Starvation Creek

[EOBeav]

Milosh: At ISO 100, my shutter time was more like 1/40, which wasn't capturing the flow of the water. Anything longer than 1/10 of a second was showing blown highlights, regardless of filter, ISO, aperture, etc... I think it had to do with the speed at which the water was coming down the hill. I've also noticed that water can show blown highlights more easily when I'm using my circular polarizer, so I need to take that into account when I'm shooting with it.

[milosh]

Originally Posted by EOBeav

Milosh: At ISO 100, my shutter time was more like 1/40, which wasn't capturing the flow of the water. Anything longer than 1/10 of a second was showing blown highlights, regardless of filter, ISO, aperture, etc... I think it had to do with the speed at which the water was coming down the hill. I've also noticed that water can show blown highlights more easily when I'm using my circular polarizer, so I need to take that into account when I'm shooting with it.

I really didn't know that exposure can depend on the flow of water (I'm not being sarcastic), it really doesn't make sense to me. The same goes for using a smaller aperture...

[SwissJon]

Well I can see how the CPL might cause blown highlights.. But I don't really understand why your ND would.. Surely you're blocking the same amount of light, highlights or shadows, or do you have an ND with a colour cast? That would blow them, the colour casts can be as much as 2 stops brighter than the rest of the colours. What make is your filter?

[milosh]

I think generally, when shooting waterfalls and water cascades, the volume of water currently flowing can only influence how it looks on the image (how "silky" and how much "frozen" it is), so you need to adjust your shutter speed according to that, and then adjust the exposure according to that shutter speed.

[EOBeav]

Originally Posted by SwissJon

Well I can see how the CPL might cause blown highlights.. But I don't really understand why your ND would.. Surely you're blocking the same amount of light, highlights or shadows, or do you have an ND with a colour cast? That would blow them, the colour casts can be as much as 2 stops brighter than the rest of the colours. What make is your filter?

Since I already had the polarizer screwed on, I didn't try an ND at all. I think the issue was that so much white matter was being created in that amount of time that the sensor, aided by the polarizer, was having a tough time keeping it all even. That's my theory, anyway. Maybe next time I should try the ND without the polarizer? All it will cost me is a few megapixels on the card.

[SwissJon]

LoL.. I like that attitude. It's all a learning experience.. The problem for the poloriser is that it's great with reflected light, where the light is generally coming at the lens with a polorisation given it by the reflection, which is why you can cut glare from water and snow reflections, but when it comes to spray, the poloriation is pretty much random, meaning that no matter what direction the poloriser os set, it's going to absorb a much smaller amount of light. So the difference between polorised and unpolorised light getting through the CPL is going to be huge.

Since the ND works in a different way, tiny particles stopping light at random places, not based on anything, it should stop light pretty evenly, white or coloured. ND filters with a colour cast block an over all amount of light, but not so much of the particular colour that you find the cast for. The B&W ND 10 filter has a red colour cast, and if you look at the transmission curves, the ND10 is an ND8 at the red end.. That's two stops less, so you need to be careful not to blow the highlights.. Their ND6 (which I have) also has a slight colour cast, but it's about 2/3rd of a stop, and correctable in PP.

B + W Filters - Filters for Digital and Analog Photography

[EOBeav]

You make an excellent point, Jon. One of the things I really like about the polarizer filter is that I can cut down the glare from wet rocks and the general sheen on top of the water. I'm finding it tough to get details from the flowing water, though, but maybe I need to find where that sweet spot is when I rotate it on the lens. I'd like to head back to that spot in the next month or so just for that purpose.

I have the B+W 10 stop. Do you find that the color cast is correctable in post production? For the most part, I've been able to remove it, but there are some times when it becomes difficult. I also have a 3-stop, which might have helped in this instance, since slowing the water wasn't a problem.

[SwissJon]

Mine is a 6 stop.. When I saw that transmission curve on the 110, I realised the colour cast would cause a problem. At times you hardly notice the colour on the 6 stopper. I'd suggest you under expose the exposure on the ND 10 by about a full stop, which should leave the highlights reachable.

[EOBeav]

Originally Posted by SwissJon

Mine is a 6 stop.. When I saw that transmission curve on the 110, I realised the colour cast would cause a problem. At times you hardly notice the colour on the 6 stopper. I'd suggest you under expose the exposure on the ND 10 by about a full stop, which should leave the highlights reachable.

Correction: I have a 6 stop, not a 3 stop. I'll keep those exposure settings in mind when I'm out using it again.