[Video] How Much Does Flash Duration Affect Photo Sharpness?

Unless you shoot fast moving objects with flash on a regular basis, you might not be aware that a strobes "flash duration" has a huge affect on an image's total sharpness. Flash duration is simply the time at which your flash is emitting light. Technical gurus will break it down into T.1 and T.5 times but for simplicity the longer the flash duration, the more your strobe light acts as a constant light for extremely fast moving objects (great article here). Recently Broncolor did a test between their Broncolor Scoro power pack and the Profoto Pro 8 Air to see which one had a faster duration. As biased as it might appear, I think it's fair to say that the Scoro does produce a sharper image especially since you can digital select the flash duration on the power packs themselves. The Broncolor packs do cost about 20% more than the Profoto packs so unless you are shooting extremely fast moving objects then you probably won't ever notice the difference. I think it could be interesting to throw something much cheaper into the mix like an Alien Bee but my suspicion is it might fail the color accuracy part of this test.

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Patrick Hall is a founder of Fstoppers.com and a photographer based out of Charleston, South Carolina.

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For cost and performance the Einstein E640 is legit.  Especially at freezing action.  I've even seen test where they out perform Profoto's.  :)

do you have a video?  I have an Alien Bee 1600 as a cheap "extreme location" strobe and I'm convinced the light it puts out has a weird green hue shift and is slightly warmer than my other strobes (dynalites and SB800s).  I want to do a test on it because it seems way off when I balance it for daylight outside.  I've heard good things of the Einsteins but I also heard great things about the ABs but right now I'm a bit skeptical of it after about 20 shoots. 

I used to shoot with the AB1600 and had the same issues with color shift.  Since I moved to the Einsteins, there has been no noticeable color shifts from one pop to the next.  One of the huge selling points of the Einsteins was the fix of color shift issue found in the AB series.  I've been using them for over a year now and love them.  Here's an article that is super in-depth on the subject and why they outperform way more expensive strobes.


I have one Einsteins but looking forward to buy at least 2 more... The only thing that frustrates me with the Einstein is the overheat when using the lamp MAX power in a Softbox.... quite frustrating.... but beside that I love it.... :)

Totally agree with you on the over heating.  Thing is that I almost never use my modeling lamps so it's really a non issue.  I could see where that could get extremely frustrating though.  It's a dream working with the three Einstein heads and the mini lithiums on location though.  :)

"I have an Alien Bee 1600 as a cheap "extreme location" strobe and I'm convinced the light it puts out has a weird green hue shift and is slightly warmer than my other strobes (dynalites and SB800s). "

The AB monolights are completely different machines from the Einsteins. I've never seen a color shift with my Einsteins. They are very neutral. 

hm. i wonder how my Ranger RX Speed holds up against the rest....

On a related note: is there any way to stop snowboarders mid air in full sun without having to shoot faster than 1/250th sync speeds? (haven't tried it yet, but planning to and i'm anticipating problems)

Agreed.  I'd love to see how the action heads fare in this test.

I do not buy the results of this test. The Profoto has a flash duration within the 1/4000 - 1/1800 to an ultra short flash duration 1/12,000 depending of the power settings. At those speeds you can surely stop motion on most "anything" - including water running down a models face. The Profoto flash-to-flash color stability is within ± 40 K over the entire power range. One of the easiest  gigs of my life was to test the color range and power consistency of the Broncolor vs Profoto for a client doing an FDA study;  they needed to show before and after results for a medical study.  Profoto was a slam dunk winner... 

Okay I think I found the flaw in this test.  Flash Duration depends greatly on what power you are firing (1/8th will be different than 1/1).  After reading a long article about the Alien Bees (http://www.robgalbraith.com/bins/multi_page.asp?cid=7-10053-10715) I can see where perhaps Broncolor picked a power setting on the Profoto packs that was intentionally slower and then they used the same power setting on their pack while digitally selecting a super fast duration.  

By doing this they were able to claim that the lights were set to the same power (f16) but maybe the flash duration was not short enough on the Profoto packs.  I could be wrong and maybe f16 is full power which if I read correctly gives most power packs the fastest FD but if this is correct then the only thing this video really proves is that Broncolor can simply adjust FD at any power level instead of having to find the fasted FD on other packs.  

Am I close on this explanation?

I agree the video does say "which power [pack] will delivery the best result at f1/16."  Additionally, setting the color balance on the camera to 5000K is of course going to look different on different systems.

I don't use Profoto, so I don't know, but in the video they quite clearly say that the Profoto doesn't tell you the flash duration, so they had to measure it with a FCC meter. I do have Broncolor units, and the feature I think they are trying to show, although doing a bad job of explaining it, is that with the Scoro, you can choose your power level, in this case 6.0, which is 4 stops down from full power (10) but not the minimum for the pack. You can then for that power level "choose" your flash duration, and the pack through electronic wizardry will maintain a consistent colour temperature.

Alex Koloskov did an extensive test of flash duration when he needed to freeze motion. Elinchrom RX series strobe review: pros, cons and comparison with PCB Einsteins lights

Color consistency is practically a non-issue as long as you're using the same units throughout your setup, and in the same mode in the case of the Einstein's. In the rare cases where it does make a difference you can easily compensate with gels. 

For a savings of over $10,000 PER UNIT there's just no question. 

I shoot with Profoto, and I recently did a product shoot for a client that wanted cascading water on the bottle. Had the exact same issue in the shots. I just thought I could have defective lights, as I'd always been assured that Profot flash durations were some of the shortest. 

Glad this video has shown that my lights are inferior by design, rather than defect. Wish I could afford Broncolor. 

Which Profoto's do you have?


So your comparing D1's to a Scoro? If  you were to set up the D1s to Bron's Minicoms you would piss on them.
I currently have both D1's, a couple of B3's and Pro-8s and I must say that what ever they did in this movie, it sure was to favor Broncolor. Ive done the exact same thing and never ever had any problems with freezing the water. 

The preach about the wb in this movie  is totally BS. Its not the set temp that matters, but the consistency from flash to flash.

I dont deny that the two brands both have their positive and negative sides. But this movie is presented to be a neutral, objective shootout. Its not:)

D1's are Profoto's entry level lights.  Pro 8's and D4 pack and head systems are in completely different classes. 

hard to believe anything put out there by the manufacturers. Maybe they used a warmer glass dome on the profoto heads, maybe the profoto beauty dish is warmer by naturevs the bron dish. (they certainly show 2 different types of dishes used)

Beautydishes can vary as much depending on brands due to paint used, central deflector installed and positioning of the flashtube inside the dish.Also to what patrick said about selecting a biased power outage to the brons.

some interesting reading on a 3rd party test of the 2: 

Thanks Jonathan the article is a good read. Basically the take (my interpretation)  of the article is: To get ultra-short flash duration with Broncolor you need to turn their color control system off and run at  minimum power...

There is also like this as well


I bought Scoro recently because it simply freeze better.

Of courase I tested both before I bought it.

Well, sort of. But the same is true of Profoto. To get shorter flash durations with ANY system, you are going to have to use lower power settings. 

As I said they have done a bad job of explaining how their system works, although not intentionally I am sure. 

As I said I don't own Profoto so I won't comment on them, past what is stated in the video. You can not "Set" a flash duration/it does not tell you? That is why they had to measure it. 

On the Scoro (and the Grafit BTW) you can for any given power setting, not just the lower ones, specify a flash duration, now there are limits to this. Some of the speeds fall within a "guaranteed" colour temp window, and others don't, and it tells you this as you are setting it. They don't mention in the video, that you can also then manually tweek the colour temp +/- 200k to help offset the colour shift, as it goes bluer the shorter you go. It is not perfect, but it gives you a hell of a lot of options.


after reading the Rob Galbraith article referenced above, I think the flash duration is actually shortest at full power if the pack uses analog capacitors.  Maybe I read that wrong but it seemed counter intuitive to me but then made sense after reading it.  

Hi Patrick, that may be the case with analogue capacitors, I don't know, but as Legacy3 says below, Bron uses IGBT, so they get the sharp cut off, just like the diagram in the RG article shows for the speedlights. Also in the article there is a great rollover graphic that shows the rotating disc which gets sharper the lower the power setting for the Einsteins, the exact opposite of what happens in the one directly above it for the Elincrom Rangers. So it is not a straight forward topic. But for the Bron, definitely lower power gives shorter durations. But more than that, you can specify and control both duration and colour temp at a set power level. Within limits of course. In short if you need that control, get a Scoro or a Grafit. If not other units will do the trick.


I'd like to see this done again, but also with Paul Buff Einstein 640's thrown in the mix, just for good fun.  ;-)

This video looks like a comparison of the different technologies used to create the lights. Broncolor is known for using IGBT to control its light's flash duration and color temperature while Profoto generally uses an analog capacitor technology.  All things being equal IGBT has much shorter flash durations and more consistent color temps throuhout the power range because it actually quenches the light once your desired power setting is met (similar to a speedlight) rather than dialing down the actual power.  Paul C Buff talks about this at length regarding the Einstein lights in a recent podcast interview with Frederick Van of "This Week In Photo".  He also explains why his lights can compare to higher end lights at a lower price point. 

You should give it a listen:http://www.thisweekinphoto.com/2011/twip-231-only-30-to-touch-their-junk/

You can get super short flash durations with both systems. It is simply a matter of knowing how to use the tools you have, just the same as you can get a short flash duration with Einsteins or speedlights. The difference is that the Brons give you more options. For example, at any given power setting the flash duration can be adjusted (to a certain extent) on the Broncolor pack, whereas on the Profoto you can only control the duration by cranking the power down - even then you don't know what that duration is at a given power setting. 

I've used both (and many others) and would pick Broncolor every time as long if I had unlimited $$$. They offer a greater degree of control and more features. I'll probably never own either though as unlimited $$$ is not in my foreseeable future. :)

That being said, the video has an obvious bias. It isn't untrue, it just doesn't give all the information.