Water shots

[mdaddyrabbit]

How do I go about capturing a stream and making it look continuous, It looks like Bulb photography but to me looks like everything else would be over exposed. I may not be explaning this right. I have seen photos with cars coming by at night and the lights of the cars are streaming.

[Sean-Mcr]

You mean like this? If so that was taken with a exposure of 5 sec. I think for water you'd only need a second or two though i've never actually tried it

Sorry about the res, i really need to get some space on Pbase:rolleyes:

[PhotosGuy]

to me looks like everything else would be over exposed. YOU have to figure out what the right f-stop will be when you use that long shutter speed. To get it right, you'll find it helpful to use a low ISO, like 100 or 50 if you have it, & probably a ND or polarizer to cut down the light level even more.

[12345Michael54321]

This question is asked pretty often here. These are instructions. Please don't be offended if they seem unnecessarily basic. And don't go pointing out that I've left out discussion of some minor considerations which would only confuse the inexperienced. They're good instructions, to the extent that they discuss some of the basic principles, as a result of which a newbie may learn a little about exposure, and wind up understanding not just what to do, but why he should do it.:

The "Sunny f/16" rule says that on a nice, sunny day, the proper exposure will be around 1/ISO @ f/16. This isn't precise to the fraction of an f-stop, but it'll put you in the ballpark.

So let's call the baseline exposure for a photo of the stream to be 1/125 sec. @ f/16. (I'm assuming you've set the camera to ISO 100, and I'm rounding the 1/100 sec. to 1/125 sec., since 1/125 sec. is a "classic" shutter speed from the olden days, and many photographers find it more comforable to think in terms of 1/125 sec. than to think in terms of 1/100 sec. Okay? Trust me, it's close enough for government work. Oh, and I'm assuming it's a sunny day, even though many shots of flowing water work best in overcast conditions.)

Well, you want the water in the stream to look all misty and smokey, right? Can't get that at 1/125 sec., unless the stream is a raging torrent of water rushing along at 100mph and sweeping away everything in its path. For argument's sake, let's assume that it's a gentle little stream, where the water flows lazily to the ocean, and not something out of a disaster movie.

Now, in order to get the water looking all flowing and all, we're going to have to use a shutter speed of around 2 seconds. How do I know this? Experience. I've photographed lots of streams, and 2 seconds works out about right, much of the time. For some streams, it's a little long. For others, a little short. The results are too misty for some people, or not misty enough for others. But we need a target, and I'm calling it 2 seconds. If you think 1/4 sec. looks better, or 16 seconds looks better, fine. But for purposes of this explanation, we're going with 2 seconds.

So, we go "125...60...30...15...8...4...2...1...2s," and realize that a shutter speed of 2 seconds is exactly 8 stops more than the indicated shutter speed of 1/125 sec.

Which means, we can simply close down the lens by 8 f-stops, and it'll balance out extending the shutter speed by 8 stops in the other direction, and net exposure will remain unchanged. Everything will be properly exposed, and the water will have that neat look we want.

Problem is, we can't close down the lens by 8 stops, because the smallest aperture the lens offers is f/22, which is only 1 stop smaller than f/16. Not 8 stops smaller. Besides, even if we could close it down to f/256 or whatever the ungodly tiny f-stop would have to be, diffraction effects would leave us with a really crummy image. Darn laws of physics. (Personally, I don't even like using f/22, unless the situation really demands an f-stop that small. Although in some macrophotography situations the increased depth of field of a tiny stop like f/22 is worth the reduction in resolution due to diffraction.)

Okay, no problem. Instead of closing down the lens by 8 f-stops, we'll simply reduce the camera's ISO setting by 8 stops. So we count "100...50...25...12...6...3..." and soon realize that we'd need an ISO of, like, 0.3, to cut ISO 100 by 8 stops, and that's just not a possibility, either.

What to do, what to do? I'll tell you what to do - we're going to use neutral density filters.

A neutral density (ND) filter does for your camera, pretty much what dark grey sunglasses do for your eyes. It cuts the amount of light way down, while leaving the colors unchanged. (The "colors unchanged" part is why I specified grey glasses, and not amber or green or some other tint.)

So we try to order an 8-stop ND filter from B&H, only to find that they don't have any 8-stop ND filters. But they are willing to make us a sweet deal on a 5-stop filter and a 3-stop filter. As a 3-stop and a 5-stop can be used together to equal 8 stops, we go for it. After all, having a 3-stop filter and a 5-stop filter is propably going to be more versatile than an 8-stop ND filter would be, anyway.

The filter arrives, and we head on down to the stream. It's a sunny day. We put the ND filters on our lens and...

What's this? The lens won't autofocus! And the exposure meter is acting sort of wierd, too.

You see, your camera has difficulty autofocusing and determining exposure when that much light is cut. The thin trickle of photons hitting its sensor isn't quite enough to permit normal operation.

So here's what we do - we meter without any ND filters on the camera. The camera says the proper exposure is 1/125 @ f/16. We remember this.

Then we let the camera auto-focus, and next we switch the lens to manual focus, so it'll keep using that focus distance, and not start hunting for proper focus once the ND filters are in place.

Oh, and did I mention that the camera's on a solid tripod? Because it is. Believe me, you don't want to take 2 second long exposures handheld, unless you find blur to be artistic and aesthetically pleasing.

Now, we screw on the 5-stop ND filter, and the 3-stop ND filter.

Next, we remember "1/125 sec. @ f/16," and mentally subtract 8 stops from that, to get 2 sec. @ f/16. We set the camera to Manual exposure mode, and set the shutter speed to 2 sec. (which looks a lot like 1/2 sec., so be careful), and the aperture to f/16.

We then take the picture, preferably using a remote release or a self-timer.

And we get to thinking, "Maybe the water would look better at 1 sec., or 4 sec." After all, it's hard to predict exactly how long an exposure will yield that nice, misty, flowing water look. These things are more of an art than a science, you know.

So we bump the lens aperture down one stop, to f/22. And consequently increase shutter speed by one stop, to 4 seconds. Then we open the lens up to f/11, and set the shutter speed to 1 sec. See, all this keeps our total exposure constant; whenever we go in one direction with one setting, we go the exact same distance in the opposite direction with the other setting.

We go home, and transfer the images from our Sandisk Ultra II compact flash card, via our USB 2.0 card reader, to our Dell 4500 computer machine. We fire up Adobe Photoshop CS2, do all sorts of unnecessary things to our images, pick out our favorite, and put it on the web, so we can link to it in a thread at http://www.photography-on-the.net.

It looks a little like this: http://www.time4email.com/falls4.jpg

Boy, we're good.

[mdaddyrabbit]

So I need ND Filters to achieve this effect?

[shortie]

12345Michael54321

Great explanation - every day I learn something new, can't beat it ;-)

Shortie

[kbreit]

While I knew a bit about f-stops, exposures, etc. I did learn a few things in your post. Great job.

[PhotosGuy]

So I need ND Filters to achieve this effect? You could stack 2 CP's & get a variable ND filter.

[Mannytkd]

12345Michael54321

I have a G6 and have just bought myself a canon adaptor with a 58mm thread and look forward to shooting some waterfalls myself and won't take them sort of shots without ND filters. The G6 has a built in ND filter but i will use the cokin 2,4 strengths for more dramatic effects and maybe the G6 one too for a longer shutter speed.....i've still got to try it yet.....we'll see?

[flam79]

That was one of the funniest informative piece of information pieces I have read.

[GPR1]

You'll notice that the example shot in that excellent post was not taken in bright sunlight, as Michael said. Often times it's not necessary to have 8 stops of light reduction. In some situations you don't need the depth of field of f16 either. However, the math still holds, and the process holds. A nice informative post.

Greg

[12345Michael54321]

I have a G6 and have just bought myself a canon adaptor with a 58mm thread and look forward to shooting some waterfalls myself
The example photo I posted was taken with a G3 and the adapter permitting the use of 58mm filters. Details at http://www.time4email.com/falls/

[MattyB]

well, i have the same problem during the day, i have a IXUS 30
can't have different lenses (can you?)
no polawhatever etc..
http://www.alphalink.com.au/~bennell/Photos/IMG_0840.JPG
that is VERY over exposed, that was with
ISO: 50
Shutter: +2

but, at night - it comes out ok, and the later at night, aslong as the streetlights give a bit of detail, the slow shutter will pick it up, but on a pitch black road, with a car's red backlights driving past, you'll only see the backlights.
this was
ISO: AUTO
shutter: +2
http://www.alphalink.com.au/~bennell/Photos/IMG_0561.JPG
http://www.alphalink.com.au/~bennell/Photos/IMG_0554.JPG


so, i suppose only good camera's with adaptable lenses can get proper ones during the day, so instead, when i goto the waterfalls this summer, i'll be waiting till dusk to take some slow shutter pics and see how that works.


-matt

[theflyingkiwi]

hi matt

couple of things to remember, when posting photos keep the image size down, it's hard to see what it looks like when one can't see all of it. and number 2 use a strong tripod, with a timer or cable release

these are very important :)

all in all what 12345Michael54321said was very good. now just need to find some ND filters :)

[Mannytkd]

Just looked at your waterfalls shot, wow i love em to bits, i only hope i can get mine like that too, i've yet to have ago soon on a well known waterfalls walk in yorkshire, a place called Ingleton falls. ;)

The example photo I posted was taken with a G3 and the adapter permitting the use of 58mm filters. Details at http://www.time4email.com/falls/

[jfrancho]

so, i suppose only good camera's with adaptable lenses can get proper ones during the day, so instead, when i goto the waterfalls this summer, i'll be waiting till dusk to take some slow shutter pics and see how that works.
-mattTry shooting with the lens of a pair of polorized sunglasses over the camera lens. You may need to experiment with the settings.