20 stop ND Filters - Who has used them

[DerekNZ]

I have an interest in long exposure photography.
I am expecting a 20 stop ND will mean very long exposure photography.
Who has used one, other than the long wait, anything to be aware of (I am thinking NIsi f100 x 100 filter)
Show me your images.
Thanks in advance

 

[Muttleyflying]

That's a very long exposure!
I do a lot of long exposure photography and the most I use is 16 stops and a polariser together and maybe a 3ND grad.
The maximum I tend to shoot is around 500 seconds.
I like to have a 10 of stopper and a 6 stopper as a separate item so I can determine on the day what I need.
The problem comes if you leave the camera to do noise reduction or do it in post.I like to let the camera do it in certain situations as doing it in post can be time consuming.
I personally wouldn't buy a 20 stop nd filter for me but I'm sure others would swear by one.

 

[DerekNZ]

That's a very long exposure!
I do a lot of long exposure photography and the most I use is 16 stops and a polariser together and maybe a 3ND grad.
The maximum I tend to shoot is around 500 seconds.
I like to have a 10 of stopper and a 6 stopper as a separate item so I can determine on the day what I need.
The problem comes if you leave the camera to do noise reduction or do it in post.I like to let the camera do it in certain situations as doing it in post can be time consuming.
I personally wouldn't buy a 20 stop nd filter for me but I'm sure others would swear by one.

I am on much the same page as you there. Just interested if people have used a 20 and what they have achieved with it. Thanks for your input

 

[Muttleyflying]

To be honest I didn't know of a 20Nd filter till you mentioned it.
I only tend to use Lee filters and I know they do a super stopper but I think that's only a 16 stopper equivalent.
I've shot a couple of 7min exposures before by going down to iso50 and with 16stop and a polariser with great effect but I cannot see what I would gain by adding more.
I avoid shooting landscapes at the height of the day with all that nasty harsh light lol.