ND 10 step filter for long exposure - I need some help

[theantiquetiger]

Going to the beach next weekend, so I bought an inexpensive 10 step ND filter for my 70-200 and/or 11-24.

I've watched a quite a few videos on it, but still not sure exactly how to determine the exposure. Most videos say shoot around f9 to f11 and set in bulb. So (for example), if the meter says at f9, it needs to be 1/250 without the 10-step filter, it will be 4 sec with the filter.

[Runmonty]

First the hard way then the easy way -

Double the exposure time for each stop

0 - 1/250
1 - 1/125
2 - 1/60
3 - 1/30
4 - 1/15
5 - 1/8
6 - 1/4
7 - 1/2
8 - 1
9 - 2
10 - 4

The easy way - There are quite a few phone apps available that will make it easier for you. Take an exposure reading then plug that into the app and it does the work for you. I use the following android app. Double the exposure time for each stop

[Marko]

Was there no guide that came with the filter?
The high end ones all come with an easy guide to follow.

But Rm's guide makes sense to me. Just extend the guide for yourself (8, 16, 32, 64, 128) for easy reference at any Fstop.

[theantiquetiger]

Was there no guide that came with the filter?
The high end ones all come with an easy guide to follow.

But Rm's guide makes sense to me. Just extend the guide for yourself (8, 16, 32, 64, 128) for easy reference at any Fstop.

Hasn't come in yet, but I hope it does. Now I need to go grab a release cable.

[mbrager]

When I use my variable filter, I set my (stupid) camera on manual exposure. I can set the Tv and Av I want, but also control the exposure with the filter. In manual, using Live View, there is an exposure meter on the screen that tells me, as I darken and lighten the filter, when I'm at the right stop, i.e. the meter is in the center. This is useful in bright sun, around water, for example, when I want to slow the shutter, still have a shallow depth of field, and need therefore to use the variable filter to help cut down the light. I will also shoot bracketed shots, i.e. several shots under and over the camera's exposure, to ensure I'll have at least one good exposure, and for HDR processing when there are dark and light areas in the shot.

[Marko]

I think a podcast about this filter is in order.

[Runmonty]

I think a podcast about this filter is in order.

If you do decide to do this I have a couple of points/comments/questions that may or may not be useful. Let me know if you want me to post here or PM, or not at all.

[theantiquetiger]

I guess you get what you pay for. My filter came in, I tried a practice shot. I put my camera in AV mode, the meter called for a 1 sec exposure @ f/9.0 ISO 100(I was shooting inside).

So I put my camera in BULB and tried a few short exposures(12-30secs).

Should I be able to see through a 10 stop ND filter? I can see light through this one.

Here is what I got with a 8 sec exposure. According to a chart, 1 sec normal exposure with a 3 stop ND filter is 8 secs.

[theantiquetiger]

Am I doing something wrong and this is a 10 stop filter or is it a 3 stop filter? I want to make sure before I send it back. The seller has offered a full refund, but I just want to make sure.

[Marko]

It's 10 stops not 3.
But why would you use it (practise) on this subject instead of moving water or clouds?