[gabro822]

Hello!
Today I was outside and I saw a perfect sky. So my idea was to make a long exposure in order to have clouds with wakes in addition to the landscape. But I realized that I didn't know how to use ND. So my question is, should I use that like in a normal double exposure? I mean, I measure the sky, the ground, then put the filter and in M mode set for the first shot the measure of the sky and then the ground and merge them together?
Sorry for the platitude, but I was lost today, and I want to learn how to do!

P.S. the problem, I think, is increased also by the fact that I was outside with a polarizing filter that I use, in that situation, as a ND. Could be relevant?

Thank you very much!!
Gabriele

[ismaelg]

Not sure I follow you completely, but are you metering with the camera or an external meter? If with the camera, just measure the sky with the filter(s) on and go from there....

[gabro822]

Ah with the filter on? But in the case I'm going to use a ND32 the camera metering won't work...I mean,it's all dark. So what can I do?

[jatrax]

Measure without the filter and then count stops. ND32 is five stops so take your reading, set to M and change exposure by 5 stops. If you want cloud trails then I assume you are going to want long exposure so change the shutter speed not the aperture.

[tuco]

A five stops ND filter is not much for the middle of a bright day. You'll be hard-pressed to get 1/8 of a second at f11 or even f16 with it under those conditions. But if you wait till near sunset or sunrise under those conditions, you'll get longer. It all depends how fast the clouds are moving for what shutter speed will work best.

You can pre focus and compose with the filter off. Your camera can meter through that ND filter if it is less than 30 seconds. Or you can meter without the filter as noted in say aperture priority mode stopped down at around f11 to f16. Note the shutter speed reading. Adjust the aperture a little to get nice whole stop values (eg 1/125, 1/60, 1/30, etc). Put the camera in manual mode and set the shutter speed five stops slower. Focus, put the filter on and shoot.

[Vylen]

Apart from all the very very helpful posts above.. I noticed some glaring details to your question.

If you're going to take two shots, one of the landscape and one of the ground and merge them together, then don't bother with an ND. Just take a fast exposure shot of the sky and long exposure shot of the ground - it'll be the same effect! A uniform ND is to darken an entire scene - useful for taking long exposures of uniformly bright scenes.

What you need for taking a single shot of a bright sky and not-so-bright landscape is a graduated ND which is generally used for darkening the sky and keeping the landscape bright..

[gabro822]

Thank you all!
But so, al Vylen says, if I take a picture where the land has different light condition, the use of a ND filter is useless, Isn't it? My new question, at this point, is how to have a photo correctly exposed using a ND not losing cloud trails. Must I use a multiple exposure (considering the fact that I haven't a GND)?

[twitch]

A square filter system where you can stack an ND and a GND will do it. Expensive solution though.

I imagine a multi exposure and post production blend would be cheaper, although I have no idea how to go about it

[RioRico]

If shooting rather hurridly is important, bite the bullet and get a GND filter.
If you have time and patience, then tripodded multiple exposures are cheap.
There's a long tradition of layering landscapes and cloudscapes together.