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Wednesday, February 25, 2009
EX1/EX3 IR Filter Shoot-Out
Art Adams | 02/25
The EX1/EX3 built-in Hot Mirrors suck. Or do they? One way to find out…
The Sony EX1 and EX3 are great cameras for the price, but they do have some fairly obvious issues with IR/far red when used with neutral density filters in front of the lens. This test taught me far more, though, than just what filters to use to eliminate a color problem on these cameras: I learned never to make assumptions about how a piece of equipment works until I’ve tested all possible options.
I’m not going to recap my testing procedures or the physics behind how the different filters work. You can find those details in my F35 and RED IR articles. I’ve gotten a lot of requests for an EX1/EX3 IR article, and as I’ve previously explained the basics this article is going to focus solely on results.
Here’s what the test setup looked like, without any on-lens filtration:


The setup consists of a DSC Labs Chroma Du Monde chart, the Chroma Du Monde polyester chart bag as an IR/far red reflector, and a slate.
Here’s the same setup with Schneider Optics ND 1.2 filters in front of the lens:


As I’ve explained before, all heavy ND filters show some color shifts because it’s impossible to make a dye that is perfectly neutral. Some ND filters go warm and others cool. In this case the Schneider filters add a reddish hue, which I’ve attempted to correct out in Photoshop. A simple white balance is enough to get rid of this hue in camera, but I chose to do it in post in order to observe the various filters’ color shifts.
In spite of white, black and gray balancing in Photoshop, the black DSC chart bag has turned a bright maroon color with four stops of ND in front of the lens—brighter than I’ve seen on any other camera I’ve tested.
The first time I looked at a black cotton shirt under tungsten light on an EX1 it turned bright maroon even without ND. Between that experience, and seeing how much red I saw with some ND in front of the lens, I figured that the built-in Hot Mirror on these cameras was either very bad or nonexistent. I was wrong, but I wouldn’t figure that out until later. Read on…
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Art Adams | 08/30
A directory of my best articles, sorted by topic.
This entry is a guide to my best articles, sorted by topic. Enjoy!
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Adam Wilt | 05/08
A few cool things I saw at the show that didn’t fit into any other articles.
NAB is too big a show in too short a time to see more than a fraction of it. I’ve covered a few things in some depth (as have other PVC folks), but there’s plenty more that slips by without proper coverage. Here, I have a few photos…
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Allan Tépper | 05/08
With an 1/2.88" sensor and 26mm wide angle (35mm eqv), the NX30 should ship in June for well under US$2500.
Although during the past year I’ve written quite a bit about the Sony NX70 (officially, the HXR-NX70) here in ProVideo Coalition magazine, I haven’t…
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Excellent test! Would the Tiffen IRND have to be the first filter light hits, or could it be used as a screw-in filter on the lens behind a matte box?
Posted by DR on 02/26 at 10:20 AM
It doesn’t have a reflective Hot Mirror so I don’t see a need for it to be the first filter in the matte box.
Posted by Art Adams on 02/26 at 05:11 PM
Test
Posted by Art Adams on 03/05 at 04:20 PM
where does one find a Schneider Tru-Cut 680? i’ve looked everywhere.
thanks.
Posted by .(JavaScript must be enabled to view this email address) on 03/14 at 12:02 PM
I don’t know that they are commercially available. I got one to test when Schneider first brought IR filters on the market but I think the only one they’ve officially released is the Tru-Cut 750, which works great on the RED.
You should give them a call. They’re about the nicest people you’d ever hope to do business with.
Posted by Art Adams on 03/14 at 12:23 PM
Thanks Art. yeah,i’ve gotta EX1. i second that about Scheider. I see many of their reps through the year. very nice people. i’ll call them monday.
Posted by .(JavaScript must be enabled to view this email address) on 03/14 at 12:52 PM
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