OK so the concept of long exposures is not new, but with a selection of 10 stop filters now available on the market, it can be a daunting prospect of which one to choose and when you get one how to get results every time.

Not sure what a 10 stop filter does here are some examples

First picture is without a filter shot at F11 100 ISO 1/160th sec

Second picture is with a Big Stopper at F11 100 ISO 15 seconds notice the blue hue

First up the B+W 77mm 10 stop, price of these things does seem a bit steep but they are all fairly close price wise.

Pro’s: fits on any 77mm screw thread lens with no adapter, cheaper than the LEE Filters Big stopper.
Cons: has to be screwed on to front of lens, creating movement (**discussed later), very difficult to use with any other filters like grads.

Next the LEE FILTERS BIG STOPPER (10 stops) seemingly the most expensive of all and always out of stock, you either pay way over the odds on ebay for short delivery time or wait up to 10 weeks for delivery from manufacturer, that said there are some major benefits to be had from the lee filters version.
Pro’s: Can be quickly attached and detached for light metering, able to use other filters with it (polarisers and grads), fits any lens size.
Cons: more expensive, delivery times.

Most filters will give you some kind of colour cast one way or another and while the LEE BIG STOPPER is a ND (neutral density) 10 stop filter it does give a slight blue hue, however this is easily combated with a warm up filter or colour balancing in Photoshop (even easier if shooting in RAW format) .
The B+W 10 stop filter comes well packaged and make no mention of any variation on the stop adjustment so appears to be a true 10 stop filter, However the LEE FILTER BIG STOPPER comes with a label in the packaging that says that due to manufacturing process’ ‘your filter may vary and will have a density of somewhere between 9 1/3 and 10 2/3 stops’ and suggests that before first use that you test your filters strength to determine its actual strength. (after testing mine is closer to 11 stops) (SEE END OF POST TO DETERMINE YOUR FILTER STOP) this is very important when setting up a shot as 1/2 a stop can have a massive time difference on exposure times.

The LEE FILTERS BIG STOPPER comes with a credit card style laminated card that is meant as a quick guide for exposure times and while accurate its not totally comprehensive.
Below is a home made chart that i have created for 10 stop filters exposure compensation time, to use it, simply put your camera on AV(aperture priority mode)( choosing the aperture you require), focus the camera and then put into manual focus mode ( if using auto)** this is where the issue lies with the B+W filter as screwing it on could un focus the camera. Now take a E-TTL time reading EG: 1/15th of a second, then attach the filter. Now switch the camera to manual mode making sure that you are on the same ISO and aperture setting as in AV mode now adjust the time according to the chart for 10 stops exposure (1 minute for 1/15th sec) and then expose.
Sounds simple but most cameras will only go up to 30 seconds exposure in camera so you will need either a timer remote or shutter release cable, either timing the exposure manually or setting the timer.
As you can see from the chart below a 2 second exposure becomes a 32 minute exposure now if your shooting a seascape for eg at sunset the light will be decreasing all the time and while the sun maybe on the horizon on shutter open it could be way below the horizon by the time the exposure has finished, so bear in mind the exposure times are for a constant light source or you may well end up under exposed.(reverse this if you are shooting sunrise)
it can be highly guess work to begin with but with some patience you can get some very rewarding photos.
it took me some time to get it right and if you want to redistribute it please do so but link to this page.

NEW CHARTS NOW AVAILABLE FOR DOWNLOADING

If you would like a copy sent to you, make a paypal payment to wayne@waynesphotos.co.uk and include your address in the notes.

To determine how many stops your filter is you will need a tripod or something to keep your camera very still and a well-lit subject preferably non moving, also away from a window unless its very cloudy or no clouds as sun variation (sun going behind cloud during exposure) will cause false readings and exposures.
Start by setting your camera in av mode and taking a picture at your lowest aperture f/4 eg. note the time value.
Now set the camera into manual mode and set aperture to same as before now insert your filter and adjust the time value to 10 stops and expose again now compare the 2 images on your pc and see if the 2nd one is darker or brighter than the first, (allowing for the blue hue)
now simply go back to the camera and take a few more samples in 3rd stop increments either shorter or longer depending or darker or lighter and compare these images to the original until you get a match. Any questions E-Mail me wayne@waynesphotos.co.uk

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