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Get Native With Your ISO’s Using The LCW Fader ND Filter

by Jared Abrams on October 1, 2010 · 28 comments

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.

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{ 10 comments… read them below or add one }

Christopher Marino October 1, 2010 at 5:33 pm

Great review on the ISOs. Seems to be a lot of confusion out there on this topic.

GPSchnyder October 1, 2010 at 5:43 pm

Would Like to know what the native ISOs are on the T2i as they are just 100, 200, … not the fancy ones up there…

Jared Abrams October 1, 2010 at 6:13 pm

I tested the Rebel T2i and they are all “Native” up to 800 ISO when is breaks up to oblivion.
Thanks for the comment,
Jared

Bennett V Campbell October 1, 2010 at 7:06 pm

I'm confused. You say that native iso on Canons is based on ISO 160. The quote seems to suggest that it's based on ISO 100, which this data seems to also bear out:

http://www.pages.drexel.edu/~par24/rawhistogram/5DTest/5DTest.html

Though I have my doubts about that as I understand ISO 50 is also non-native.

Clarification?

Paul October 2, 2010 at 2:35 pm

This is a great post about an essential part of kit for shooting video, keeping that shutter speed fixed low with a wide aperture. The ISO discussion is good as well and a great reference. I never thought of combining the two into one article. Good job.

Jared Abrams October 2, 2010 at 4:36 pm

100 ISO is a “pull” down on the Canon HDSLR's 1D, 5D, 7D ETC. 160 ISO has less noise than 160 ISO as a result. I suspect that the graph in the link refers to Stills and not Video. I hope this helps.
Thanks,
Jared

Brad October 4, 2010 at 1:43 pm

This is really sweet. I want one. Great coverage Jared, as always.

David Mosquera October 4, 2010 at 1:50 pm

Great stuff man! keep them coming!

Dave,

Todd Harter October 4, 2010 at 1:52 pm

Great Jared! I am familiar with using a variable ND filter to account for shutter speed/aperture, but never knew about the native ISO issue. Numbers are on a sticky note on the top of my camera bag now. Thanks!

Anderw Harbert October 4, 2010 at 1:54 pm

Hello,

Stupid question of the day. Can you explain in a bit more idiot terms exactly what exactly is “Native ISO” and why I should be concerned with it.

I think, from what I read above, that what comes out of the camera, Canon 7D in my case, in H.264 and then converted for editing, the video if it is not shot in a “Native ISO” will not look as good? Have more moire and or noise in the final video?

Cheers

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