It just keeps getting better….
Normally you do not see much in the way of Long Exposure photography in the Infrared world. The reason is that it is necessary to use Neutral Density filters (ND) to cut down the amount of light reaching the sensor to enable very long shutter speeds. The infrared spectrum will reduce the the effective value of any ND filter that you attach to your lens from between 20% to 30%. Have you ever taken a photograph of a person wearing a pair of sunglasses in infrared and noticed that they are totally clear? This is the effect that I am talking about. The general rule is that the cheaper filters suffer much greater loss in infrared and the variable ND filters do not work well at all (yes, even the expensive Singh Ray).
Should you desire to pursue this style of photography I strongly suggest that you purchase and use B+W ND filters which loose around 20%. I am also told that Lee filters do not loose too much effect as well but I have not yet tested them even though I own them all.
The B+W ND filters display the ND values on the side of the ring, but the easiest way to understand them is to simply look at the 3 digit number.
- 110 equals 10 stops
- 106 equals 6 stops
- 103 equals 3 stops
- 102 equals 2 stops
- 101 equals 1 stop
I am using the Fuji X100s for the images in this post. It is a 16 mpix camera that is a rangefinder styled system. I includes an internal, drop down 3 stop nd filter that actually gives about 2 stops of reduction when used in the infrared spectrum. I had the camera recently converted via Kolari Vision, http://www.kolarivision.com to what they call the Dual Spectrum conversion. This is where the internal UV/IR blocking filter is removed and a strong UV filter is put in its place. This gives you the same capabilities as any Full Spectrum conversion except that it will not work with any IR or UV filter that combines multiple spectrums that include UV. This means that the 047b in camera Faux Color or Super Blue filter and the UG1 UV/IR dual band filter will Not work. All of the others work fine from 590nm up!
Plus you can convert the camera back to normal visible color with the addition of a filter on the lens to block UV and IR. With the Full Spectrum filter you need to stack the B+W 486 reflective UV/IR blocking filter with the LDP http://maxmax.com CC1 absorption filter. With the Dual Spectrum conversion you need only add the B+W 486!
So, I have ALL of the normal IR filters sized for 49mm which is what the X100s uses including the B+W 486. I am using the B+W 093 820nm IR filter for this camera almost 100% of the time though.
Another nice thing about the X100s is the fact that it has aperture priority mode with a shutter speed up to 30 seconds and a BULB MODE that goes up to 60 minutes! Where the X100 really excels is the fact that is gives a count up timer in the viewfinder or on the back LCD panel for timing your bulb exposure!
The camera is so small and easy to handle that it is a pleasure to work with and as you can see, the images are stunningly sharp!
I will be posting more long exposure images here in the future and discussing the various post processing recipes with you. Now, one last image. Here is the same shot with only the 3 stop internal filter engaged in the X100s. The shutter speed at ISO 200 and f/16 was 1/6 second. Not nearly long enough to slow the water down or blur the cloud movement but it would likely work for slowing down the moving water in waterfalls!
If any of you all out there shooting in Infrared work in long exposures please drop me a line or comment and we can share data about the various ND failures and successes!