Stopper Calibration

[Stagecoach]

Having recently purchased a LEE filter system I have just had my first chance to give the Big Stopper a test under controlled conditions.

Prior to this I undertook LEE's recommendation and calibrated the stopper to determine my examples 'real' stop value.

I had previously come across this article http://www.achim-sieger.de/en/exposu...e-big-stopper/ with its download and highly recommend it.

The spread sheet is easily modified by anyone conversant with exel with respect to reading range and font/print size for individual needs.

As an example, LEE's exposure guide that comes with the Big Stopper states for an exposure time of 1/60s without the BS, with the BS fitted this would be 15 sec. For my filter calibration (equivalent histogram) it required 26 seconds exposure giving the stopper a value of 10.6 stops.

Armed with my spreadsheet and the BS a visit to the foreshore in the afternoon light with exposures up to 50s (f/14 ISO100) confirmed my calibration results good.

Now to confirm longer times, combining the BS & LS and occasional use of the GNDs

Grahame

[Polar01]

Grahame one thing that I have learned over the years using the BS, is to not worry about so-called accurate shutter times. Example you have set up the camera and you find that you require 6 minutes, so you push the shutter release, locking it, remembering to cover the viewfinder (very important), then the one who shall be obeyed comes over to talk. Next thing and it is now 12 minutes instead of 6 minutes "all is lost", not so fast that extra 6 minutes only equals 1-stop. So the thing about the BS is not to worry about the exact exposure time what is a stop or so, remember that your camera's light meter is likely about 2/3 to 1-1/3 stops under exposing anyways.

Cheers: Allan

[Stagecoach]

Grahame one thing that I have learned over the years using the BS, is to not worry about so-called accurate shutter times. Example you have set up the camera and you find that you require 6 minutes, so you push the shutter release, locking it, remembering to cover the viewfinder (very important), then the one who shall be obeyed comes over to talk. Next thing and it is now 12 minutes instead of 6 minutes "all is lost", not so fast that extra 6 minutes only equals 1-stop. So the thing about the BS is not to worry about the exact exposure time what is a stop or so, remember that your camera's light meter is likely about 2/3 to 1-1/3 stops under exposing anyways.

Cheers: Allan

I suspect I will come to the same conclusion Alan regarding accuracy for long exposures but to date I had been concentrating on the shorter ones with the BS.

One of the reasons I got the stoppers was to enable opportunities for playing more in daylight conditions and my initial thoughts were very much that I was looking for water smoothing, that really does not need much, but from yesterdays play I can see the potential for far longer times for the clouds.

But back to the chart, whilst shooting yesterday and determining exposure before pressing the shutter along comes the selfie pair who spend ages by my subject snapping various silly poses and by the time they move on light has changed. The ability to be able to very quickly reset things confidently was a bonus.