Lighting Power

Hey there,

How's day?

Fast question: when do you use high power and when do you use low power? and what is the maximum power can be used? in portraits say indoors (studios, Halls,...etc) or outdoors[on Location] what range of power are used? for products wether small sizes or large sized what range of power are used?

Let's say if i want to use F22, ISO 50-100, 1/100-1/320s, what power is ideal for that setting?

Hmm.
The short answer is, use enough power to get correct exposure.
But it's a bit more complicated than that.

You can look at it several ways. The flash power required for proper exposure depends on distance, aperture, ISO, and how the light is diffused (flash reflector, umbrella, softbox, diffusion panel, flash zoom setting).

Conversely, if your lights don't have enough power to get proper exposure at their maximum output, then you need to change one or more of those factors.

Determining the amount of power required can be done several ways. You can measure it with a flash meter; calculate it based on a flash unit's guide number, aperture and distance; let your camera's dedicated flash metering system adjust it automatically; or simply by trial-and-error, taking a shot, checking the histogram, and adjusting accordingly.

I don't know if I'm anywhere close to answering your question. If you can elaborate, perhaps we can explain further.

Curtis N wrote in post #2703667
Hmm.
The short answer is, use enough power to get correct exposure.
But it's a bit more complicated than that.

You can look at it several ways. The flash power required for proper exposure depends on distance, aperture, ISO, and how the light is diffused (flash reflector, umbrella, softbox, diffusion panel, flash zoom setting).

Conversely, if your lights don't have enough power to get proper exposure at their maximum output, then you need to change one or more of those factors.

Determining the amount of power required can be done several ways. You can measure it with a flash meter; calculate it based on a flash unit's guide number, aperture and distance; let your camera's dedicated flash metering system adjust it automatically; or simply by trial-and-error, taking a shot, checking the histogram, and adjusting accordingly.

I don't know if I'm anywhere close to answering your question. If you can elaborate, perhaps we can explain further.

Thank you very much.

Just there is someone who told me that in portraits i need only 400-500w.s and no more, even 750 is too much, and i heard there are people using 5 heads and someone told me he got lighting power about 2400w.s, so i don't know when i should use low power and when i need 2400 or even 4000w.s in some cases.

I asked this because till now i didn't get any studio lighting because of which brands to get and what power to get, about brands i end up with few to choose between, now about power, i want to get high power because i don't want to limit myself to a certain power then i feel that i need more later, and i told people that with high power i can lower and decrease the amount or output but i can't increase with low power kit, so i want to be sure what are the sitautions that need high power and what situations need low power, i can see that with high power i can use it in all situations as i can control the power by lowering or rising up.
Someone on another forum told me that he shooted for almost 10 or 20 years and he didn't use more than 2 heads and above 750, so i am wondering who should i believe.
I want to shoot portraits one person or groups indoors or outdoors and i think i will do some commercial photography sometimes so i can expect i will shoot different sized products, so I ask my question to be sure of my lighting kit to help me in most situations, and do you think that 400-800 is enough power (if to shoot many things)?

If your question is "how many watt-seconds should my strobes be?" Then it is frequently asked and difficult to answer. Here's an example of why it's difficult:

If a certain strobe provides sufficient power when placed 4 feet from the subject at f/5.6 and ISO 400, it will require 128 times as much power if it is placed 11 feet from the subject at f/11 and ISO 100. Throw in another variable like a softbox and you have even more range to cover.

Any light you buy will have insufficient power at maximum ouput for some situations, and too much power at minimum output for other situations. Since there are several ways to reduce the output beyond the power control on the unit, the most common advice is to err on the high side when making your buying decisions.

Tareq wrote in post #2703786
Thank you very much.

Just there is someone who told me that in portraits i need only 400-500w.s and no more, even 750 is too much, and i heard there are people using 5 heads and someone told me he got lighting power about 2400w.s, so i don't know when i should use low power and when i need 2400 or even 4000w.s in some cases.

I asked this because till now i didn't get any studio lighting because of which brands to get and what power to get, about brands i end up with few to choose between, now about power, i want to get high power because i don't want to limit myself to a certain power then i feel that i need more later, and i told people that with high power i can lower and decrease the amount or output but i can't increase with low power kit, so i want to be sure what are the sitautions that need high power and what situations need low power, i can see that with high power i can use it in all situations as i can control the power by lowering or rising up.
Someone on another forum told me that he shooted for almost 10 or 20 years and he didn't use more than 2 heads and above 750, so i am wondering who should i believe.
I want to shoot portraits one person or groups indoors or outdoors and i think i will do some commercial photography sometimes so i can expect i will shoot different sized products, so I ask my question to be sure of my lighting kit to help me in most situations, and do you think that 400-800 is enough power (if to shoot many things)?

Personally I think that far to much copy has been spent on the possibility of having too much power.

If you are purchasing studio flash units for general photographic use, the downside of not having enough power when you need it, is far more more likely to sting you than problems associate with too much power.

So, my advise for general photographic use, purchase all the power you can afford and are willing to carry (more power = heavier units). This will likely net you a more versatile setup than lowballing the power needs and on occasion coming up short.

In general I think the grand thirst for flash portraits at F/1.4 is way overblown. If portraits at F/1.4 are needed, why even bother with flash gear as most room level light at ISO 400 will get that done.

But, having 800 Ws of flash power in a power pack/head setup, is likely to be fine for most general photographic needs. If you go with monolights the total of all the flash units may need to be higher to allow you to have at least one head with 800 Ws of power.

Enjoy! Lon

Curtis N wrote in post #2703850
If your question is "how many watt-seconds should my strobes be?" Then it is frequently asked and difficult to answer. Here's an example of why it's difficult:

If a certain strobe provides sufficient power when placed 4 feet from the subject at f/5.6 and ISO 400, it will require 128 times as much power if it is placed 11 feet from the subject at f/11 and ISO 100. Throw in another variable like a softbox and you have even more range to cover.

Any light you buy will have insufficient power at maximum ouput for some situations, and too much power at minimum output for other situations. Since there are several ways to reduce the output beyond the power control on the unit, the most common advice is to err on the high side when making your buying decisions.

I know that and thats why i want to keep myself on the hide side as you said but someone try alot with me not to get high power at all as i will not use it (very rarely or maybe never), don't know how can he expect that.

I know that with distance changing and softbox or umbrellas and with those camera settings the power will vary in different situation, but all what i believe as you said is to get available power is better than get so minimum power and then can't get more for different situation then need to wait to get more power, even using reflexes or so i think maybe sometimes we need high pwer.
Let's say i want to shoot a car in a studio (or logically indoors), will that 400 to 800 enough for me? and what about if i want to shoot indoor room for design and decoration, can i light the whole room with just 1000 (assuming the room area is about 10X10m or larger in one direction or both).

londuck wrote in post #2703891
Personally I think that far to much copy has been spent on the possibility of having too much power.

If you are purchasing studio flash units for general photographic use, the downside of not having enough power when you need it, is far more more likely to sting you that problems associate with too much power.

So, my advise for general photographic use, purchase all the power you can afford and are willing to carry (more power, heavier units). This will likely net you a more versatile setup than lowballing the power needs and on occasion coming up short.

In general I think the grand thirst for flash portraits at F/1.4 is way overblown. If portraits at F/1.4 are needed, why even bother with flash gear as most room level light at ISO 400 will get that done.

Enjoy! Lon

I said that i want to use F11-F22 with ISO 50-100. even shutter speed i want to keep it about 1/100 or faster.

Shutter won't normally matter. You can use as fast a shutter speed as your camera will sync to. My 20D has a sync speed of 1/250th sec.

Tareq wrote in post #2703912
I said that i want to use F11-F22 with ISO 50-100. even shutter speed i want to keep it about 1/100 or faster.

In studio like settings (relatively low ambient) using electronic flash, the shutter speed will have no meaningful effect on the exposure.

If you want to just take pics of pedestrian type images of human beings in a studio settings, 800 Ws would be typically enough for a power pack / head type studio flash gear. With monolights you would be nice to have at least one monolight with about 800 Ws.

Enjoy! Lon

EOS_JD wrote in post #2703958
Shutter won't normally matter. You can use as fast a shutter speed as your camera will sync to. My 20D has a sync speed of 1/250th sec.

ok, i will use fixed speed of 1/250

londuck wrote in post #2703967
In studio like settings using electronic flash, the shutter speed will have no meaningfull effect on the exposure.

If you want to just take pics of pedestrian type images of human beings in a studio settings, 800 Ws would be typically enough for a power pack / head type studio flash gear. With momolights you would need a bit more as at least would be nice to have at least one of your monolight to be about 800 Ws.

Enjoy! Lon

OH MY GOD!!!

Thank you anyway, seems i will never get any lighting.

londuck wrote in post #2703967
With monolights you would be nice to have at least one monolight with about 800 Ws.

I don't own any studio strobes yet, but that seems like a lot.

Admittedly, the only brand I have studied in any detail is AlienBees, which I understand are not in the "high power" category where studio strobes are concerned. But their most powerful unit is only 640 watt-seconds, and according to their specs it will give you f/11 to f/16 with a shoot-through umbrella at a distance of 10 feet.

Maybe you would want more than that for location group shots, but would you really need that kind of power in a typical portrait studio?

This Thread is very interesting. Let me just put it into perspective (my perspective). To me more power = more money invested!! It would be insanity to invest so much into getting powerful heads and then not using the power, or adjusting your settings to accomodate the strobes being too powerful. I think in a typical studio setup, a total of 800 w/s would suffice. Most studios r not large enought to place your lights 20 feet away and it doesnt even make sense...did u think about the catchlight? the further you place your lights, the smaller the size of the catchlight no matter how powerful your unit is.

ok people, what do you think of this Package?

http://alienbees.com/b​usy.html

I may look for another brand but with similar power or close.

again, when i shoot portrait i will use one head or power of 400-500 only, i can increase little bit if necesary, but when i work in large space with large sized or many people say around 20 persons and using F22 and ISO100 for example, i have to look far than just think i will shoot only portraits of one person all the time.
I can keep all heads away or use 2 heads with less power, as long there is enough power i can use it is as minimum or as maximum, about price doesn't matter that much as you all know i buy more and more, so i am sure when i buy one head and i love to shoot more and use more power i will go to buy another head then i will try to shoot larger and larger which means more power to supply, simply i take high power and use 20% of its full power and use 80-100% for something else in another situations, is that difficult to do?