Underwater Bubble Blowin' Users Group

[chuck colburn]

Get someone to put an Olympus mount on your Red and you can use some of the finest still camera optics ever made. Including this little ditty.

http://www.adorama.com/IOM714.html

[Michael Hastings]

The Olympus e sensor is 18 x 13.5 mm so would probably have the vignetting issue - also it seems to only have internal iris control like the other digital specific lenses.

Get someone to put an Olympus mount on your Red and you can use some of the finest still camera optics ever made. Including this little ditty.

http://www.adorama.com/IOM714.html

[chuck colburn]

The Olympus e sensor is 18 x 13.5 mm so would probably have the vignetting issue - also it seems to only have internal iris control like the other digital specific lenses.

Ahh I see. Should have read up on that 4/3 sensor size!

[Michael Hastings]

There has been some info in the lens section about a mount for the EF lenses. I posted this over there, but think it has relevance here too.

I have a strong interest in this sort of thing for use in making the underwater housing for the RED. We have a compact board with an onboard micro controller that we use to do focus, iris, etc. through LAN C that I believe could be easily reprogrammed to send whatever RS232 commands the birger adapter needs. It seems to me that with what they have done already and if RED will give us the information on the front plate of the camera and flange distances to the sensor it wouldn't be that hard to do the physical part either. It seems like the RED team should be seriously considering the utility of the EF setup as it seems like the Iris is easier to do on the canon EF than the Nikon system. Also, it seems like the EF-S 10-22 would be a possibility since the sensor size is almost identical and it would provide the phenomenal wide angle zoom that I think a lot of us are looking for - but particular us underwater guys. We have a CNC machining center, so if RED is overloaded, with a little help we could do it here.

The Guys at Birger Engineering are looking into this. They have an intelligent adapter which allows control of EF mount lenses, but it currently requires a computer to be connected to it for communication with the lens. http://www.birger.com/Merchant2/merc...een=ef232_home

There has been an amount of discussion about repurposing this technology to make a RedOne mount for EF lenses which would have a separate hardware controller, could be wired or wireless. This would allow for focus as well as iris control and it could be configured to act as a very effective follow focus. The mechanical action of the focus ring on the lens could be remapped to allow for much more effective manual control than could be executed with the focus ring. Parts of the focus range could be expanded, preset focus points could be assigned to buttons... lots of potentiol.

This is all exciting stuff, but still vapourware at the moment, however Birger have suggested that there may be an announcement coming up to NAB. I have attached a quote from a post by Erik at Birger which comes from the "Spike Black... First Prototype photos" sticky on the Red One forum.

Martin

Just remembered that the 12-24 has no iris ring - a bit of a problem with the RED. Anybody know if you can dig into these lenses to hot wire the iris motor? - we've done it many times with video lenses and it sure would make external control easier than with gears.

[David Nardini]

... the EF-S 10-22 would be a possibility since the sensor size is almost identical and it would provide the phenomenal wide angle zoom that I think a lot of us are looking for - but particular us underwater guys. We have a CNC machining center, so if RED is overloaded, with a little help we could do it here. ...

Yep AquaVideoRed206 ... great lens if somebody could give us an aperture control mechanism

The Birger Engineering folk appear to be working on an EOS adapter, so fingers crossed, we'll end up with a wider pick list than just the older style (aperture control) lenses.
Have not seen this lens on their 'list', but I assume the protocol is the same for all EOS lenses ?

[Ken Corben]

AquaVideoRed206...

EOS adapter with LANC control for the Canon 10-22mm sounds like the slickest lens solution I have heard. Would you "CNC" a canon front plate for the red camera? That would be far more elegant than other work arounds.

Are you planning on RED PVC and plastic or glass dome for the housing design?

Sharky

PS- If you would share your expertise on the pros and cons of plastic vs glass domes for a hypothetical Canon 10-22mm underwater that would be much appreciated. "Explain it to me as if I were a six year old," from Denzel Washington in Philidelphia.

[David Nardini]

... If you would share your expertise on the pros and cons of plastic vs glass domes for a hypothetical Canon 10-22mm underwater ...

Not quite an explanation for 6 year olds, but here is a starting point :

http://scubageek.com/articles/wwwdome.html

Plastic is great in that you can polish off small scratches (eg: t-cut) ... glass you are pretty much stuck with it, but underwater you will hard pressed to see their effects. For split level shots, however, you may see the defects clearly (stopped down & close focus) ... depends of the shot.

An excellent (old but still good) reference book is 'The Manual of Underwater Photography' by T. Glover, G.E. Hardwood and J.N. Lythgoe (Academic Press). Not sure if it's in publication ... worth picking up an old copy.

The thing I don't like about domes is the curved depth of field they inherently exhibit. I much prefer Ivanoff ports (they also work better in air & for split levels). I'm trying to find somebody (?) who can machine / polish one up :help:

I've got the formula somewhere ... once I find it (Ivanoff port + corrective diopter pair) I'll post it ...

[chuck colburn]

David,

There are lots of sites for surplus optics (windows, lenses etc.) out there.
Some with anti-relective coatings already applied. These could save you a bundle over having one generated and coated. Do you have an idea of how large of one you would need. I like to poke around at these sites and might stumble onto one that would serve your porpise. hehe

Chuck

[David Nardini]

... Do you have an idea of how large of one you would need ...

Below is a picture summarising the Ivanoff-Rebikoff correction lens and some formulas ... hope I've not made a typo !
Essentially it's a reversed Galilean telescope in which the front (plano) concave lens is used for the watertight window. The lens system will be afocal if :
fd = fn + d
where :
fd = focal length of the positive lens
fn = focal length of the negative lens
d = separation between the lenses

In summary, the main benefits of this port system (as can be found on the Hassy SWC housing) :

• it is afocal and can be used in conjunction with a conventional camera lens of any focal length as long as it does not vignette the corners
• the focal length and field of view of the camera lens are the same in water as in air
• pincushion distortion, chromatic aberration and other aberrations of a plane (flat) port are corrected
• depth of field is increased by about a factor of 2 over a plane port with the same camera lens and aperture

Alignment of the optical axis of camera lens and correcting lenses (+ve and -ve) is critical. Ideally, they should all be mounted on one rigid mechanical unit (any flexing of the u/w housing under pressure will not affect quality; this is clearly only an issue for deeper work).

That's it anybody out there that can machine up / polish a perpex port for me :help: (I can sort out the +ve diopter). The underwater community could really do with a supplier of these ports ... !

EDIT : oh ... forgot to say, I don't know how zoom lenses will stack up in this scenario, but will find try and find out ...

[Mark Thorpe]

This thread is really coming into its own. A lot of information from a lot of talented people. Let's keep it going. I too am wondering what we will all end up with. David I'm hoping it will become possible to use the SWP44 but I think we are all starting to look at avenues that point to other glass options. I really do like this lens. The following is a shot from about 1 ft from the subject. Great coverage I reckon.

Cheers,
Mark