Variable ND or Combine Single NDs?

I'm going trekking in Nepal in March. There will be some scope for moving water and waterfall pictures, mostly in exposed situations (i.e. not in forest), although there may be some forested water opportunities as well.

I'll be taking a circular polarising filter.

I want to take some ND filtering capability. I don't currently have any ND filters, apart from one 2 stop GND.

While I may invest in a square system at some time, this trip is not one that I want to take a square system on - light and compact gear is the order of the day.

So I'm thinking about buying either a variable ND (9 or 10 stop), or a combination of single exposure NDs (probably 3 and 6 stop).

I think that the disadvantages of each choice (based on internet discussions, no personal experience) are:
* Variable - cost of a quality variable ND filter; banding in skies on a wide angle lens at higher stops;
* Combo - carrying multiple filters, possible vignetting from using multiple filters.

What do you think? Which way should I go? And what brand/model should I looking at - I don't mind spending for quality (within reason, I'll be buying 82mm (as my largest filter thread size), and prices seem to jump significantly at that size).

What focal lengths (and body) are you going to be shooting with?

First, the VND filters tend to be pretty thick by themselves, so going that route isn't a guarantee against vignetting (and the filter is always at that maximum thickness). Second, with wider angle lenses, and at higher density settings, they tend to form an "x" of darker area on the images. How wide and how dense the filter setting varies with the filter brand; quality ones like Singh Ray tend to be better. I'd be inclined to go with the 2-filter solution unless you think you'll really need 9-10 stops a whole lot of the time.

The only ND I own and use is a VND. I use it to slow down water in streams and waterfalls. For high range scenes I do bracketed shots and combine them later.

Snydremark wrote in post #16631148
What focal lengths (and body) are you going to be shooting with?

I'll be taking my 600D with 15-85 as a base setup, haven't decided yet whether to take extra lenses. I mention 82mm filter size because I'll be leaving my 6D and 24-70 at home. I'll use a step up/down (I can never remember which is which) ring on the 15-85 (72mm filter thread) for this trip.

Jon wrote in post #16631162
First, the VND filters tend to be pretty thick by themselves, so going that route isn't a guarantee against vignetting (and the filter is always at that maximum thickness). Second, with wider angle lenses, and at higher density settings, they tend to form an "x" of darker area on the images.

The "x" effect is what I meant by banding - perhaps I used the wrong term.

Thanks. My problem is that I have no experience with NDs, so I don't have a feel for how many stops I will actually need. I am thinking that the 2 filter solution gives me 3, 6 or 9 stops, which may be enough.

I have no experience with VNDs but I travel pretty light with a CPL and two NDs (+3 & +8). Mine are 77mm and I use three step rings (72mm, 62mm, & 58mm).

This small kit fits nicely into a Tamarac filter pouch that will handle up to 82mm and rides nicely on my belt. It's compact, light, doesn't get in the way, and easy to get to when needed. Since I no longer carry GNDs (I use PP methods) I no longer need bulky squares and their holders/adapter rings.

Hope that helps a little. I have not stacked my +8 but have occasionally stacked the CPL with the +3. That combination seems to work well.

Jon wrote in post #16631162
How wide and how dense the filter setting varies with the filter brand; quality ones like Singh Ray tend to be better.

I've often seen this quoted, but I've seen no evidence to support it. Not even anecdotal placebo-effect 'evidence'.

dodgyexposure wrote in post #16631505
...I am thinking that the 2 filter solution gives me 3, 6 or 9 stops, which may be enough.

I'd go with this to start, and see if you need anything more later. The only way to know, for sure, is going to be to try it out.

hollis_f wrote in post #16633199
anecdotal placebo-effect 'evidence'.

I'm stealing this and using the heck out of it

I see you are a "senior member" and realize that does not necessarily infer age but perhaps longevity involved with photography. You might consider making a variable ND by combining the circular with an old linear polarizer you might have laying around. I don't do a lot of photography using variable ND but my "homemade" actually works surprising well, but then I have decent quality circular and linear polarizers. Sometimes you have to keep the f-stop up to avoid vignetting as the older linear polarizer then to be thicker.

Good instructions are at http://petapixel.com …e-neutral-density-filter/.

You should definitely consider taking a graduated filter ND as the air is very clear at the elevations you will likely encounter.

John from PA wrote in post #16635603
I see you are a "senior member" and realize that does not necessarily infer age but perhaps longevity involved with photography.

Ha! "Senior" is a title earned by number of posts, but I am, indeed, of an age to have experienced film photography. In fact, I skipped SLR film after dabbling in primary school, and only got back to SLR after the "D" was added. So no linear polarisers hanging about (well, apart from those used by my science teacher wife, but I suspect that those are not optical quality).

I will take my 2-stop GND (it's screw in, so is not always useful for mountain type scenes), but I'm curious why it would be more advisable to have one when the air is very clear?

Here in the States you can still find the occasional "true" camera store and many have a box of old miscellaneous filter that can be had for very cheap prices. If you have such a place that is convenient it might be worth a trip. My experience is you sometimes have to ask about used filters.