Pedro Guimaraes, SOC ~ Life Behind the Lens

The “Ruby” lens has been out now for some time but it is relatively “new”.

It is essentially a re-housed and improved Nikon 14-24mm (click here for more info) I own this lens and have been a fan ever since it found it’s way onto my Nikon DSLR camera.

So when I first heard about the Ruby I was super excited. The Ruby Covers the FF35 sensor. The focus travels 126 degrees and focus direction was reversed to go cine direction. The focus marks are as follow:1′ 1’2″ 1’4″ 1’6″ 1’8″ 1’10″ 2′ 2’6″ 3′ 4′ 5′ 8′ 10′ and infinity, with complete accuracy with a anti back lash design that works great. It will work on all 35mm PL mounted cameras, Arri , SonyF35, Red, Canon 7D with an additional adapter.

Specs:
Front diameter:110mm
Largest diameter is 110mm which is the focus gear
Weight: 3 pounds
Overall length: 138mm

There have been some great test’s of this lens in 2D. watch one here by DP Francis Kenny, ASC. on VIMEO CLICK HERE

So for me now the big question was how is the Ruby on a 3D rig?

Here was my testing setup- Element Technica ATOM rig, RED EPIC cameras, custom made chart (by me!) and a 4 bank Kino giving me some light to work with.

I’m working with a company that just purchased 2 Ruby lenses to go with their Atom rig. So I had the perfect opportunity to test at Element Technica’s headquarters.

I was also lucky enough to have the “STAN” to assist me in getting some hard numbers for test results. The STAN stands for “stereo analyzer” and it is made by the Fraunhofer Institute in Germany. It analyzes the 2 stereo images and displays any disparity in pixels or percentages. It can also auto-correct and image pair. In many ways it is very alike a Sony MPE-200 stereo analyzer. This provided me an amazing tool to get definite readings and results for my testing.

For more info on the “stan” click here

The 3D TV and the “Stan” analyzer….

So I began testing on the Atom rig set to “ZERO IO” and expertly and perfectly aligned by myself to attempt to achieve 2 perfectly overlayed images. Right away and was very impressed….I mean very…..I was able to align the rig in about 2mins…..near and far in just about perfect alignment. WOW……

Naturally I started my testing at the wide end at 14mm

I was surprisingly quickly able to achieve a perfect alignment on the ATOM rig.

0% Vertical match (perfect)

Here is the L&R eyes overlayed in “difference mode” which is one of the best ways to align a 3D rig. In this case it was provided by the STAN.

0% roll match (perfect)

Also notice the fact the lens is extremely rectilinear …. really amazing for a lens at this price point and aperture.

Most importantly they were a near perfect focal length match right on the barrel marks.

Not happy with near perfect I adjusted a tiny bit and got to perfect.

I repeated the same tests at 16mm, 20mm and 24mm.

All with the same near perfect results.

Here is the result for the lens @ full zoom 24mm. Judge for yourself……

Zoom Tracking
Extremely important in 3D since it’s affect how much we need to adjust the rig after a focal length adjustment on a zoom lens. The ruby’s tracked near perfect in 2 directions with a slight vertical movement when going from 14-24mm.

This is the lens tracking error going from 14mm to 24mm….

As you can see the lenses did not de-center in a diagonal(up and to the right) like most zoom lenses do. It just resulted in a small vertical mis-match. EASILY corrected on the Atom rig with a quick tweak of one of the adjustment knobs. Easy fix when compared to other zoom lenses.

Most stereographers can live with a bit of horizontal disparity but a vertical is just not acceptable. One way to fix this would be to just rotate both lenses in the mount so that the vertical disparity turns into a horizontal….this would result in a lens in 3D that you could zoom during a shot or at least at a minimum one that I could change focal lengths at a moments notice and not have to re-align the rig.

Here is a screen capture from the “right” EPIC camera. I will make the full res 5k tiff available to download soon.

Conclusion

In short for 3D these lenses are a dream…..their rectilinear nature and great focal range for 3D coupled with the astounding focal, alignment matching and tracking performance makes this a great lens for 3D.

I’m extremely pleased with their performance and very happy to be working with them in a major upcoming 3D production shooting on RED EPIC cameras and Element Technica ATOM rigs.

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Thank you to Stuart at Focus Optics for the great lenses, Element Technica for the use of thier facility and STAN station and Tonaci Digital for the use of his EPIC cameras for this test.
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Next up!
I’m headed underwater to test their performance underwater on a dome port and a flat port using a RED ONE and a Element Technica housing.

The purpose is to see the viability of using a 14mm on a flat port underwater beam splitter housing like the Gates “Deep Atom”