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Member Since 07 Nov 2004
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#391775 Ambient Backscatter

Posted by Tom_Kline on 27 January 2018 - 03:48 PM

I have the same problem as well when shooting salmon in streams using ambient light. There is a fair amount of drifting debris. Bubbles can be a problem (as just suggested) as well. Shooting with a fisheye lens at point blank range helps to minimize the problem. As well, it is best to avoid shooting into the light. Sometimes one does not much of a choice other than not shooting at all.

Check out this shot:




(easier for me to find image on my site). Note the light blotches in the water column. I see a dark one too (left side), probably a twig. Not too bad backscatterwise at the spawners that were real close. I angled the camera to avoid shooting into the sun - this gave the reverse perspective from many of my other shots - but easy to see the eggs emerging from the female from this angle! A downside is that the housing cast a shadow on the bottom (shot taken less than 2 hours from true noon).

#390538 RETRA Strobe Thread

Posted by Tom_Kline on 26 December 2017 - 09:58 AM

I wonder if the FIX / upgrade to solve the TTL issue on the UWT circuitry be an easy fix?



The RETRA strobes will not be able to do any sort of wired TTL.  There are just TWO contacts in the wired bulkhead. They are for basic flash synchronization, nothing more. There is thus no Nikonos film style TTL as found in older strobes. Therefore the various converters for using Nikonos TTL will NOT give you TTL!!!

#390183 New Inon Z330

Posted by Tom_Kline on 09 December 2017 - 03:18 PM

Adam, would be great to get a direct comparison against the RETRA as the cash is burning a hole in my pocket and not sure which option to choose :)



I took some pix to address your question. The Inon Z220 shown in the pix is the model that preceded the 240 and now 330 is the same form factor as the newer models. The Seacam 60D also shown is another new strobe for 2017. Maybe we should call 2017 the year of the underwater strobe!  As well, there is a new J version of the Sea and Sea AA battery model - I keep wanting to call it R2D2 but that is not the correct name. All these new strobes use AA batteries. We just got a foot or so of rain (with storm and gale force winds) so the snow is all but gone (why not in pix) - air temp right now is 8C.

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#390022 ISO adjustment for Aperture

Posted by Tom_Kline on 03 December 2017 - 03:19 PM

f/4 to f/5.6 is a full stop not f/5. Closing down by one full stop is halving the amount of light passing through the lens so requires a doubling of the ISO to compensate if you keep the shutter speed the same.  BTW I use auto-ISO in combination with aperture priority auto-exposure quite a bit for my non-flash underwater photography. This is because of the need to keep the lens stopped down to work OK with a dome port.

#389855 Canon 8-15 behind Nauticam 180mm Wide angle port

Posted by Tom_Kline on 28 November 2017 - 05:39 PM

Fisheye lenses seem to tolerate being displaced from the dome's center of curvature. For example I got better corners using the Seacam 9" diameter Superdome, which is a hemisphere segment, than the Seacam full hemisphere but smaller diameter fisheye port with my 10.5mm fisheye lens even with just 12 Mpix (D2x camera). Seacam does not specify curvature radii. 


This website has some interesting cartoons showing how the position of the entrance pupil center as well its disk diameter (line) shifts with angle. It is forward (inside the front element) with the 10.5mm fisheye (scroll almost halfway down the page to see this) at 90 degrees. The 15mm rectilinear example is very interesting as well (scroll way down). It shows the entrance pupil shifting towards the lens' rear with the line going beyond 90 degrees from the optical axis. The 28mm shift is not as radical (last example on page).




I have used the Canon 8-15 at 12mm (APSH) and 15mm (FF) with the Seacam Wideport quite a bit for close up shots (salmon in streams). The Wideport thus used is better at smaller stops.  The Wideport probably has a smaller radius of curvature than your Nauti 180mm.

#389452 Retras in the water

Posted by Tom_Kline on 16 November 2017 - 03:57 PM

Nice report! Were you using Eneloops?


I guess one will have to learn how to hold the battery cover in one hand while swapping out the batteries - maybe wedged between fingers or cupped in palm with one finger allowing use of the other fingers? I have done this while swapping out batteries with rig in very cold (barely above freezing) stream (strobe was above water allowing for battery swap).


Backscatter has posted a video:

#384590 How to create great images...

Posted by Tom_Kline on 31 May 2017 - 06:06 PM

Nice job. There was an interesting thread on this topic that was started by Steve Williams a few years ago. It is here:


#384528 DX to FX and back again

Posted by Tom_Kline on 30 May 2017 - 08:11 AM

Justification for sticking with FX may be announced shortly:


Especially if this is anything like the Canon 8-15 qualitywise.


No longer a rumor:


Note the minimum focusing distance!!!!!

#382508 Mounting both Keldan's and strobes

Posted by Tom_Kline on 22 March 2017 - 11:39 AM

I  attach focusing lights to the sides of my ULCS arms by mounting a simple ballhead to the arm while using a large washer for the bolt. The bolt runs through the latticework of the ULCS arms. I found this jpeg on my HD from a couple years ago. It shows my gear after arriving at one of my salmon sites but after putting on my waders (topside shoes in pic). The rig closest to the back of my SUV has a light (Fisheye light) on one of the balls while the other has a Seacam clamp on it but no light. You can see the large washer from the side on the unused side. A similar arrangement would likely also work with Keldans equipped with a standard ball fitting.

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#382063 Performance of Sigma 12-24mm ART underwater?

Posted by Tom_Kline on 07 March 2017 - 06:51 PM

I'm also interested to hear about this one, and would LOVE to see a side by side with the Canon 11-24.

Ditto here!!! And Aloha! - I am currently right next door on the Big Island.

#381087 Pole cam and Nauticam

Posted by Tom_Kline on 30 January 2017 - 04:05 PM

Does anyone know how to do a pole cam rig with nauticam housings? Specifically, the Nikon D4 and nauticam d4 housing?

I cannot answer your questions specifically, but I can more generally.


There are two main concerns for adding a camera pole: 1. How will it be attached? 2. How will the camera be triggered?


There are two main ways of attaching the pole. One involves dovetailing to two attachment points such as the tops of the handles (one left, one right). One can buy a ready made camera pole like this here: http://www.cmdiffuse.../product/cmpcam

I believe this was designed for Aquatica housings as it looks like the one they announced a few years back.

The other attachment method uses a center point attachment - typically a ball like those made by ULCS. I use this type with my Seacam housings. See: http://www.seacamusa...m-instructions/

Scroll down until you see Stephen Frink holding the rig in the third vertical shot.

This type can also be used on a handle to do vertical shots like so: http://www.seacamusa...cam-components/

Scroll down to the last shot.

It is possible to make a cheap pole for the center variety. Just add a ULCS ball to the end of a long piece of anything handy.  This will probably involve drilling a hole to fit the bolt fixing the ULCS ball. This needs to be secure for obvious reasons and more so if the water is moving as it is quite a drag (literally). I have used scrapped underwater camera trays for short camera poles (there may be a shot or two here on Wetpixel showing this).


Now for triggering the camera. I am using the Seacam system which uses a 3-wire release. The trigger has two stages like the release button on SLRs. Stage 1 turns on the AF and wakes up the camera if asleep. Stage 2 triggers the shutter. I also have an Aquatica release but it only has a 2-wire release so you have to short out the wires so that the camera is always on or have the release close both circuits at the same time, which is what I did. Using focus priority helps get in-focus shots but one might miss the peak of action or not get any shot at all. One could also use manual focus but I have not found this to be a successful approach for photographing salmon. My preference is to use release priority. I used the Aquatica release when I retrofitted my Seacam Nikon D1x housing for remote control over a decade ago. There are other third part releases as well but I have not used them


The Aquatica release uses Ikelite cables that are fitted to a Nikonos 5 pin bulkhead. I simply sacrificed one of the existing flash bulkheads on my D1x housing by de-soldering the wiring to the flash shoe and soldering in a Nikon remote control wire (has a plug on one end to attach to the camera) inside the housing. Seacam remotes use S6 fittings (developed by Subtronic for six wires such as Canon flashes). One needs to have an S6 bulkhead on the housing to fit the cables and thereby releases. Newer Seacam housings come with several bulkhead holes - four on my Canon 1Dx housing. I use the one that is on the top of the housing for the remote control bulkhead. I added it myself as it is easy to do plus I like having a bunch of loose cable on the inside so I can leave the camera attached when I pull the body out of the housing. This way I won't forget to re-attach it when putting the body back in! The loose cable gets "tucked in" before closing the housing - one needs to be careful not to jam any control and not block sealing the housing but it is my choice to have the spare length. This is NOT the way Seacam does it by the way. BTW I use the fourth bulkhead hole on my 1Dx housing for a Backscatter housing sucker: http://www.backscatt...&ftn=youbetcha


FYI the bulkhead holes in Seacam housings are M14 (a standard metric size). So the first question for you is what are the bulkheads in your housing? You may be able to swap them out. Bulkheads are available at some underwater photo retailers. If you already have a Nikonos bulkhead installed you may be able to get by re-wiring the inside to a Nikon release and use an Aquatica release. You would have to lose flash functionality for this bulkhead.


I hope this helps


#380817 Peterson/Gates Hasselblad SWC First Look Video

Posted by Tom_Kline on 21 January 2017 - 04:59 PM

Solid Camera and Housing.

Would love one on my shelf of treasures.


If you haven't already - check this guy out.

A legend with the SWC underwater.


I had one of the H38s but it has been sold. Brooks probably used one the earlier SWC housings sold by Hasselblad - the '60s model was grey, the '70s model was blue. Alex Mustard has the correction lenses made for the later model which he had adapted to his Subal housing and has written on her on this website.

#380577 Custom white balance and noise

Posted by Tom_Kline on 13 January 2017 - 01:13 PM

This is not entirely correct. The eye+brain (I include the eye because it is my understanding that some "post-processing" of the image data takes place in the retina) does some color correction even though it is incomplete. I had an experience that illustrates this: After shooting some soldierfish in a mini-cave in the side of submarine lava flow formation (Big Island) I decided to chimp to see if my flash exposure was correct as there was time to re-shoot in case I screwed up. The lava formation was large enough that I was in its shadow so the light was very blue even though it was not too deep. When I looked at the image on the camera's screen the soldierfish appeared day-glow orange. I later re-checked these images when I got topside and the orange color was normal. My eye+brain had been compensating for the rather blueish light. Recall also that when you shoot under tungsten lighting the image will be rather red unless the WB is set to tungsten. However we do not perceive all this redness with our vision. Our eye+brain is doing some color correction.




. Because usually and without lights we dont see reds more than the camera sees it,we dont see a white balanced image.

So if its not there anyway why do we try to create it (can also use fake it) and try to give to to the audience, whatever that audience is, a fake white balanced image.


#380476 Flat port vs dome port - pros and cons?

Posted by Tom_Kline on 10 January 2017 - 02:21 PM

What is not often stated is that the refractive index of water varies by wavelength of light. This results in chromatic aberration which can be seen even in a swimming pool. Behind a flat port the chromatic aberration is a function of the angle of view measured from the optical axis, i.e., the half angle. It gets much worse as the angle increases. Therefore one can only use flat ports with near normal focal lengths and longer. One can get away with a flat port with a 35mm focal length on the 24x36mm format for example. The non-SLR Nikonos 35mm lens used a flat port - this is why it was amphibious and not underwater only (all the non-SLR Nikonos lenses with focal lengths <35mm were under water only).


The main purpose of the dome port is to restore the angle of view of the lens. This also results in the removal of the magnification (that you get with a flat port - see Bill's comment) and thus variability of magnification related to chromatic aberration. However, one needs to properly set up the dome port (correct amount of port extension).  As well, one cannot avoid the field curvature of the virtual image. For example with a 105mm macro you would need to move the dome port some distance way from the front of the lens and you may lose some of the lenses macro capability. The resulting air space between the dome surface and lens could also be problematic in terms of rig buoyancy.


Also important is the distance to the dome port virtual image is quite close. Most 50 1.4 lenses cannot focus close enough, i.e. at minimum focus (e.g., 0.45m) the lens is focused beyond infinity when behind a dome. The solution is to use a close-up diopter lens. These may degrade the image to the point of uselessness - it varies by individual lens design. For example I found that when using one with a 24-70mm zoom (min. focus of 0.38m) the result with single lens diopter was unacceptable. OK however when used with a two-element achromatic diopter except that the thickness of the diopter caused additional vignetting.

#380423 Nikon 85mm Micro

Posted by Tom_Kline on 09 January 2017 - 12:04 PM


I should point out that I'm not looking at the 85mm for cost savings.  Compared to every other expense in this hobby (ports, housings, dive travel, etc. etc.) the cost differential of the lens itself is completely in the noise.  If we were looking at lenses that cost $2000 or more, I'd be singing a different tune!  LOL


The potential advantages I see for the 85mm:

  1. Good working distance (way better than 60)
  2. Ability to make good use of wet diopters (way better than 60 / not quite as good as 105, but close)
  3. Small size = small port (same as 60)
  4. Somewhat more flexible in subject size than 105, though not as good as 60


Sounds like an 85mm macro is in your future as it does fit in between the 60 and 105 nicely. I might have purchased the 85 had Nikon brought it out sooner. After going digital I bought the 60 and 105 D lenses (felt a need for AF for UW) and then the 105 and 60 AFS when they came out. As well I have the older manual focus 55 and 105s, the macro zoom, and the 200 medical lens. Thus my lack of interest in the DX macros, which came out more recently.


A few years back I shot an entire diving trip to Maui with the 105VR using the D2X. Got some great shots of small reef fishes on that trip but it was a bit too narrow the day a White Tip Reef Shark and a moray were going around in circles in front of me! Even the 60 might have been too narrow for that. However I have taken half-shark pix with the 60 (the front half!). The 60 is pretty good for shooting APS-C format in more limited visibility too.