Variable IR filter

[Nisei]

Came across this on eBay

Variable IR filter

Has anyone ever tried it?

It should turn from yellow to orange to red although pictures are only showing different shades of red so I think the stated specs are completely wrong.

[Cadmium]

Some of the older ones I have, SPIRATONE COLORFLOW (various color/color, and red/IR), Vivitar CROMO BLEND red/blue.

Some have PL built in, some need to be stacked with PL, some they have a tendency to fail over time given the sandwiched inner layer becomes corrupted,

I have three like that. Any will change color alone when revolved in front of a typical monitor, but like the COLORFLOW's need to have the PL stacked for normal use.

For example, the red/ir version goes from red to black. I assume that is what they one in the link you show does.

[eye4invisible]

Variable IR filters are a combination IR + variable ND. I would avoid them, as cross-hatching is a common issue.

[Nisei]

Seemed like fail when I first saw it.

Glad you guys confirmed it !!!

Thanks

[Cadmium]

I don't know about IR + ND, the ones I have don't work like that, they are changed by polarizer.

I can show pics if you want. Mine don't work by means of ND, and I would guess the one in the link doesn't work that way either.

I think the one in the listing is variable by means of a built in polarizer.

Also, I think for the price, if you don't have any of those, and you have never tried one before, that it is worth the money just to play with and fine out.

I would, if I didn't already have some that I never use.

 

Below, is an example of one of my variable Vivitar Red/Blue filter with internal separation, or whatever it is, it is not on the surface.

My Spiratone Red/IR will go to black, but has developed some uneven internal color to it now also, so now it too is worthless.

These are older to ancient filters however, I don't think you should judge the newer ones by these.

The rest of my Spiratone variable filters are all still perfect.

 

They are interesting filters, but I haven't found much use for them, using 'prime filters' (made that term up) are much preferred.

[Nisei]

Thanks Steve, that red/blue filter looks quite interesting. I assume you get different shades of purple inbetween the red and blue?

It's an interesting concept but with the IR version you have know idea about the wavelength and if you're getting results you like you'd have to remember which setting you were using.

But for the price I agree it's an interesting thing to experiment with.

[ulf]

For the visual filters they are based on polarisation effects. If you have two circular polarising filters try to stack them in different direction and order. In some of them there are interesting colour shifts when one of them is rotated.

 

For a circular polariser the light's direction is important as the buildup isn´t symmetric.

One of the sides have different optical properties than the other.

Normally the filter's threads (inner and outer) fix that.

 

The variable IR-filters are a hoax, not shifting the cutoff wavelength, just variating the transmission level.

A waste of money IMHO.

[ultrainfra]

I know this is an old topic by now, but a fotga branded one of these things was my first IR filter. This is the kind I bought back in July, though I got a fotga one instead. Not that it matters, they're all the same generic junk made somewhere in china. I've seen a few variations of the name. Just avoid these. Really. To any newcomers to IR photography, don't be swayed by the convenience of a single filter and cheap price.

 

 

It sucks. Does it pass infrared? Yes. Does it sorta roughly follow the longpass cutoffs marked on it? Roughly, at least on mine. But it suffers from that x-pattern seen on Variable Neutral density filters, and is extremely difficult to avoid.

 

It's actually labeled a variable IRND on the filter thread's side. I guess that part is honest, insofar as it is basically just adjusting visible light exposure as a previous post said.

 

If I put this on an unconverted camera and take a longer exposure , I don't get an IR image. I get a very red image that ranges from totally blown out to normal but monochromatic red long exposure. Barely any IR. Yet a kolari filter on my unconverted camera does give a proper IR image. So, if I ever use this it's on my full spectrum converted camera as just a variable ND with red tint. Just have to be careful to avoid the x shaped banding.

 

Anyone is so much better buying neewer's IR kit or some kolari or life pixel filters. Even 20 usd is overcharging for these things.