How many ND stops to slow water during day?

Captured Exposure

Hi There,

I have a set of graduated Cokin P series and am wanting to get some ND filters for slowing down the freshwater streams around where I live.

Would you be able to recommend what stop filter or filters could be used for slowing water down enough during the day, if it's possible.

Thanks
Dan

ziggy53

Captured Exposure wrote:

Hi There,

I have a set of graduated Cokin P series and am wanting to get some ND filters for slowing down the freshwater streams around where I live.

Would you be able to recommend what stop filter or filters could be used for slowing water down enough during the day, if it's possible.

Thanks
Dan

What ISO do you wish to use?

By "during the day" do you mean that the water is in direct sunlight on a sunny bright day?

How quickly is the water flowing?

How smooth/creamy do you want the water to appear?

Captured Exposure

ziggy53 wrote:

What ISO do you wish to use?

By "during the day" do you mean that the water is in direct sunlight on a sunny bright day?

How quickly is the water flowing?

How smooth/creamy do you want the water to appear?

Hi Ziggy,

Well, I have a couple weeks off as of this Friday and it has been bright and sunny, is it even possible to slow water enough?. On an overcast day I could probably get it low enough with my polarising filter and low ISO...not to sure.

It would be at 100 ISO, this is as low as the Canon 450D allows.

It is a modest flowing stream at the moment as we haven't had a lot of rain.

Would just like the water to show it is running, not all that creamy really but for the effect of movement.

Thanks

ziggy53

Captured Exposure wrote:

Hi Ziggy,

Well, I have a couple weeks off as of this Friday and it has been bright and sunny, is it even possible to slow water enough?. On an overcast day I could probably get it low enough with my polarising filter and low ISO...not to sure.

It would be at 100 ISO, this is as low as the Canon 450D allows.

It is a modest flowing stream at the moment as we haven't had a lot of rain.

Would just like the water to show it is running, not all that creamy really but for the effect of movement.

Thanks

A single ND filter will not cover all situations and conditions. A polarizer will indeed reduce the transmitted light, but it will also eliminate some/much of the water's reflection, affecting the outcome.

I suggest starting with a 3-stop ND filter, which would have a designation "ND8" or "0.9", depending on the manufacturer. That allows 3 times longer exposures and will blur water without removing all detail. This filter is also handy for allowing larger apertures in bright sunlight, yielding shorter DOF.

If you should want to get the creamy look, I suggest either an 8-stop or 10-stop filter.

Chris H

<input id="gwProxy" type="hidden"><!--Session data--><input onclick="jsCall();" id="jsProxy" type="hidden">I have a 10 stop B&W ND filter, these were shot in broad daylight giving an exposure time of around 60 seconds. The sea wasn't exactly rough so there's not as much 'mist' as there might have been, but you still get the nice effect of flattening the sea and seeing movement in the clouds.






Cheers
Chris

RogersDA

See this thread. Stacked 1.8 and 0.9 ND filters (9 stop reduction).

Here's another thread too.

Captured Exposure

Thanks all, appreciate the information. Will take a look.

jforbes

I've made do with a 3 stop + polarizer (~2 stops) - it's fine for early/late in the day, and also works well in shaded areas a la this, which was probably f/16-f/22..






But shooting in more open sunlight like this (a while before sunset) can be tough - to get the water in this shot, I was at f/32, and pushing the exposure very high (the shot is blended exposures, I have a variant of it with more naturally exposed water). Shooting f/32 is not a pretty compromise - photos turn to complete mush.




I'd recommend at minimum a pair of 3 stop NDs, but you'd be best off with an 8 or 10. You can marginally work with less, as I have, but it forces you to make compromises like tiny apertures when there's more light, which really hurts sharpness and contrast more than I'd like.

Captured Exposure

Thanks I think I'll order a Cokin ND8 stop after looking around. It will help hold back the light in the sunrise mornings as well. I have a polarising filter which should drop it another 2 stops as well.




Dan

pyry

In case you know your way around Photoshop a little bit, you can do this without filters. It's a lot of images and work, but possible and gets easier as the light fades.

If you can manage an exposure time of about half to one second or more by using low sensitivities and small(ish) apertures, it is then possible to shoot a couple on minutes worth of images and average them together in post (open as layers, make into smart object and choose average as the stacking mode).
The effect should be very close to using a dark ND-filter, but with less noise.

(I haven't tried this myself yet, I should find a nice spot and give it a go )

Scott_Quier

This was taken at approx 2:50PM under a clear sky at the Acadia Shootout with a B+W 10-stop ND filter. If you look at the EXIF, you will note that this would have been pretty much impossible without such a dark filter.



EXIF:

• Camera: 5DII
• ISO: 50
• Shutter: 25s
• Aperture: f/10
• Focal Length: 105mm

I suppose it's possible to generate something like this in PS, but it would take a lot of work, a lot of images, and (I would think, some pretty serious computer processing power and memory.

pyry

Scott_Quier wrote:

This was taken at approx 2:50PM under a clear sky at the Acadia Shootout with a B+W 10-stop ND filter. If you look at the EXIF, you will note that this would have been pretty much impossible without such a dark filter.

I suppose it's possible to generate something like this in PS, but it would take a lot of work, a lot of images, and (I would think, some pretty serious computer processing power and memory.

Looks like you're right.

Exposure times would have been in the milliseconds, so it would take thousands of individual photos to do that. And pushing futher would require stacking photos taken with the filter...

I suppose then that the stacking method requires twilight.

travischance

This was a great thread!!! I too have had questions regarding ND's and am in the market for some that I could use for "middle-of-the day shots". I took these photos between 10AM & 12Noon by combining a B+W CPL & Cokin Gradual Gray ND8 filter.

Scott_Quier

uncletrav wrote:

This was a great thread!!! I too have had questions regarding ND's and am in the market for some that I could use for "middle-of-the day shots". I took these photos between 10AM & 12Noon by combining a B+W CPL & Cokin Gradual Gray ND8 filter.

Beautiful colors!!

rpcrowe

Thoughts on blurring water...
I really think that a lot of blur which reduces water to a totally creamy complexion is overdone.

I also wish that the new Canon 7D had an ISO 50 like the 5DII (or even better an ISO 25) setting. ISO 25 with a CPL filter could do a lot of blurring without having to resort to a ND filter.

Has anyone combined a CPL and LPL polarizers to make a DYI variable neutral density filter?

http://digital-photography-school.com/create-your-own-variable-neutral-density-filter

travischance

I haven't used both. I use a B+W Kaesemann CPL with a really inexpensive Cokin P series filter. You have to hand-hold the Cokin but it's only for a few seconds. Check Craigs List as people are always dumping this type of gear.

That was an interesting article..... However, using the combo above, I didn't experience problems with focusing as Darren noted. Manually focus your subject, IS disabled, mirror lockup, remote shutter release and placing the square filter over my CPL was pretty easy. Granted I'm no pro as this was my first stab at blurring water, but I felt that I achieved great photos using this method.

Joves

As has been said it depends on how much creaminess you want. I used my Hoya ND8 for this shot.

Shot at 100 ISO- f/14 @ 1/2 second shutter. It was a nice sunny day and, I had the place alone for a change. Usually there are people swimming there. THe one thing I miss about my D80 is its base 100 ISO.

astockwell

First, search is your friend...
http://www.dgrin.com/showthread.php?t=132827&highlight=neutral+density

Also, you shouldn't need more than about 3 stops to get the exposure you need during the middle of the day. For a waterfall, I like to try to stay around 2-4 seconds max. You keep detail, and get the effect you want. The only time I try to add more time, is if I have a small pool in front of me with a rotational flow through it from the waterfall. You can do some really neat stuff with that. Especially if there are some leaves or foam in the pool to cause a streak effect. Don't run out and buy a ten stop unless you understand what you are buying it for. Mostly a 6-10 stop filter is to cause a certain effect in the shot, and you don't need this to give the misty water effect in a waterfall, as you will also loose detail in the water.

-Andy