Water drop HSS

[pixmedic]

What is the air speed velocity of a coconut laden swallow?

 

[Overread]

What is the air speed velocity of a coconut laden swallow?

Too fast for HSS of course

 

[Derrel]

What is the air speed velocity of a coconut laden swallow?

Too fast for HSS of course

Interestingly, a friend of mine has a bird feeder in his back yard. A few years ago, he called me up and referred me to a photo he had done of a black-capped chickadee coming in to the feeder...he could not figure out why the bird's wings were blurry. He was perplexed. He had used High Speed Sync flash on his Canon d-slr with a telephoto lens. The multiple,rapid-fire pulses of the HSS flash pulse caused the bird's wings to be...blurry.

 

[Overread]

Aye HSS is good for bird and wildlife photography for giving fill light to bump up shadows, but not main light.

 

[Judobreaker]

This calculation doesn't take subject distance into account...

The reason a car is less easily blurred at 5 mph than a drop of water at 5 mph is because the car is further away.
Why is camera shake so much more of an issue in macro photography than it is in landscape photography? Because the landscape is much further away. It's really the same story.


Now I'm going to use the metric system as the imperial system is just weird to me...

Say we've got a water drop falling at 8 km/h (5 mph) and we're using a standard 50 mm lens on a 16 MP crop sensor (my D7K for example).
The focus is as close as possible (roughly 50 cm) which will give us roughly 15 cm in the frame. That's 15 cm for the drop to pass the frame at 8 km/h.0

Some calculation steps:
Drop speed in mm per hour = 1,000,000 * 8 = 8,000,000 mm/h
Drop speed per second = 8,000,000 / 3600 = 2222 mm/s
Drop time past frame = 150 / 2222 = 0.0675 s

So, in roughly 1/15th of a second the drop will pass that frame.
That frame is roughly 4900 pixels long. I will make the assumption that to freeze motion we'll need a maximum movement of 5 pixels (let's not be picky).

Some calculation steps:
4900 / 5 = 980
980 * 15 = 14700

The time it will take that drop of water to pass the maximum of 5 pixels is 1/14700th of a second.
That's pretty damn fast...

Anyways, at a shutter speed of 1/8000 you'd get the following movement on the sensor.
1/8000 / 1/14700 = 1.8375
1.8375 * 5 = 9.2 pixels.

Because HSS will light the entire frame evenly during shutter movement this means we will get the full motion of the water drop. The only way to freeze motion using HSS is with your shutter speed, NOT with your flash (which would be the case in a standard flash burst).
Yes, I think you might have a hard time freezing that drop with HSS.

Is it impossible? No.
How can we do it? Quite simple... Back up. The larger your subject distance, the less motion blur. The drop will just be a lot smaller so you'll have to crop more.


I'm afraid I'm going to have to agree with Derrel here.

 

[Derrel]

Getting back to the 'controversy' Robin wanted to address in this thread, and in another thread, this morning I did a quick web search for some of the suggestions from "famous water drop photographers". Here are suggestions on how to properly do high-speed water droplet photography. Since this is the Beyond The Basics section, I decided to look for world-class water drop photographers on Google, and see what they had to say about high speed water drop photography.


Somewhat interestingly the advice I have been giving here on TPF comes from information I learned years ago from a local TV show's segment profiling one of the world's most well-known water droplet photographers, who lives right across the river from me. His name is Martin Waugh. His process and his recommendations are somewhat well-known among the photographic community right here in our little corner of the world. His portfolio of images is without peer. Here is the tutorial that Martin Waugh recommends on his website. It pays to listen to people who actually know what they are talking about.


You can see Mr. Waugh's amazing work here:http://www.liquidsculpture.com/ and get additional, expert, knowledgeable, accurate tech info here:
Martin Waugh Father, engineer, artist


A very brief quote from Martin Waugh:
"I am currently using a Canon 5D and a 180mm macro lens, but other equipment works, too.I use fairly typical high-speed photography techniques."


"I leave the shutter open for a relatively long time (in a darkened room) and use a flash to illuminate the splash. The flash needs to be of a fairly short duration to stop the motion well. I use something like a 50 microsecond flash. “Speedlite” flashes (as opposed to studio strobes), control the amount light output by varying the flash duration. Not surprisingly, the shorter the duration, the less light (many studio strobes are the opposite!). So, you can get a short duration by setting the flash for low power (1/16 or 1/64). I get this by modifying the photo sensor circuit on Vivitar 285HV flash (a bit more detail) ."


Here is the tutorial site that Martin Waugh recommends to hobbyists, photographers, and teachers interested in doing true, stop-motion flash photography: HiViz - Tools - Flash Characteristics


Again: the true experts in the field realize that the camera's shutter is far too slow to stop water droplet motion. In fact, one of the world's leading experts (Martin Waugh) prefers to use LONG shutter speeds, in darkened rooms, and use ULTRA-brief, single-pop electronic flash, by using auto-thyristor flash power reduction, in other words fractional flash power settings, like 1/64 or 1/128 power.


If you want long, stretched-out, or blurred, or, stroboscopically-rendered water, rendered as inch-long blobs, or oval droplets, HSS might be just the ticket. However,the world's foremost experts suggest using single-pop flash of exceedingly short duration; durations so,so,so brief that there is no mechanical device that can even come remotely close to the brief time units that such flash pops span.

 

[Ballistics]

If only this much effort,thought and exposure went into critique threads. You would think that it would in a photography forum,
those would be the threads that receive this much attention, but no. Discussions about the physics behind something so trivial,
or why a video is or isn't interesting, are what keeps TPF turning. The best(worst) part about this argument is, that proof is being presented
in paragraph form, not in real world image form (with the exception of the OP).

 

[Overread]

Ballistics you do realise this thread is an extension of a critique thread. Furthermore why is it bad that we are discussing a core process of the photography world? The debate and discussion on HSS is very valid.

If you're concerned that critique isn't enough, well, only thing you can do is right that problem yourself. Well thought out and constructive critique given encourages it further.

 

[Ballistics]

Ballistics you do realise this thread is an extension of a critique thread. Furthermore why is it bad that we are discussing a core process of the photography world? The debate and discussion on HSS is very valid.

If you're concerned that critique isn't enough, well, only thing you can do is right that problem yourself. Well thought out and constructive critique given encourages it further.

There are more philosophers and physicists than there are photographers in this forum. That's my point. And the longer discussions are almost always an argument about who's more right
and it's usually started by a passive aggressive member who implements subtle insults which carries this crap out further.

This is not an extension of anything but the same argument in the original thread. It's got nothing to do with critique. But I'm being more general in my first post regarding the trends of TPF
as a whole.

 

[Gavjenks]

Gavjenks, i agree with you 100% about the pixel blur. But do you also agree with me if it was shot with macro, it would have been ok too?

No, it only has to do with the number of pixels that the object takes up in the final image. And the number of pixels that it moves over the course of the light exposure. Macro vs. not macro, lens focal length, etc. etc. should all just be intermediate details that get you in different ways to what matters: pixels in size and pixels of movement in terms of the final image.

In fact, if somebody used a macro lens to not just capture the same image, but to cause the water drop to take up a little less than the entire frame of the sensor (2000 pixels or so), then it would be 10x MORE difficult to freeze its motion, because the tolerances would become much tighter. In order to get within 2 pixels of blur, you'd have to have it move no more than 0.1% of its diameter during exposure, instead of 1%.

[being too adamant about gravity stuff, something something, the quote is on a different page]

Fair enough. You're right, I don't have a strong grasp on it, and it doesn't really matter for the thread, so okay, I give up on that, with more than one person disagreeing.

Still, it's not anywhere close to 6mph at like half an inch away from the faucet, by any formula.

Again: the true experts in the field realize that the camera's shutter is far too slow to stop water droplet motion.

Derrel, just because all the experts use longer exposure and instantaneous flash in a dark room, that doesn't necessarily imply that a shutter wouldn't be POSSIBLE.

Experts will always try to use the best method. But "best" could simply be a matter of 10% better. "Best" doesn't necessarily mean 100% better or that any other method will completely fail.



I think that both the math and the shots in the OP show that it is indeed possible to capture water drops with shutter only. It would be really annoying, and that the parameters are pretty constrained as to WHEN it could work at all (including the original ones here), but it can.

You could have captured motion with shutter only with an old mechanical camera with only 1/500th or 1/1000th or so (and flash bulbs not any faster), even. You might have to do something like attach the camera to a moving track to match the speed of the drop. Or spray drops upward so that they are suspended at almost no speed at the top of their trajectory, or whatever. But you could do it if you set it up right. It's even POSSIBLE to freeze the motion of a water drop at like... 1/10th of a second in outer space =P

It's just that the slower you go, the more ridiculous hoops you have to start jumping through, so anybody with a better means would surely use it (unless they just wanted the challenge). You can't just use the shutter to casually capture droplets without thinking about it at all or putting forth any effort besides pointing and composing and shooting a bunch. But that doesn't make it not possible.

 

[Overread]

IF some people enjoy the physics of light and photography then more power to them. You won't see me discouraging them from discussing the topic - I might not understand it but I won't stop them.

Just as the gearheads can chat gear
and the macro addicts shoot macro and try to guess things
and the bird photographers shoot birds
etc...

TPF has multiple overlapping communities and it is unfair to tar one with not being worthy of being here just because you don't like them/they don't post stuff you find interesting/don't post in places you want to see them post etc... That is a foolish and stupid way to approach a forum and if you do you'll only set yourself up for endless disappointment.

Now that's enough derailing for one thread - if you want to discuss this further start a new thread up on the topic if you must.

 

[Derrel]

Ballistics you do realise this thread is an extension of a critique thread. Furthermore why is it bad that we are discussing a core process of the photography world? The debate and discussion on HSS is very valid.

If you're concerned that critique isn't enough, well, only thing you can do is right that problem yourself. Well thought out and constructive critique given encourages it further.

Yes, I agree with Overread: this is an extension of another critique thread entitled Captain America Water Drops. This is the Beyond The Basics segment of TPF, where we talk about more-advanced techniques. I have a friend, and one of his friends works at The Oregon Zoo, after a 25-year career as a staff photographer for The Oregonian newspaper, he shifted focus somewhat to nature/outdoor/insect photography, and he now holds a nice position at the zoo. He specializes in insect and high-speed, stop-motion photography. I have some insight into how high-speed, stop-motion flash is being done by a few different people.

As you can see from the above links, for a long time the Vivitar 283 flash has been a "standard tool", for the fact that it is low-cost, AND it is very,very easy to access the plug-in flash sensor module, as well as very easy to tinker with that module, as well as to simply plug in a paper clip into two of the connector holes, and thus short-circuit the AUTO-thyristor sensor and thus achieve INSANELY brief, almost microscopic, ULTRA-high-speed flashes. The "standard" high-speed,stop-motion flash unit among my two friends is three, or four, or even five Vivitar 285 HV flash units, wired together, and mounted inside of a PVC pipe, fitted with a large Fresnel lens, and each flash is dialed down to 1/4 or 1/8, or 1/16 power, or set to a specific AUTO-thyristor setting, so as to achieve the power level of a single flash, but with the motion-stopping ability that ONLY comes from one, single, ultra-short flash. Steve has produced utterly astounding 4x6 foot prints of wasps and bees flying inside of long PVC tubes, with artificial,colorful "nature" backgrounds just behind the insect, behind a plexiglas rear compartment door; this is very much like the water drop/oil and water pyrex/colorful background/backlighted flash setup so many hobbyists use. The wasps and bees fly through optical beam triggers, and the flashes only fire when the insects are in "the crosshairs" of a camera's pre-focused spot. This is high-magnification, single-shot, single-burst, ultra-high-speed photography. My friend, Steve's buddy, uses his 4-unit, 283+ Fresnel lens tube-flash for high-speed hummingbird photography. He's a birding "nut".

The crux of the matter here is that Robin was suggesting, in the first thread, that a camera's focal plane shutter is fast enough to freeze motion on water droplet work. The top speed of 1/8000 second sound fast, but as you can see from this link, fractional-power speeds from common flashes are in the 1/35,000 second range, with NO modifications to the flash.
The Rod And Cone: Flash Durations for Canon 580EX II and Vivitar 285HV

Canon 580EX II -- Distance from Flash to Sensor: 2 feet
1/128 power = 1/52718 seconds Flash Duration ---- SCALED to REPORTED DATA
1/64 power = 1/38845 seconds
1/32 power = 1/26887 seconds
1/16 power = 1/18626 seconds
1/8 power = 1/13039 seconds
1/4 power = 1/8447 seconds
1/2 power = 1/5006 seconds
Full power = 1/871 seconds

Of course, there are methods of measuring flash out which incorporate not just the peak of output, but also the long, low-output "tail" section of the burst, which can easily give 'unscaled' measurements that are 4 to 5 times longer in duration than the above figures. The thing with photography "Beyond The Basics" is that it's complex, and can't be handled in two or three sentences, like a portrait C&C can be. Please read the above link for additional insight.

 

[Olympus E300]

If nothing else, this thread is quite educational! We have some very smart people amungst us! Gavjenks, you support a very strong argument. I'm probably enjoying this thread more than I should. Then again, I always did like science...

Carry on.

 

[Majeed Badizadegan]

http://weknowmemes.com/wp-content/uploads/2012/12/yeah-science-*****-meme.jpg

 

[jamesbjenkins]

tl;dr. @ pretty much every post on this thread.

You guys need to shut up and go take a picture of something.