ND filtration for the Pocket

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Sean van Berlo

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ND filtration for the Pocket

PostSun Aug 19, 2018 6:15 am

Hey folks, this might be a very basic question, but here goes nonetheless. I am looking to switch from variable ND's to glass filters for when I buy the new Pocket. Currently I am doubting between the Nisi IRND's and the Lee IRND's.

My questions would be:

Do any of you have any experience with these filters on Blackmagic camera's? Do they work as advertised? The Lee's are a bit more expensive, is that worth it to you guys? Furthermore, what stops of filtration do you guys most often use? For budgetary reasons I would probably only start with 3 and 6 stops filters before expanding, since I figure that would cover quite a wide range. Does that make sense? Thanks in advance!
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Brad Hurley

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Re: ND filtration for the Pocket

PostSun Aug 19, 2018 11:37 am

One key consideration in switching from variable to fixed ND filters is your lenses. If you have standard DSLR or MFT lenses with fixed aperture stops, you're probably better off with variable ND since you can fine-tune your exposure by turning the ND wheel. If you're using cine lenses with aperture/iris rings then fixed ND is fine. My approach is to keep a fixed ND filter on my lenses (e.g. 3 or 4 stops) at all times and supplement it with a variable ND as needed.

On the original Pocket camera you needed to use ND filters for nearly all outdoor shooting to keep the aperture wider than approx. 5.6; once you stop down further than that the image starts softening due to diffraction. The new Pocket has a bigger sensor (full MFT size), and diffraction shouldn't start to become a risk until you go higher than about f11.

I guess the question of how many stops depends in part on what kind of conditions you envision shooting under and your goals in terms of depth of field -- if you're shooting portraits on bright sunny days at the beach, you may need 6-8 stops or possibly even higher. I was recently shooting at a beach in sun and had to use my variable ND filter on top of my fixed 6-stop filter to hit the lens's sweet spot.

I bet Denny Smith can chime in here with some of his wisdom on this topic.
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Denny Smith

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Re: ND filtration for the Pocket

PostSun Aug 19, 2018 5:13 pm

I have one Lee Pro IR/ND filter I got to test, and a set of three NiSi filters. They both work well, and the amount of IR cut is going to depend on the sensor being used. I tested both on my AF100a, which has about the same size sensor as the new Pocket 4K and used them on my Micro Cinema camera. On the AF100 hard to tell the difference, very slight color shift perhaps. On the BM Sensor. I think the NiSi fi,gets work a little better, with a more natural color (no shift).

That said, it is going to be hard to tell on they are going to perform on the new camera, without to test.
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rick.lang

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Re: ND filtration for the Pocket

PostSun Aug 19, 2018 5:42 pm

Sean, excellent comments from Brad and Denny. I have a complete set of the NiSi Nano 4x5.65” rectangular filters that I use in my Bright Tangerine Misfit Atom matte box. I also have a complete 10 filter set of SLR Magic IRND circular screw-on filters when I want to forego using a matte box.

Both are much more economical than the Lee Filters which are a slightly better filter. But when I say slightly, I mean they perform very well through the range with only one or two strengths that might benefit from some simple and optional compensation in post.

I also use the 4-stop SLR Magic IEND circular screw-on filter which can be combined with the SLR Magic Vari-ND II to provide up to 10 stops total ND.

If you want to shoot light (no rig) and not draw too much attention, the screw-ones make the most sense.

I have posted videos on this forum using these filters on the URSA Mini 4.6K PL camera. I’ll be testing all the possible combinations of these filters on the BMPCC4K as soon as I’m able, hopefully next month.


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Rick Lang
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Sean van Berlo

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Re: ND filtration for the Pocket

PostMon Aug 20, 2018 6:29 pm

Thank you guys so much for the advice, it's really appreciated! Looking forward to your tests, Rick. Brad, I want to move away from vari-ND's because I dislike their color cast and slight reduction in resolution (even in the high-end ones I have). I don't think using still-lenses (which I do when I am not renting) will be a problem, they're adjustable in one-third stops which should be precise enough for virtually any project.
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Mattias Kristiansson

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Re: ND filtration for the Pocket

PostTue Aug 28, 2018 1:47 pm

I use the Formatt Firecrest 4x4 myself. I got the 2 mm version, a lot cheaper than 4 mm and they fit in my matteboxes if I put som rubber trim on one of the edges. Whatever brand you buy, I do recommend a 4x4 filter holder so you can use them without a mattebox if you want to. I have two really nice matte boxes, but most often I just use a cheap plastic filter holder:

https://www.ebay.com/itm/Metal-Adapter- ... 0005.m1851
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Rakesh Malik

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Re: ND filtration for the Pocket

PostTue Aug 28, 2018 3:14 pm

I've been using Formatt Firecrests also, with a WineCountryCamera filter holder. I've been very pleased with them. They're not cheap, but they're great filters.

The small size and high resolution of of the sensor in the Pocket does have the side effect that you'll be magnifying flaws in your filtration and lenses, so don't skimp on the filters. All you'd be doing is shooting your nice new camera in the foot.
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Denny Smith

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Re: ND filtration for the Pocket

PostTue Aug 28, 2018 5:14 pm

We are talking about the new Pocket 4K here, not quite a “small” sensor anymore, it is about the size of Std. 35mm Academy Cine gate size. But, you are correct, you do Not want to skimp on filters or any part of the image chain.
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Denny Smith
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