The Light Craft Workshop Fader ND Ultra MK II filter is one of the most cost effective tools available for HDSLR work. When shooting video with a Canon HDSLR, we use what are called “Native ISO’s”. Through extensive testing by many reliable sources out there, myself included, we have found that popular Canon HDSLR cameras like the Canon 5D Mark II, the Canon 7D and Canon 1D Mark IV use a type of gain feature when moving up the ISO scale. This means that ISO 250 will have a greater signal to noise ratio than the native 160 ISO. This is barley noticeable when you are shooting with a 21MP camera, however when the image is downsized to a mere 2K for video, the noise is prevalent.
Shane Hurlbut, ASC has also done major testing on this and it is a fairly simple scale. The Native ISO scale is based on a multiple of 160 ISO. This is the important part.
The Native ISO’s on Canon HDSLR’s are as follows.
160 ISO, 320 ISO, 640 ISO, and 1250 ISO.
I do not recommend shooting any higher than 1250 ISO for video on any canon HDSLR. We have found that anything in between these ISO’s is simply a gain up or a pull down and the S/N ration is unacceptable. The noise at 100 ISO versus 160 ISO is dramatic. Here is a Quote From Shane Hurlbut, ASC.
“We found that when you go down from the native ISO of 200 ISO, it is like pulling the negative. Then, when you go to 250 ISO it is like you are pushing the negative and it adds video noise. 400 ISO is another native ISO and with it you will get more detail in the highlights, but if you want a cleaner image you would go to 320 ISO, again like pulling the film. 800 ISO would be the next Native ISO, giving you more detail in the highlights, but if you want less noise then I would recommend 640 ISO. This goes all the way up to 1600 ISO and after that the image completely falls apart.
Shane Hurlbut, ASC. Hurlbut Visuals”
When your lowest ISO is 160 you have to have some way to stop down. Shutter is not really an option in video as we tend to merely double the frame rate. Twenty- four frames per second keeps us around a 1/50-degree shutter. The MAX shutter with most HDSLR cameras will be double 60fps at a 1/125th shutter. This is too slow for any decent light prevention. The LCW ND Fader does a great job with eight stops of ND from one simple filter.
The variable ND has been around for some time. It is based on a double polarization system that lets you dial in the darkness. In video we try to shoot as close to wide open as possible. On a bright Sunny Day trying to get to an f2.8 means stacking a ton of filters. The LCW filter is a great solution at around $150 for the 77mm LCW ND Ultra MK II filter, it is a real bargain. Check it out here.