Just out of curiosity:

Elinchrom claims the Ranger RX Speed AS battery pack has a maximum power of f/64 @ 2m distance, ISO 100 with a 48 degree reflector.

Profoto claims the AcuteB 600 battery pack has a maximum power of f/64 @ 2m distance, ISO 100 with a 50 degree Magnum reflector.

But the Ranger is rated 1100 w/s and the AcuteB is rated 600 w/s...

What's the catch here

Arg. Not another power output with varying modifiers thread.

Carmen has a thread somewhere comparing a 600WS mono with a Ranger, and the output difference was only .6 or .7 IIRC.

The Magmun is a much more effcient reflector and is 13+" in diameter.

A 600B with the 7+" Zoom reflector puts out about f32.

The Ranger has a small reflector, like you would use with an umbrella. That's why there is a difference.

Reflector design and size is much more important than WS when it comes to output.

Typically the difference between 1100 w/s and 600 w/s should measure about a full stop... when using the same modifiers. That should teach me not to compare power output based ONLY on w/s...

Thanks for clearing that up

BTW That Magnum reflector is one powerful mod

Daan B wrote:
Typically the difference ...

Typically or theoretically? There's plenty of data to prove that packs are less efficient than monos.

bacilonur wrote:
Daan B wrote:
Typically the difference ...

Typically or theoretically? There's plenty of data to prove that packs are less efficient than monos.

I don't doubt battery packs are less efficient than monolights

I was comparing battery packs of different brands... with different mods

Right, but you're going off of what two companies have officially stated about their gear, which you should never be believing in the first place. Just like in the last thread about power output differences, the only intelligent way to compare is with something like a softbox that fits each head identically.

My point about Carmen comparing a 600RX and a Ranger is that even between two of Eilnchrom's own models, there's a definite power anomaly. I wouldn't be surprised if an old Norman or Photogenic or Speedo pack rated at the same WS as a modern Profoto pack was .5 of a stop off. You could ask Simon and Jonathan to run a test sometime, but it's a fairly pointless exercise. Weight/size vs power. Pick one.

I think the Maxi reflectors are more equivalent to the Magnums. Not sure, don't use them much myself.

In any case here are the ratings for:

Maxi Lite f64.6
Maxi Spot f90

at same settings above.

difference f 64 and 64.6 is more in line with the power differential. But similar to what cd says, reflector design and size is at least as important as WS when it comes to output.

Good luck.

bacilonur wrote:
Weight/size vs power. Pick one.

I thought that was one of the main differences between the Ranger and AcuteB as well... Until I realized that when using the AcuteB you need at least two batteries where you can suffice with one battery for the Ranger. An AcuteB + 2 batteries weighs about as much as a Ranger + 1 battery... Looking at it this way it is all about power...

Daan B wrote:
bacilonur wrote:
Weight/size vs power. Pick one.

I thought that was one of the main differences between the Ranger and AcuteB as well... Until I realized that when using the AcuteB you need at least two batteries where you can suffice with one battery for the Ranger. An AcuteB + 2 batteries weighs about as much as a Ranger + 1 battery... Looking at it this way it is all about power...


Sort of, until you consider that you'll realistically want a second Ranger battery as well, and having two batteries is a definite plus with these units since you can then have one charging while the other is shooting, since the actual plug-in adapters are ridiculous expensive. I've seen two different specs, though, one saying that the Ranger battery is good for 260 full power pops, another that says it's good for 100. (probably a 10-12aH battery, vs the 7aH for the Profoto.

bacilonur wrote:I've seen two different specs, though, one saying that the Ranger battery is good for 260 full power pops, another that says it's good for 100. (probably a 10-12aH battery, vs the 7aH for the Profoto.

Most probably what you are quoting is the difference between the Ranger RX and the Ranger RX Speed packs. The RX has a 12v/7Ah battery, the RX Speed has a 12V/12Ah battery. Both put out 1100Ws, the difference is recycle time and number of flashes per charge.

You will always want to have at least 2 batteries, with any unit. That is one of the concerns about the Tronix - you really need 2 units.

I have had batteries that I *thought* were perfectly good and fully charged. Put them in the pack and - nothing - or maybe 10 pops at most.

The difference in the number of pops for each system is almost purely based on the number of amps of the battery, as noted. It is almost completely linear to the ws rating of the unit and the battery amperage.

There are some units that have a "slow" recycle mode available that can increas the number of pops by about 30% though.

bacilonur wrote:
There's plenty of data to prove that packs are less efficient than monos.

I haven't seen much good data on that.

If you look at the cable to the heads on a high end pack, you will see the obvious size differencre between the cables on the cheaper systems and the high end systems.

A good quality cable does not lose much power. I have seen some propaganda from monolight manufacturers, but no good quality data (especially with the reflector issues that also come into play.)

mmurph wrote:
I haven't seen much good data on that.


See here: http://www.fredmiranda.com/forum/topic/627180/1

The graphic that's posted a few threads down has showed up a few times, and the authors vehemently defended it, so I don't think they're trying to trick us. Of note is the bare-bulb AB800 vs bare-bulb Acute2 2400. The Acute2 is definitely not putting out 7.5 times the light of the 320WS AB800. And sure, the Acute2 is a rather old design (though it's not exactly low-end), but so is the AB800.

Oh geez, *no way* I want to open up that thread again!

If you want data, do some tests. I just tested one of my packs against one of my monolights.

The methodology was this:

1. Put a head in a large Photoflex Q39 Platinum softbox. No reflector on the head of course. Both internal baffle and front face in place.

2. Use a digital distance meter to measure exactly 10' from the face of the softbox (I used a Wagner Fat Max, measures to .01 feet.)

3. Use a digital incident light meter to measure the strobes output at 10' (I used a Sekonic 608 that measures in .1 stops.)


The pack I used was a Broncolor Topas A2 - 1600 ws. The Monolight was a Visatec Solo 300 ws. Visatec is made by Broncolor.


The reults:

Topas

800 ws 11.0 +.3
400 ws 8.0 +.3
200 ws 5.6 +.3
100 ws 4.0 +.3
50 ws 2.8 +.3


Visatec

300 ws 5.6 +.5
150 ws 4.0 +.5
75 ws 2.8 +.5
37 ws 2.0 +.5


I suppose I should have dialed in the ws on the Topas to equal those on the Visatec (the Topas has digital controls in .1 stops.) Instead I dialed down each unit by a full 1 stop each time, starting at full output.

Anyway, you can see that the Visatec output at 300 ws was 5.6 + .5. That is about .8 stop below the 400 ws output of the Topas. It **should** be only .5 stop lower if the outputs were equal at 400 ws.

In other words, the pack is putting out about .3 stops more light than the monolight is at the same ws rating.

These results should be easily repeatible. I measured at least 5 times at each power setting. The readings were exactly on each time.

The output is stable within .1 of a stop for most of the area covered by the softbox. When you get out to the corners it starts to fall off by .1 stop. It should be easy to find the center spot of the softbox to repeat the test in your own setup.

The results are a little more sensitive to distance. But it is not a problem to repeat the distance measurement with .1 or .2 accuracy using the digital distance meter. You would have to go from 10' to 14' to reduce output by 1 full stop.

You can see that the results were exactly at a 1 stop reduction on the meter when reducing power by an indicated 1 stop on the controls for each unit. That has always been true for all of my digitally controlled units. It might vary a bit more for the dial or slider (POT) controlled units.


I have 7 more types of packs and 2 more types of monolights I could measure. It will take me a while though, I have a lot of other work right now that I need to finish first.

I don't have an AB monolight or any Profoto lights, two units that I am sure folks would be interested in seeing results for. I'd like to see what kind of measurements folks get if they do this test.

Best,
M.

Couple things I'd mention...

The Profoto Acute2 probably has a frosted glass bulb cover, which I'm sure eats up some light compared to the bare AB bulb. Yet another thing that makes these apples-to-oranges comparisons...at that point, why not include different reflectors in the mix, since we're already skewing the results?

Secondly - and this was probably already mentioned and I just missed it - 300w/s on one light does not equal 300w/s on another light, as those are ratings of capacitor power dumps, not power output by a bulb...correct? I'm an idiot when it comes to these things, so I'm quoting others. Regardless, there are any number of design factors and component efficiency issues that affect how much light a given strobe actually outputs at any power level that will make units of the same watt-second rating unequal. I remember reading, for instance, that Dynalite packs were known to be much more efficient whereas Speedotron were notoriously inefficient...so a 1000w/s Dyna pack was generally understood to put out a fair amount more light than a 1200w/s Speedo pack.

Yeah, Simon, I mostly agree.

But this discussion has been bubbling for a couple of months here with a lot of messy and inaccurate information and conclusions.

They finally tricked me into doing the testing myself in a way tthat neutralizes the effect of the different reflectors.

In other discussions, some folks did not realize the difference in relative output for a Magnum reflector over a wide angle reflector, for example. They have tried to compare those 2 numbers directky.

Profoto has a really nice - but complicated - chart indicating the f stop output (rating) for all of their reflectors on the same heads at various Ws ratings. Can't find that right now though.

Funny, I actually did forget to include the UV protecting glass on the Broncolor head that I used in the test. That probably accounts for my .3 stops difference!!

The Visatec uses a clear protecting glass for their tube, as they are only 300 Ws. The Broncolor uses a UV coated protecting glass for the 3200 Ws tubes. The ntubes run too hot at that power level to coat the tube directly.

Looks like Bron already compensates for the glass in their Ws rating calculations.

I suppose I could rerun the tests to verify that. I also should run them at 2 meters so that we can compare directly to the manufacturers specs, which are quoted at 2 meters,

(It looks like converting my 10 foot measurement to 2 meters would require us to add about 1 and .7 stops. So the Topas, at 400Ws at 2 meters, with the SB, would be about f/ 16.0 The Visatec at 300 Ws at 2 meters would be about f/ 11.0 +.2

That sounds about right. The Profoto rating for the Acute 1200 with a Zoom reflector at 2 meters is f/ 45. The Topas at 800 Ws, at 2 meters with the SB, would be an f/ 32. That would be f /45 at 1600 Ws.Bron rates it at f/ 45 +.7 at 2 meters with 1600 Ws and their standard P70 reflector, or a loss of .7 for the SB.. )

OK, enough technical BS. I want to think about making images!! Totally different use for the brain.

As I said in the last thread on this, I went 25 years without ever caring about these number comparisons!

Best,
Michaewl

I prefer sitting in my basement and testing packs, heads, and lenses. Much safer and no chance of failure

So power output is related to a lot more variables than just w/s... So how can you say that the Ranger is more powerful than an AcuteB? It really depends, doesn't it?

All I really care for is to know what battery pack + modifier is able to overpower the sun at sunny 16 (for example) or will go low enough to use wide apertures in a studio setting (for example). The answer is obviously more complicated than doing a comparison based on the dry numbers provided by the manufacturers. These numbers are merely an indication. But I trust the data provided by Profoto a little bit more than the data provided by Elinchrom. If only because Elinchrom seems to contradict itself everytime (different values for the same items in their brochures and on internet for example).

About battery capacity... The AcuteB is rated 160 shots @ 600 w/s. The Ranger is rated 195 shots (fast recycle) and 250 shots (slow recycle) @ 1100 w/s. So according to my math (when comparing at 600 w/s), you need about two batteries for the AcuteB to get the same amount of shots with one battery for the Ranger. But again, this is based on dry numbers provided by the manufacturers. There are more things to consider. Is the output @ 600 w/s the same between the AcuteB and Ranger? Which head is more power efficient? How is the quality of the individual battery?

In practice you probably would want to carry 3 batteries for the AcuteB and two batteries for the Ranger. Just to be sure (also depending on the task ahead). These become heavy packages with no real weight advantage for the AcuteB anymore IMHO

I owned a Ranger RX AS for several months before trading it for some Profoto gear.

I had a spare battery. Carried it everywhere. Never needed it once. Shot two 6 hour weddings and 2 outdoor fashion tests in bright sunlight, at or near full power.

It keeps going and going and going...