Underwater Bubble Blowers User Group Thread NEW

[Frazier Nivens]

Other imaging

Other imaging

I always evalutate sharpness of my optics by looking at a small Youtube video clip.

Thanks Pawel, it's even sharper in the original file...and it's on Vimeo, not Youtube. Same place as you posted your Seadragon video which looks very good and sharp, for vimeo it's quite a great shot.

Corners are sharp in this image that I shot in the Red Sea, some curvature but I was very close with a great UW lighting. But you can't fault this image. I shoot quite a bit of vertical imaging.

http://www.flickr.com/photos/oceanimaging/7755955970/in/photostream

Image is a bit downsized but one of my favorites. Tom, you may have been here, This is at Ras Muhammed, I spent a bit of time here filming, from Eliat to Ras Muhammed and then down to Hurgahda and then down to Elphinstone.

 

[Johnny Friday]

I always evalutate sharpness of my optics by looking at a small Youtube video clip.

But isn't that what you did when you posted the pool frame grab? Posted a frame grab for all of us to view? If i recall you loaded it up in your post and as most images loaded via reduser....

....and Im sure if you showed up at Frazier's home....he may or may not show you the original file at full 5k rez.

 

[Pawel Achtel]

Again: Anyone wanting to evaluate image quality produced by Nikon Nikonos 15mm lenses on a motion picture can contact me to arrange for a private screening on a 4k monitor at Band Pro.

Full 5k frame grabs are posted here: http://achtel.com/DeepX/images.htm

There will be more real-life sample footage and frame grabs coming, although I do not intend to do any filming myself until November/December.

But, to properly evaluate and compare underwater optics one needs to measure the MTF. I did this and can say with full confidence that a typical 9" dome port + land lens combination are not able to resolve more than about 300 lines per picture height in the corners. By saying "not able to resolve" I mean the MTF reaches 0%. Obviously, the contrast suffers at larger detail and away from the corner too. MTF charts allow you to measure exactly how much deterioration is there: at each point of the frame and each detail size (a 4 dimensional graph).

I can also say with full confidence about a dome port is that the micro-contrast across the important part of the frame is far inferior to that produced by a 30-year old marvel of underwater photography - the Nikonos 15mm, which is actually modern retrofocus design optimised not only for underwater, but for close focusing range too.

I can also say with full confidence that Nikonos 15mm does not produce image plane curvature and performs exceptionally well at f/2.8.

I can also say with confidence that Nikonos 15mm is the only rectilinear wide angle underwater optics able to out-resolve the Epic 5k sensor in each and every pixel. I can't wait for 6k Dragon.

Frazier, with all due respect, these images are pretty, well composed and colourful, but they do look very soft to me. It is not your fault. All land wide angle lenses that I tested performed poorly at close focusing distance. Add a dome to the equasion and you end up with a soft image with low-contrast detail.

BTW, The irony is that, at close focus, the actual lens performs poorly and at longer subject to camera distances, the image curvature of the dome reaches the maximum, which is a kind of a double whammy because the virtual image distance still remains relatively close to the lens even if the subject is far away.

 

[Tom Hamilton]

Beautiful shot Frazier, very much so in fact, classic Red Sea stuff.

Unfortunately, the Egyptians are busy bombing and strafing the Sinai at the moment, internal terrorists apparently, Ras Muhammed not safe for travel, but still a spectacular place.

Was at Elfinstone a few short months ago in very heavy seas, drove the camera down to 170 feet, still had surge even at that depth, very difficult to capture the beauty of the place in those conditions. But still, some of the best the Red Sea has to offer on the Egyptian side.

Can I interest you in a trip over to the Saudi side? Have connections, will travel, you'd be surprised at how different it is.

 

[Ross Isaacs]

I always evalutate sharpness of my optics by looking at a small Youtube video clip.

I believe Pawel is being sarcastic !

 

[Johnny Friday]

Thanks Pawel, it's even sharper in the original file...and it's on Vimeo, not Youtube. Same place as you posted your Seadragon video which looks very good and sharp, for vimeo it's quite a great shot.

Corners are sharp in this image that I shot in the Red Sea, some curvature but I was very close with a great UW lighting. But you can't fault this image. I shoot quite a bit of vertical imaging.

http://www.flickr.com/photos/oceanimaging/7755955970/in/photostream

Image is a bit downsized but one of my favorites. Tom, you may have been here, This is at Ras Muhammed, I spent a bit of time here filming, from Eliat to Ras Muhammed and then down to Hurgahda and then down to Elphinstone.

GREAT image Frazier. Love the tilt on it to vertical. I highly doubt anyone will find this image not up to HD standard....nor soft in the corners....Thanks for sharing it. the word BEAUTIFUL comes to mind.

....and i don't need MTF to evaluate it....looks great.

 

[Frazier Nivens]

Again: Anyone wanting to evaluate image quality produced by Nikon Nikonos 15mm lenses on a motion picture can contact me to arrange for a private screening on a 4k monitor at Band Pro.

Full 5k frame grabs are posted here: http://achtel.com/DeepX/images.htm

There will be more real-life sample footage and frame grabs coming, although I do not intend to do any filming myself until November/December.

But, to properly evaluate and compare underwater optics one needs to measure the MTF. I did this and can say with full confidence that a typical 9" dome port + land lens combination are not able to resolve more than about 300 lines per picture height in the corners. By saying "not able to resolve" I mean the MTF reaches 0%. Obviously, the contrast suffers at larger detail and away from the corner too. MTF charts allow you to measure exactly how much deterioration is there: at each point of the frame and each detail size (a 4 dimensional graph).

I can also say with full confidence about a dome port is that the micro-contrast across the important part of the frame is far inferior to that produced by a 30-year old marvel of underwater photography - the Nikonos 15mm, which is actually modern retrofocus design optimised not only for underwater, but for close focusing range too.

I can also say with full confidence that Nikonos 15mm does not produce image plane curvature and performs exceptionally well at f/2.8.

I can also say with confidence that Nikonos 15mm is the only rectilinear wide angle underwater optics able to out-resolve the Epic 5k sensor in each and every pixel. I can't wait for 6k Dragon.

Frazier, with all due respect, these images are pretty, well composed and colourful, but they do look very soft to me. It is not your fault. All land wide angle lenses that I tested performed poorly at close focusing distance. Add a dome to the equasion and you end up with a soft image with low-contrast detail.

BTW, The irony is that, at close focus, the actual lens performs poorly and at longer subject to camera distances, the image curvature of the dome reaches the maximum, which is a kind of a double whammy because the virtual image distance still remains relatively close to the lens even if the subject is far away.

Thank you Pawel for the nice comment saying the Red Sea image was pretty, well composed and colorful but You have got to be kidding me, the Red Sea image soft? Where?

http://www.flickr.com/photos/oceanimaging/7755955970/in/photostream

 

[Frazier Nivens]

Another vertical, shot on Epic at 5k.

http://www.flickr.com/photos/oceanimaging/7536811394/in/photostream/

Sigma 14mm lens.

 

[Frazier Nivens]

GREAT image Frazier. Love the tilt on it to vertical. I highly doubt anyone will find this image not up to HD standard....nor soft in the corners....Thanks for sharing it. the word BEAUTIFUL comes to mind.

....and i don't need MTF to evaluate it....looks great.

Thanks Johnny for the kind comments, can't imagine where Pawel could find the Red Sea image very soft.

 

[Frazier Nivens]

I believe Pawel is being sarcastic !

Yep...but it was on Vimeo.com. Not YouTube. Same place as his Sea Dragon video is posted. I love the Sea Dragon video he shot. For Vimeo it's great. I'm sure it's even better when viewed in full res on a good monitor. But to share our images and film clips we can easily put them up on YouTube and Vimeo and flickr but can't show them easily at full res to each other. These are compressed movies and all even Pawels are slightly soft due to compression.

Nice to be able to share imaging with fellow redusers from the underwater world we love.

Best,
Frazier

 

[Pawel Achtel]

...You have got to be kidding me, the Red Sea image soft? Where?

exactly my point, you need to measure it and it is not easy to show or explain because what I see, what audiences see, what you see and what Johnny sees are all different subjective things. But, I will try to explain what I see...

Your shot is 2k, so in order to see pixel-for-pixel on Reduser I shrunk my and Phil's images taken with Nikonos 15mm to 2.5k, still giving 25% sharpness advantage towards your picture, when looking at 1:1 (pixel for pixel).
I selected a couple of centre areas that I thought could be in the sharpest focus as I was not able to actually see what was in sharp focus in your image as all looked soft to me.

versus Nikonos 15mm

What you should be looking at is contrast at which the detail is rendered. Of course, the more you go away from the centre of the frame, the difference in sharpness between a dome and Nikonos 15mm is more prominent.

I hope it ilustrates my point

 

[Frazier Nivens]

RED Sea Image was shot with a Nikonos 15mm lens, not a dome.

RED Sea Image was shot with a Nikonos 15mm lens, not a dome.

exactly my point, you need to measure it and it is not easy to show or explain because what I see, what audiences see, what you see and what Johnny sees are all different subjective things. But, I will try to explain what I see...

Your shot is 2k, so in order to see pixel-for-pixel on Reduser I shrunk my and Phil's images taken with Nikonos 15mm to 2.5k, still giving 25% sharpness advantage towards your picture, when looking at 1:1 (pixel for pixel).
I selected a couple of centre areas that I thought could be in the sharpest focus as I was not able to actually see what was in sharp focus in your image as all looked soft to me.

versus Nikonos 15mm

What you should be looking at is contrast at which the detail is rendered. Of course, the more you go away from the centre of the frame, the difference in sharpness between a dome and Nikonos 15mm is more prominent.

I hope it ilustrates my point

Yes, but I don't understand your reasoning, this image was not shot with a dome port at all,this was actually shot with a Nikonos 15mm lens and a Nikonos V camera. Actually it was a compressed JPEG image that was uploaded to flickr. It's definitely in focus and very sharp, but I guess image quality is very subjective depending upon who's viewing the image. Maybe I wasn't as accurate focus wise but I don't think that's the case. The Nikonos 15mm lens is a great lens and sharp from edge to edge and designed for UW use. Contrast is quite good. But these two images were shot with the Nikonos 15mm lens so there shouldn't be too much difference.

http://www.flickr.com/photos/oceanimaging/7755955970/in/photostream Anyway the image looks good to me, just compressed a bit hence maybe a bit softer image.

Best to you,
Frazier

 

[Johnny Friday]

Pawel, since you are critiquing, here is a 1:1 grab of a shot from red 1 m sensor using 18-50 PL lens....Now i took a center crop at 1:1 and fail to see your logic how this image is soft because it is NOT a Nikonos 15mm lens. My coloring and transcoding may be off from 3-4 years ago, but i don't see what you seem to see. And if we don't see it how do you expect an audience to see it? I probably was off slightly focus wise...but i also recall being near f 2.8 and f4 split...not making any excuses, but I also know the limitations of this 18-50 lens and also what each of us is up against when it comes to getting proper focus with this large a sensor.

[/url] RED 18-50 PL by RedCineUnderwater, on Flickr[/IMG]

[/url] Red 18-50 PL by RedCineUnderwater, on Flickr[/IMG]

 

[Pawel Achtel]

Yes, but I don't understand your reasoning, this image was not shot with a dome port at all,this was actually shot with a Nikonos 15mm lens and a Nikonos V camera...

This explains a lot. On stills, film would always appear softer than digital because of the grain. It is the irregular location of the grain that made film images appear sharp in motion as compared to digital. There is also a lot dependent on the scan too. The resulting contrast (and sharpness) depend on the combined MTF of all of the elements in the system: the lens, the film, the scan... and is only as good as the weakest link.

In such case, that comparison shows how good the RED Epic sensor is compared to 35mm FF film

 

[John J Ellerbrock]

Just loved the Elkhorn corals at this spot. I see new life and Elkhorn beginnings here and other places in the Florida Keys, today I saw many new beginnings of Elkhorn stands that hopefully in the future will be covering the ocean floor again as is this wonderful Elkhorn garden at Horseshoe Reef, Florida Keys. Shot from behind a regular glass dome port with a Sigma 14mm lens, Aquavideo aluminum EPIC 5K Digital Cinema housing.

https://vimeo.com/46946462

All compressed to 720HD webmovie.

Just catching up on your videos Frazier. Always a pleasure to watch, and great to see you back in the water.

FWIW Tiger Beach cannot be explained. One must really stare down a few Tiger Sharks to realize your in the middle of a bucket list event.

J-

 

[Mark_Thorpe]

Never been to Tiger Beach but have heard so much about it. Had a blast in southern AFrica for six months working on a project where we'd float chum drums to see what came along. Mainly Blacktips but on many occasions Tigers. I dived with Johnny on one occasion too but got skunked by the Tigers. At a later date the waters cleared and in came the predators. On one occasion 14 Tigers around two divers, started to get a tad hairy. Good times....

The standard view (from an old Z1) with the welcoming party of Blacktip sharks and a Tiger entering frame lower left.

The African Way....

Cheers,
Mark.

 

[Frazier Nivens]

South Africa memories

South Africa memories

Never been to Tiger Beach but have heard so much about it. Had a blast in southern AFrica for six months working on a project where we'd float chum drums to see what came along. Mainly Blacktips but on many occasions Tigers. I dived with Johnny on one occasion too but got skunked by the Tigers. At a later date the waters cleared and in came the predators. On one occasion 14 Tigers around two divers, started to get a tad hairy. Good times....

The standard view (from an old Z1) with the welcoming party of Blacktip sharks and a Tiger entering frame lower left.

The African Way....

Cheers,
Mark.

Loved seeing this, brought back some great memories of South Africa, spent some time there with Ken Corben, Andre and J.P Botha of Marine Dynamics at the time, we were shooting Arri Super 16 film, good old days. Went up to Aliwal shoal and Protea also, was with Mark Addison. Great memories. Thanks for sharing Mark.

 

[Frazier Nivens]

Tiger Beach

Tiger Beach

Just catching up on your videos Frazier. Always a pleasure to watch, and great to see you back in the water.

FWIW Tiger Beach cannot be explained. One must really stare down a few Tiger Sharks to realize your in the middle of a bucket list event.

J-

Thanks John for your kind comments, love Tiger Beach, great stuff working in nice clean water, shallow good light and colors. I don't know what was up with that shark, she kept circling and didn't let up on me for a while, you can see the eye membrane flicker when she came close, I wasn't that close to the bait, maybe she saw her reflection in the dome port.

Want to get out with Stuart to the Oceanic White Tips off Cat Island soon.

Frazier
http://www.flickr.com/photos/oceanimaging/7656020112/in/photostream/

http://www.flickr.com/photos/oceanimaging/7656053608/

 

[Frazier Nivens]

Pawel, since you are critiquing, here is a 1:1 grab of a shot from red 1 m sensor using 18-50 PL lens....Now i took a center crop at 1:1 and fail to see your logic how this image is soft because it is NOT a Nikonos 15mm lens. My coloring and transcoding may be off from 3-4 years ago, but i don't see what you seem to see. And if we don't see it how do you expect an audience to see it? I probably was off slightly focus wise...but i also recall being near f 2.8 and f4 split...not making any excuses, but I also know the limitations of this 18-50 lens and also what each of us is up against when it comes to getting proper focus with this large a sensor.

[/url] RED 18-50 PL by RedCineUnderwater, on Flickr[/IMG]

[/url] Red 18-50 PL by RedCineUnderwater, on Flickr[/IMG]

Wow, Johnny, sharp and really great grab. nicely lit. Great shot..

 

[Johnny Friday]

Thanks Frazier.....I only posted to show that indeed it can be sharp enough....maybe not as sharp as the 15mm Nikonos...but again, evaluating our frame grabs and moving images are so totally different as we know....but certainly being able to do this is a marvel as far as i'm concerned....

....but i'm sure after putting it under the microscope, we can all find something wrong....but again, it's a moving image and comes and goes in a blink of an eye....