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Member Since 07 Nov 2004
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#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.

#378628 Land based diving at Cabo San Lucas, Mexico

Posted by Tom_Kline on 09 November 2016 - 02:36 PM

Thanks Thomas, I think Cabo Pulmo is a good place to dive since it's a marine national park. I read that Cabo San Lucas is closer to the Sea of Cortez, specifically the Gordon Bank, so now I'm torn.

They are both on the Sea of Cortez/Gulf of California at the southern end of Baja.  I found a map with Pulmo circled:

Looks like about the same distance to either from the airport. Gordo Banks is offshore of Punta Gordo about halfway between them. See http://www.mexfish.c...smp/cabosmp.htm

#376007 new 28mm macro canon or 60 macro venus or 6o macro canon

Posted by Tom_Kline on 11 August 2016 - 11:15 AM

The new Canon 28mm macro lens with the ring flash is an EF-M lens, designed for the EOS-M mirrorless cameras. The 60mm EF-S macro lens is quite popular among Canon APS shooters. Do not have one myself so cannot comment. I would recommend an AF lens over a MF lens like the Venus. You can still MF the Canon lens but will need a focusing gear, also for the Venus lens. I seem to recall that the Venus lens has a manual diaphragm - you should check on this. A manual diaphragm is going to be particularly challenging to use under water if even possible as you will need a control gear for this as well.

#374819 Lembeh Gulen Shootout - Charlton's filefish photo - how?!

Posted by Tom_Kline on 23 June 2016 - 04:00 PM

Looks too powerful to be a dive light or torch in British lingo. For me, the noun version of torch is something with flames leaping from it! :->>  A slaved strobe, maybe with a lensed snoot like the LSD - note the sharp-edged spot of light on the bottom. Maybe a night dive?

#370540 Philippines Fish

Posted by Tom_Kline on 16 February 2016 - 12:56 PM

Very nice color contrast between the anemone and clownfish (pic #1 above)!


#369309 Great Lakes, not so exotic but worth it just the same!

Posted by Tom_Kline on 14 January 2016 - 04:35 PM

Great images! The divers provide a very nice sense of scale too.

#367933 Best photograph/er lists -What makes for a great image?

Posted by Tom_Kline on 04 December 2015 - 10:37 PM

The question posed in the thread title reminds me of the iconic image thread started by Steve Williams a while back. IMHO this is a different question then what gets selected for a given publication.


Lists of "best" seems dubious at best given the great diversity in range of underwater image content. As well the majority of people have not been underwater in a natural habitat while maintaining vision; thus most underwater images are a bit exotic to them.

#367856 Strobes versus Video Lights

Posted by Tom_Kline on 03 December 2015 - 08:54 AM


edit. The concept of the I-torch symbiosis I like better (strobe and LED-lights are thermally separated), their specs (poor CRI LED, high CT strobe) less so. 



Good point! To get the specs you need you will have to buy lights and strobes separately. Combo units are likely to compromise one or both with respect to your needs.

#367410 Full Frame SLR wide angle corrector port tests

Posted by Tom_Kline on 23 November 2015 - 11:11 PM

Did some more shooting with the ICL today. Swapped the 16-35, ICL, etc. and shot it @ 16mm on my 1DX to take advantage of the better AF. The in-focus corners are particularly impressive. No corner smearing! I am attaching a full frame and a blow-up of the lower right hand corner.


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#366876 How to have a clear photo of a fish moving in front of a camera ?

Posted by Tom_Kline on 06 November 2015 - 12:32 PM

I am posting here a couple of "technique" shots that may better explain what I do. Both cameras in the shot showing two housings are set up with a single Seacam strobe positioned at 12 o'clock and above the water. These are my primary light sources. I also have some available light pix done with no strobe - most of the recent (last few years) shots on my site showing schools of salmon are done this way. High ISO is generally needed. Available light shots generally have less issues with reflective parts of salmon bodies. Even when it is sunny such as the shot with two housings, the light is very patchy in forest settings so strobes are generally needed on the spawning grounds. There is no sun at all hitting the ground late in the season, like right now (November), at spawning grounds located in valleys due to very low sun angle.


You can see the remote cord from the housing in top of the frame (two housing pic) - it ran over to where I was standing to shoot the technique shot. From this vantage point I was able to shoot both cameras. Note that there is a salmon pair in front of each housing. These salmon are about 0.5m long (for scale). I have to anticipate where a salmon is going to be in the next second when I push the button. Two housings (different models, one being older or "obsolete") is a convenient set up - I hold one release in each hand.


The shot showing one housing shows evidence of one of my "issues". It had rained a bit in the days before the shot. The water level had been much higher leaving a layer of sediment on the leaves of the trees - mostly willows (genus Salix). Rain brings in glacial sediments from the main stem of the creek into the side channel creek seen in the pic. There is still some fine sediment even though the water looks pretty clear. So almost all shots from here have very fine backscatter. Mature Sockeye Salmon do not have too much of a reflection issue except for their mouths. I have had blown highlights in the mouth and had to throw those pix out. Dolly Varden are partially reflective even when mature. This is most evident when the female turns on her side to make a dig as seen in the posted pic. They also have white in the mouth. I have had blown highlights from both of these reflective areas and have had to toss a few pix. This is not my only issue with shooting local Dolly Varden spawning. My local spawning area is just downstream from a small waterfall, which is barely visible in the background of the shot. It generates a lot of tiny air bubbles which you can see in the pic. They can also get stuck on the port due to surface tension. Bubbles are especially bad when there is a lot of flow such as after rain, which is when they spawn. This site does not have glacial sediments, instead the water is stained like tea. Staining is worse after a rain as well. Staining darkens the water a bit, about a stop less light transmittance. Lots of problems that need some adaptation in order to get the shots. I have worked them out (more or less) with trial and error. BTW, the fallen tree I described in my earlier post is what is seen in the middle of this pic. I was standing behind where the male is and the spawning was upstream of the tree in the dark part of this pic.


I hope this helps!




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#366844 How to have a clear photo of a fish moving in front of a camera ?

Posted by Tom_Kline on 05 November 2015 - 11:53 AM

Thanks Tim! I do both!


I believe the problem is that a salmon sees us as a potential predator (a good reason!) and so will move away from us very quickly. However, if one is very still they can be approached. For example, last month I had one rest against my foot (but another salmonid, a Dolly Varden) while I was standing in a stream shooting them spawning by remote control - you can see examples of my work on salmonography.com. However, I avoid being in the water with them as much as is possible for a given shooting situation. I was in the water to shoot the DV because a treefall next to the spawners was blocking my view of them from out of the water. So I stood just behind it and ~1.5 m from the activity to see and know when to "push the button". Still, I could only see the front end of the fish (which was enough) as the fallen tree blocked the rest.


Your image suggests a possible solution. You will notice that some of the salmon in the background are sharp - also it looks like your visibility in Norway is much better than what is typical in Alaska fjords, at least in the summer. I do not have a Gopro but saw some University of Oregon students use them at one of my sites. They left the cameras on the bottom in some sort of self-shooting mode and got some decent shots. If your Gopro can do this you might consider clamping yours to a fixture holding the net (visible in your shot) and letting it shoot for you. The next level up in expenditure would be to get a pole cam set up for it. You may want to use this from the surface (from a boat?). The next level up would be a remote control to use with the pole cam so you could decide exactly when to shoot.


I use a pole cam type solution. There is a blurb on it on the about me page on my site. As well, I have made a few technique postings on Wetpixel over the past decade. Most recently I have added a Canon 1DX to my arsenal. When doing available light shots with the 1DX I have been using autoISO with a 12800 ceiling value. Many shots end up being done at 12800 as the light level is not too high here even during the long day time (i.e., July). I did one shoot at 25600 (in May) because it was after the sun went behind the ridge forming the valley I was in, which was forested, and it was getting close 7pm. Even with such high ISO the shutter speeds get a bit long for a moving fish. I do not go higher in ISO because I need to do quite a bit of color correction as well as some highlight recovery - recall that dynamic range goes down as ISO goes up and I need as much of this as well. I also do long soak times. I have had a camera in one spot without moving it for as long as 12 hours. More typically it is less, but a few hours nonetheless. The pro body DSLRs have a big enough battery power to last. IMHO this is one of the main shortcomings of any camera that uses live view as they use more power and seem to have undersized batteries. As well one needs very fast autofocus that works well in low contrast.


Any questions?

Good luck!


#362621 Strobe positioning with fisheye - tips needed!

Posted by Tom_Kline on 24 June 2015 - 11:23 PM

FWIW I have been shooting a fisheye at ground level with a single strobe positioned at 12 o'clock for a few years. The reason for that is to use the port shade to block direct lighting of the dome's glass. Lights from strobes positioned to the side ended up striking the glass through the shade cut-out resulting in flare. Subjects are right up to the dome. There are some videos on my web site showing this set up in action for shooting salmon - located under the species listings.


#356180 Your Favourite/Best Image of 2014

Posted by Tom_Kline on 02 January 2015 - 12:53 PM

Alex: congratulations on your marriage!


It is always a challenge to pick just one favorite shot! This year I had more than one candidate from the same day of shooting the most challenging local (i.e., location not requiring a plane trip or boat ride to get to) salmonine species to shoot, the Cutthroat Trout. Locally, this species is about three orders of magnitude less abundant than salmon. The alternate pic to the one chosen here is in my Christmas E-card (posted on another thread).

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