February 22, 2013

Blackmagic Cinema Camera, RED EPIC, and Arri Alexa RAW Camera Test Part 1: IR Pollution

If you've been using a newer large sensor digital cinema camera, you may have noticed that your image takes on more reddish tones when using increased neutral density filtration. This is related to the way many of these ND filters block visible light, but let in more infrared light which can pollute the image. We've seen a few examples showing what IR pollution can do, and today, we have a video comparing RAW cameras, specifically the Blackmagic Cinema Camera, Arri Alexa, and RED EPIC, and how each of them handles black cloth when using IR cut filters of different strengths along with increased ND filtration.

This is a guest post by Cinematographer Ryan E. Walters.

I recently spent a day testing and comparing the Arri Alexa, Blackmagic Cinema Camera, and the RED EPIC. My goal for these tests was to explore how each of these cameras handles real world shooting environments. It was not to determine winners and losers. If you are of the opinion that there is only one great camera out there, then this series of tests is not for you. If, on the other hand, you are open-minded enough to get past the camera hype, and you want to know how these cameras respond, then I invite you to keep on reading. (I have also made the RAW files available for download).

Part 01 explores how each of the cameras handles IR contamination as ND is increased and how the Schneider IR Tuner Kit works with these cameras. Part 02 examines low light performance in order to evaluate noise levels. And part 03 takes a look at a high dynamic range scene to see how these cameras handle overexposure, skin tones, as well as how diffusion filtration affects the final image. I will be publishing part 02 next week, and part 03 the following week. (It is taking me a considerable amount of time to evaluate these images and publish the results. Believe me, if I could have had it all done this week, I would have ...).

I'd like to thank the following people & companies that made this series of tests possible:

Picture This Productions
(Provided the Blackmagic Cinema Camera)
Shawn Nelson
(Provided his EPIC)
Patrick Eggert
(Provided his Alexa)
Isaac Marchionna
(Assisted for the shoot)
Laurie Slater
(Was our Talent for the day)
180 Films
(Provided the Cooke 20 - 100mm Zoom)
Letus
(Provided the cage for the Blackmagic camera)
Schneider Optics
(Provided the IR Tuner Kit)

Here is the overhead diagram showing how I lit part 01:


And here is a 10 minute video I produced to walk you through the results. A summary and links to the downloadable RAW files are below.

Observations & Recommendations:

  • Use natural fibers in wardrobe and set dressing (like Cotton).
  • Stay away from blends, especially if they have Rayon.

When shooting on the Alexa:

  • For color critical applications, IR filtration is needed at all strengths of ND.
  • For color critical work a different IR filtration system will be needed at 1.2 ND and above.
  • For non-color critical applications, IR protection is needed at 0.9 ND and above.
  • From the Tuner Kit, the 680 works the best.

When shooting on the Blackmagic:

  • Need IR filtration at all strengths of ND.
  • IR pollution becomes very noticeable at 0.6 ND.
  • If IR filtration is used any remaining pollution can be graded out of the image.
  • If IR needs to be completely eliminated in camera, then a different IR filtration system is needed.
  • From the Tuner Kit, the 680 works the best.

When shooting on the EPIC:

  • For color critical applications, IR filtration is needed at all strengths of ND.
  • For non-color critical applications, IR protection is needed at 0.9 ND and above.
  • From the Tuner Kit, the 680 works the best throughout the range, the 750 can be used up until an 0.9 ND.

Downloadable RAW Frames (396MB): SLIR-IRTest.zip

If you want to see additional filtration options and how they mix with other cameras, I recommend checking out Abel Cine's Expo.

What do you think? Do these results surprise you? Have you been using IR filtration on your camera, or is it an issue that doesn't concern you?

This post originally appeared on Ryan’s Blog.


Ryan E. Walters is an award-winning Oregon-based cinematographer. His work has allowed him the opportunity to travel worldwide in the pursuit of telling stories that are visually compelling. His experience includes feature films, documentaries, commercials, and shooting for Comcast, TLC, Oxygen, and the Discovery Channel.

Your Comment

34 Comments

Awesome! Definitely in the market for a hot mirror/IR filters for the Scarlet. Was very curious about which level of IR filtration works best. Thanks!

February 22, 2013

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Anytime- glad to help. :) Definitely check out the Abel Cine video too- they cover a lot of options that are on the market. :)

February 23, 2013

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So...I learned that the Epic has crap color science??? Just kidding. Will definitely be looking at getting the Schneider kit when my BMCC arrives.

February 22, 2013

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LOL! Glad it was helpful info. I know you are just kidding about it being crap. I would call it different. :)

February 23, 2013

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Great info, Ryan. I've been using the Tiffen T1 IR on my EX-1 for a couple of years with great success (I automatically slap it on when I see a tuxedo) - wondering if the Tiffen will work as well on the BMCC.

February 22, 2013

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ronn

Check out eh Abel Cine video- I think they use a T1 in there and form what I remember, it worked decently there. I do know that the T1 works well with the Alexa, and since the BMCC is so close to the Alexa, I would think that it stands a good chance of working well. :)

February 23, 2013

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This was wonderfully informative. Thanks to Ryan. Very curious about the tests to come. I'm noticing more and more how much of a wonderful highlight roll of film really has and still haven't seen it matched in digital. Very curious about how Red Dragon will handle that situation.

February 22, 2013

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Very true. Highlight roll off is hard for digital cameras, but they are getting a lot better. :)

February 23, 2013

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This was fantastic!

February 22, 2013

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Thanks. :)

February 23, 2013

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Why no Canon C500 in this shoot out? I'd love to see how that one handles it. From what we saw on a different test posted earlier, the internal ND filters on the Canon's handle IR pollution quite well.

February 22, 2013

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Simple- I don't have unlimited funds and resources. I would have gladly tested it out, but I didn't have the resources to make it happen. :) If it handles anything like the C300, then I would guess that it would have done the best. Canon does a great job at taking out IR in their cameras. :)

By the way, if anyone wants to hook me up with a C500, and the proper RAW recorders, I'll test it out. :)

February 23, 2013

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Thanks for the great test Ryan! For the BMCC, which filtration option makes the most sense? Using the 680 in front of standard NDs or using dedicated IRNDs like the Tiffen series? (which seem to work well with the BMCC) Thanks!

February 23, 2013

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I have no 4X4 filters yet, so I'm starting from nothing.

February 23, 2013

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From watching the AbelCine video, it looks like the Tiffen IRNDs look better than Schneider on the BMCC. But then the EPIC is opposite! I'm actually pretty amazed at how different IR filters work completely different on different cameras. The C500 looks like a boss when it comes to IR! Here's the link to that vid: http://www.youtube.com/watch?v=_T9u-1Ib6vo

February 23, 2013

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Clayton Arnall

For sure- and that is part of the struggle filter manufactures are having, and why there isn't just one system that works for everything. I wish there was ...

Like you mention, Canon is doing a great job at addressing IR at the camera level. I hope more camera companies follow their lead ...

February 23, 2013

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Personally, I am of the opinion that it is better to get standard ND's and then add in the IR separately. I used to own the Schneider Platinum IR ND's, but they work well on some cameras and not on others. Since I shoot on a wide range of cameras, I would rather have an IR filtration system that is flexible. If I new that I would only be shooting on one camera for the rest of my life, then I would buy ND's that have IR filtration built into them. (I like to use fewer filters in my matte box to help prevent internal reflections, etc.) And by having flexible IR soltuions, it means that my regular ND's will have a longer shelf life, as I will only have to buy or rent one new filter to match the camera system I'm using. I am also hoping that more companies will address IR pollution in their OLPF so that it becomes a moot point. (Just like Canon is doing in their cameras.)

In short, I think separate IR is the better long term investment for my filter purchases. :)

February 23, 2013

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Using two filters stacked like a polarizer and a graduated ND is not un-common. Adding an IR filter makes three glass layers. The extra layer of glass doesn't degrade the image?

February 23, 2013

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Any time you add a piece of glass in front of the lens it degrades the image. More Glass = More Degredation. More Glass = More Potential For Reflections. Which is why I like to use fewer filters infront of the lens. However, we do have one thing working in our favor- shooting at higher resolutions, and shooting with digital cameras. Personally, I like using older lenses on digital cameras (when appropriate) as the degredation they provide makes the image feel more organic to me. Adding glass infront of a modern lens, can ever so slightly degrade the image in a similar way. So for me, it is all a balancing act - getting the look that is needed to support the story, and maintaining the appropriate quality level. Presitine / exact / techinically correct images are not alway "the best" images ...

February 24, 2013

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For the BMCC, would it make sense to leave a 680 filter on the front of a matte box at all times, even when no ND is desired? Does the 680 cut down on any visible light? I thinking it might serve as a type of protection filter.

February 24, 2013

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Personally, I would not leave it in front of the lens unless I was using ND's / polarizers, due to the potential for reflections. You could leave it in there if that suits your style, and you want ultra clean blacks. As you can see in my example in the video the 0.3 ND + the 680 actually cleans up better then the T22 exposure is at it's natural state.

February 24, 2013

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Oh, I forgot to say, that it doesn't cut any perceptible amount of light. Or rather that the amount of light that the tuner kit absorbs, does not effect exposure levels. :)

February 24, 2013

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Hi,
this report only applies to the 'old' Alexa and not the new XT which has behind the lens ND filters. The new NDs are a new technology and supposed to be color neutral. Every Alexa can be upgraded with the new system.

Here is what the website says:

Less weight and easier working with internal NDs
In-camera Filter Module IFM-1
Internal filtration reduces reflections, weight and hassle
New high-tech filters based on white-water optical glass
Neutral color balance at all densities through absorptive IRND coating
Accurate infrared cut off
High image sharpness through precision polishing
High contrast through anti-reflective multi-coating
Available in 8 densities from ND 0.3 to ND 2.4

February 24, 2013

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Michael J

As that announcement came out on the same day that I originally published this on my blog, I did not have access to those cameras, but you are correct. The bigger question, is how quickly will the thousands of Alexas on the market be upgraded accordingly? I know the rental shop here in town is always renting the Alexa out (not so much with the Epic) so I wonder when they will actually have the time to send in their 10+ Alexa's for the upgrade ... Until that happens, this will still apply for the Alexa. :)

February 24, 2013

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how similar is tuner kit to the tiffen hot mirror or differences? (yes i understand there is 3 different ones just wondering how similar they are to possibly one in particular)

Ive read some interesting reduser threads but am still up in the air to which solution is the most effective yet future proof.

my current set up is tiffen HM and tiffen .6 .9 1.2.

February 24, 2013

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Tharp

Hot Mirror and the turner kit are completely different ways of handling IR. The Hot Mirror REFLECTS the light back into the scene, the Tuner Kit ABSORBS the light. If you can handle the light reflections back into the scene, and actors do not get distracted by seeing their reflections in the Hot Mirror, then that can be a very helpful solution.

Unfortunately, at this point I do not think there are any future proof IR solutions on the market. (which is why I made the move away from IR + ND combinations.) Camera manufactures keep changing their sensor technology, what they use in their OLPF's, and how they process the imagery in camera. All of that adds up to a moving target that is to quick to hit, or to guarantee any "future proof-ness". Hopefully, camera manufactures will follow the lead of Canon, and now Arri and address IR at the camera level, making IR filtration a moot point, and we can go back to only using ND's. :)

February 24, 2013

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Thanks for your insightful responses Ryan!

Maybe my last question: Have you tried the Rosco TruColor IR filter on a Blackmagic or Alexa? Between the Scheider True-cut and Tiffen T1, I'm leaning toward the Schneider because the Tiffen appears to over correct leaving a slight green cast and even though both are corretable I'd rather fix a majenta cast than a green one. Plus is there a chance that the T1 is pulling TOO much red out that could affect how much can be brought back in alignment?

The Rosco is the filter I know least about and was tring to find out more about it before I pulled the trigger on the Schneinder.

Thanks again for your great service!!

February 24, 2013

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I haven't tested out the Rosco on the Alexa or the BMCC. I have used it on the Red One with the MX sensor, which is the same sensor on the Epic - and it worked on that camera.

What I like about the Schneider, is that it gives options, where the Tiffen is only one option, but it seems to work well. From the examples online that I've seen of the two, I think that they will both perform well on the BMCC, but I'd have to test it out for myself to know for sure. If you can, I woud suggest renting the T1 from your local rental shop to see which fits best for your use. :)

Green and magenta are on oposite sides of the color wheel, so when you are correcting one, you are adding the oposite color. So the way you choose to correct is all about preference. And if you would rather stay away from added green, then going with the Schneider will be the better choice for you.

February 27, 2013

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I know absolutely nothing about this subject but Wouldn't the blackmagics IR problems actually be a good thing if you were shooting something like this? http://vimeo.com/60233275

February 25, 2013

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Matt

Yep- you are correct. If you want something like that, then in the examples above, there isn't enough IR pollution going on. :) And for IR photography / video, the BMCC is well suited for it, as it doesn't appear to be doing any IR filtering. So it would just be a matter of getting as much ND in front of the lens as possible. A variable ND might be the best way to go for that application ... :)

February 27, 2013

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I belive you would mainly need to use a deep red filter ot IR filter (the kind that lets the IR through, not blocks it like the ones tested above) The image in color will be WAY TOO red looking, but when converted to B+W the deep green tones of leafs and grass will reproduce very light and blue sky becomes very dark.

February 27, 2013

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Thanks Guys. Now all I need is a Camera :)

March 2, 2013

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Matt

Interesting comparison!!!

February 28, 2013

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Nice Information...
Thank You

March 6, 2013

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