Technique for 10-Stop ND filters?

chrisdg · October 5, 2008

Hello,

I just received my [FONT=Verdana, sans-serif]B+W 110 (3.0) NDx1000 77mm Neutral Density Filter and took a few [/FONT][FONT=Verdana, sans-serif]daylight [/FONT][FONT=Verdana, sans-serif]test shots of the water feature in my backyard. So, aside from having to manually focus while the filter is not mounted, it appears that proper exposure is simply a matter of using Manual mode with a lot of trial and error, correct?

I had some luck by setting aperature at the desired stop (f4, f5.6, f8, etc), and then first setting time value to 30-seconds (or going into bulb mode with a shutter release cable to extend beyond 30 seconds). Following the shot, I checked the histogram and shortened or lengthened the time accordingly until I reached the proper mix. Seems like most of these ND shots are going to be well over 30 seconds.

Am I on the right track? Appreciate any further insight.
[/FONT]

Dave Clee · October 6, 2008

Well once I have set the aperture, I'll meter the scene without the filter. Then I know approx 10 stops more of shutter (longer) should get me in the neighborhood. From there a few test shots and checkout the histogram to make sure nothing is blown.
Also pending on the time of day your camera may be able to meter with the filter attached. I have found that my D3 will meter correctly at very low levels BUT I do have to manually set the focus.

Cheers

Dave

chrisdg wrote:

Hello,

I just received my [FONT=Verdana, sans-serif]B+W 110 (3.0) NDx1000 77mm Neutral Density Filter and took a few [/FONT][FONT=Verdana, sans-serif]daylight [/FONT][FONT=Verdana, sans-serif]test shots of the water feature in my backyard. So, aside from having to manually focus while the filter is not mounted, it appears that proper exposure is simply a matter of using Manual mode with a lot of trial and error, correct?

I had some luck by setting aperature at the desired stop (f4, f5.6, f8, etc), and then first setting time value to 30-seconds (or going into bulb mode with a shutter release cable to extend beyond 30 seconds). Following the shot, I checked the histogram and shortened or lengthened the time accordingly until I reached the proper mix. Seems like most of these ND shots are going to be well over 30 seconds.

Am I on the right track? Appreciate any further insight.
[/FONT]

jfriend · October 6, 2008

Can't you still use your light meter, even when the filter is on? It's TTL (through-the-lens) metering so it should still be accurate even with a heavy ND filter. Auto-focus won't work because there isn't enough data for good auto-focus, but can't metering still work?

chrisdg · October 6, 2008

Dave - Thanks for the info. I'll check that method. Seems I always overlook the obvious scientific approach!

John - When I let the 30D's TTL meter do it's thing with the filter attached, it consistently sets a ridiculously fast shutter speed (like less than a second) and the image is 100% completely black. I was very surprised by this behavior - and should have mentioned this in my original post. I have no other metering issues with this camera. My tests were taken a late afternoon daylight. (thought: since it's on a tripod and I'm not using the viewfinder, maybe extra light is coming in through the eyepiece and fooling the meter? The Canon manual says this is possible when not using the viewfinder)

Also, I've yet to try this filter with my new 50D, which arrived on Friday. Hope to do so soon.

jfriend · October 6, 2008

chrisdg wrote:

Dave - Thanks for the info. I'll check that method.

John - When I let the 30D's TTL meter do it's thing with the filter attached, it consistently sets a ridiculously fast shutter speed (like less than a second) and the image is 100% completely black. I was very surprised by this behavior - and should have mentioned this in my original post. I have no other metering issues with this camera.

I've yet to try this with my new 50D, which arrived on Friday.

If the meter doesn't work, then it sounds like you go with Dave's suggestion. Meter without the filter and then apply the 10-stop difference. You could also use an external meter and apply the 10-stop difference.

Dave Clee · October 6, 2008

I found this link awhile ago on this forum. Its pretty handy for getting the correct shutter speeds for long exposures..

http://www.8thcross.com/blog/wp-content/uploads/2007/02/filter-tables.pdf

I carry a print out in my camera bag..

Cheers

Dave

Scott_Quier · October 6, 2008

In addition to all the above, you can use AF if you move the AF function off the shutter release: Position the camera, focus, very carefully mount your filter, press the button on your remote ---> Done!

Check out CF-4. Once you get used to it, you'll never go back!

Technique for 10-Stop ND filters?

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