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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Hot Mirror/IRND/Mirror ND Filter Matrix [Parts 1-4]

This is an excellent comparative test, it is great to see this info published!

I don't know what other tests are still to come, but just FYI, this test does tell only part of the story. The IR LED source used here is probably a very narrow slice of the IR spectrum (around 880 nm? just a guess). So this is really just one data point (but a good one) on an extended curve. In most "real" scenes you will have the entire IR spectrum, so you care about all the different wavelengths of IR that the Red sensor picks up (I'm not sure how much that is). If any tests were done looking at color shifts with tungsten lights, day exterior, golden hour etc. that will tell you more about the "full spectrum" response.
 
Very good! Part two seems much more objective than part one, thanks for the useful info thus far.
 
The Rosco filter was my first choice after performing the tests yesterday... hands-down. It cut the most IR light, it had acceptable off-angle viewing characteristics [I thought it was the best by eye... but these data don't lie] and cost the least. Then I heard that Rosco isn't planning on making a true sandwich filter in the short term. They'll be out eventually [and they'll certainly kick ass then...], but in the short term, I don't want to have to baby a filter to protect its coating.

Ultimately whichever company can get me some 4x5 and 6x6 filters first [Rosco or Tiffen... not the Schneider] will win my money. :)
 
ayarbro said:
Very good! Part two seems much more objective than part one, thanks for the useful info thus far.
Click to expand...

What wasn't objective about the first test? The off-angle viewing characteristics are massively important to the usefulness of these filters... and the data were presented clearly...

Just saying.
 
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  • #25
Hot Mirror/IRND/Mirror ND Filter Matrix... (Part 3)

Hot Mirror/IRND/Mirror ND Filter Matrix... (Part 3)

Part 3: Outdoor Field test

This is where the rubber really hits the road...
The first thing I have to say is that all the mirrored filters (Hot or otherwise) do the trick as far as attenuating the IR issue with the Red One. They all approach that goal from different directions but in the end they do all deliver the goods.

First off let me thank Danna Kinsky for being the patient model and AC as well as Christian Sprenger and Brook Willard for assisting with this test.

These frames were all processed identically using the Grey card in the top control image as a color reference. Thus any deviation in color shift or exposure is consistent with the filter's properties.

So first off Danna and her lovely IR reflective nylon pouch and gray card...
DannaTestTiffen.jpg


I had expected this pouch to reflect a stronger purple cast than it did (Based on the EVF image) but you can still see it and the loss of black contrast in the foliage behind is considerable. This first set is all Tiffen because they have the most filter combinations. In this test the IRND seems to contribute a bit more than was suggested by the Lite Panel test. Still there is little to choose between them. The Hot Mirror alone does a fine job. The Tiffen line seem to cut about 2/3 of a stop more light than their stated density, this may be because of the lack of an IR boost in exposure. Cross reference your in camera meters if you plan on using an external one.
The Tiffens seem to exhibit a warm/green cast to the image as well.

DannaTestOthers.jpg


Here we can see the Schneider, Rosco and Pancro also getting the job done. All of these eliminate the color cast of the pouch and punch up the blacks of the foliage. The Schneider filters add a slight cyan cast and the Rosco ever so slight Red. The Pancro is almost dead neutral, and the only filter that seems to be exactly the density stated. Although this may be because the Panchro is the only filter that is cutting an equal amount of both visible and IR light.

Here are the same tests done with some levels and color correction added for a peek at what a more corrected image would look like. I let photoshop auto color correct each frame thus accentuating the individual nature of each image.
DannTestTiffenCor.jpg


This is obviously more subjective but you can clearly see the cast in the pouch now as well as the color dilemmas you might face in post.

DannaTestOtherCor.jpg

Again the cooler Schneider's character is obvious, the Rosco is doing very well, especially in regards to the nylon and the Panchro is still the most neutral and best exposure, however a slight hint of blue is now visible in the nylon., but no worse than in the control, it's only when viewed next to the Rosco that it is apparent.
 
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  • #27
Build Quality...

Build Quality...

One last thing before we move on to Part 4, Tungsten.

The Tiffen, Schneider and Pancro filters are all professional camera filters that use a sandwiched or otherwise hardened design to resist fine scratches and abrasions. They all seem to perform as expected. The Rosco filter I received was a single coated prototype on some 1/2 thickness plate glass and was never intended to be a permanent camera filter. That being said the Rosco production filters will be produced on standard thickness, optical quality glass but the coating will remain a single layer, un-sandwiched design. This is unfortunate because they have arguably the best formula for iR attenuation but I'm concerned that the coating will not be robust enough for heavy duty production or rentals. Although I have urged them to go to and sandwiched design this first batch will for sure be single coated. I will still recommend the filter, especially given it's great price, but all who have ordered or are considering an order should be aware that extra special care will be needed when handling and cleaning this filter. You should treat it as you would any coated camera lens, and avoid any unnecessary contact, if possible.
 
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  • #29
I've added a "real world" example of the Hot Mirror filters using the Nikon D3 and a 17-35mm lens to eliminate any potholing or inconsistency in post processing.

(The marked focal lengths are Red One 4K 16:9 equivalents)
RealWord.jpg
 
Why Tiffen have called his filters IR-ND if they don't cut IR.... beacuse they simply don't look at the top right image ir-nd .6 on the left ND .6 on the right... no difference.
Fraud?
 
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  • #33
Hot Mirror/IRND/Mirror ND Filter Matrix... (Part 4)

Hot Mirror/IRND/Mirror ND Filter Matrix... (Part 4)

So, after much poking and prodding we're finally at the end. But before we come to the conclusion we have one more test to endure...

Tungsten.
As you many of you have found out shooting the Red One with tungsten light can be a challenge. You probably have figured out by now that one factor is the blue channel being starved of light, but another is the high IR content of most Tungsten sources. Here we investigate the effect of our three Hot Mirror options in this environment. IT is important to not that It is unusual to use ND filter when using tungsten so I have omitted the Pancho and IRND filters from this test.

The top 4 frames are uncorrected based on the "Control" filter less frame.
The lower 4 frames are individual corrections for reference.
TungTest.jpg

Here you an see the same characteristic color shifts we saw in the daylight test. The Schneider is showing it's strenght in this test. In fact I might go as far as to say the Shcneider seems as it was designed with Tungsten in mind. The Rosco and Tiffen are neck in neck here with an edge to the Rosco.

Tungtest1.2ND.jpg

Although you would usually not use an ND filter when shooting in a controlled tungsten light environment I though it useful to demonstrate the effects of the IR and the filtration. ND filters do this by increasing the ratio of IR light to visible, thus creating an IR pass filter. You can see clearly here that at 2 stops less ND than in our outdoor test the IR is overwhelming the control scene. Again the Schneider seems the best suited to the tungsten with the Tiffen now a little ahead of the Rosco.
 
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  • #34
Conclusion...

Finally, after a month of pleading and begging all the filter Co. to provide samples, and three days of testing, what have we learned?

First off the failures...
I truly believe that, although the Schneider True-Cut IR lives up to it's name, especially under tungsten light, the off axis color shifting issues make it useless on any lens shorter than 32mm. For me that rules it out.
Also the Tiffen NDIR filters do not seem to me to add much to the equation. Although they seem to attenuate a little farther into the red spectrum than the standard filters they are not capable of competing with either the Panchros or a Hot Mirror + ND together.

Not a loser but...
The Tiffen Hot Mirror/IRND 1.2 combo filter does the job but not any better than separate filters and arguably with more color shift. It also is the most expensive single filter with a list price of $600 ($450 street). This make it a specialty Item in my mind, really only suited to those who have to use clip on matteboxes and are very limited in filter trays. Although the Panchro 1.2 ND accomplishes everything this filter does for a little over 1/2 the price.

The Winners...
I'm going to address these solutions by price range because they all get the job done adequately but have varying degrees of cost and connivence associated with them.

Beer budget: Rosco TruColor
The Rosco has arguably the best formula for cutting IR. There is no doubt it works but the single exposed, un-hardened coating makes it a fragile butterfly in the wilds of production. Be careful and it may serve you well, and at as low as $130 there's little to argue about price.

Wine budget: Tiffen Hot Mirror
The Tiffen is more expensive than the Rosco because it's a sandwiched, highly durable design. It also has the best off axis color performance of all the Hot Mirrors while still getting the job done. If you already own a complete ND set (Regardless of brand) this will work great for you provided you have enough filter trays to accommodate two filters and preferably a 4.5" or 138mm Polarizer.

Champagne:Pancro Mirrored IRND set
The Pancros are my top pick for one very important reason...
They maintain the original character of the sensor regardless of density. Because they reflect exactly as much IR as they do visible light you can use them singly or in conjunction with other filters or Polarizers and the image is the same color and character as if you weren't using any ND at all. They also have no discernible color shift. If you have yet to purchase an ND set this is the way to go. They are expensive but not much more than a set of competing regular NDs (About $350 each filter). If you really want to cover your bases pick up a set of Panchro filters for outdoor use and a Tiffen or Rosco Hot Mirror for tungsten shooting.

Reflections on reflections...
All the Hot Mirror and Pancro filters essentially become mirrors once the filters are in the matte box. They all reflect enough to catch the talents eye or possibly reflect a bright light into the scene. Be aware and try to use common sense and good light discipline and you'll do fine. Unfortunately if your subject just can't take his eyes off himself in your filter, call his agent.

ReflectionDanna.jpg
 
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  • #37
The conclusion is above now.

digitalfx said:
why did you omit the Pancros in this test?
Click to expand...

I thought about it, but since there is not really any reason to use ND under tungsten light I omitted them as well as the IRNDs. The second set is really just demonstrative. Also from my tests and experience the Pancro filters cut exactly as much IR as visible, so there would be no real difference from the control in the first set.
 
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