Hot Mirror

[Anthony DeRose]

For hot mirror/IRND filters do they need to face a certain way? I read that the reflectance side should face out. We picked up some Tiffen Hot Mirror ND combos and the rental tech said they can go in any way.

[Jay A. Kelley]

This is very wrong.. The mirror must face OUT.

Jay

[Jeff Kilgroe]

Not only that, but you should never use more than one mirror filter. It should always face out and be the first filter in line (furthest from the front of the lens) so that light reflecting off of it doesn't bounce off any other filters.

[Mitch Gross]

There are some types of Hot Mirror filters that do in fact work in either direction, but the vast majority need to face the correct direction. If it is the Tiffen filter I think it is, orientation is important.

[Jeff Kilgroe]

Mitch, I thought any filter that qualified as a "mirror" could only be used in one direction. As in it's a mirror, it reflects undesired light... Reflections within the optical path = bad juju.

ND filters or IR+ND filters (no [hot] "mirror"), can be used facing either direction in many situations, but still depends on their construction. Some absorb IR best when facing one way vs. the other.

[D Fuller]

There are some types of Hot Mirror filters that do in fact work in either direction, but the vast majority need to face the correct direction. If it is the Tiffen filter I think it is, orientation is important.

Mitch, i own the Tiffen filter, and it is virtually impossible to tell which side is which from the reflectivity. I've assumed that the inscription "TIFFEN HOT MIRROR" goes away from the lens (toward the subject). Is this correct?

[Ivan G]

Since were talking ir glass is pola still ok to combine?

[D Fuller]

Since were talking ir glass is pola still ok to combine?

Yes. Just don't put in front of a hot mirror.

[JonathanF]

David,

The inscription is typically on the front of the filter so the IR reflective coating will be on the side with the inscription. I know this is the case with the Schneider and the Formatt filters I have used (and I way prefer the Formatt if anyone cares).

In either event, if you make sure the inscription is on the side AWAY from the lens you're all good.

Hope that helps,

J

[Carlo Rho]

Mitch, i own the Tiffen filter, and it is virtually impossible to tell which side is which from the reflectivity. I've assumed that the inscription "TIFFEN HOT MIRROR" goes away from the lens (toward the subject). Is this correct?

Hi D Fuller,
are you sure? We use Tiffen Hot Mirrors and appears very simple to understand witch side is it!
A Tiffen HotMirror Filter has a side almost exactly the same redish reflecting color of the M sensor itself, it's not possible to mix it up with the black ND side.
But I never see the HotMirror without NDs, we're waiting for it right now.

I'm not related to Tiffen, actually I really like some Schneider product (as Digicons) (http://www.schneideroptics.com/Ecommerce/CatalogItemDetail.aspx?CID=1410&IID=2475) but I think that this is a good link to learn something, at least remembering that they are selling filters!

TIFFEN Product Literature (http://www.tiffen.com/tiffen_product_literature.html)

[Mitch Gross]

Ugly weirdly reflecting color side away from camera.

[D Fuller]

Ugly weirdly reflecting color side away from camera.

What's odd, Mitch (and Carlo), is that the difference seems very small. It's not at all the mirror-like reflectivity I expected. I'm actually wondering if this filter is not right.

[Dave Blackham]

So is the new Red One sensor Mysterium X have any improvement on IR.

I believe jim said that Epic had improved IR filtering so had assumed the new Red sensor has the same new IR filter.

[Jeff Kilgroe]

What's odd, Mitch (and Carlo), is that the difference seems very small. It's not at all the mirror-like reflectivity I expected. I'm actually wondering if this filter is not right.

Is it just an IR filter (or IR+ND) and not a "hot mirror"? The mirror ones are pretty obvious. Other IR or IR+ND filters are not so obvious. But typically the inscribed label faces out as others have said.

[D Fuller]

Is it just an IR filter (or IR+ND) and not a "hot mirror"? The mirror ones are pretty obvious. Other IR or IR+ND filters are not so obvious. But typically the inscribed label faces out as others have said.

Yes, it's a straight hot mirror -- inscribed "TIFFEN HOT MIRROR USA". I've always used it with the inscription facing out but I've always wondered at the fact that there's not more "mirror" to it.

[Damian Grady]

Hi there,

We've just bought the Tiffen W4565HM Hot Mirror IR filter for use with our Red One and we weren't sure which way to face the filter either as the only inscription we have on ours is "Tiffen Hot Mirror USA" on one side.

So I just called Tiffen's Customer Support in the US and they said that it doesn't matter which way round it goes.

Can anyone else confirm this?

[Jon B.]

The mirror must face OUT.

Jay

...

[ericyoung]

Sounds like that particular Tiffen is like the Rosco Trucolor IR Cut - ie not mirror like in appearance and not sensitive to which side faces out. Especially as that advice is direct from the manufacturers!

[Damian Grady]

...

Not quite sure what "..." means?

[Thomas Wright]

Yes, it's a straight hot mirror -- inscribed "TIFFEN HOT MIRROR USA". I've always used it with the inscription facing out but I've always wondered at the fact that there's not more "mirror" to it.

perhaps cos it's reflecting light that's not in the visual section of the spectrum

[Carlo Rho]

Just Received today a TIFFEN HOT MIRROR first I see/have without ND. It's not so simple to see the mirror side without looking to the script or moving it reflecting a light source. With HM+ND is definitely more simple too understand which side is out.