good job, from some articles i have read it seems to be much easier to work with. I have watched quite a few videos where people show their constant lighting setup and pictures they have taken and the pics look really good.

strobes seem like they are higher end equipment and have allot of bells and whistles, can easily put out more light, but i just cant see why people do not like constant lighting,

 

[WayneF]

All the technical talk is cool and all but I have one more questions. why do people not like constant lightning, it seems simple and looks to do a good job, from some articles i have read it seems to be much easier to work with. I have watched quite a few videos where people show their constant lighting setup and pictures they have taken and the pics look really good.

strobes seem like they are higher end equipment and have allot of bells and whistles, can easily put out more light, but i just cant see why people do not like constant lighting,

Because continuous lights are simply VERY DIM for photography. See the message #16 just a few above here.

We may think it is bright in the house at night, but the camera tells us flash is needed there.

Continuous lights are fine (arguably even preferable) for fixed non-moving subjects, products, tabletop, architecture, etc,, when a long shutter speed is acceptable (even one second... if the subject is not going anywhere). We can see their shadows, and the camera can meter them.

But humans move, and flash is greatly superior for portraits. Attempts to use even quite large continuous light arrays always end up suffering with high ISO, wide apertures, and slow shutter speeds trying to make it work. Whereas flash can allow normal sunlight exposures, f/11 at 1/200 second at ISO 100... etc.

Faster shutter speeds drastically reduce continuous light exposures, whereas shutter speed has no effect on flash exposure (the flash duration is faster and briefer than the shutter duration).

Continuous lights can be HOT too, uncomfortable, sweaty.. All the time the shutter is not open, they are merely creating heat. But it is true today that modern cameras are able to work better with high ISO, like ISO 800 or 1600. It could be acceptable to you? Not to me though.

 

[dannylightning]

that makes sense, if i get these strobes i think i will have a learning curve here. hopefully it wont be too bad.

The people i rent the room from do not seem to be too keen on the idea of me making a photo studio in their basement, well its more about them not wanting strangers coming in the house if i try to make a business out of it, i guess i can understand that but i need to talk them into it.

Its not like they have anything nice in the basement any ways, except for the pool table, the rest of it is just worthless junk they are hoarding lol.

 

[WayneF]

Three thoughts I guess.

It is their house, period.

Someone pondering buying a light, probably has no experience yet to consider starting a studio business.

That mannequin guy thingie in your basement photo could be a good starting subject to begin learning lighting.

 

[dannylightning]

Starting the business would be down the road a bit. learning how to use the lighting correctly and practicing with some friends would be the fist step.

I can get a couple of lights and have some friends come over for shoots, that is not a problem. They just don't want strangers coming in and out which I can understand.

The punching dummy would probably not be a bad thing to use but I think it weighs around 200 lbs or something like that since the base is filled up to keep it from tipping over when you beat on it, its a big pain to move around.

I have been saving up money to buy my own house, but as cheap as it is to live here it kind of seems smart to stay here until they decide they want more money or decide they want me to move out. When and if I think I am ready to make a business out of this I am sure I can figure something out. I don't really expect to get allot of clients at first, it just seems like a fun way to make some extra cash here and there that could possibly turn into a descent amount of cash down the road if I get good enough at it.

 

[WayneF]

The punching dummy would probably not be a bad thing to use but I think it weighs around 200 lbs or something like that since the base is filled up to keep it from tipping over when you beat on it, its a big pain to move around.

I didn't realize what it was, it's more clear after you explained it... But I can see that 200 pounds would not be the best situation

 

[dannylightning]

I you can kind of tip and and rock it across the floor but I am always scared the base will break, plus i have some back problems and i need to keep a straight back any times i am lifting, I try not to move him except a few feet here or there when it slides around from hitting it, I though 200lbs would have been enough to keep it stable but you cant really unleash on it or it will tip back and move all over, its a good cardio workout though..

 

[Village Idiot]

All the technical talk is cool and all but I have one more questions. why do people not like constant lightning, it seems simple and looks to do a good job, from some articles i have read it seems to be much easier to work with. I have watched quite a few videos where people show their constant lighting setup and pictures they have taken and the pics look really good.

strobes seem like they are higher end equipment and have allot of bells and whistles, can easily put out more light, but i just cant see why people do not like constant lighting,

Because constant lighting takes a lot more power and produces a lot more heat to get similar effects of strobes.

Say for instance that you manage to get enough power to get to ISO 100 and 1/200 second shutter speed while shooting a moving object. That object still has the potential for motion blur where as a low powered strobe emits it's entire light usually at a much faster speed than your camera can even move it's shutter. Some strobes can flash under 1/30,000 of a second. If your ambient is killed at that point, it's essentially like using a camera with a 1/30,000 shutter speed.

Also, it takes much less energy to produce the same light. I can go outside and shoot at 1/200 @ f/2.8 with a 9 stop ND filter and kill the sun, yet with one 800w/s light I can appropriately light my subject. I can also do this off of a battery pack. The equivalent constant lighting needed would drain a battery in no time flat and could probably cook the model in the process. That's one of the reason you often hear them called hot lights.

There's a lot of other differences too, those are just a few examples.

 

[CameraClicker]

All the technical talk is cool and all but I have one more questions. why do people not like constant lightning, it seems simple and looks to do a good job, from some articles i have read it seems to be much easier to work with. I have watched quite a few videos where people show their constant lighting setup and pictures they have taken and the pics look really good.

strobes seem like they are higher end equipment and have allot of bells and whistles, can easily put out more light, but i just cant see why people do not like constant lighting,

The flash from a strobe, even a small one, is very bright, and very brief. Speedlites are at the other end of the speed spectrum. You can stop water drops with them because the flash is so brief. The light from continuous lights is relatively not bright and if you get enough light together to match the strobe, you won't be able to keep your eyes open. Even low power single continuous lights bother my eyes because they are too bright, but you have to set ISO 400 with them and have them right in your model's face to get a good shutter speed. If your model is perfectly still, continuous lights work. If your model is moving, you only have shutter speed to stop motion, with strobes, the flash stops motion.

 

[dannylightning]

Good info, makes sense.

how would say I constant light do and a off or on camera speed light. I found a 5 socket constant light where you can turn each bulb on and off individually for around 20 bucks and I already have the speed light. would something like that work ?

 

[CameraClicker]

Good info, makes sense.

how would say I constant light do and a off or on camera speed light. I found a 5 socket constant light where you can turn each bulb on and off individually for around 20 bucks and I already have the speed light. would something like that work ?

Usually with off camera flash, you are trying to create shadow, or different levels of brightness. A flash in the hot shoe would overpower the continuous light and make everything flat, unless you turn the flash power way down.
The main benefit of continuous is that you can see the shadow. Studio strobes have modeling lights to help with that. Speedlites (Canon ones anyway) have a modeling light that flashes rapidly. It hardly helps, so I seldom use it. It can help the camera focus when focus is too far for the little red lines.
White balance can be a problem if you introduce lights from several vendors, and sometimes even different models or ages of lamps. The ideal arrangement is to have enough lamps of the same kind that you can set all the lighting with them. Then life is easier. Possibly more expensive, but easier.