The Gentleman's Underwater Bubble Blower Thread

[Rudi Herbert]

Speaking of which,

How about a rectilinear lens, a zoom that is about 7-19mm, yielding over 120 degrees HORIZONTAL at the wide end and letting you frame tight enough at the narrow end? Of course, no discernible corner softness and an average field curvature of around 3%, which means straight lines remain pretty straight. Front element only 6"wide, total length less than 4", with its own actuators to control focus, iris and zoom, so it attaches to any housing without further need for reworking gears and whatnot. Sorry for taking a page out of Jim Jannard's book and tease you guys with an image that does not say much, but this is all I can share right now. Shot less than 10" from the wall, take a look at those corners.

 

[Johnny Friday]

I have to say i'm really loving the Optimo 16-42....rectilinear and a lens that stands out next to my Nikon pkg in terms of contrast and image quality....it is a beast though...but the result is worth it...

 

[Michael Hastings]

Michael,
have you used the Canon 8-15 yet? I'm not much of a fan....since it is kind of a myth....you don't get to use the lens until around 13 or 14mm if i recall in 5k full frame. I'd prefer a more useable focal range. That said, i only used it once, but did not care for it in open water with not much background. It did show images well in highly dense areas like kelp beds, but no more than a more useable focal distance. But i'm also not aware of what other fisheye zooms are out there.

Actually the whole point of the 8-15 and the reason it is a zoom is so that it covers all of the sensor sizes APS-C (Red1, and Canon 7D, Nikon D7000), APS-M (Epic5K and Dragon6K sensors as well as some of the 1D and 5D series canon - mostly the high frames per second cameras designed for sports) and Full Frame 5DMII and such.

The 8-15 even has a lock switch marked C and M so you can lock the zoom on the proper setting for the sensor size.

It isn't really meant as a "live" zoom lens - it is more for being able to be properly set for the various sensor sizes.

 

[Rudi Herbert]

I guess I wasn't explicit enough. That is the first image from my corrected underwater optic, which at this point, consists of a corrected aspherical dome port and a second element that attaches to the lens. The second element corrects field curvature and improves contrast and color rendition, as well as eliminates the cool (as in bluish) bias all wide zooms exhibit on the edges. This image is taken without the second element, only the dome, and I am pretty happy with the results. The system is designed with a wide variety of rectilinear lenses, although it is optimized for the geometry of some lenses much more than for others. It will increase FOV by a factor of .33 without introducing further distortion, so it will turn a 14mm into a 10mm, a 10mm into a 7mm, and so on and so forth. If a lens exhibits soft corners on land, like the Tokina 11-16 does, then my system won't cure that malady too much, but you can then shoot that lens at, say, 16mm, where it shows its best corner performance, and still get the equivalent FOV of 11.5mm. The front dome being non-concentric and aspherical, it greatly decreases color fringes and chromatic aberrations, although some lenses, mostly Canons, will show plenty of that no matter what. So far, the best performance has come from Nikon primes and zooms.

 

[Pawel Achtel]

...So far, the best performance has come from Nikon primes and zooms.

Sounds interesting. So, what is the MTF performance and how measured?

 

[Jon Shaw]

I thought the Canon 8-15mm covered full frame all the way through...... obviously not.

Looks really interesting Rudi

 

[John J Ellerbrock]

Jon Shaw on Location

Jon Shaw on Location

Jon found an idyllic beach locale for the production of 'DROWN'.

Special thanks to Nick Amidy and Amelia McCarten for the images.

www.GinClearFilm.com

 

[Ross Isaacs]

Jon is a great shooter!

 

[Tom Hamilton]

If you've ever had a roll with a gal on a beach, you'll know that sand gets into the tightest spots , it's truly magical stuff.

Careful cleaning that housing Jon, partially flooded one in a previous life after using it to shoot waves on a sandy beach, thought I'd gotten it all, even one little grain overlooked will do it.

 

[Greg F]

Sand is evil Tom.. Talk about CHAFING!!

And yeah I have a soft bristle brush that I knock all the sand off my housing when I get it on there. Its pretty magical how well it works, I dont think it would work in those *delicate areas* as it needs to be dry!! HAHAHA

 

[Michael Hastings]

I thought the Canon 8-15mm covered full frame all the way through...... obviously not.

Looks really interesting Rudi

Here's a review of the 8-15 that shows what you can expect with various sensors. Just remember that Red4K is equivalent to APS-C and that Epic 5K and Dragon 6K are essentially APS-H

http://www.the-digital-picture.com/Reviews/Canon-EF-8-15mm-f-4-L-USM-Fisheye-Lens-Review.aspx

The first picture shows the zoom ring with markings for APS-C and APS-H settings. These settings (and the lock switch if you use it) make it so you get a full frame picture. You can still go wider on APS-H and Full frame but you will begin to get black corners - and on a full frame sensor - a full circular 180 degree fisheye image with black all around.

 

[Frazier Nivens]

Oceanics and Marlins for you

Oceanics and Marlins for you

Hi all,

I'm leaving for Cat Island to film Oceanics with the Epic and Gates.
I was thinking about shooting the Canon 8-15 Fish Eye.
Just got myself some brand new Keldan CRI pair, thrilled to test them.

Any good tips?
Thanks and hope I'll live to show you some shots.... LOL!

Michael, I wish for you good filming with the Oceanic's smiling faces coming at you and also wish for you a Marlin. Have fun, some beautiful dives and if you stay at Hawks Nest, you'll love it.

Best,
Frazier

 

[Michael Maes]

Michael, I wish for you good filming with the Oceanic's smiling faces coming at you and also wish for you a Marlin. Have fun, some beautiful dives and if you stay at Hawks Nest, you'll love it.

Best,
Frazier

Thanks Frazier and thanks for our chat too!
Not sure where we're staying, not something I took care of :-/
I hope to see (some) Marlin, that would be awesome!
Nice shots you have there
Cheers!

 

[Mauricio Handler]

I've been following the posts whenever possible - I see interesting developments all around....

Here are a few Still grabs from my last shoot in clear but greener environment of the Mexican Cenotes.
I am very happy with the compact combo of the Scarlet and Amphibico Rouge- extremely well balanced rig.
I am though looking for a much sharper image that that of my Tokina 10-17 which I love but feel does not pull 100% under all conditions.....
Still waiting to hear a report on using the Zeiss 15mm - Anyone?
Sequences are very nice- crisp and inspiring...


Best - MH

 

[James Killion]

I agree Mauricio, the 10-17 is nice but there has got to be something else out there in that focal range with better optics. I wish Angenieux had some wide glass like that. I think Johnny has some good glass in the Optimo but needs to be a touch on the wider end. And something that will cover 6K!

 

[Johnny Friday]

I don't think you can go wrong with the Sigma 15mm fisheye at FF. That is one of my fav. pieces of glass. Also have a zeiss PL 14mm std. prime i like that's rectilinear. but a good wide zoom in DSLR glass would be nice....i'm at a loss for what that is....but 16-42 the beast it is is a very beautiful lens and i think it's wide enough in most conditions...

 

[Rudi Herbert]

Gentlemen, a few things to keep in mind,

Still lenses ARE designed to be sharper than cine lenses since they need to cover sensors whose megapixel count is routinely double or tipple that of digital cinema cameras. The Nikon D-800 has a 36 MP sensor while Dragon will be "only" 19 MP. That said, not all wide lenses are created equal, and fisheyes for one, exhibit some of the worst performance of still lenses, and that's due to their nature, not the manufacturers. The much touted Canon 8-15 fisheye has such horrible color fringes and CA all across the frame it is beyond me how some people continue to use it. Then again, so do many rectilinears exhibit the same problems. The Tokina 11-16 comes to mind, with fringing and CA not as bad as a fisheye but plenty visible AND soft corners to boot. The best performance in both groups seems to reside in the 14mm retilinear primes and the 15-16mm prime fisheyes. The Sigma 8-16 rectilinear is crazy sharp BUT corners are soft AND light falloff at the edges is so noticeable it cannot be used underwater without having to crop, so it is not truly an 8mm lens. The best rectilinear zoom out there nowadays is the Nikon 10-24, which is plenty sharp and is magically devoid of corner softness even behind a regular dome. It also has the most usable range.

The reason, I suspect, why cine lenses appear sharper than still lenses is because they have a lot of high contrast glass in their design which is something still lenses avoid, save for some notable exceptions such as the Nikon 14-24 full frame zoom, which produces the most saturated colors of any wide zoom I've seen. Coupled with the fact that RED goes out of its way to design its OLPF to avoid the appearance of sharpness in its images, I think some still lenses look softer than they truly are when used with a RED. I recommend pushing detail to 2 and sharpness to 1, even 2 sometimes, on Redcine and you'll get much better performance out of those soft still lenses.

My corrected optic does not work with fisheyes but it does help rectilinears quite a bit. I am in the process of optimizing it for the Nikon 10-24, where it will yield 120 degrees horizontal (not diagonal) at the wide end and 80 degrees at the narrow end, so it will be around a 7-17 zoom for APS-C sized sensors, equivalent to a 11-25 on full frame and about a 9-20mm zoom on Dragon. There is no wider rectilinear zoom that I'm aware of. I cannot emphasize what a big deal 110 deg + horizontal FOV truly is! Couple that with 6" MFD, 3% maximum field curvature and I'm hoping this will be a genuine option. Here's a 200% crop of the corner area shot with the Nikon 10-24 at its widest, about 6" from the wall and aperture of f5.6, and that is without the second element that increases contrast and saturation.

 

[Mauricio Handler]

James, Johnny and Rudi

Thanks for the input and lens direction... I have been applying the +2 on Detail and +1 on sharpness and indeed it does look better.... Still fine tuning it all...
I will look into the Sigma 15 and the Nikon 10-24..... Has anyone tried the Zeiss 15 mm yet?

Rudi- Looking forward to your ports... it will be a welcome tool!

Thanks again.
MH

 

[Pawel Achtel]

Gentlemen, a few things to keep in mind,

Still lenses ARE designed to be sharper than cine lenses since they need to cover sensors whose megapixel count is routinely double or tipple that of digital cinema cameras....The reason, I suspect, why cine lenses appear sharper than still lenses is because they have a lot of high contrast glass in their design which is something still lenses avoid,....

I'm confused. Sharpness is generally measured by measuring contrast at high spatial frequencies.

My cine lenses (specifically MP 14mm) comfortably outresolves 4 micron pixels at all apertures (up to f/1.2) in every point of the frame. But, that does not matter much when this lens is placed behind an underwater port.

What you and most others seem to confuse is that sharpness of the housed lenses is mostly irrelevant because the limitation is in the port that is housing it. It is the port that is changing the characteristics and performance of the taking lens in so many ways and to extent that selection of the lens based on its land performance is a big mistake.

 

[Tom Hamilton]

Hey All,

would like your collective opinion here, installing the dome port cover underwater before handing the cam up to the boat crew, does that trap salt inside that could potentially damage the dome?

Thanks