I hate my time being wasted, so I do my best not to do it to others, even if it means doing worse here on KZfaq. Love to hear when it’s noticed and appreciated.

Definitely send me your attempt! I could see this going many different ways lol. Bri should be applauded for maintaining a great facial expression, that must be so difficult.

My test exposures were 1/32nd output and that didn't freeze the front water. That's where I both ruled out HSS (as it wouldn't keep up with the 10 fps) and decided to up the ISO and drop the output even further. HSS can be odd for motion, depending on how the motion travels. If it's traveling across a (landscape oriented) frame, then there are few issues, as the sensor captures groups of lines at a time. But as soon as it starts travelling up or down a frame, the same object can be lit multiple times by the flash, resulting in blur A great example of this is here, you essentially create rolling shutter due to multiple flash pulses : www.scantips.com/lights/flashbasics2b.html It's so ridiculously nuanced between if you need to freeze motion exposed by ambient light, how the motion is traveling, as well as the regular things that affect motion blur like megapixels and focal length. I'm really not sure a "order of operations" for the best approach can even exist.

@@robhallphoto That makes a lot of sense Rob...Explains a few failures I have experienced as well. Indeed the The A7Riv is very unforgiving for any sort of movement! More pixels....Not always better. Keep up the awesome work!

Happy to answer that! It’s better to think of a grid as “restricting” light, not “focusing” light. Focusing occurs by pushing light through an optic, like a fresnel lens. Focusing narrows coverage and increase brightness. However a grid, because of the black material absorbing / obstructing light, will narrow coverage and decrease brightness. So adding a grid would simply lead to having to increase the strobe output, lengthening the flash duration and reducing its action stopping potential.

It would have worked somewhat, in that it can freeze motion in both flash and ambient, but it would also make the act of shooting the sequence impossible, as the flash output increase and HSS would make the recycle time much longer. Thats the main reason I didn't use it in this scenario. The second reason is, had I used HSS a tool to underexpose the ambient light more and omit that motion blur, I'd have to get up to 1/8000 to come close to match the action freezing result of the strobe in standard sync at 1/128 power. And in this instance, that would mean a high ISO (6400), or it would mean significantly underexposing, including the ambient fill that is on the model. HSS does work for motion that can be frozen by 1/8000. But as you can see here, that wasn't fast enough to freeze all the water.

@@robhallphoto thank you. I understand better now.

I think it works like this... Let's say you are taking a photo with no ambient light, but just the strobe. The shorter the time span of the strobe light, the more frozen the motion will be. Let's say that the flash duration is 0.01 seconds. Even if the shutter on your camera stays open for 0.05 seconds (5 times longer) - since there is no ambient light, the camera will only be able to capture the 0.01 seconds of light from the strobe. However, if there is ambient light... then what is being lit by the ambient light will be captured based on the shutter speed rather than based on the strobe light duration. I am new to this also and this is what I understood so far...

It’s slightly worse at freezing action, because it has similar flash durations at each power level but less output at every power level.

Well, the V1 actually reaches a shorter flash duration than both the 400 Pro and 600 Pro, but that doesn’t tell the whole story when it comes to action freezing potential. We have to also look at output equivalency. So while the 400 Pro has similar T.1 flash durations, it would also have to be at a higher power level (~+.7 stops) to achieve the same brightness as the 600 Pro. Because of the higher power level, the t.1 duration would be longer and therefore slightly less capable at freezing action. So is the 400 Pro capable of freezing action? Yes. Is it as capable as the 600 Pro? No.

@@robhallphoto Ach! That makes perfect sense. Mind you the AD400 looks to be more than adequate given the size of my environment (home studio) so I'm hoping to get away with using this not just for everyday shoots but also the occasional moments when I want to freeze action. I looked at the chart (in your KZfaq community tab) that showed the different Flash Duration for the AD400 Pro compared to the Profoto B10 and AD200 for each power sertting but unfortunately this didn't also show the AD600 Pro. In any case can I ask you what sort of flash duration I should be aiming for to freeze a dancer in mid air or freeze water. Sorry if I missed this in your videos, but I'm not entirely sure what the min flash duration for this should be.

Broncolor definitely has better flash durations on the Siros. But beyond that, Godox tends to punch up in the flash duration/output department compared to other battery powered flashes. In every one I’ve tested, it slightly beats Profoto products in t.1 FDA. Not sure how Elinchrom ranks in this department.

@@robhallphoto now there is a comparison review, waiting to be done!

It's hard to say whether HSS works or doesn't, as it really depends on the ambient light level. In this instance, HSS would really only harm the result, as I was already at a t.1 flash duration of 1/8270, which is more action freezing potential than a shutter speed of 1/8000. To get the same exposure here, I would have had to use ISO 6400 to get a shutter speed of 1/250. However if I underexposed the ambient light more, say ISO 800, 1/8000s (-2 EV), that would have cleaned up a lot of the motion blur from ambient light. But at the same time, id have to use a higher flash output + HSS, so my recycle wouldn't keep up with the sequence. So there's pros and cons to using HSS in a scenario like demonstrated. Ultimately, I didn't want pitch black ambient. Bri's dark side would have blended right into the background. Though I would have been ok with that approach had I been using a rim light as well. Now, let's say instead you were shooting in broad daylight, where you can't underexpose ambient light while staying in standard sync like I did here. In that instance you do want to use HSS, and max your shutter speed. Because no matter what, your ambient light will show the subject's motion. So you need to stop motion with your shutter speed instead, that way both the flash and ambient are frozen. You are unfortunately limited to 1/8000s, which as you can see from my results, isn't really that fast. The other thing to consider is a shutter speed of 1/8000s is effectively a "T1.0" flash duration, as both the flash and ambient light will be at their peak brightness the entire time. That is a massive difference vs a T.1 flash duration of 1/8000, which represents the flash darkening by over 3 stops in 1/8000s. So it's very likely for fast motion at 1/8000s with HSS, you'll still see blur.

@@robhallphoto appreciate your replies and your always willingness to help here and Facebook, I admire your work and you as a person helping photographers online

@@robhallphoto I will try Freeze action with your method in daylight and also regular sync with an ND filter I think will work great

also remember that HSS is not ONE flash...its many continues shoots of flash, so it is very BAD for freezxing motion

no, none of my subjects have ever complained of the ad600 "blinding" them. And it doesn't make sense that below 1/16 (1/256-1/32) would be worse than above 1/16.

@@robhallphoto yeah sorry..I meant above😁...tnx for the reply..I had the same issues with the ad400 pro too..I'm from Italy .maybe here they sell lower quality strobes

I'm thinking you got confused by "if you decrease two stops the ambient exposure". I said I would wait for the ambient level to drop by 2 stops, meaning I would wait for it to get darker outside. Ambient light: If the ambient light dropped 2 stops (gets darker outside). Then I increase my ISO 1 stop (from 200 to 400), then my ambient light will be 1 stop darker than results shown. Flash: ambient light darkening does not affect the flash brightness. 1 stop ISO increase (from 200 to 400) makes flash brighter by 1 stop. Flash output drop from 1/128 to 1/256 decreases the flash brightness by 1 stop, and offsets the ISO adjustment. Result: ambient exposure drops 1 stop, flash exposure stays the same. So the subject would be the same brightness (at least where she is being lit by flash), but the background and ambient motion blur would be 1 stop darker.

Thank you for your response....if your shutter speed is 1/250 sec how you will decrease the ambient light by 2 stops?...how that it will affect the flash duration?...sorry for my Englishs...I mean you will pass the sync speed and this will not effect the flash ...?

1/128th power

no idea on Profoto D2, but I covered 1200 Pro and 600 Pro in my reviews. I think Profoto markets their products t.5 flash duration, and while it's not perfect math, you can estimate the durations x3. The trickier part is figuring out how the power correlates. For instance A profoto D2 at 1/128 is not necessarily the same output as another flash at 1/128, even if they are the same watt/seconds. Like when I did my Profoto B1X vs. Broncolor Siros 800L vs. Godox 600 Pro comparison, the Profoto looks good on spec sheets but because it's output is the worst per w/s, it was actually the worst performer in flash duration.