How accessible is the CMOS chip?

[Ryan Damm]

I'm just wondering how easy it would be to get at the actual chip - the announced lens mounts are nice, but what if I've got lenses with vastly shorter flange focal lengths than that? Can I remove the front mount entirely?

I ask because I'm repurposing some large format optics and planning to custom build some lenses of my own - they would be barrel lenses with no fixed flange focal distance (you would move the entire lens back and forth to focus). Short focal lengths would require correspondingly short throws for proper focus (an 18mm lens would focus at infinity just 18mm away from rear nodal point). Unfortunately, a 44mm flange length restricts such optics to 44mm and longer... so I was really hoping the end user would be able to reach the chip fairly easily without strapping the camera down on a mill.

Also, if there's no obstructions, you could get some fairly extreme lens movements with optics designed for larger formats. Just as long as the camera housing doesn't vignette the lens when moved off-axis.

Also, the camera could see use in non-photographic regimes: I had a friend in biotech ask me about large-format sensors for doing some on-chip chemistry. He wanted a physically large sensor that he could couple to reaction plates featuring thousands of individual chemical reactions. I think he ended up using a smaller chip glued to a fiber-optic taper... but the point stands that a more-accessible chip means wider applications. (For the record, he needed quite a few sensors.)

On a related note, there's something kind of funny about the 18-85 zoom: S35-sized, single chip video cameras have a huge advantage over other cameras: there's no spinning mirror or beam-splitting prism to deal with, so lens elements can be arbitrarily close to the chip. That would help lens design rather markedly - ironically, the RED zoom is almost certainly retrofocus at its shortest focal length, a requirement of the PL mount and not the camera itself. Maybe future RED-only lenses could take full advantage of this fact....


Cheers,


Ryan
#794


PS - sorry for the cross-post, but I asked a similar question on DVinfo.net just a couple of days ago. Rob Lohman was kind enough to set me straight on the CCD/CMOS thing, but couldn't give me a definitive answer about the optical path.

[jbeale]

I don't know what optical considerations are involved but given there's no prism, mirror, etc. in front of the chip, could the rear element of the lens not actually protrude beyond the plane of the mounting surface? If the PL mount is 54 mm in diameter and the imaging circle for the RED sensor is 28 mm diameter, it seems possible for some lens elements to extend inside the camera body. Maybe not for a very wide lens at low f-number, but for many lens designs it seems the optical elements closest to the image plane aren't much larger in diameter than the image circle.


http://www.bealecorner.com/D30/misc/cine-lens-designs.jpg

On the other hand, I suppose you are talking about a design like the Zeiss Biogon (http://www.zeiss.com/de/photo/home_e.nsf/Contents-Frame/99A977A1FF4BB056C12570FA00609656) (?) In the Biogon design I was looking at (for the Contax 35mm camera), all the lens elements are quite a bit smaller than the image circle diameter. You could in theory stuff that entire lens through the PL mount ring without modifying the camera (if you wanted to design the lens housing that way, of course!).

Lens tilt and shift movements are something else again, though.

[Ryan Damm]

Funny you should mention the Biogon - I'm planning some simple double-gauss type designs, which are quite similar (I think the Biogon is descended from the double gauss).

And again, the RED camera seems to be all about possibilities. I'd hate to give up the possibility of lens movements if we didn't have to. Even if virtually no one uses it, it's a feature that would distinguish RED even further from the competition. Besides, who's to say the way we shoot today is the way we'll shoot tomorrow? I think the reason we don't see lens movements in motion pictures is because no camera has been inherently capable of movements since time eternal.

And whether or not it's easy to do, I'm going to try to do it. But I'm only an adequate machinist, and I'd rather be able to mount all the elements in a single barrel - it makes centration a lot easier. That would make recessing the rear elements in the lens body pretty difficult. I suppose it seems like a lot to ask the RED team for, but really, all I'm asking is that they make the front completely removable... or not put vital electronics up there. What are the odds?

[Michael Hastings]

Ryan:

I have been trying to get at the same thing. We make underwater housings and one of my thoughts was to make the entire frontplate become the front of the red camera and build a Nikonos mount into that front plate. (and if I make it a Nikonos mount, there are already adapters that make it possible to use regular nikon lenses on top of the Nikonos mount.

All of the renderings show a front held on by eight screws. If the chip is behind that plate I think we are set. If the chip is mounted on that plate and it is just the electronics behind it then we have to start at the lens mount portion.

Anybody know the answer to where the Mysterium chip is mounted?





I suppose it seems like a lot to ask the RED team for, but really, all I'm asking is that they make the front completely removable... or not put vital electronics up there. What are the odds?

[Ryan Damm]

I'd love to hear from the actual RED team, though I understand they're probably a little bit busy at the moment.

Maybe we'll have to wait 'til NAB.


...and that sounds like a great solution, AquaVideo - I did a quick web search and read a bit about the Nikonos.... interesting to note that many Nikonos bodies weren't reflex at all, and the user had to rely on rangefinders or guessing. (But it's the perfect setup for a single-chip video camera.) Now I understand why you need complete access to the chip.

I think if the physical structure of the camera is as open as the company, we'll be in good shape. I'd love to see the RED adapted to many, many different uses, and it sounds like they could corner the underwater market, too. Time to brush off the scuba gear....

Oddly enough - I'm shooting a documentary in Fiji in May (probably too early for me to get #794 anyway) on a couple of XH A1s (my stopgap cameras until RED comes out). The piece has very little to do with underwater photography, but I'm going to build a dumb housing and get some B-roll anyway - just because I can. I'd be insane to be that close to reef diving and not get some video, right?

[Matt Uhry]

Hi Red Team,

I'd also like to get the dimensions of the part the PL or Nikon or B4 attaches to on the camera body. The "submount" of the camera, what is the inner and outer diameter, focal depth to sensor, and screw layout ?

I'd like to get a jump on a few machine shop projects.

Matt Uhry
www.mattuhry.com