Blackmagic Forum

Hi everyone,

I was wondering which Fader ND would be recommended in terms of sharpness and quality for the BMCC considering we're dealing with 2.5k RAW images and not h.264 compressed 1080p content anymore?

-Chris.

Heliopan are widely regarded as the one of the best all round, especially for sharpness - http://www.google.co.uk/search?q=heliopan&ie=utf-8&oe=utf-8

A mild caution: Although "variable ND" filters are convenient, be aware that because they consist of two polarizer filters, polarizing the light reflecting from your subjects is often not a desirable effect.

For example, polarizers have a noticeable effect on how skin looks, and not usually for the better.

True, conventional (non-adjustable, non-polarizer) ND filters don't have these typically adverse effect, especially if they are of good quality (such as Tiffen, etc.)

I totally understand the convenience and speed advantage of shooting with a "variable ND" (especially a good one such as the Heliopan), but regardless of the brand used, they are all polarizers.

Just a heads-up. Cheers.

Peter J. DeCrescenzo wrote:A mild caution: Although "variable ND" filters are convenient, be aware that because they consist of two polarizer filters, polarizing the light reflecting from your subjects is often not a desirable effect.

For example, polarizers have a noticeable effect on how skin looks, and not usually for the better.

True (non-adjustable) ND filters don't have these typically adverse effect, especially if they are of good quality (such as Tiffen, etc.)

I totally understand the convenience and speed advantage of shooting with a "variable ND" (especially a good one such as the Heliopan), but regardless of the brand used, they are all polarizers.

Just a heads-up. Cheers.

Are they ?

I think you might be getting a bit muddled here Pete. A neutral density filter blocks light, it doesn't involve polarizing it, otherwise highlights would become brighter...

There are different polarizers for different things. Light is polarized in different ways and a particular polarizer only deals with certain types of polarized light. In point if fact: i generally prefer a linear polarizer because the way they deal with a certain phase of light makes them efficient in dealing with reflections in windows. Taking two circular polarizers and screwing them together probably won't work as well as a purpose-built vND, and I'm weary of such things anyway since I likke the measurable control of slide in square filters in a mattebox, but, yeah what Pete said was right.

Luke Armstrong wrote:

Peter J. DeCrescenzo wrote:A mild caution: Although "variable ND" filters are convenient, be aware that because they consist of two polarizer filters, polarizing the light reflecting from your subjects is often not a desirable effect.

For example, polarizers have a noticeable effect on how skin looks, and not usually for the better.

True (non-adjustable) ND filters don't have these typically adverse effect, especially if they are of good quality (such as Tiffen, etc.)

I totally understand the convenience and speed advantage of shooting with a "variable ND" (especially a good one such as the Heliopan), but regardless of the brand used, they are all polarizers.

Just a heads-up. Cheers.

Are they ?

I think you might be getting a bit muddled here Pete. A neutral density filter blocks light, it doesn't involve polarizing it, otherwise highlights would become brighter...

Hi Luke: It's my understanding that variable ND filters use two polarizers. So, in addition to blocking light as they rotate relative to each other, they always polarize the light, too.

A true, conventional (non-adjustable, non-polarizer) ND filter only blocks some of the light, it doesn't polarize it.

Is the above not correct?

Peter J. DeCrescenzo wrote:

Luke Armstrong wrote:

Peter J. DeCrescenzo wrote:A mild caution: Although "variable ND" filters are convenient, be aware that because they consist of two polarizer filters, polarizing the light reflecting from your subjects is often not a desirable effect.

For example, polarizers have a noticeable effect on how skin looks, and not usually for the better.

True (non-adjustable) ND filters don't have these typically adverse effect, especially if they are of good quality (such as Tiffen, etc.)

I totally understand the convenience and speed advantage of shooting with a "variable ND" (especially a good one such as the Heliopan), but regardless of the brand used, they are all polarizers.

Just a heads-up. Cheers.

Are they ?

I think you might be getting a bit muddled here Pete. A neutral density filter blocks light, it doesn't involve polarizing it, otherwise highlights would become brighter...

Hi Luke: It's my understanding that variable ND filters use two polarizers. So, in addition to blocking light as they rotate relative to each other, they always polarize the light, too.

A true, conventional (non-adjustable, non-polarizer) ND filter only blocks some of the light, it doesn't polarize it.

Is the above not correct?

Sorry I misread what you said - forgive me! I read "they are all polarizers" and thought you were talking about ND filters in general. I only ever use linear ND filters (and polarizers for that matter).

As stated above vari-ND filters do more than just cut down the light in an even 'neutral' way.

The biggest advantages are speed & convenience - 1 filter that can cut out basically as much light as you want.

This said there is another factor to consider here, when shooting with DSLRs we couldn't change the exposure in the fashion as we will be able to with raw on the BMCC. Therefore it wouldn't be so difficult to use 1 or 2 standard ND filters and then push/pull to get perfect exposure in post....

Bit of a can of worms but if you get the heliopan go for a large size that will be adaptable to all you lenses.
Unlikely that you will regret it as it will invariably (no pun intended) be useful in many situations.

If I am mainly shooting interiors of old buildings for an upcoming project, will the polarising effect from the Fader ND filters have negative visual effects in situation (or is there more of a problem with skin tones, skies etc.)?

cschmeer wrote:If I am mainly shooting interiors of old buildings for an upcoming project, will the polarising effect from the Fader ND filters have negative visual effects in situation (or is there more of a problem with skin tones, skies etc.)?

Since a polarizer (including in a "variable ND") mostly affects reflected light, it affects every scene differently -- as the light changes, as surfaces change orientation, with different surface textures/reflectivity.

When in doubt, test.

In general, you can't know whether a polarizer's effect is negative or positive for a particular scene until you try it, although there are people in both "camps": Some say you should avoid using polarizers except when absolutely necessary, and use a conventional ND filter instead of a "variable ND". Others say don't worry, be happy, especially as long as you use a very good "variable ND" such as Heliopan.