Using Soft GNDs

[nicshow]

I'm second-guessing how I use soft GNDs (soft for in mountain scenics, for instance). I find myself usually pulling the (rectangular) filters down so that the dark part gets well over my sky (and in some cases down just before the top of the filter shows through the lens) but also realize that in most scenes this means that I'm getting the beginning part of the darkened filter over my foreground too. Perhaps I would get just as much effect from the filter if I left the clear area over my foreground and had the "medium" part of the graduation over my sky?

I know some have suggested using the DOF preview button which does help some.

Can anyone help by thinking through this with me or telling me how you use yours?

Nic

[Jon]

You absolutely should use the DoF preview to see where the divide is falling. Using the lower part of the filter so you don't have any graduation over the foreground is sort of self-defeating unless you get stronger grads If you're dealing with an irregular horizon, the grad will fall across the transition zone and hold that back some, but will only have minimal effect on the actual foreground. The maximum effect will be on the sky where you need the most effect. Shifting to a stronger grad (or a hard transition) will give you a steeper transition; this may be a good thing if you've got a smaller sensor.

[nicshow]

So you are saying, in addition to using a 3-stop or so, it's better to have some of the graduation over the foreground and the darkest part pulled into the sky than to have nothing over the foreground and the soft "line" right at the horizon?

Nic

[Jon]

If you have nothing over any of the foreground, you won't have the full 3 stops over the sky. If you have the divide lower, maybe some of the foreground will be under ND, but some usually won't and the sky will get more darkening.

[argyle]

You should be bracketing your shots anyway...bracket for exposure differences as well as for gradient positioning. Its very rare that you get the shot you're looking for with only one press of the shutter. Proper use takes patience and practice...to double-check the gradient position, stop the lens down to f16 or smaller and use the DOF preview button (but don't forget to re-set the aperture once you're satisfied with what you see). ;)