So... we were talking about photography in the intertidal zone.
kgd had some questions:
Great comments on the Tidepool Evolute. It strikes me that light conditions can be challenging in this example though. Reflections from the tinyest ripples, turbidity - especially when moving rocks can be difficult to control.
Are there any filters that help - I used to use a polarizing filter on my old film SLR, wondering if it cuts down glare from water surfaces?
Yes, lighting conditions can be challenging for intertidal photography, In fact, all around, intertidal photography is exceptionally challenging... among the most challenging types of nature photography.
The easiest light to work with in tidepools is relatively low angle light, i.e., mornings or evenings, on days with clear skies. Mornings tend to be preferable to evenings, because the air is usually more still, so there are fewer issues with ripples.
Quite likely, you will have to deal with overcast skies. Fog is common along the beaches, and further, Pitdog's area is cloudy a lot of the time. Moreover, the best low tides tend to be in winter, and also, the conditions which cause the storms off the coast are likely to cause overcast skies right over the coast.
Overcast skies are somewhat difficult lighting to work with for intertidal photography. There will be bright reflections on the water, and polarization doesn't work very effectively in these situations.
There are several somewhat effective strategies, if you are photographing the intertidal zone from above water, with overcast sky lighting. As to which strategy is ideal... it varies, and sometimes it is best to combine several strategies.
One way is to block the light. Bring a dark tarp. If you can, make it into a rigid square/rectangle by putting some tent poles through it. Ideally, you would have your assistant hold the tarp in position for you, but you can also do it yourself. Just place it in such position so that it is blocking the sky reflections. An alternative way to do this is to just throw the tarp over you, and take a very slow exposure in the almost total darkness beneath the tarp. (The advantage of this technique is that it also blocks the breeze from rippling the water.)
Another technique is to completely overpower the natural light with artificial light. Do this by using an off-camera flash, close to the subject, at a high power setting.
A third technique is to photograph the scene with the reflected sky greatly lowering the contrast, and increase the contrast greatly in the processing and post-processing.
Ripples are a separate issue. Yes, they cause uneven sky reflections, but that is the least of the concerns they cause. The main issues are that ripples cause distortion and also cause uneven refraction, which messes with focus. Sometimes ripples can be avoided by shooting in tidepools that are fairly deeply set into the rocks, so that they are better blocked from the wind. Also, completely covering yourself and the tidepool and a tarp can help. Another option is to place something flat and clear, such as a picture frame, onto the water, and photograph through that.
Turbidity is yet another issue. When most of the tidepools and the nearby ocean is turbid, look for very small tidepools with no outlet to larger bodies of water. The material in the water will settle most quickly in these. You can also, again, go ahead and photograph in such conditions, and then increase contrast and correct color in the processing and post-processing stages.
As to filters which can help: Yes, polarizing filters can cut sky glare on water surfaces. For examples, see here (unpolarized)...
...and here (polarized)...
A polarizing filter can help when photographing in clear weather with low angle light. It won't help much in overcast conditions, and it won't help much when the sun is overhead.
More coming, soon.
Cheers.
