We've already seen the GoPro HERO3 get some interchangeable lens abilities thanks to the Novo modification from Radiant Images and View Factor, but that system is a rental only, and according to the designer would retail for around $30,000, based on the work involved and the low volume. Well, now we've got a much, much cheaper solution that you can actually own, the Ribcage from Back-Bone -- which will be available in a fully-modded camera with C-mount, or a DIY mod kit for a camera you already own. Check out more details below.

Thanks to Wide Open Camera and Eric Diosay for the heads-up on this, here is the Back-Bone Ribcage, which is essentially a faceplate mod kit for the HERO3 or HERO3+:

And what they said on Vimeo about the Field of View:

The Hero 3 Black has a 1/2.3" sensor, so the crop factor on 35mm SLR lenses is 5.7, however should you use 1/2" C-Mount lens very little cropping will occur. We're currently investigating the use of focal reducers to help reduce the crop factor.

Here is some test footage with the mod:

These video clips were filmed with our 'Ribcage' modified GoPro Hero 3 Black, with a 11.5 - 60mm f1.4 C-Mount zoom lens. The footage was shot using the 720p 120fps setting played back at 24fps. The fourth shot of the bee (1:05) begins at an F-Stop of 1.4 and ends at F16. The GoPro keeps up nicely with the dynamic change in F-Stop.

Some more test footage, only available in SD however:

The Ribcage, besides giving you the ability to use M12, CS, or C-mount lenses, also lets you mount virtually any lens in existence like Nikon, Leica R, PL, and many more, as long as it is adaptable to C-mount. Using SLR lenses is good from a convenience standpoint, but the crop factor can actually work in your favor by getting you much closer to a subject that's very far away (and still giving you fantastic slow-motion).

This mod not only gives you full control over your lens and will mean a less distorted image, but you've also got a much better ability to control exposure. You can effectively get your GoPro to bring the shutter down to a normal speed by stopping down on the lens and adding ND to the lens itself. This, in turn, should give you much better quality in your final images and help you actually match them better to other cameras in post (if only GoPro would just add some sort of manual exposure). There are some interesting possibilities that people might be able to make use of without the IR cut filter, and you can see what removing the IR cut filter can do to regular daylight footage here.

The full kit with HERO3+ camera included is going to run $800, with the DIY kit coming in at just $200 for the whole setup, and both kits also include additional tripod mounting points on the bottom of the camera. They are planning to release these in the first quarter of 2014.

If you're worried about whether they will be delivered on time, they are already in production:

#Ribcage parts in full scale production! You can make out the face plates on the left. pic.twitter.com/p6JSWHV6BN — BACK-BONE (@backboneca) December 4, 2013

Read more about the Ribcage or pre-order one right now over at the links below.

Links:

[via Wide Open Camera & Eric Diosay]