when is a watt/second a watt/second?

Does the name of the PCb B1600 have anything to do with watt/seconds? I understand the Einstein and the B1600 have the same maximum light output. Why is Einstein 640w/s and the B1600 1600w/s. Or do they not pump out the same energy? Does a speedlite w/s mean the same as a strobe w/s?

why can't strobe manufacturers use the same language when it come to measuring light output. When I want to know how much light comes out of the bulb, I don't care about how much energy the bulb sucks from the battery. I don't care about the relative brightness of the bulb compared to other manufacturers' bulbs. All I care about is how much light comes out--period. I feel like I can't trust the specs on different strobes without first doing my own tests.

when I say my car goes a max of 120 miles/per hour, I don't mean that it goes a speed that is perceptively similar to another car's speed while using twice as much fuel. I mean it goes 120mph. But with strobes, you have to take a class in the theory of relativety to understand what's going on.

PCB is the only one I know of that use the "effective" W/S BS in their names.

This is why he places the following in the spec for the B1600

6 f-stop power variability (20 Ws to 640 Ws)

He made up his own measuring system and then in small print there are the real numbers.

texshooter wrote in post #13147533
Does the name of the PCb B1600 have anything to do with watt/seconds? I understand the Einstein and the B1600 have the same maximum light output. Why is Einstein 640w/s and the B1600 1600w/s. Or do they not pump out the same energy? Does a speedlite w/s mean the same as a strobe w/s?

why can't strobe manufacturers use the same language when it come to measuring light output. When I want to know how much light comes out of the bulb, I don't care about how much energy the bulb sucks from the battery. I don't care about the relative brightness of the bulb compared to other manufacturers' bulbs. All I care about is how much light comes out--period. I feel like I can't trust the specs on different strobes without first doing my own tests.

when I say my car goes a max of 120 miles/per hour, I don't mean that it goes a speed that is perceptively similar to another car's speed while using twice as much fuel. I mean it goes 120mph. But with strobes, you have to take a class in the theory of relativety to understand what's going on.

monoblock, studio strobe what ever you want to call it use WS watt seconds. PCB AB 1600 is not 1600ws it is 640ws. It is deceiving.

dedsen wrote in post #13147793
This is why he places the following in the spec for the B1600

6 f-stop power variability (20 Ws to 640 Ws)

He made up his own measuring system and then in small print there are the real numbers.

This is true. The lower end of power spectrum is not useful on the AB strobes. If you go too, lower than 1/16 you may see a magenta color cast. Above that you are fine.

WS is pretty meaningless (both of them...effective and WS).there's power loss during the conversion to light.
What matters is only what your light meter measures because that's what your camera sees...

texshooter wrote in post #13147533
Does the name of the PCb B1600 have anything to do with watt/seconds? I understand the Einstein and the B1600 have the same maximum light output. Why is Einstein 640w/s and the B1600 1600w/s. Or do they not pump out the same energy?

As has been said above, you need to look at specifications and not just model numbers.

texshooter wrote in post #13147533
why can't strobe manufacturers use the same language when it come to measuring light output. When I want to know how much light comes out of the bulb, I don't care about how much energy the bulb sucks from the battery. I don't care about the relative brightness of the bulb compared to other manufacturers' bulbs. All I care about is how much light comes out--period. I feel like I can't trust the specs on different strobes without first doing my own tests.

A basic fact that you need to understand is that Watt-second values have nothing to do directly with the light output level of a flash unit. The Watt-second number (the same as Joules) is simply a measurement of how much energy is stored in the capacitors within a flash unit's power supply.

You will find that if you five different manufacturer's lights - all "rated" at 640 Watt-seconds - the light they put on the subject could be different from each one of them. Why? It's because of variations in the internal circuitry and wiring in the units, differences in the design of the flash lamps themselves, and differences in the reflectors that control where the light goes.

Most of the low-end studio flash equipment manufacturers do not do what PCB does with the AlienBees units' specifications. PCB actually lists what a light meter would read with their units set at certain power levels, with specific reflectors or other light modifiers used, and with the meter located at a specific distance from the flash. This is information that is useful.

texshooter wrote in post #13147533
when I say my car goes a max of 120 miles/per hour, I don't mean that it goes a speed that is perceptively similar to another car's speed while using twice as much fuel. I mean it goes 120mph. But with strobes, you have to take a class in the theory of relativety to understand what's going on.

PCB is very truthful about their specifications and explains exactly what their numbers mean.


By the way - the abbreviation Watt-seconds is Ws or W-s and is not written with a slash (such as W/s), as the slash indicates a division of one number by another. The thread title is also wrongly written with slashes.

My balcar which were rated at 1600 watts had less output then my elinchrom 1200 watt strobe

krb wrote in post #13147542
PCB is the only one I know of that use the "effective" W/S BS in their names.

PC Buff was the FIRST...unfortunately a few other vendors (like Photogenic) later fell victim of the use of similarly inflated model numbers, which were meant by Buff to be indicative of greater light output than the electrical energy stored in the power capacitor!

After much criticism, Buff quit strongly advocating 'effective watt-seconds', but nevertheless still continued to use the inflated model number designation. "White man speak with forked tongue!" to use a sentence from Native Americans in old westerns.

At least he is quite open about providing measured light output figures using a light meter, on his web site.

texshooter wrote in post #13147533
Does the name of the PCb B1600 have anything to do with watt/seconds? I understand the Einstein and the B1600 have the same maximum light output. Why is Einstein 640w/s and the B1600 1600w/s. Or do they not pump out the same energy? Does a speedlite w/s mean the same as a strobe w/s?

why can't strobe manufacturers use the same language when it come to measuring light output. When I want to know how much light comes out of the bulb, I don't care about how much energy the bulb sucks from the battery. I don't care about the relative brightness of the bulb compared to other manufacturers' bulbs. All I care about is how much light comes out--period. I feel like I can't trust the specs on different strobes without first doing my own tests.

when I say my car goes a max of 120 miles/per hour, I don't mean that it goes a speed that is perceptively similar to another car's speed while using twice as much fuel. I mean it goes 120mph. But with strobes, you have to take a class in the theory of relativety to understand what's going on.

If you are looking for accuracy, it is actually Watt seconds or Ws not Watt per second or W/s.

A Ws is the same a joule, which is a measurement used for energy or work. In this situation, it is the amount of energy stored in the power capacitors of the flash unit.

Enjoy! Lon

SkipD wrote in post #13148755
PCB is very truthful about their specifications and explains exactly what their numbers mean.

Ah, yes. In the same way that the Government is honest about things. Or Nikon are honest when they say a huge announcement is coming.

AB1600 is a very honest name, you are right.

SkipD wrote in post #13148755
...By the way - the abbreviation Watt-seconds is Ws or W-s and is not written with a slash (such as W/s), as the slash indicates a division of one number by another. The thread title is also wrongly written with slashes.

FlashZebra wrote in post #13149412
If you are looking for accuracy, it is actually Watt seconds or Ws not Watt per second or W/s.

A Ws is the same a joule, which is a measurement used for energy or work. In this situation, it is the amount of energy stored in the power capacitors of the flash unit.

Enjoy! Lon

Yeah, that's a pet peeve of mine, too. Even a big photo gear seller like B&H makes the same mistake. I've already pointed out that error to them (because I didn't think it was very cool for a big store like B&H to be making such a basic mistake) in an email which they've acknowledged, yet they still continue to use W/s instead of Ws.

I have always thought of small, medium, and large. AB400-small, AB-800-medium, AB-1600-large. No need to turn this into rocket science.....

jwp721 wrote in post #13151765
I have always thought of small, medium, and large. AB400-small, AB-800-medium, AB-1600-large. No need to turn this into rocket science.....

Small, medium and large is fine for ordering soft drinks at a fast food establishment, but even then a McDonalds "large" is not always the same size as a Burger King "large" or an Arbys "large".

Looking at Elinchrom's RX line, you might think that 300=small, 600=medium and 1200=large. And that's fine unless you make the mistake of thinking that a "large" AB and a "large" Elinchrom are comparable in power.