Singh-Ray 10, 15, or 20 stop ND Filter recommendation?

I have several Singh-Ray filters and I am very happy with them. So, now I intend to purchase a 10 or 15 stop circular ND filter for verryyy long exposures. Still trying to decide...and now I see they JUST came out with a 20 stop filter! wow.
My inclination is to get the 10 stop and add my Vari-ND to that if I find I need additional stops. Or, am I better off just getting the 15 stop? That is, will I find that I'll eventually "want" a 15 stop if I get the 10? And is there any justification for the 20 stop...I'm thinking that's not for me.
Does anybody have any experience specifically with the Singh-Ray 10 and 15 stop ND filters who could help me with this decision?
Thanks!

I've done few-minute exposures with a 10 stop (B+W). I dont see any reason to add more stops unless you need to do 'verryyy' long exposures during the bright daylight.

Frank H wrote in post #17289208
I've done few-minute exposures with a 10 stop (B+W). I dont see any reason to add more stops unless you need to do 'verryyy' long exposures during the bright daylight.

Agreed.. I couldn't imagine a use for 15+ stops unless you really wanted to do something crazy during bright noon sunlight.. A 20 stop would be all but useless in the brightest of light (unless you wanted in increase ISO..)

Consider that dropping a shutter speed of 1/1000 to 1 seconds is 10 stops.. 15 stops would put you at 35 seconds, and 20 stops would be 1,000 seconds.. that's over 16 minutes long.

I can't imagine going to 20 stops. I've shot in the middle of the day with 12 stops and felt I could use just one more stop, but that was about it. Be that as it is, I think I'd rather start with a 10 stop. I've used my screw on 10 stop in conjunction with my LB color combo to get about 12 stops. If you already have a vari-nd then getting a 10 stop will give you about 18 stops assuming you're not using an UWA lens.

Thanks SO much! I really do appreciate the responses.
As I had thought, the 10 stop is likely the way to go. The replies confirm that. I'm going to put in my order for that filter.
(I've got lots of ideas of where I want to try using it...)

Steve,
I too am a Singh Ray fan. I have a several of their filters in my bag. If you haven't already seen it, I recommend also looking at the new-this-year Hitech Firecrest 16-stop ND filter. It's very affordable and has very impressive color integrity (which is probably why you're looking at Singh Ray to start with). I think you should get that 10-stop you've decided on, but maybe consider the inexpensive Firecrest 16-stop as a nice complement.

16 stop is very interesting for day time shooting. My recent shot:

IMAGE LINK: https://flic.kr/p/pMXW​SP

^Very cool!!

David Arbogast wrote in post #17292321
^Very cool!!

Indeed!!

Hmm....I'll take a look at the Firecrest, too. As you said, it might be a nice complement to the 10 stop.
Thanks!

Sweet lord, 20 stops?

I have a 10 stop and have stacked two 3 stops on that, for 16 stops. It's crazy how dark it is. You can go for several minutes in super bright light. Or in just good light, you can do a super long exposure. Depends on what you goal is. I've yet to need more than 10 minutes, ever, even when trying to get cloud blur. So I've not needed more than my 10 stop and a few 3 stops to stack depending on my needs.

I don't think you'll need more than 10 stop, plus or minus one other filter to fine tune the time.

Very best,

I agree 20 stop is very niche, but can imagine some uses: e.g. using with fast primes wide open during daytime: you can get both nice cloud blur (5-10 minutes) and shallow DoF. Never seen examples of such, you might try to be the first one .

How many stops is a lens cap? You could try one of those!

Mike-DT6 wrote in post #17299794
How many stops is a lens cap? You could try one of those!

Haha, so true.

Then gain, a pinhole lens cap is usually around f45...

Very best,