ND filtering advise needed...

[Piotr Wozniacki]

In preparation for my (hopefully soon) FS100 purchase, I'd like to ask the fellow users for advise on ND filtering.... Here are my main concerns:

1. Screw-on variable ND filter: which one offers the best price/performance ratio (Heliopan, Tiffen)? Also, the largest filter diameter lens I currently have is 72mm (see below) - should I go with a 72mm ND variable filter, or pick the 77mm one?

2. Reduction rings: using my rig without a matte box, I'll be using the following filter sizes (including the kit 18200 and several Canon still lenses I have): 72, 67, 55, 52mm. Any good source for reduction rings? Any considerations re unwanted side effects of using them (vignetting)?

3. 4x5.65" ND filters: using my RR mattebox (mainly with the tripod rig), I'd like to be able to get as wide ND range as possible without ill effects of stacking 2 filters. I already have an ND0.6 4x5.65" filter; which densities should I be getting to achieve 8-10 f-Stop Reduction (needed for fully opening my F1.4 lens in bright sunshine), and anything between 2 stops (that I have now) and the 8-10 maximum?

Please bear in mind I have no particular experience in this aspect of videography, so I'd appreciate exhaustive answers a lot :) Also of some importance is suggesting a single on-line source for getting all this stuff (shipment charges, and import hassle). TIA

Piotr

[Serena Steuart]

ND 3.0 will give 10 stops cut, if you want to go that far. Would you want to use your prime lens at f/1.4? I presume you are thinking of shallow DoF, but have you checked what that will be? If assume a 50mm lens shooting a CU (dist 1.6M) the DoF will be approximately 63mm at f/1.4 . In terms of diffraction limiting, this won't become an issue wider than about f/8 (DoF about 380mm). These are 35mm film figures (similar sensor size), and using same CoC for that format.

[Charles Papert]

Do understand that in all of the years of 35mm filmmaking that preceded the advent of affordable large-sensor digital cameras, it was a rare and exceptional case when one was to shoot day exteriors at f1.4 or anywhere near it. This fascination with super-shallow depth of field is, at a certain point, baffling. You can't hold focus on a moving subject that way. It can be a distracting look for the viewer. Plain and simple--it's a special effect. It's turning into what zoom lenses were in the 70's: a gimmick. Can we please start to move on?!

[Piotr Wozniacki]

Originally Posted by Charles Papert

Plain and simple--it's a special effect. It's turning into what zoom lenses were in the 70's: a gimmick. Can we please start to move on?!

Dear Serena and Charles,

Thanks for your answers; of course I understand shooting at F1.4 with a prime lens in bright sunshine is only for that "special effect" of a super-shallow DOF. Nevertheless, I'm trying to get prepared for a situation when such a special effect is needed.... What's wrong with it? And why get so impatient, Charles?

Funny how many more constructive answers where given to the very same inquiry of mine on the "other forum"...

Piotr

[Les Wilson]

Coming from built-in ND filters, screw on ND filters are a pain. Getting the threads lined up is a pain and in a hurry, even moreso.

I found they were needed on the 5DM2 just to get to 5.6. Look into the vari-ND filter... I found some reported the image going soft at certain focal lengths....you get what you pay for.

[Charles Papert]

Piotr: I'm sorry if I sounded grouchy. It has been a trying few years watching so many people become convinced that the only way to shoot large sensor work is wide-open, because they are all copying one another rather than studying the vast history of work that has been shot in similar formats over the past 100 years. To me it represents something of a "shortcut" to beautiful imagery--it's certainly easier to open an aperture to blow out a background than it is to learn how to light that background. Selecting the degree of depth of field is an artistic choice that is one aspect of fine cinematography, along with choosing the optimal focal length, framing, movement, and dynamic of a given shot. The way I was trained and now work from instinct is to mentally select a particular degree of depth of field and place the aperture accordingly. For bright exteriors, I will generally opt for a mid-range aperture of f5.6 and the occasional minimum aperture of f2.8 to 4 as that "reads" more realistically to me than a super-shallow look, unless there is some reason to create that effect that is suggested by the emotion and content that one is shooting. However that is all mitigated by the focal length and the action within the shot and the reality of pulling focus against those factors (even if it is pretty, I don't want to force my focus pullers to battle with a subject moving into a closeup on 100mm at f2.8 as it may require too many takes to get it tack-sharp). So yes, I do find it frustrating that so many who are new to the visual option of depth of field control see it as an "all or nothing" situation.

Whether this is a constructive answer or not is a matter of interpretation. I'd like to think that it is far more valuable information than a simple "here's a link to what you are looking for". You indicated that this is a new area for you, and I am imparting what my experience tells me is the most relevant answer; that shooting bright day exteriors at f1.4 should be an exotic concept and thus not a major concern.

Probably the most concrete answer I can give you is that if you use quality ND's, stacking two of them shouldn't be an issue optically; I've done it for years (more often a polarizer and ND). Now that the "legitimate" filter manufacturers (Tiffen, Schneider, Heliopan) have gotten into the game of variable ND's, I would consider one of those for convenience, although that does force you into a polarized situation which may not be desirable for all circumstances--setting exposure and opting for polarization are two different choices.

[Piotr Wozniacki]

Dear Charles,

Oh yes - this one is a very constructive answer, showing it comes from a true and experienced professional; thank you very much!

You have touched a great lot of issues involved in the matter, so let me just answer that I'm not at all a blind follower of the recent "shallow DOF is a panacea for film look" hype. I'm using it occasionally, and only for well thought-out, artistic purposes.

Oh, and on a more technical note: my "8-10 max F-stop reduction" requirement has probably been too much; if my ND solution allows anything in the 2- 8 range without introducing unwelcome side effects, I'll be more than happy :)

Thanks again,

Piotr

[Serena Steuart]

Sorry if you thought my answer other than constructive -- must be a language problem. On the matter of variable NDs, I'm wary of using polarising filters other than for specific purposes. Don't like the gradients they induce in the sky, but your experience is probably different.

[Piotr Wozniacki]

Dear Serena,

Frankly, my "constructive or not" comment applied to Charles' answers (which we have just sorted out), not yours :)

As to the cross-polarizer filters: I have no experience with them whatsoever, but from what people are saying the high-end ones (like the Heliopan) are OK optically. Which variable ND filter have you used?

Best,

Piotr

[Brian Bang Jensen]

I use a Heliopan vari ND.
It gives up to 6.6 stops = ND2.0. You are not going to need any more!!!
It gives me a max aperture in daylight between f1.4 and f2.8 depending on the sun.
For normal shooting with my 35mm Zeiss prime I like to stay between f2.8 and f5.6. Even at f4 it gives a nice DOF.
For more arthritic shooting I will use my 85mm and still use the same f stop.
I am only using wide open when forced to because of lack of light.
The hype of shallow DOF is not going to work all the way trough a production. It´s like using ultra closeup all the time. It seems to loose it´s effect and meaning.

If you are on a budget go for a high quality vari ND.
If money and complexity does not matter buy a stack of high grade 4x4 ND´s. Do not buy the cheaper 4x4´s I have tried them, they sucks and ruin the picture!

[Pedro I. Vazquez]

I just got the Heliopan from there website which are back in stock just in case any one needs one

[Serena Steuart]

[QUOTE=Piotr Wozniacki;1664227] Which variable ND filter have you used?
/QUOTE]

None, I'm afraid; should have been clear on that. My observation was about polarisers in general. If you opted for a lens-mounted screwed filter (say a 2.0) will the inconvenience of changing filters actually be a problem? That is, would you need to change filters in a particular situation? When shooting in controlled situations you will be using a matte-box, and in uncontrolled you have at least 3 or 4 stops on the lens (without diffraction softening).
However these are merely points for consideration, against which I note generally satisfactory reports of variable NDs.

[Gabe Strong]

Serena,

Well, if shooting in uncontrolled situations with the FS 100, depending
on what you want to do, the Heliopan can be a BIG help. It can literally
mean the difference between shooting at F3.5, or F18. Unless, you want
to up the shutter speed, which people may not want to do. I just shot
outside, and without the filter I was at around F20 for correct exposure,
with the Heliopan I was at about F4. I will be doing more tests tomorrow
with specific numbers and pictures on this. Also, I have no idea HOW
they make this Heliopan filter, polarizer or what. But, I can't see
anything bad introduced into the image, but I've only had it for a day
or so, so I don't know for sure. I CAN say, that I understand why
Philip Bloom called it the best variable ND he had ever used.
I think it is an almost 'must have' for anyone that wants to shoot
and 'less controlled' stuff with the FS-100.

[Serena Steuart]

>>>>. It can literally mean the difference between shooting at F3.5, or F18. <<<<

Of course. My point wasn't that no ND is needed, it was that a fixed ND may be quite sufficient. Unless you wish to work at a pre-determined nominal aperture. With small sensors we have been used to working at near maximum aperture to avoid diffraction softening of the image, but with a Super35 sized sensor diffraction shouldn't be a problem for apertures f/11 and wider. So a variable ND isn't necessary for setting aperture (but you DO need an ND in daylight to put you into the right ball-park). Think of it in terms of film: we chose a film stock suitable for the conditions. Here we can choose the ND to tailor the camera's sensitivity to conditions. But if, for artistic reasons, you want to keep apertures, say, to f/4, then you have to change NDs (or use a variable ND). There is no blanket reason that you must use a variable ND.

[Gabe Strong]

Serena,

Yup, you are right. The video still looks nice and sharp, even at higher
F stops. My reasons for wanting a variable ND were 2 fold.

#1. Convenience. I do enough 'run and gun' stuff, it is easier
for me to use a variable ND then to mess around with a mattebox.
But that won't be the case for many people, especially people doing
more controlled work. Plus, with some bigger lenses, you will
need rail support anyways, so you might as well have a mattebox.

#2. Choice. As you say, you can get in the ball park with a
mattebox and slide in ND. I like to be able to really dial
in EXACTLY what I want as far as my F stop. I'm kind of a
crazy control freak this way. Probably way more than I need
to be.

So, I spent the money buying the absolute best variable ND that I
could find. That being said.....I will probably be buying a mattebox
with a couple slide in filters as well......I will need rails for one lens
I am planning to purchase, so with that lens, I will probably go
'cinematic' instead of run and gun. If you DO choose to go with a
variable ND, I would suggest not skimping on the money, and buying
something really good. There are a lot of the variable ND's out
there, and many of them do introduce things that may be objectionable.
I myself figure a few hundred dollars as cheap compared to what
I am spending on the rest of the camera package.