Test Driving the Profoto Pro-B4 at 1/25,000 of a Second

Several weeks ago I wrote an article about Profoto's new-ish pack, the Pro-B4, which has a flash duration of 1/25,000th of a second. Well, last week I was finally able to take it for a test drive. And what better way to test an insane flash duration than with water?

I am a speedlite photographer. That's all I own, and for the most part, all I use. Speedlites are also great for freezing liquids because, when fired at a lower output, they have flash durations upwards of 1/30,000th of a second. The problem with using speedlites at low outputs is that you are either stuck with a lower aperture or forced to use a higher ISO to have a greater depth of field.

Power and speed is where the Pro-B4 excels. I do need to note that though the Pro-B4 is a 1,000 watt pack, when you are shooting in "freeze" mode, you using less than half of the 1,000 watts. Even with this wattage handicap, I was still sitting pretty at f/20 with an ISO of 400 during my test. Note that the light on the left side of the model is the sun.

nick fancher profoto pro-b4

nick fancher profoto pro-b4

As you can see in the photos, the water is captured in several different ways. To disperse the water, the only tool I had at my disposal was a watering can, which accounts for the longer streaks of water. The droplets in the image, as you can see, are perfectly frozen. Given another opportunity, I'd like to try a different method of getting water into the frame. In hindsight, simply tossing water from a cup may have been a better choice. Either way, I view the test drive as a success.

Unrelated question- do human kidneys fetch anywhere close to $8,000?

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Mike Last's picture

The cause of the streaks isn't really the watering can, it is your shutter speed vs ambient light. They are reflecting the sun. Shooting this indoors or at a higher flash sync speed would have solved that.

Nick Fancher's picture

Didn't think of that. You may be right. I'm interested to find out now.

Dregd's picture

Yeah. Though indoors, as long as the ambient is low, sync speed probably wouldn't even be an issue.

Von Wong's picture

Yeah the streaks are from the ambient. Do this indoors, at the very least not in bright sunlight if you want to freeze waterdrops lol

Mark Lee's picture

Very cool shots. No hope of getting this sync speed on my budget. I need two kidneys for now.

Ken Yee's picture

could be done w/ Einsteins indoors easily...you don't need that high a sync speed for water...

camflan's picture

It's not sync speed, it's short flash duration. I have no idea why sync speed is referenced in this article or comments so many times.

Ken Yee's picture

And I even knew that...was just replying to Mark's comment and automatically copied "sync speed" :-P
Still would be easy w/ Einsteins indoors...doing this outdoors in full sun is just...weird. :-)

Tam Nguyen's picture

That song is hilarious for some reason.

Nick Fancher's picture


Simon wardenier's picture

Quite sad that he didn't use rear curtain sync on this one...

Nick Fancher's picture

Good call. I know my personal camera is on rear sync but I was using a camera from my work.

Roman Kazmierczak's picture

Rear curtain sync is more speedlight option not camera and it requires TTL.
Maybe (i don't know) it is possible to setup Pocketwizard's to use 2nd curtain sync but it wouldn't have any effect at high shutter speeds anyway.

Roman Kazmierczak's picture

For rear sync you need TTL capable flash. And with higher sync speed it doesn't have an effect anyway.

Yuri's picture

Funny that this gear-drooling guy is the same that made a video talking "number 2" about Yuri Arcurs video showing off his Profoto gear. Finally he did it and was able to touch a Profoto, congrats!

Nick Fancher's picture

I've owned a Profoto pack in the past. I just prefer speedlites. I don't see that ever changing. But it's fun to play with them for sure.

Mark T's picture

Not so much a test drive as a revelation (i.e. reveals that you need to do this again). If I was Profoto I'd be frustrated with this post and the pics. As others have noted, you got a few things wrong here and have not demonstrated the capabilities of this flash in an effective manner. It's good to make mistakes as it's a fantastic way to learn (for both you and the reader), but I think you owe it to Profoto to update this post with a follow-up review that picks up on what you have learnt. I don't see anything wrong with experimenting (or a "test drive" as you have put it), but I think fstoppers need to think about their editorial oversite, as an editor should have challenged your copy before publication. Apart form that, thank you - it's interesting to learn about this flash.

Nick Fancher's picture

If I do another shoot with it in the future, I may post the results. I realize that the light streaks could have been prevented, but I really like the way they look. They are different than normal blurry water drops. They still have the super fast sync speed and so they look like shards of glass. I choose to call it a "happy accident". And for what it's worth, Profoto retweeted this photo on Twitter.

Albert Phan's picture

Every time I see the UPS truck I stop EVERYTHING and check to see if my Amazon Prime products have arrived.

Brooks Clayton's picture

Correct me if I'm wrong but the Pro-B4 doesn't allow you to achieve higher sync speeds, it simply is the super short flash duration that freezes motion. You were still in the 1/125th-1/250th shutter speed range correct?

Nick Fancher's picture


Allan Gichigi's picture

Hi Nick, I need clarification on this.. walk me through it. The Profoto can get to 1/25000th of a second, to freeze motion however you cannot go above 1/250th shutter speed. So how then is that different from using a different light source at 1/250th? If say my setting was say 1/250th at f8 and Iso 200 and shot a similar model with water like yours, what would be the difference if I shot using the Profoto-B4 vs if I used some generic strobe?

Roman Kazmierczak's picture

First of all with this settings in bright sun you are overexposing by 2EV.
You have to cut the ambient as much as possible. Assuming from Nick's setting that you have f10@100ISO and you will setup in open shade you can set shutter to highest synch speed 1/200-250. This way you will be underexposing ambient for around 2.33-2.66EV. This way B4 with extremely slow flash duration will freeze the water and ambient will have a little impact.
If you will use strobe with longer flash duration, the water movement will not be frozen and you will get blurry drops. Of course there are different brands making products that can deliver short enough flash duration.

Roman Kazmierczak's picture

It is not Flash limitation. It is a camera limitation, a focal-plane shutter to be exact.
If you will use camera that uses leaf shutter, you will be able to sync at all speeds.
I.e modern Schneider Kreuznach and Mamiya leaf shutter lenses synch up to 1/1600s

Brooks Clayton's picture

I know this. I was asking to point out that high sync speed really shouldn't be mentioned in the article or the comments as it has nothing to do with what he was accomplishing.

Roman Kazmierczak's picture

Yes, I see what you mean. You are correct but I think it is typo. "Insane sync speeds"... I believe he meant "insanely short flash duration" ;)

Nick Fancher's picture

You are correct. Sorry for confusion.

Moshe Yefet's picture

Amazing! Thanks for sharing, what speedlite do you use that can be fast as 1/30,000?

Nick Fancher's picture

At low outputs like 1/64 or 1/128 power, most speedlites have a flash duration of that speed. Just not much wattage, so your ISO is higher and aperture is opened up.

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