GoPro Diving: Subspace has the solution!

We had mentioned the problem in a previous issue of Mag: the GoPro HD Hero being equipped with an ultra-wide Angle lens, in immersion (even at shallow depth), the videos are blurry! This phenomenon went relatively unnoticed with the 1st generation GoPro Wide models due to their poor definition. But on high definition films, the result was disappointing. Only one solution so far to correct this defect: the flat lens. We therefore offered you a number of more or less satisfactory solutions, but we found better.

As soon as the field angle exceeds 80 ° or 90 °, the difference in refractive indices between aquatic and aerial environments creates aberrations that are all the more significant as the field angle is large. The further you move away from the center of the window, the greater the deformation. Your GoPro®, in 1080p recording, gives you a spectacular 127 ° angle of view with Full HD quality. So that there is no distortion, all the light rays must arrive perpendicular to the window, so a spherical window must be used. But the spherical porthole in turn poses problems of focusing. In fact, behind a spherical diopter, a virtual image is formed, the position of which in front of the objective depends in particular on the radius of curvature of the window. If the minimum focus acceptable by the Gopro lens is beyond this virtual image, then focusing is impossible, the camera is farsighted. It is therefore necessary to have a porthole with the largest possible radius of curvature to move the virtual image away and enter into the range of adjustment of the focus. This is why the original very small porthole does not provide a sharp image when shooting underwater.

SUBSPACE PICTURES found the solution, developing an optical system consisting of a spherical window completed by a lens. The window removes the aberrations and keeps the angle of view. And it is corrected, under water, by a lens mounted between the camera and the porthole. This system, called "afocal", is based on the same principle as the larger optics that equip the waterproof boxes of the Swiss manufacturer. It ensures sharp and sharp images, free of field decreases, aberrations and blurs in the angles inherent to flat windows mounted in front of lenses having a wide angle of view. Even the deformations specific to the lens of the camera could be slightly diminished. In summary, the aberrations are removed, we do not lose an angle of field, and we do not lose brightness.

The manufacturing has just begun, so it will probably wait a few weeks before you can acquire the system. But you can still discover it at the end of the month, since Jean-Claude Protta will be present at the Festival de l'Image in Marseille, on the 77 stand, with many other equipment: projectors, boxes, boxes ... Ready to share your passion: if he founded Subspace 20 years ago, after a trip of 10 years around the world, it was for that: "to share his experience and his passion for everything related to underwater images" .

Price of the set including:
1 GoPro® HD housing (without camera), 1 Full spherical window mounted and tested at -60m: CHF 252.- (Swiss Francs incl. VAT)