Long expouser Panorama and a Question for Measuring...

Personally, I would get a grey card if you're shooting landscapes. But that's just me, because I almost never shoot landscapes. And even then, you have the main issue that I'd have (and that I'd therefore default to trial and error for....): you have to decide whether you want to expose more or less for the sun or for the sky/landscape itself.
In any case, I do a lot of middle-of-the-night long-exposure work with an LA artist. We like to shoot at a higher ISO (doesn't matter...it can be ridiculously maxed out) and a wide-open aperture just to quickly get a good exposure and see where we're at. Then we simply and easily calculate what that would equate to at ISO 100 and f/8 or f/11, give or take, depending on what we're looking for. Sure, it can be 8 stops off. But that's fine. If you calculate it correctly, it should be damn near perfect when you do your long exposure.
We do this for film, too, where we'll take a D800 just for test shots, exposure, and to make sure we like our composition, more or less (and then we shoot on a Fuji GX617). You can use any digital camera...but the instant visual feedback has been a HUGE help for us since the "early days" just a few years ago when we used to never take a digital camera along....
Hope that helps...?

Hello guys,
First, I'm a little bit surprised of your feedback concerning the Lee Big Stopper.
As a landscape photographer, I often use it. And as long as I set my in camera white balance to 10000K (ok, may be it could be an issue for you, especially if you use film), I only have a very light blue cast in my images. Nothing that could not be post-processed.
Same surprise with your feedback for Hitech filters that are, with Cokin, the worst filters I bought, with a magenta cast, almost impossible to remove, more than the light blue cast of Lee.

Anyway, that's not your question!
First of all, I always use Lee ND grad filters, manual exposure and LiveView with my D800e. With the LiveView, you have the possibility to superimpose a real-time histogram of the frame. It's helpful to correctly set the shutter speed (my camera is always set at f/11 or f/16 for landscapes) to avoid highlights. Due to the fabulous dynamic range of the D800, I'm almost never in front of a landscape impossible to post-process with both highlights and darks.
If I'm in front of such a case (less than 5% of my production), I shoot in bracketing and I hand blend the pictures in Photoshop (or, since a few days, with Lr CC).
With the Lee BS, to find the proper exposure value, I do almost like Adam explain.
I set y ISO to 4000 instead of 100, adjust my exposure speed and keep my aperture value (f/1 or f/16, depending of the scene). Because a BS is 10 stops, I know that I have to multiply the exposure speed at 4000 ISO by 40 to find the correct exposure speed at 100 ISO.
Of course, it could always be a trial and error process, but due to 4000 ISO, you don't have to wait for long minutes between each trial.

This is the way I do, this is not perfect, but it works.
Hope also that helps!

(and sorry for my poor english, I write as a french guy!)

Alexis

www.duboaa.net
www.horizons-naturels.com

download an nd calculator on your phone. if you compose your shot as it is normally say 1/8th than 10 stops is 2min 8 sec. put on filter then go to bulb and use remote for that time. expose for the highlights.. how are you doing your panos? look at the photo i did that i put on here 99 percent of landscape photos i do are multi row panoramas.