New Optical Low Pass Filter Makes the RED DRAGON Sensor Even More of a Beast
There is little doubt that RED's DRAGON sensor is a major step forward for digital cinema, at least in the resolution and dynamic range departments. However, like all new digital sensors, there are some kinks that need to be worked out before the cameras are 100% ready for action. In the case of DRAGON, the optical low pass filter originally designed for the sensor was causing some issues, chiefly some strange magenta flaring when the camera was pointed at bright sources. A brand new OLPF, and a bit of sensor calibration, has not only fixed this issue, but it has improved upon the sensor's colorimetry and dynamic range even more. Check out the details below:
In a recent post over on REDUSER, Phil Holland revealed the new OLPF and some of the tests that he conducted. Here are some stills from the before and after tests for the new OLPF. Click the images for full size:
Completely swapping out the optical low pass filter at this stage is a large undertaking, especially considering that the original OLPF for the DRAGON sensor was wildly efficient in some areas, especially reducing IR pollution and color shifting when using heavy ND's. Luckily, with some custom sensor calibration for the new OLPF, DRAGON is even more efficient in that regard. Here's what it looks like:
Here's what Phil had to say in regards to the results:
If you look extremely closely you will notice color has slightly improved overall. Additionally in shadows and highlights IR contamination has been eliminated with the New OLPF. Those blue shadows are extremely pure (check out the sky in the Sun Flare image too). White highlights are white. Dark shadow areas are clean. You may noticed that chroma is richer in the 2800K WB/ISO 2000 Match test image as well. Good stuff.
The new OLPF also has benefits in another important area, an area where the DRAGON already excelled: highlight retention and roll-off.
That's approximately 1.3+ stops improvements in the highlights. Also to note, the New OLPF wrangles light fall-off and bloom a bit nicer. So you get richer shadow detail, where the previous OLPF with its IR contamination flattened out those areas a bit. Subtle, but visibly noticeable in captured material.
I am not an expert in digital imaging technology, but these results are absolutely fantastic and further proof that optical low pass filters play a crucial role in the digital imaging pipeline. It's also great to see the RED engineers responding so quickly to the OLPF flaring problem on the early DRAGON cameras.
In terms of getting this upgrade for yourself, all new DRAGON cameras will ship with the new OLPF and sensor calibration, but if you're one of the few current DRAGON owners who have received a camera, you will need to ship the camera back to RED in order to perform the upgrade and calibration.
What do you guys think of the new DRAGON OLPF? Are you impressed with the myriad other improvements that the upgrade offers? Let's hear your thoughts down in the comments!