Still learning my “new” Bronica medium format camera.  After some work on my 75mm lens (nothing worse than a stuck aperture) I headed out around the Fox Valley to find some moving water to photograph. 

All of these photos were taken using a 10 stop ND filter by Gobe.  The ND filter allows you to take long exposure pictures in the day time and created beautiful effects with water or other moving objects.

The procedure for a 10 stop filter is you compose and focus the picture with your camera on a tripod.  Meter the picture to get the unfiltered exposure time.  You then screw the filter on the lens being careful not to move anything – the view will be too dark to adjust once the filter is on the lens.  You then calculate the exposure time using the formula   exposure time = metered time x 1024. 

Actually I calculated backward. My Bronica has a 4 and 8 second setting for exposure so I calculated the exposure time to get to 4 seconds with the ND (4sec / 1024 = 1/250 second) and then set the aperture to get 1/250 seconds exposure.  I also shot some of the frames with 8 seconds of exposure i.e. double to see the difference – film has a property called reciprocity which means for long exposures film gets less sensitive so you have to add time to get a proper exposure.

Here are some of the pictures – what to you think?