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John Bantin

Member Since 24 Mar 2005
Offline Last Active Nov 24 2013 01:21 PM
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#337910 Strobe "Shutter speed"

Posted by John Bantin on 08 October 2013 - 10:02 AM

The flash makes a burst of light. Its duration is dependent upon the size of the flashtube and the power output of the flash. For example, I have a studio flash at full-power (2000j) that has a long duration of about 1/150 sec. The duration of a little flashtube at low power is very fast indeed. So as long as the pulse of light can fit into the time the camera shutter is open, it will be effective. I suggest it was so dark that the ambient light on the tentacles was so little as to be negliable. (By the way, Bob, I was just thinking I should get rid of my Subtronic strobes too - if they still work!)




#337408 New Housing "Airlock" Vacuum from Backscatter

Posted by John Bantin on 24 September 2013 - 02:59 AM

http://www.undercurr...ests201304.html




#334087 New Housing "Airlock" Vacuum from Backscatter

Posted by John Bantin on 10 July 2013 - 03:43 AM

When I first saw an SPG I thought it a good idea and got one - despite those who didn't have them telling me it could explode and kill me.

When I first saw an ABLJ (the original equivalent of a BC)  I thought it a good idea and got one - despite those who didn't have them telling me it could send me hurtling to the surface with my lungs hanging out of my nose.

When I first saw a diving computer I thought it a good idea and got one - despite those who didn't have them telling me it could kill me and that I should use tables.

When I first saw a drysuit I thought it a good idea and got one - despite those who didn't have one telling me it could leave me inverted and drowned.

When I first saw a BC and thought it a good idea and I got one - despite those who didn't have them telling me BCs could leave an unconscious diver floating face-down at the surface.

 

Why do divers hate ideas that are obviously good? You will ALL be using vacuum leak tests (complete with flashing green lights) within a decade, apart from the dinosaurs among you!




#332317 diving with a camera

Posted by John Bantin on 03 June 2013 - 09:57 AM

As far as air consumption goes, after 20 years of making thousands of dives with a camera, I know that my air consumption far exceeds those few times that I dive without one. I put this down to the brainpower needed and the oxygen metabolised whilst thinking about the picture and readjusting fine pitched buoyancy.




#332277 Great Hammerhead Dive

Posted by John Bantin on 02 June 2013 - 11:56 AM

How it's done. JB with Hugyfot photographed by Bob Semple. (Thanks Bob.) Frazier Nivens with the Epic, Charlie F. chumming by scraping a dead barracuda!

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#331511 Spare Body or not

Posted by John Bantin on 17 May 2013 - 10:07 AM

Get a spare body but if you flood the first, I can tell you that you won't want to risk the second!




#330697 5D Mark III Nauticam or Aquatica?

Posted by John Bantin on 01 May 2013 - 11:16 PM

Jean, I know about that... I bought one for the safety of my cameras and lenses during tests. :) I was referring to 2 extension rings combined, which as far as I know, isn't possible with Aquatica.

 Fit a vacuum leak test, apply the pump and everything is locked on any housing. Rely of physics not mechanics!




#330588 Boat Water Entry with Camera Gear Methods

Posted by John Bantin on 30 April 2013 - 06:38 AM

I am well known for my with-camera rig entry. I put the camera into the water and follow it in head-first. Works for up to 2ft of free-board.




#330450 Vacuum Leak Test Update

Posted by John Bantin on 28 April 2013 - 06:08 AM

Well,

that is one reason to NOT open the housing on the boat.


Chris

 

After a few days, my camera battery needs charging. It's a bit expensive to ask the captain to put into land to do that!  :)




#330441 Vacuum Leak Test Update

Posted by John Bantin on 28 April 2013 - 04:23 AM

People who live in the UK are very familiar with low-pressure conditions and precipitation.




#329511 What's wrong with harassment?

Posted by John Bantin on 10 April 2013 - 10:20 AM

Was that the fish version of Pavlov's dogs :-)

Probably correct - but it lived a long life! Like the Napolean wrasses at Ras Mohammed that, when they died, people said they got cancer from the food divers had been giving them. When I researched an article about it, David Frape, the distinguished animal nutritionist, pointed out that they had lived much longer than normal because they were so well-fed and they got cancer because that's what happens when you get very old.

It's never as simple as we think and we should not ascribe human characteristics and feelings to other species of animal!




#329259 Fastest fins for sailfish

Posted by John Bantin on 06 April 2013 - 11:04 AM

If you want to swim fast and maintain that speed, I recommend one of these:

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#329166 I hate the dead blue faced zombie diver photos

Posted by John Bantin on 05 April 2013 - 01:30 AM

Nothing to do with this thread, but looking at Mark's pictures makes me wonder at the fact that we all take the same pictures of the same things. I'm embarrassed to say I recognise that telegraph!!!




#328962 Recommended wide angle zoom for FX

Posted by John Bantin on 01 April 2013 - 12:21 PM

I found that the 12-24 Nikkor gave me such poor results that, if you were happy with it,  you'll be happy with almost anything else. I wasted a lot of time and money getting it wrong with other lenses too, but the consensus on Wetpixel eventually told me to get the 10-17 Tokina for DX and the 15 Sigma (and 16-35 Nikkor) for FX and I haven't looked back! That's not to be confused with lenses for use topside and not behind a dome port.




#328882 New Housing "Airlock" Vacuum from Backscatter

Posted by John Bantin on 31 March 2013 - 01:28 AM

I know of someone who did forget to pull a vacuum and went in the water without the plug. This is essentially like diving with a hole in the bulkhead of your housing. Fortunately, he had a dome port on and caught it as the water started rushing in so he was able to turn the camera so the water began collecting in the dome as he was aborting the dive.

To Adam's point, having a vacuum system isn't completely fool proof. You still need to check your system before jumping in.

This doesn't add up. Surely, if water could get in, air would have got in first, before he hit the water. Sounds like someone ignoring the red light. Thank goodness he doesn't have a rebreather!