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Tom_Kline

Member Since 07 Nov 2004
Offline Last Active Jun 11 2017 09:24 AM
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#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:

http://wetpixel.com/...showtopic=41757




#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:

https://nikonrumors....heye-lens.aspx/

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

 

No longer a rumor:

http://www.nikonusa....ctTabs-Overview

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.

Attached Images

  • IMG_8420.jpg



#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

Tom




#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.

http://erniebrooks.com/index.html

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.

 

quote:

 

. 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)!

Tom




#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.