Something from Lon Chaney

[stevet1]

I was trying to do some long exposures. I failed miserably, but this one came out at 20 seconds with a 10 stop ND filter. It looks like something out of a Lon Chaney movie.

Steve Thomas

[LeeP]

That is exceptional. I follow several people on Instagram that specialize in this kind of photography. Is this overcast daylight with a 10 stop ND filter?

On a side note I shoot Delta 3200 in my Pentax 17 with a 3 stop ND filter and the effect is magical. I need to buy a 10 stop ND for my Canons.

[stevet1]

Lee,

I learned a quick way to calculate your setting for an ND 10 filter.

Take a regular exposure. Whatever yoir ss speed is, take that and multiply that by 1000.

Say it's 1/30th. 1 divided by 30 equals .03333. Multiply that by 1000 and you get 33 seconds

For your 3 stop filter, use the same method, but use the number 8.  1/30th X 8.

Steve Thomas

[LeeP]

Thanks for the calculation. On the Pentax 17 I just let it's meter do the metering and it works astoundingly well. I didn't think it would but it did. I am going to start on a 5 ND filter on my 45mm f1.2 RF lens.

[stevet1]

Lee,

On a 5 stop filter, your multiplier will be 32.

Meter your scene for a good exposure, take the shutter speed and multiply it by 32, add your filter and set the new shutter speed.

You should be good to go.

Steve Thomas

[LeeP]

I Amazoned (sic) a cheapie variable filter because I like cheap thrills and will play this weekend. 

[Jkarl]

Interesting topic I found this from B&H Elxpolra.

https://www.bhphotovideo.com/explora/photography/hands-on-review/a-guide-to-neutral-density-filters 

[LeeP]

Great article.