Ivanoff-Rebikoff corrector/adaptor

I'm planning on buying an Olympus 5060, and have therefore been following threads here and elsewhere regarding this camera, wide angel lenses, flat ports, dome ports...

Recently I found an old book on underwater photography. It mentioned an Inanoff-Rebikoff corrector that makes the housing and the water "disappear". Under water in a housing with this corrector, camera lenses would function as on land. The book mentioned that Hasselblad used this corrector in an underwater housing.

Anyone heard of Ivanoff and Rebikoff? Are there any housings using this construction?

The book basically said that:

Flat ports are preferred above 35mm and not acceptable below 28mm.

Dome ports are better for wide angle lenses in terms of distortion, but the dome is in fact a lens and it will affect picture quality when using large apertures. You also need a lens that can focus on really short distances because the dome will make everything appear much closer.

The only downside with the Ivanoff-Rebikoff corrector seems to be that it was expensive! It is part of the housing, and I assume, specific to the lens you are using. From a sketch in the book I see that it has two parts. One concave lens that “is” the port, and one convex lens closer to or attached to the camera lens.

Providing you plan to use the whole zoom range of the Olympus 5060 a flat port is probably the right choice. If you only plan to use the wider angles (28-35) a dome port would be better.

I don't understand how the WCON-07C 19mm wide angle converter and the PPO-02 port (flat) can perform well?

/Anders

Very interesting read!

http://camerasunderwater.co.uk/info/lenscorrect.html

same same but different

http://www.dpreview.com/news/0402/04020301...xoopticspro.asp

As long as the optical ”problem” is predictable and consistent it can be compensated for in software.

/Anders

And if the problem is of a certain type. Not all are correctable.

Even for correctable problems, digital correction requires that you accept some loss of detail. It's always best to get the best optical quality, best conversion, best color, etc. every step of the way.

Domes effect picture quality but so do flat ports. Flat ports are preferred for longer lenses because they are easier. Domes work well for macro, too.

Sure, there is a price tag on everything.

All cameras are designed for in-air use. Even if we buy a perfect camera we’ll get optical problems when we put it in a housing a take it underwater. Flat ports and domes are both compromises. It’s just a matter of which is the best for a particular lens/use.

These software solutions can help us reduce the effects of those problems.

I’m trying to decide what camera to buy next. (I’m sure it will be an Olympus 5060.) It seems to me that cameras are either made for:

1) Professionals (expensive, complicated and bulky)

2) People who don’t even want to know anything about photography

There is no camera for me!

I want a digital Nikonos VI!

For on-land use the new Leica/Panasonic gives me hope.

http://www.dpreview.com/reviews/specs/Leic...ca_digilux2.asp

http://www.medievalvillage.com/pana/Panaso...4_Lumix_LC1.pdf

/Anders

Perhaps you should consider the new Aquatica 300D. It relatively compact and inexpensive for an SLR yet it provides iTTL strobe control with traditional underwater strobes. For macro shooting you shouldn't have to worry about strobes with this rig. With wide angle it is trickier but then it always is reagardless of camera.

It's still expensive as all housed cameras are, but I think you would find it not as complicated as it first seems.

I have had the hasselblad with the Ivanoff-Rebikoff Ziess port. It's amazing! Ernie Brooks is the only other person I know that has one. They are hard to come by but worth every dime.

Ric Frazier

underwater photographer / underwater director

http://www.frazierproductions.com

Finally!

Do you know where I can get more info on how it's dessigned?

The Hugyfot Hasselblad housing pops up on ebay from time to time. The Ziess port has only showup once on ebay in 8 years. I don't ever plan on selling mine.

It's basically is a flat port with the 'dome' on the inside. It looks to have two to three lens elements which goes with the Ivanoff-Rebikoff corrector/adaptor.

best,

ric

Ric Frazier

underwater director / underwater photographer

http://frazierproductions.com

An Ivanoff Corrector consists of two components - a plano-concave lens with the flat side in contact with water (and a curved surface cut into the air side), and a second positive lens which has a focal length equal to that of the front component plus the separation of the components.

In practice you will find that the rear component is made up of several elements and, in order to have a substantial field of view, the corrector becomes very large very quickly. I think that the Hasselblad one was only usable with 50mm (and perhaps 80mm) lenses, but Ric will no doubt be able to confirm this. There have been other designs and I actually have copies of the paper on at least one. Sadly, all are expensive to build and are limited in scope and the likelihood of any being produced for ephemeral camera models is low!

Software can only correct so much!

I also have the Ziess Ivanoff and corrector lens for my Hasselblad. I had hoped to use it with lots of lens, but Peter Scoones told me that it was made specifically for the 38mm SWC. I have a SWC but I am yet to take it underwater. Maybe if I get a digital back one day...

Also the second lens that goes inside the housing will only screw onto certain Hasselblad optics.

Alex

Alex

If you EVER try a digital back on the SWC be aware that the Biogon is a very old design and almost certainly will produce less than ideal light paths for the edges of the sensor! I'd be very interested in hearing how it would work but have a sneaking suspicion that a good modern wide-angle on your D2X may be a better option!!!

Guess which camera I am taking away with me tomorrow!

Alex

Here is a quicktime that I made back in 97 of the housing with the Ivanoff-Rebikoff port.

Hasselblad Housing with Ivanoff-Rebikoff port

At least 96% of my images are shot with this housing over 12 years. I tried the Phaseone 11 megapixel back on it about 4 years ago and the camera is too old for all the electronics in the back.

Ric Frazier

underwater photographer /

underwater director

As Paul said, the Ivanoff corrector design isn’t suitable for larger field of views as the whole thing would become quiet big and difficult to manufacture. I have talked to Zeiss about using it for different lenses and it does only make sense for medium field of views. But the problems we encounter with dome ports are mainly in the extreme range with great field of views where corner problems become stronger. If someone wants to explore high quality custom housing optics for wideangles, I would start considering aspherical dome-/front glasses like in the movie business.

Julian

Julian

Have you come across Fathom imaging ports (for underwater video housings) - I've read somewhere that one has been adapted for EOS1DS use and I'm intrigued!

Hi Paul,

I’ve heard good things about it for video. But I haven’t heard about adaptation for still reflex cameras. Sound very interesting! I understand the Fathom ports include wideangle conversion? What lens is used with the 1Ds MkII in conjunction with the port optic?

Thanks,

Julian