The upper portion of Vermillion Falls in Hastings, Minnesota.
Taking long exposure photographs with a very dark Neutral Density filter (6 or 10 stop) can create some issues because it messes with the exposure metering system in your camera. It becomes easier for light to enter the camera through the viewfinder than through the lens. Sometimes I use an exposure calculator app on my phone where I can tell it an exposure setting without an ND filter and then calculate the proper exposure settings to account for the 6 or 10 stop ND filter. I have found that unless the viewfinder is completely covered it will dramatically impact the result of the image. I have been using a piece of black electrical tape which I place over the viewfinder after I have composed and focused. I take a test shot with no ND filter on and then use that for the baseline in my exposure calculator. I prefer to shoot with my camera in Aperture Priority mode and most of the time I can get it to work correctly with these ND filters, but only if the viewfinder is completely covered.
The effect of the ND filters on the exposure calculation can actually be observed by noting the exposure reading once, while looking through the viewfinder, second by moving away from the camera leaving the view finder uncovered and third with a cover completely blocking the viewfinder. Most of the time (during daylight) you would see three different exposure readings. Only by putting a cover on the viewfinder can the proper exposure be calculated (as close as possible by the camera).
ISO 50 – f/11.0 – 2.0s – 23mm – Tripod – Single Exposure
Canon EOS 5D MkII Body and Canon EF 17-40mm f/4L Lens with Cricular Polarizer and 6 Stop ND filter.
Photographed in St. Paul, Minnesota on 7-28-2014 at 5:30 PM