Using Hot Mirror Filters to reduce IR pollution?

[lensworx]

Hi all,

I have been doing some research over the past week, I have been trying to find a way of using my existing ND filters without having that horrid colour cast.

Now as I understand it there are a few filters that do not produce such a harsh colour cast due to the dies that are used within them, but these do cost a lot more. I spoke to a company today regarding this matter to see if their filters produce this cast to be told that although they are looking into producing a new line that will minimise this side effect, at present even their low density ones will still produce a slight cast.

Whilst speaking to one of the sales team I was told about a filter that is used within the movie industry that cuts out the amount of IR pollution that is associated with this problem. The only problem is that from what they said, These tend to be large filters and made of glass.

Has anyone else come across these types of filters?
would this be viable solution in minimising the colour cast when using ND's (in particular when stacking two or more together)

I am waiting to hear back from them as they recon they could do one in a threaded housing which would be smaller and slightly thinner.

any input and / or experiences on this subject would be great,

Thanks in advance

Mark

 

[bostin]

B+W make a 486 UV/IR filter that is designed to neutralise the cast caused by ND filters.

 

[lensworx]

Thanks for the reply.

I will take a look and see, Thanks.

 

[Cheng]

Think it'd be very expensive to purchase any of these hot mirror filters (going by the tiffen price list..ouch!) My idea and what I consider the solution of choice would be a new big stopper filter from Lee - apparently has an IR block built in- expensive but anything else is going to be more expensive, yes you may have a cheap ND filter but it's a false economy because the hot mirror will cost far far more!

 

[HoppyUK]

Have you tried a custom white balance? That should sort it (see handbook). Or fix it in post processing.

 

[lensworx]

Thanks for all the replies.

HoppyUK: I have been trying to correct as best possible in pp. I have not done it via a custom wb but would that not course a problem when using grads?

I was looking to try and find something for when im stacking filters together (eg a 1.2 ND + say a 0.6 Grad)

Cheng: a big stopper is on my list of stuff to get

I had a reply from the company today and after seeing the price of the hot mirror filters I may well be getting some new ND filters instead.
any suggestions on which ones to go for? I was looking at maybe the Lee filters.

 

[HoppyUK]

If you do a custom white balance with your ND filter, then adding a grad will be fine - assuming that is actually reasonably neutral. A trick for doing it in post is to include a piece of white paper in one of the shots and use the dropper to reference that and it should pull everything in line.

If you're into square filters, then Lee is the best system and their Big Stopper is good. But even that is not 100% neutral, even if it's pretty close and certainly better than most others - it's very slightly bluish but nothing to worry about. I doubt that you have any IR issues with your camera, it usually refers to older CCD sensors, not CMOS.