Neutral Density Filters HD100

[David Scattergood]

Hi,
Mentioned this in my previous thread but thought it best to create another one as slightly off that topic (overexposed/blueness thread).

I need to pick up a ND filter asap. Money contraints at this time leave me with no other option than picking up the screw in types.
I believe (and I best double check here) that the size is 82mm for the stock 16mm HD100 lens (fujinon).
I'm going for the 0.6 only at this stage (I will more than likely end up with Mattebox and 4x4's...eventually, thought they're quite pricey).
Really struggling to get hold of one at the moment - the usual video company stockists have none in. I've just phoned the head office of Formatt and they too are out. They advised me that one can be cut for early next week...however...couple of questions:

1: I'm told that I really need a HD ND filter which are more suited to HD camera's - first I've heard...would you get 4x4 HD glass for example? Stumped me a little so I witheld the original ND filter (the HD ones will take longer to source).

2: (more uk related) Are there any other good manufacturers of screw in type filters? One company (photography) is selling Hoya I believe. Another (Kenro) is selling Marumi but these are half the price of the Formatt which rings a couple of bells.

3: Would adding an external ND filter affect the on board ND's thereby cancelling out their effects - I read this on these boards but related to a different camera (Canon I believe).

Apologies for the anxious nature of this post but I have stuff to shoot by the end of mid week next and after understanding the workflow of eliminating my previous 'errors' it's frustrating not to put them into practice.

Many thanks.
Dave.

[David Knaggs]

Originally Posted by David Scattergood

Hi,
Mentioned this in my previous thread but thought it best to create another one as slightly off that topic (overexposed/blueness thread).

I need to pick up a ND filter asap. Money contraints at this time leave me with no other option than picking up the screw in types. I believe (and I best double check here) that the size is 82mm for the stock 16mm HD100 lens (fujinon).

Hi David.

I am going to pass on some advice here. Purely because it is "real-world" experience and in no way should you consider this "expert advice". Tim and the others will provide plenty of that!

If your budget is limited and you want one circular screw-in filter, you should get a polarizer - to be specific, a Formatt 82 mm polarizer (this polarizer has a double-ring to allow for independent rotation) - and I'll tell you why.

The previous summer we shot a feature with the GY-HD101E, with a lot of exterior shots in the harsh, glaring Aussie sun. Budget was so tight (ah, the joys of Indie filmmaking!) that we could only afford one ND filter. My cinematographer advised me to get a polarizer. Remember that Tim D. said in the other thread that "Polarizers can cut your exposure as much as 2 1/2 stops and the effect is controllable." So it has the benefit of being a kind of "pseudo" ND filter (2 1/2 stops of exposure) plus, as Tim also pointed out, "The versatility of a polarizer for controlling reflections in glass/water as well as the "blueness" of the sky means I never leave home without it."

So you are on a win-win situation with a polarizer given the fact you can only afford one filter.

And remember that Tim also said, "I should have also mentioned that I'm trying to sway people from purchasing "screw on" type filters that you typically see on SLR cameras, unless it has a "double-ring" that allows for independent rotation."

Well, this Formatt polarizer has a double-ring and so you can control it without having to spring extra dough for a matte box at this point.

And we got excellent results with our footage that summer using the Formatt (they're an English company from Middlesex too).

So it's purely practical experience talking.

[Bill Ravens]

ND filters are merely optical glass flats with coatings or additives that reduce the optical transmission by a known amount. I fail to believe there is such a thing as ND filters specifically for HD. (love these acronyms) The only rationale that could possibly be applied is that the glass flats are really not truly flat, non-flatness would have to be an error that is in angstroms, thereby adding distortions that DV wouldn't see but HD would, with its higher resolution. Moreover, the thought that ANY ND filter would cancel out another is pure BS. Once light is attentuated, how can a simple glass flat add it back in? Where do these people come up with these things?

[David Scattergood]

David: That might be a good idea David and I understand where you're coming from. If they are available then that's a bonus also (I spoke with the company this morning though I think they're based in Wales).
It's fairly urgent whilst on a budget (does/did anyone find they were accepting jobs knowing that they could buy kit from the job they were about to do...and considering the 30 days pay rule, it left you in the red for a while :( )

Brian - I'm just a beginner when it comes to advice like that, which is why I thought it best to run it by you folks first! I thought it a little strange (specific glass for HD camera's...perhaps noticeable through real high end kit, but I suppose that's debatable?
As for the cancelling out effect...not sure where they were coming from there, but again without the ammunition of knowledge it's hard for me to say why. Cheers.

[David Scattergood]

The company I buy some of my gear from has one of these polariser's in stock which means I'll get it pretty quickly. Like you said David, this is perhaps not the purest way of obtaining what I require but it's probably my best option, certainly given the fact that it's available (and can be with me tomorrow rather than late next week for the ND filter...when the footage has to be in).
Well done for pulling that information out of Tim's thread also....you're like Detective Columbo!

[Gary Morris McBeath]

Using a polarizer as an adjustable ND is a great idea, and I've had to do it a few times. However, I've yet to find one that doesn't change the color balance, which will require some color correction in post on the scenes where you used it; many ND's also change the color a bit, some are better than others.

I use the internal ND's, combined with shutter speed where possible (scenes without much movement) to achieve exposure; only when that doesn't work do I go to my screw-on ND or the Polarizer. The internal ND's are as close to color neutral as I believe is possible.

FYI, my screw-on is a Tiffen, and my pol is a B+W. Excellent qual (flat glass!), but both change the color balance.

Keep the shiny side up (your car that is).

Gary

[David Scattergood]

I was utilising both ND filters the other day (and pushing the iris far enough), but altering the shutter speed wouldn't have worked - fair bit of 'construction action' going on for that, a bit "saving Private Ryan's JCB"!

David - did you require any colour correction with the Formatt Pol?

Um, thanks for the car tip too Gary!

[David Knaggs]

Originally Posted by David Scattergood

David - did you require any colour correction with the Formatt Pol?

I always white balance as part of my set-up procedure. If I were to be doing outdoor shooting with a polarizer, I'd put the polarizer on BEFORE I did my white balance. (Or if I had to put on a polarizer half-way through, then I'd do a new white balance. I always keep some white copy paper in my camera case for white balancing.) This should help obviate the necessity to fix these things in post. But I always use my MacBeth Color Checker chart (record at least 10-15 seconds of it) with every lighting set-up or location. This is an invaluable reference point for color correction in post. Even if you don't anticipate any need for later color correction, it's always good insurance to have that footage there.

And remember that you may need to change your white balance every 30 seconds when outdoor shooting, depending on the conditions. It happened to me 2 weeks ago on a corporate shoot. I was taking footage of two "actors" in a swimming pool and the sun would disappear behind the clouds then come out again at intervals of 30-180 seconds. So, eventually I set a white balance (using my white copy paper) for when the sun disappeared behind the clouds (and it was 8000K - exactly as Tim said in the other thread) and another one for when the sun came out again (which was 6500K - exactly as Jiri said in that thread). Then I simply toggled the switch back and forth between the two settings as the sun went in and out (plus change the exposure each time, of course).

That's why I love all of the pro features of this camera. It gives you a lot of control over the varying conditions!

[Stephen L. Noe]

You'll need a circular polarizer as mentioned and a ND 0.6 (at least). The onboard ND is not strong enough even at very high shutter speed in bright sunlight for you to keep the aperature where you'll likely want it (F2.8-F5.6). The polarizer will cut the glare only.

good luck..

BTW: I like Tiffen.

[David Scattergood]

Well, the Formatt circular polariser turned up this morning (real quick turnaround). As I have to film this weekend and couldn't get hold of a ND filter for this weekend (anywhere!!) this was my only option.
Double glass with a noticeable tint to it, it feels quality at least.

Bit confused now that Stephen has mentioned it won't really eliminate any of the brightness, but glare only...is that general circular polarisers or inclusive of the Formatt also? I read the in the absence of polarised light then this is little more than a 1-2 stop ND filter, so I presume I can use this under bright but overcast skies.

Found an interesting site here, though it's a bit of a walk through:

http://dpfwiw.com/polarizer.htm#circular

However, shooting construction in bright skys you do get an awful amount of glare - bit of rain on white concrete under such skies shows an immense bright glare, so if it does it's part in this then at least one rasher of bacon has been saved!
Cheers.

[David Scattergood]

Forgot to ask (I haven't as yet set it up) - is the rotation of this fliter noticeable to the untrained eye? Aside from knocking out the glare (and hopefully brightness) I'd like to think with the right sky (one should come along soon) I could achieve a nicer image using this effect.
[EDIT]
Skip that...it's highly visible - just rotating it (without being attached to camera) and looking outside you can see the split very clearly (though subtle).

[Phil Balsdon]

A word of caution about using polarizers as ND filters. They are designed to cut reflections from water, glass etc. When you rotate them you will see the effect changing, this can also appear as an apparent change in colour balance, this is why they are in a rotating ring. They also need to be set to function at the angle the camera is pointing from and panning the camera 90° can change the job the polarizer is doing and this change can effect the colour of things, especially a bright blue sky.
By all means use them as an ND sustitute but be sure to check carefully the effect they have, using a colour monitor, when panning the camera.

[David Scattergood]

Thanks Phil.
I'll eventually end up with a mattebox (probably chrosziel). Noticed the slight colour change already and it's difficult to notice the effect unless facing a blue sky (which is clearly what they are designed for, alongside the reflections you mentioned). They will get me out of a few scrapes (the overblown sky etc) and should land me a few decent true sky shots but eventually I'd like to have dedicated equipment (additional ND filters) rather than relying on these to bail me out.
Is there a certain time of day/light when these should be taken out of the mix? Managed to get a decent day of light last week (it's been atrocious weather wise) and towards the sunset I was still using this polariser (pointing the camera towards the rich blue sky). However, facing a different direction (and not really using much of the sky - shots of a city for example) the colours were a little muted to be honest. Pain in the neck to keep on unsrewing/screwing the polariser depending on where I'm shooting the camera - hence an eventual foray into the mattebox and 4x4's....meanwhile I'm trying to make do with what I have at hand.

[Bill Ravens]

David...

One thing to remember about polarizers...
Yes, the change in filter effect is noticeable to the untrained eye when you rotate the filter. And you can see the effect in the viewfinder. The effect is quite noticeable in the sky(deepening the blues) when facing orthogonally (90 deg) to the sun's path across the sky. If you try to see the effect when parallel to the sun's path, you'll not see much, if any effect.

[Adam Letch]

for Tiffen filters, you'll see first hand how the filters look when applied to the JVC's. It's great, and Jonathon produced the 2nd Unit TV series just for these sort of questions that indies have.

http://www.2nd-unit.tv/

Enjoy

Adam