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BottomTime

Member Since 18 Jan 2008
Offline Last Active Mar 03 2014 08:39 AM
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#343773 Strobe with the deepest depth rating

Posted by BottomTime on 24 February 2014 - 06:59 PM

No contest, the seacam offshore series of strobes have the deepest depth rating at 200m. However, for the cost of a pair of seacam seaflash 150O's, you're probably better off taking a pair of Inons down and risking the occasional loss of a strobe.


#342967 Bottom of image underexposed when using TTL

Posted by BottomTime on 06 February 2014 - 02:27 PM

I've heard of people having similar problems using wireless triggers.

 

When Heinrich Weinkamp was still making TTL converters, he used to provide a (fairly comprehensive) table of strobe timings that listed the minimum time required between a pre-flash and the main flash. Inon strobes were generally in the 2000 microsecond range while my memory was that the Sea & Sea strobes were considerably longer (I think the YS-110a was ~18000 microseconds).

 

HW provided a second list with the minimum timing requirement of the camera. The timing for the nikon's are faster than most and the D300 was around 8000 microseconds. You're D800 will be atleast as fast as that and will do it's thing without regard for strobes that can't keep up. I suspect that in your case, the rear curtain has started to close before the minimum timing for the strobe has elapsed (10000 microseconds is 1/100s).

 

In the case of using manual powers, then the strobe ignores the preflash and the minimum timing between the pre-flash and the main flash is no longer relevant.

 

This is all speculation freshly squeezed from my butt cheeks though. An Oscilloscope would probably be able to tell you exactly what is going on.




#341340 Do you think Ocearch really love sharks?

Posted by BottomTime on 02 January 2014 - 12:41 PM

More interesting is that they think there is no pattern.  I mean SOFA sorta proves the pacific sharks go to an area, albeit a huge area.  The other way to think about it is that they haven't got a big enough sample section to see a pattern.   :)  "Mommy instinct" can only go so far in discovering patterns.

 

What are you saying? Are you suggesting that a sample size of 2 is insufficient? BLASPHEMY!!!! Though I do admit, "Mommy Instincts" are a powerful force to be reckoned with, every good psuedoscientist knows that all you need is one piece of inferential evidence and a bag of magic chicken bones or a good Ouija board to crack the code.




#339723 Do you think Ocearch really love sharks?

Posted by BottomTime on 20 November 2013 - 03:11 PM

There are plenty of organizations that support conservation and do good work even though I may not be a fan of their underlying motivation. Ducks unlimited is a very large conservation organization that does some really positive things for wetlands and waterfowl conservation. It’s all done so they can kill them…errrrr… enjoy and preserve the sport of hunting.

 

I’m not a big fan of some of the methods Ocearch uses and I certainly would not call them a research organization. I have no time for “Shark Men” but it’s not the worst shark drivel on TV. But, just because I don’t care for their show and have concerns about some of their methods doesn’t mean that their work isn’t valuable. Biologist are tagging all kinds of animals all over the planet trying to understand their movements, so clearly this kind of data is something that the science community values. I only hope that the value of the data Ocearch’s work yields outweighs the negative consequences that all work of this nature brings.

 

Yes, they are responsible for the mortality of at least one shark. But we can add many more organizations to that list. The first White shark the Monterey Bay Aquarium ever put into captivity died after 10days so they are responsible for the death of at least one Great White.

 

The TOPP project used long line fishing equipment to capture and tag Blue sharks and Short Fin Mako’s. They mentioned in a blog that they “occasionally lose a shark” and that they try to part out various organs to support different research projects when that happens. I’m guessing that they have more than one in their tally.

 

And of course, I keep reading disconcerting reports of White sharks accidentally getting stuck in shark cages. I fear that if it hasn’t already happened, it’s only a matter of time before a shark dies or is seriously injured after being entangled with a cage. If that comes to pass then everyone who has supported cage diving through their participation (including myself) will assume part of the responsibility for that event.