AlienBees Exposure Consistency: Bad News and Good

Based on complaints in the forum from several people, I tested five samples of Alienbees lights (three B800s, two B400s) for shot-to-shot exposure consistency at various power levels. I tested with a Sekonic L-358.

Bad News: The first test series with each light was using the the rear panel slider. Basically, I discovered that they all became inconsistent in shot-to-shot exposure at levels lower than 1/4 power. The farther below that, the more inconsisent they were, varying as much as a full stop at the lowest power level. At 1/4 power and above the consistency was fine--the meter showed no change from shot to shot.

Good News: The second test series with each light was with the Lightgear radio remote (also by Paul C Buff for both the Alienbees and White Lightning) that plugs into the telephone jack at the rear of the light units. First, the radio remote provides for a stop less power than the rear slider (-6f or 1/64th power), which already told me that it controls power by a different mechanism. Using the radio remote, I found the lights to be consistent down to the -5f level (equal to the lowest level on the rear slider). It became inconsistent at the -6f level, but the inconsistence was less than the slider control--about half a stop.

Good News: The third series of tests was with the Lightgear wired remote. It has a slider control similar to that at the back of the light, but like the radio remote, it plugs into the telephone jack at the rear of the light and also goes down to -6f. Despite the slider control, the actual power regulation mechanism through the telephone jack was like the radio control--it was also consistent down to the -5 level, becoming inconsistent at the -6f level, but with less variation (about half a stop) than the rear slider control.

I've sent an email to Alienbees about this, just to get some technical background on why this is the case. But in case nobody has seen a Bee dissected, here is a website with an internal view:

http://davidweikel.com/E20_Page/alienbees/bees.shtml

--
RDKirk
'TANSTAAFL: The only unbreakable rule in photography.'

Very interesting post....Will keep an eye on it. Please keep us updated of any response from the folks at the hive.

ST

RDKirk said:

Based on complaints in the forum from several people, I tested five
samples of Alienbees lights (three B800s, two B400s) for
shot-to-shot exposure consistency at various power levels. I
tested with a Sekonic L-358.

Bad News: The first test series with each light was using the the
rear panel slider. Basically, I discovered that they all became
inconsistent in shot-to-shot exposure at levels lower than 1/4
power. The farther below that, the more inconsisent they were,
varying as much as a full stop at the lowest power level. At 1/4
power and above the consistency was fine--the meter showed no
change from shot to shot.

Good News: The second test series with each light was with the
Lightgear radio remote (also by Paul C Buff for both the Alienbees
and White Lightning) that plugs into the telephone jack at the rear
of the light units. First, the radio remote provides for a stop
less power than the rear slider (-6f or 1/64th power), which
already told me that it controls power by a different mechanism.
Using the radio remote, I found the lights to be consistent down to
the -5f level (equal to the lowest level on the rear slider). It
became inconsistent at the -6f level, but the inconsistence was
less than the slider control--about half a stop.

Good News: The third series of tests was with the Lightgear wired
remote. It has a slider control similar to that at the back of the
light, but like the radio remote, it plugs into the telephone jack
at the rear of the light and also goes down to -6f. Despite the
slider control, the actual power regulation mechanism through the
telephone jack was like the radio control--it was also consistent
down to the -5 level, becoming inconsistent at the -6f level, but
with less variation (about half a stop) than the rear slider
control.

I've sent an email to Alienbees about this, just to get some
technical background on why this is the case. But in case nobody
has seen a Bee dissected, here is a website with an internal view:

http://davidweikel.com/E20_Page/alienbees/bees.shtml

--
RDKirk
'TANSTAAFL: The only unbreakable rule in photography.'

Click to expand...

This is extremely useful information.

I'm in the market for lights and AB's are an option once again, but only if the wired remote isn't extremely clumsy to work with . The wireless system adds too much expense to the system and AB's lose the price advantage.

RDKirk said:

Based on complaints in the forum from several people, I tested five
samples of Alienbees lights (three B800s, two B400s) for
shot-to-shot exposure consistency at various power levels. I
tested with a Sekonic L-358.

Bad News: The first test series with each light was using the the
rear panel slider. Basically, I discovered that they all became
inconsistent in shot-to-shot exposure at levels lower than 1/4
power. The farther below that, the more inconsisent they were,
varying as much as a full stop at the lowest power level. At 1/4
power and above the consistency was fine--the meter showed no
change from shot to shot.

Good News: The second test series with each light was with the
Lightgear radio remote (also by Paul C Buff for both the Alienbees
and White Lightning) that plugs into the telephone jack at the rear
of the light units. First, the radio remote provides for a stop
less power than the rear slider (-6f or 1/64th power), which
already told me that it controls power by a different mechanism.
Using the radio remote, I found the lights to be consistent down to
the -5f level (equal to the lowest level on the rear slider). It
became inconsistent at the -6f level, but the inconsistence was
less than the slider control--about half a stop.

Good News: The third series of tests was with the Lightgear wired
remote. It has a slider control similar to that at the back of the
light, but like the radio remote, it plugs into the telephone jack
at the rear of the light and also goes down to -6f. Despite the
slider control, the actual power regulation mechanism through the
telephone jack was like the radio control--it was also consistent
down to the -5 level, becoming inconsistent at the -6f level, but
with less variation (about half a stop) than the rear slider
control.

I've sent an email to Alienbees about this, just to get some
technical background on why this is the case. But in case nobody
has seen a Bee dissected, here is a website with an internal view:

http://davidweikel.com/E20_Page/alienbees/bees.shtml

--
RDKirk
'TANSTAAFL: The only unbreakable rule in photography.'

Click to expand...

--
http://www.pbase.com/wsolum

I'm not surprised. I discovered the same results with my Flashpoint 2 - 300ws units. Theese flash units vary the voltage applied to the capacitors and flashtube to vary the power. I suspect the lowest voltage level causes inconsistent results because the voltage fails to completely ionize the gas in the flashtube. It would be interesting so see if some of the other low priced units (JTL, Britek, Smith Victor) have the same problem.

Thanks for conducting this test. I've had White Lightnings for a short while and haven't noticed a significant difference in exposures from shot to shot, although I noticed a small difference once or twice. I almost got the wireless remote kit but decided I could get by with the wired remote, so that's what I've been using. I wonder if they behave like Alien Bees as far as consistency? Hmm... maybe I should've gone with the wireless.

-Yohan

Yohan Pamudji said:

Thanks for conducting this test. I've had White Lightnings for a
short while and haven't noticed a significant difference in
exposures from shot to shot, although I noticed a very small difference
once or twice. I almost got the wireless remote kit but decided I
could get by with the wired remote, so that's what I've been using.
I wonder if they behave like Alien Bees as far as consistency?
Hmm... maybe I should've gone with the wireless.

-Yohan

Click to expand...

I just noticed that your 3rd test was with the WIRED, not wireless. That makes your test even more useful for me.

-Yohan

RDKirk said:

I've sent an email to Alienbees about this, just to get some
technical background on why this is the case.

Click to expand...

I was about to order a lighting setup but held off to see how this issue resolves. I also sent an email to Alienbees telling them that at least two users are reporting inconsistent light output when the units are used below half power, and asked if it is a known issue and if there are any workarounds.

Here is the reply:

"First off, thanks for your interest in Alien Bees and our accessories. I assure you this is not the norm. To our knowledge there is no known issue regarding the Alien Bees inconsistent output. Our lights go through various testing procedures including a 300+ flashing sequence on each unit. However, we have had a few and I mean VERY few lights pass all our testing procedures only to fail in the field. If there is a problem with the unit we will gladly repair it and return in a timely manor. Remember, there is a 60 day money back guarantee on all Alien Bees and accessories. If you don't like the Bees for any reason, return them inside 60 days and we'll refund the full purchase price minus shipping. "

It seems that they claim the units exhibiting the variations are defective and in need of repair.

So maybe RDKirk and plumcrazy20 might want to call Alienbees about these fluctuations. I'm still hesitant to order them. Although I plan to buy the wired remote, which apparently mostly solves the problem, I don't know if, over the long term, I will find that I will always want to put up with all those wires.

Stan

Wayne Solum said:

This is extremely useful information.

I'm in the market for lights and AB's are an option once again,
but only if the wired remote isn't extremely clumsy to work with .
The wireless system adds too much expense to the system and AB's
lose the price advantage.

Click to expand...

If your set-up is relatively static, the wired remote is nice because it's even quicker and easier to use than the wireless remote (although it can't control as many different lights). Using the wireless remote requires a lot of button pushing even to see how each light is set. With the wireless remote, you can see that at a glance and change it with a sweep of the finger.

OTOH, if you have to set up and break down your lighting a lot, the wired remote will drive you crazy. That's the reason I went wireless...the wired remote is kind of like a "gateway drug." Once you experience controlling the lights from the camera position, you can no longer stand getting up and walking over to a light to change it. It's great to be able to run through lighting variations in just seconds.

Inasmuch as it would cost considerably more to achieve this level of control with any other system, even the wireless is still a bargain.

--
RDKirk
'TANSTAAFL: The only unbreakable rule in photography.'

Thank you very much for this information. I was hesitant after reading the threads on consistency...now I know I want some bees.

Pierre

http://www.pbase.com/northflyboy

RDKirk said:

Based on complaints in the forum from several people, I tested five
samples of Alienbees lights (three B800s, two B400s) for
shot-to-shot exposure consistency at various power levels. I
tested with a Sekonic L-358.

Bad News: The first test series with each light was using the the
rear panel slider. Basically, I discovered that they all became
inconsistent in shot-to-shot exposure at levels lower than 1/4
power. The farther below that, the more inconsisent they were,
varying as much as a full stop at the lowest power level. At 1/4
power and above the consistency was fine--the meter showed no
change from shot to shot.

Good News: The second test series with each light was with the
Lightgear radio remote (also by Paul C Buff for both the Alienbees
and White Lightning) that plugs into the telephone jack at the rear
of the light units. First, the radio remote provides for a stop
less power than the rear slider (-6f or 1/64th power), which
already told me that it controls power by a different mechanism.
Using the radio remote, I found the lights to be consistent down to
the -5f level (equal to the lowest level on the rear slider). It
became inconsistent at the -6f level, but the inconsistence was
less than the slider control--about half a stop.

Good News: The third series of tests was with the Lightgear wired
remote. It has a slider control similar to that at the back of the
light, but like the radio remote, it plugs into the telephone jack
at the rear of the light and also goes down to -6f. Despite the
slider control, the actual power regulation mechanism through the
telephone jack was like the radio control--it was also consistent
down to the -5 level, becoming inconsistent at the -6f level, but
with less variation (about half a stop) than the rear slider
control.

I've sent an email to Alienbees about this, just to get some
technical background on why this is the case. But in case nobody
has seen a Bee dissected, here is a website with an internal view:

http://davidweikel.com/E20_Page/alienbees/bees.shtml

--
RDKirk
'TANSTAAFL: The only unbreakable rule in photography.'

Click to expand...

Stan Prevost said:

RDKirk said:

I've sent an email to Alienbees about this, just to get some
technical background on why this is the case.

Click to expand...

I was about to order a lighting setup but held off to see how this
issue resolves. I also sent an email to Alienbees telling them
that at least two users are reporting inconsistent light output
when the units are used below half power, and asked if it is a
known issue and if there are any workarounds.

Here is the reply:

"First off, thanks for your interest in Alien Bees and our
accessories. I assure you this is not the norm. To our knowledge
there is no known issue regarding the Alien Bees inconsistent
output. Our lights go through various testing procedures including
a 300+ flashing sequence on each unit. However, we have had a few
and I mean VERY few lights pass all our testing procedures only to
fail in the field. If there is a problem with the unit we will
gladly repair it and return in a timely manor. Remember, there is a
60 day money back guarantee on all Alien Bees and accessories. If
you don't like the Bees for any reason, return them inside 60 days
and we'll refund the full purchase price minus shipping. "

It seems that they claim the units exhibiting the variations are
defective and in need of repair.

So maybe RDKirk and plumcrazy20 might want to call Alienbees about
these fluctuations. I'm still hesitant to order them. Although I
plan to buy the wired remote, which apparently mostly solves the
problem, I don't know if, over the long term, I will find that I
will always want to put up with all those wires.

Stan

Click to expand...

Although the slider is very nice, and accurate (at least according to RD) above 1/4 power, I still make manual adjustments based on my light meter readings. If I need one stop less light, I don't even look at the slider's position. I just move it until my light reading is what I want. However, it's nice to see that someone is interested enough in the linearity of the controls to do these tests. Any data is good. Nice work RD....

Rick

--
'Effort equals Results' as told to Roger Penske by his father.

All I can say is that I've had my Bee's a few months now and really put them through their paces everyday. I never see them off by more than 1/10 of a stop. For their price, that is something I can live with. I would recommend these units to anyone who may (or may not be) budget minded.

I also know that Paul C. Buff's service is top notch if anything should ever go wrong. They do stand behind their products.

Mike

--
'Change the way you look at things, and the things you look at change.'

I rarely use mine as low as 1/4 power, and then I'm always using the remote, so I was surprised by people reporting inconsistent exposures of a stop or more.

Oh, well. So I can't use itty-bitty blips of light.

--
RDKirk
'TANSTAAFL: The only unbreakable rule in photography.'

Now I have some questions: How careful were you with your "test parameters"?

Did you mount the flash meter in a fixed position, was there any other source of light, and did you stand in the same position each time? Reason I asked is IF it were the inaccuracy of the sliders, for instance, it would still be consistent if you did not move the slider, and I'm not sure a flash tube would be that inconsistant and still be used by Paul. Inconsistency in testing would be more likely to show up at the lower end of the scale. Not trying to be a smart a$$, just curious.

thanks again,

don

RDKirk said:

Based on complaints in the forum from several people, I tested five
samples of Alienbees lights (three B800s, two B400s) for
shot-to-shot exposure consistency at various power levels. I
tested with a Sekonic L-358.

Bad News: The first test series with each light was using the the
rear panel slider. Basically, I discovered that they all became
inconsistent in shot-to-shot exposure at levels lower than 1/4
power. The farther below that, the more inconsisent they were,
varying as much as a full stop at the lowest power level. At 1/4
power and above the consistency was fine--the meter showed no
change from shot to shot.

Good News: The second test series with each light was with the
Lightgear radio remote (also by Paul C Buff for both the Alienbees
and White Lightning) that plugs into the telephone jack at the rear
of the light units. First, the radio remote provides for a stop
less power than the rear slider (-6f or 1/64th power), which
already told me that it controls power by a different mechanism.
Using the radio remote, I found the lights to be consistent down to
the -5f level (equal to the lowest level on the rear slider). It
became inconsistent at the -6f level, but the inconsistence was
less than the slider control--about half a stop.

Good News: The third series of tests was with the Lightgear wired
remote. It has a slider control similar to that at the back of the
light, but like the radio remote, it plugs into the telephone jack
at the rear of the light and also goes down to -6f. Despite the
slider control, the actual power regulation mechanism through the
telephone jack was like the radio control--it was also consistent
down to the -5 level, becoming inconsistent at the -6f level, but
with less variation (about half a stop) than the rear slider
control.

I've sent an email to Alienbees about this, just to get some
technical background on why this is the case. But in case nobody
has seen a Bee dissected, here is a website with an internal view:

http://davidweikel.com/E20_Page/alienbees/bees.shtml

--
RDKirk
'TANSTAAFL: The only unbreakable rule in photography.'

Click to expand...

--
dwn

dwn said:

Now I have some questions: How careful were you with your "test
parameters"?
Did you mount the flash meter in a fixed position,

Click to expand...

Yes.

dwn said:

was there any
other source of light,

Click to expand...

Low level ambient. The Sekonic L-358 measures and displays the percentage of flash content to the exposure (versus ambient light), and the flash exposure content was always 100 percent. At any rate, the ambient light was constant.

dwn said:

did you stand in the same position each
time?

Click to expand...

The position of the meter was fixed.

dwn said:

Reason I asked is IF it were the inaccuracy of the sliders,
for instance, it would still be consistent if you did not move the
slider,

Click to expand...

I don't think it was simply the position of the sliders. Alienbees lights operate on a different principle from most other electronic flash on the market, and although it's a different principle, it is apparently not by any means an unknown or disreputable principle. The science is out of my league (the only information I have on it is here: http://davidweikel.com/E20_Page/alienbees/bees.shtml ), but I suspect that the inconsistency at low power levels as well as the RETURN to consistency when the power levels are electronically controlled is explainable as a matter of how Alienbees particularly work.

dwn said:

and I'm not sure a flash tube would be that inconsistant
and still be used by Paul. Inconsistency in testing would be more
likely to show up at the lower end of the scale.

Click to expand...

Which is exactly what I reported: The inconsistency shows up at the lower end of the scale.
--
RDKirk
'TANSTAAFL: The only unbreakable rule in photography.'

Interesting test, kind of got me curious. Since you make no mention of how much of a variance we are talking about, I wasn't sure if it should be of concern. So I decided to try and set up a test of my own. Parameters follow:

Meter - Sekonic L-508, Tripod mounted, Fixed Position, Lumisphere 5' from ground, Lumisphere lowered. Meter set 1/125, ISO200.

Lights - (4)AB1600, Standard Reflector, Fixed position, Bulb 8' from Lumisphere same height as lumisphere, Cable triggered by L-508.

Lights were powered on and allowed to sit for 1 minute then dumped. After change to each power setting light was dumped twice before first reading. Lights were fired for 15 readings (too lazy to do a bigger sample).

Unit #1
Full power - f32 9/10 - No variance
1/2 power - f22 9/10 - No variance
1/4 power - f22 0/10 - 1 shot at f22 1/10
1/8 power - f16 0/10 - 2 shots at f16 1/10
1/16 power - f8 9/10 - No variance
1/32 power - f5.6 8/10 - 3 shots at f5.6 7/10

Unit #2
Full power - f45 0/10 - No variance
1/2 power - f32 1/10 - No variance
1/4 power - f22 2/10 - No variance
1/8 power - f16 2/10 - 2 shots at f16 3/10
1/16 power - f11 0/10 - 1 shot at f8 9/10
1/32 power - f5.6 7/10 - 3 shots at f5.6 4/10, 4 shots at f5.6 5/10

Unit #3
Full power - f45 1/10 - No variance
1/2 power - f32 1/10 - No variance
1/4 power - f22 2/10 - No variance
1/8 power - f16 1/10 - No variance
1/16 power - f8 9/10 - No variance
1/32 power - f5.6 8/10 - No variance

Unit #4
Full power - f45 0/10 - No variance
1/2 power - f32 0/10 - No variance
1/4 power - f22 1/10 - No variance
1/8 power - f16 1/10 - No variance
1/16 power - f11 1/10 - No variance

1/32 power - f5.6 8/10 - 5 shots at f5.6 7/10, 2 shots at f5.6 6/10, 6 shots at f5.6 5/10

Looks like Unit #3 will be used as main, but I don't really think most of the variances are large enough to cause concern, with exception of unit #4 at 1/32 power. Although since the meter itself has a repeat accuracy of + - .1 EV, who's to say. Since the meter can only display changes at the .1 level, variances could be as small or large as the resolution algorithm permits (i.e. if reads to thousandth .001 or up to .199). I'm not sure if the variances documented here should be of any concern, I will have to shoot 15 shots at each power of poorest performing unit, subject Gretag Macbeth colorchecker, and examine results. Then again, since I don't really see any variance in the images I am getting, maybe I'll just not worry about it. YMMV!

Hope this data is of some use, no real conclusions, just information.

Be well,
Carl

Good data for the database (anyone compling one?).

The difference between the models is the number of main capacitors. The B400 has one, the B800 has two, the B1600 has four.

Reducing power in the B400 is straightforward in general principle: The system dumps the capacitor completely for a full power flash, but cuts the dump short at lesser power levels, and the remaining power is retained by the capacitor (which is why it recycles--reflils to maximum-- quicker at lesser power levels). HOW it performs the cut-off apparently differs, depending on whether one uses the rear panel slider or a remote control option.

My understanding of the AlienBees literature is that the power for every flash is always drawn from BOTH capacitors in parallel, so that it's always dumping twice as much power as a B400 at a given power setting. It would seem to me, though, that recycle times should always be identical to the B400 if both capacitors are replenished simultaneously. Because the recycle times are double the times of the B400, I'm guessing they must be replenished sequentially.

--
RDKirk
'TANSTAAFL: The only unbreakable rule in photography.'

Forgot to mention that, I was using the rear panel sliders for my test. I have a couple B400 lying around too, will have to check those as well. Have not tried with the wired remote. In my case I don't think the variance was enough to make a noticeable difference in a shot, may have to check if I get ambitious, would much rather shoot something/someone more fun though. Tests are kind of a drag.

Cheers,
Carl

RDKirk said:

Good data for the database (anyone compling one?).

The difference between the models is the number of main capacitors.
The B400 has one, the B800 has two, the B1600 has four.

Reducing power in the B400 is straightforward in general principle:
The system dumps the capacitor completely for a full power flash,
but cuts the dump short at lesser power levels, and the remaining
power is retained by the capacitor (which is why it
recycles--reflils to maximum-- quicker at lesser power levels).
HOW it performs the cut-off apparently differs, depending on
whether one uses the rear panel slider or a remote control option.

My understanding of the AlienBees literature is that the power for
every flash is always drawn from BOTH capacitors in parallel, so
that it's always dumping twice as much power as a B400 at a given
power setting. It would seem to me, though, that recycle times
should always be identical to the B400 if both capacitors are
replenished simultaneously. Because the recycle times are double
the times of the B400, I'm guessing they must be replenished
sequentially.

--
RDKirk
'TANSTAAFL: The only unbreakable rule in photography.'

Click to expand...

I have white lightnings and a L358. Do you have anuy calibration and/or compensation set for your meter?

RDKirk said:

Reducing power in the B400 is straightforward in general principle:
The system dumps the capacitor completely for a full power flash,
but cuts the dump short at lesser power levels, and the remaining
power is retained by the capacitor (which is why it
recycles--reflils to maximum-- quicker at lesser power levels).

Click to expand...

I don't believe the ABs control total flash output by changing pulse width, I think they change the voltage on the capacitor bank. That is why they have to be dumped when reducing power or enough time allowed for the bleeder resistors to bleed off the excess voltage when the power is reduced.

RDKirk said:

HOW it performs the cut-off apparently differs, depending on
whether one uses the rear panel slider or a remote control option.

Click to expand...

I haven't physically inspected a unit to see what kind of devices the sliders are, but my first guess is that they are linear potentiometers. Many of these kinds of devices exhibit erratic behavior, particularly the cheap ones. The erratic behavior comes from how they are made: a resistive film of some sort deposited on a substrate, and a spring contact of some sort that slides along the film. This mechanical contact is not always very reliable and exhibits a variable "contact resistance" which can be significant. How significant it is depends on the quality of the linear potentiometer, how well sealed the device is from contamination, and how well contamination was avoided during the manufacturing process from soldering, flux cleaning, washing, etc., and what kind of electrical load is presented to the wiper of the pot. Let's speculate that the fixed element (the film) of the potentiometer is connected between a voltage reference and ground. The wiper will then pick off a voltage between the supply voltage and zero volts, with respect to ground. The wiper voltage would then be fed to a circuit that controls the voltage stored on the capacitors, with the higher wiper voltage corresponding to higher capacitor voltage and lower wiper voltage corresponding to lower capacitor voltage. If the circuit connected to the wiper has an input resistance that is not very high compared to the wiper contact resistance, then the contact resistance variation, or contact noise, will become more significant under certain conditions. There are many ways to design a circuit like this, but some of the ways will result in the random contact resistance variation affecting only the low end of the range. This discussion is intended only to illustrate that there are well-defined electronic design and component issues that can cause the kind of fluctuations that have been reported here, including that the fluctuations disappear when a remote is used, or in other words, when the sliders are not used.

Unfortunately, if the primary source of the observed variation derives from potentiometer contact resistance fluctuation, there is no assurance that a unit that now shows no significant variation will remain so over time. If the design of the potentiometer is such that it is susceptible to atmospheric contamination, then effects of atmospheric contaminants (esp. smog) can accrue over time.

One test that might help resolve whether slider contact resistance is the culprit would be to repeat a noisy data set after moving the slider back and forth over the offending setting a number of times. Often this will temporarily rub through contaminants and reduce the contact resistance and its variation.

Why would there still be some residual fluctuations at the lowest power setting when a remote is used? Again, some reasonable speculation can show that this can happen, due to another source of variation. There will be a certain amount of ripple voltage on the flash capacitors, since there is apparently a bank of bleeder resistors connected to them. Five volts of ripple on five hundred volts is less of a problem than five volts of ripple on 100 volts (2% energy ripple vs 10% energy ripple). At low flash energy settings, if the flash fires near a ripple peak, then fires again near a ripple minimum, there will be a difference in flash output that will be greater at lower power settings. Another factor is that the remote still has a linear potentiometer slider.

RDKirk said:

My understanding of the AlienBees literature is that the power for
every flash is always drawn from BOTH capacitors in parallel, so
that it's always dumping twice as much power as a B400 at a given
power setting. It would seem to me, though, that recycle times
should always be identical to the B400 if both capacitors are
replenished simultaneously. Because the recycle times are double
the times of the B400, I'm guessing they must be replenished
sequentially.

Click to expand...

I believe they are connected in parallel and will be charged and discharged in parallel. The recycle time is longer at full power because it takes longer for the charging power supply to supply the greater amount of energy into the capacitor bank.

Thanks for all your work in alerting us to this issue with ABs. I don't think it seriously degrades their value to most of us, and I plan to order mine today.

Stan

Nice data, Carl. Thanks!