Introducing Nauticam’s WACP - The Wide Angle Corrector Port: Discuss Here

[ianmarsh 38]

Congratulations to Alex on his work with this emerging (re-emerging?) technology. Also a very well written lay-man's review of the optics and physics related to dome ports and wide angle underwater photography.

 

I agree with Alex. I don't think megapixels are the issue. It's all about the water-glass-air interface.

 

I would like to start this thread as a place to discuss the concept, so...fire away!

 

ian

[Matt Sullivan 27]

we've discussed just recently the nikonos 13. I sure as s**t am not selling it but i sure as S**t want this thing also hahaha

 

I love the compactness and IQ of the 13mm so its not going anywhere, but the versatility of this lens also is highly appealing.

[divegypsy 23]

Alex, you talk about using the Nauticam WACP with a Nikon 28-70mm lens. Nikon's own website does not list any 28-70mm lens. Please supply more details about the Nikon lens you used with this port

[ianmarsh 38]

Any optical physicists out there? My understanding ends with Snell's Law:(

 

 

 

How is "Water Correction" achieved?

 

When we talk about water corrected optical lens design, are we talking about the curvature, combinations of elements, different types of glass with specific refractive index or a combination of all of the above.

 

The concept of using a land lens behind the port would assume that the light must be re-refracted as it exits the glass on the inside of the port at the glass air interface to produce a planar virtual image. Is a diopter still needed?

 

I am assuming the field of view will be restored by the corrector?

 

I am guessing that there are a number of ways to achieve the end result. However as with most things in the real world, different approaches will have different compromises and advantages.

 

Any discussion?

Edited September 30, 2017 by ianmarsh

[Ryan 57]

The current compatibility chart is available here:

https://drive.google.com/file/d/0BzggKvdoNvhkUmppUmIxR0dTY0E/view

 

WACP compatibility is still being determined, and this is not a complete list. Updates will be continually as this product is brought to market in the coming weeks.

 

All of the current field testing is essentially to define the compatibility limits. Stress testing, if you will. Personally I expect some of the most popular prime options to be in the 35mm range for full frame, providing even better quality at a narrower field of view. There may actually be two different use strategies that emerge, with prime lenses providing the very best quality at narrower field of views (35mm = 120deg, and even 50mm = 100 deg), and zoom lenses like 28-70 providing very good quality across a wide range of coverage angles.

 

Ian, this is both a wide angle conversion and correction lens. It takes an existing lens, makes it wider, and works very hard to neutralize defects that are introduced by that action AND the air to water interface.

 

Many solutions to the fuzzy corners problem were explored, including lenses that were simply correctors (without wide angle conversion) for current wide angle lenses. This solution (wide angle conversion and correction for 75 degree fov primary lenses) turned out to yield the best mix of performance at a reasonable size and cost.

 

I'm sure this is just the beginning, and I very much look forward to seeing what Nauticam and other manufacturers create.

[ianmarsh 38]

Ryan

 

It sounds like magic.... perhaps the Harry Potter Autograph model?

 

Seriously though, this sounds like what every wide angle photographer has been waiting for since camera technology caught up with existing port physics.

 

Is the Nauticam technology based on Alex's previous experiments with the Ivanoff-Rebikoff corrector, or is it a new concept? How proprietary is the technology?

 

Can you explain how this concept differs from the older, (but still amazing) Nikonos RS concept.

 

As I look at my Seacam 13mm conversion, it is extremely compact. It is interesting that the "correction" in this system goes beyond the front glass. The RS 13mm will not focus in air, even when removed from the front glass element. The RS lens is a complete system, that needs water to function, not simply an adapted land lens.

 

(I have also converted the 20-35 RS, which is more complex than the 13mm due to the integrated zoom gear. I was not able to adapt this to Nauticam (with the Nauticam-Seacam port adapter) due to the gear incompatibility. I have since moved to Seacam specifically because of this.)

 

Perhaps Borut Furlan, Andrej Belic, or Harald Hordosch can chip in?

 

ian

[Tom_Kline 143]

Alex, you talk about using the Nauticam WACP with a Nikon 28-70mm lens. Nikon's own website does not list any 28-70mm lens. Please supply more details about the Nikon lens you used with this port

 

The f/2.8 lens is a discontinued lens model. http://www.nikonusa.com/en/nikon-products/product-archive/camera-lenses/af-s-zoom-nikkor-28-70mm-f%252f2.8d-if-ed.html As well, Canon has discontinued L type (and others) zoom lenses that started at 28mm. Both companies replaced their f/2.8 28-70s with 24-70mm lenses. As well, both have zooms that range from 24mm (and 28mm) to longer focal lengths.

 

@ Alex and Ryan: I recall the older zooms had a minimum focus distances of 0.5m or greater - the newer ones focus to ~ 0.38m. How close were you able to focus the lens behind the WACP in terms of working distance? Would newer (pro type - gold ring or L) zoom lenses be able to focus closer (with the WACP) as well as primes as they have closer focus limits? If one needs to consider older lenses as well as current ones, both pro grade and not, the list is going to be long as suggested by the table so far. Then there are the third party lenses...

 

How bad is a 24-70 (any one of the various models from N or C) with the WACP? The newer lenses have improved optical technology as well as lens to camera communication. How does changing lens length such as when one zooms (i.e. gets longer in size) affect WACP functionality and performance?

Edited September 30, 2017 by Tom_Kline

[Nicool 30]

And my bonus question: any plan for a smaller WACP for APSC dslrs like the D500 or 7D serie?

 

 

Envoyé de mon iPhone en utilisant Tapatalk

[Geo Cloete 6]

I am also wondering how does the minimum focal distance of a lens relate to working with the WACP.

Also and hopefully not off the topic, but could those who have it share or point me in the right direction on working out the correct dome placement for a given lens.

Thx

[ianmarsh 38]

For the inquisitive, but somewhat mathematically feeble, this gem might be of interest, especially the last chapter.

 

http://www.cinemarine.com/cinemarine/fichiers/File/optiqueus.pdf

[Alex_Mustard 0]

Hi All,

 

Sorry to be late to this discussion - my wife is overseas and I was looking after our baby daughter alone this weekend - so no internet was possible!

 

Physically smaller diameter lenses are definitely better with corrector ports, which tends to mean using older lenses. The large front elements of the latest generation of lenses would require huge corrector ports to work as well as the older lenses. And as Ryan says these would just be too heavy and too expensive - importantly with very little improvement in image quality - remember it is the port that the bottleneck on image quality, not the lens. Nauticam ran lots of tests to settle on the size they did. (This is also something I have found with my own rectilinear corrector port - (http://wetpixel.com/forums/index.php?showtopic=54681), which after much testing I now use only with 20mm f/2.8 (90˚ FOV). My own corrector port is an Ivanoff style port, made by Carl Zeiss, it is rectilinear, and does out perform a dome port, but is outperformed in image quality by the WACP. Plus is FOV 90˚, rather than 130˚)

 

To answer Fred's question - the lenses I tried behind the WACP have been Nikon 28mm f/2.8, Nikon 28-70mm f/3.5-f/4.5 and Sigma 28-70mm f/2.8-f/2.8. I know that Jason Isley also used the Nikon 28mm f/1.8.

I don't own the Nikon 28-70mm f/2.8-f/2.8 and considered buying one second hand. But speaking with Edward at Nauticam he thought that it might not offer any advantage over the f/3.5-f/4.5 with the WACP - which is actually a sharp lens, despite being small and slow. I will try it one day.

I tried the Sigma 28-70mm f/2.8-f/2.8 with an earlier prototype of the WACP and also send my lens to China for Nauticam to test in the lab with the production WACP. But for luggage allowance reasons I haven't retested in the field (I was also testing the Retra strobes and 8-15mm (reviews on Wetpixel) on these same trips - as well as doing my own photography.

 

I would like to try more lenses - but the focus thus far has been evaluating the WACP - and it was sensible to all be using the same lenses to do that, rather than introducing another variable. For me the best lens was the 28-70mm f/3.5-f/4.5. I liked that it is small, it is also a very useful travel lens for topside stills and video. Picture below:

 

 

The WACP allows you to focus to the port with all the lenses I tried. I guess this is partly because the WACP sticks out so far, but I guess it is also designed to help lenses too. Here are two shots of my fingers on the dome - one at 28mm and one at 70mm. These are on the preproduction prototype (from Oct 2016) - which is why there is cut off from the dome shades @ 28mm - you don't get this now.

 

 

Alex

[Alex_Mustard 0]

As I look at my Seacam 13mm conversion, it is extremely compact. It is interesting that the "correction" in this system goes beyond the front glass. The RS 13mm will not focus in air, even when removed from the front glass element. The RS lens is a complete system, that needs water to function, not simply an adapted land lens.

 

(I have also converted the 20-35 RS, which is more complex than the 13mm due to the integrated zoom gear. I was not able to adapt this to Nauticam (with the Nauticam-Seacam port adapter) due to the gear incompatibility. I have since moved to Seacam specifically because of this.)

 

In comparison to the two RS lenses the WACP is a very useful addition with a 28-70mm.

RS 13mm - FOV 170 degrees

WACP + 28-70mm - FOV 130-57 degrees

RS 20-35mm - FOV 68-42 degrees (from what I understand)

 

Although if you owned the WACP you could easily use a longer lens behind it to cover the whole range of the RS 20-35mm.

 

Alex

[Ryan 57]

Is the Nauticam technology based on Alex's previous experiments with the Ivanoff-Rebikoff corrector, or is it a new concept? How proprietary is the technology?

 

No, not at all. Ivanoff-Rebikoff is overly restricting in field of view in my opinion, and I'm glad that isn't the route we pursued. Ivanoff is a corrective lens, WACP is a wide angle conversion and correction optic.

 

 

 

Can you explain how this concept differs from the older, (but still amazing) Nikonos RS concept.

 

RS 13mm is amazing, 170deg with fisheye distortion. This is a very difficult focal length than anything paired with WACP will ever be, and also has much more barrel distortion. I can certainly see how someone would want to travel with both...

 

I can't imagine a situation in which I'd find the narrow field of view of RS 20-35 (which is actually a 24mm lens at its widest) useful.

 

Both of these RS lensers are purpose built, single use optics. WACP is a wide angle conversion port (.36x magnification, converting 75 deg to 130 deg at its widest) for off the shelf lenses.

 

 

 

I recall the older zooms had a minimum focus distances of 0.5m or greater - the newer ones focus to ~ 0.38m. How close were you able to focus the lens behind the WACP in terms of working distance? Would newer (pro type - gold ring or L) zoom lenses be able to focus closer (with the WACP) as well as primes as they have closer focus limits?

 

All of the currently recommended combinations are focusing on the dome...

 

 

 

 

And my bonus question: any plan for a smaller WACP for APSC dslrs like the D500 or 7D serie?

 

This lens will actually perform better in terms of overall sharpness, and with a wider range of lenses, on APS-C. The smaller formats have benefits...

Edited October 2, 2017 by Ryan

[ianmarsh 38]

Thanks Alex

 

Let's see if I understand this:

 

The Nikonos RS 13mm is a fisheye, so not really fair to compare to the WACP which is rectilinear.

 

I guess one thing to keep in mind is that the focal length quoted on the lens barrel is the "true" focal length, in air. This is a physical property of the lens construction. The actual focal length in use (underwater) must be multiplied by 1.33. This also changes the FOV of the lens.

 

I had long assumed that Nikon would have originally quoted the focal length (and therefore FOV) on the Nikonos RS and 15mm as the focal length in their native medium (water), since the lenses where designated as R-UW, and don't focus in air. I guess that is not the case.

 

I am assuming this does not happen with the WACP, and in fact, just the opposite. Because of the "Correction", the field of view is increased, at the same time "repairing" the damage done to the corners of the image due to refraction (CA) and curvature of field (DOF).

 

That's got to be some fancy physics. As you said... "You CAN have your cake, and eat it too".

 

That doesn't often happen in the real world:)

 

ian

 

 

 

 

Thanks Ryan.. I just spotted your response while I was typing:)

Edited October 2, 2017 by ianmarsh

[Bumbi.dombovari 3]

Hi there.

I am a new boy, my question is:

I'd love to read a test about the Nauticam Sony A7 II / A9 + 28mm + WWL-1 against WACP, given the price of WWL-1, is one third of WACP.

 

Bumbi

[Alex_Mustard 0]

I'd love to read a test about the Nauticam Sony A7 II / A9 + 28mm + WWL-1 against WACP, given the price of WWL-1, is one third of WACP.

 

 

Hopefully the WACP will get much more testing soon - I don’t think the WACP has been tested on a Sony yet.

 

During the development of the WACP, I shot a prototype version in the Red Sea that was half way between the WWL-1 and the WACP. On my Nikon this was about a stop better than a dome and a stop worse than the the final WACP. So maybe this is a guide for now.

 

Alex

[Architeuthis 179]

Hi Ryan,

 

I currently use Olympus EM5-MII, NA-EM5MII, Zen DP170-N120, Nauticam 60mm Extension with Panasonic 7-14mm 4.0. Acccording to your data, shown in Alex's review, the WWL-1 with kit zoom-lens would perform better than this combination.

 

=> is this true in real life?

=> would the new WACP even perform better?

=> where is the rest of the data available (e.g. also center performance)?

 

Wolfgang

[Bumbi.dombovari 3]

Thanks Alex,

 

I'm very interested in this because I want to replace my Nikon Dx / Subal equipment with Sony FF / Nauticam. From the following description, it seems to me that Sony A7RII / A9 + 28mm + flatport + WWL-1 compiles all wide-angle subjects (from CFWA to split images).

 

http://www.nauticam.com/news/freshwaters-illustrated-puerto-ricos-wild-rivers/

 

This can be solved with DX machines with Tokina 10-17 only with two different size doms. For FF it has not been a good solution to CFWA. Now it looks like Nauticam has solved Canon's Nikon’s full-frame machines with WACP.

 

Just the weight and the price ...

 

Hi

Bumbi

[Alex_Mustard 0]

But with the Sony setup you will be limited to only 130˚ with the WWL-1 or the WACP. You still need a 180˚ fisheye. Also while it is possible to shoot splits with the WWL-1, it is not advisable - as there is water in front and behind it to contend with. Again you want a fisheye and normal dome for that.

[Bumbi.dombovari 3]

Hi,

Why does Nauticam only recommend Sony to WWL-1?
Why not for Nikon, for Canon?

Bumbi

[Bumbi.dombovari 3]

In the quotation article Jeremy Monroe & David Herasimtschuk wrote:

 

The WWL-1 is a wet-connect lens, which makes split shots challenging, but the Reef Photo team helped us find a perfectly sized o-ring that we could place in the wet-connect chamber to keep water sealed in and allow us to capture cleaner split shots.

 

 

 

Edited October 4, 2017 by Bumbi.dombovari

[Bumbi.dombovari 3]

[Architeuthis 179]

Here is another review on WWL-1: https://www.bluewaterphotostore.com/nauticam-wwl1-review-tests

 

The conclusion is the opposite to the recent Wetpixel review: WWL-1 is simpler to use with MFT and FF (Sony), but image quality is better with WW-lenses plus dome ports.

 

Is this review nonsense?

 

Wolfgang

[Draq 134]

I would be interested in seeing what the experts have to say on this topic, but perhaps you should post it in the mirrorless forum also

 

Here is another review on WWL-1: https://www.bluewaterphotostore.com/nauticam-wwl1-review-tests

 

The conclusion is the opposite to the recent Wetpixel review: WWL-1 is simpler to use with MFT and FF (Sony), but image quality is better with WW-lenses plus dome ports.

 

Is this review nonsense?

 

Wolfgang

Edited October 4, 2017 by Draq

[Alex_Mustard 0]

Hi,

Why does Nauticam only recommend Sony to WWL-1?

Why not for Nikon, for Canon?

Bumbi

 

I couldn't get the WWL-1 to mount close enough to my lens to use it with Nikon with 28-70mm (this was 18 months ago):

https://www.facebook.com/photo.php?fbid=10156695440455713&set=pb.796325712.-2207520000.1507125929.&type=3&theater

 

The WACP is the solution for this failed attempt!

 

Alex