Calibrating and matching lenses for Professional VR use

Filmmaking for VR means using a lot of lenses. With our EYE™ VR Camera System for example you could be using up to 42 lenses at once, which makes calibrating and matching lenses very important.

Lenses and lens adapters are typically variable in terms of quality control, even from the best manufacturers. This is perhaps unsurprising considering these are complex mechanical and optical parts. It’s not usually a problem when using a single camera system, but for VR it’s very different.

Lens calibration for 360 cameras

Calibrating a lens for VR using a microscope-like custom tool

The problem is made worse with VR, since the lenses are typically ultra-wide angle lenses. While ultra-wide angle lenses are very forgiving in terms of focus and depth-of-field, they are completely the opposite when it comes to calibrating for focus from the factory. This can manifest itself in a couple of ways – it might not be possible to get focus at all (in combination with an adapter), or the focus distance may be inaccurate compared to what it says on the barrel. Some are simply soft at one end of the range. Metabones Speedboosters, and similar adapters, which are a practical necessity currently if using the Blackmagic Micro Cameras in a small VR rig (due to the sensor size and crop factor), are a frequent cause of problems.

Calibrating lenses for VR

Testing a wide-angle lens on the Blackmagic Micro Studio Camera with a Metabones Speedbooster

Explains Matt Duclos of Hollywood lens technicians Duclos Lenses… “It’s not a problem at the long end… a few hundred millimeter lens for example… you could be out a wide margin and it wouldn’t matter, but it becomes infinitely more critical when you get to the very wide end of the scale”.

Specifically, the flange focal distance (the distance from the lens element to the sensor) becomes extremely critical the wider you go, and tiny errors, measured in tenths of thousands of an inch, can throw a perfectly good lens soft.

At 360 Designs we test a wide range of lenses constantly and have experienced this issue from almost every manufacturer. Some combinations of lenses and adapters work out of the box, but rarely. Approximately 90% of lens adapters and 35% of lenses we’ve tested are unusable for VR without professional calibration.

At 360 Designs we test and calibrate each and every lens we supply. We use an advanced process to match every lens and its adapter. Once calibrated, these lenses become maintenance free.

If you are thinking of using the Blackmagic Micro Cinema Cameras (or Blackmagic Micro Studio Cameras) for VR, contact us to find out the services we offer, which extend well beyond what we currently offer on the site. We are currently working on a bespoke basis with many leading cinematographers, directors, filmmakers and broadcasters.