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Jock

Member Since 16 Dec 2005
Offline Last Active Today, 10:59 AM
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Posts I've Made

In Topic: Second thoughts about vacuum systems

26 March 2015 - 10:22 PM

This one seems pretty obvious (to me...): Vacuum systems give you a pre-dive security check against user errors, i.e. twisted o-rings, a hair on an o-ring etc. In your case the shutter gland was loose. Would you have noticed without a vacuum system? No. Could you have noticed with the vacuum system? Yes - IF you had operated/knocked/twisted the shutter button while on land. Does anyone do that (operate all housing controls pre dive excessively)? No.

And IMHO the camera shop owner is completely wrong! It does not make any difference if you pull from inside the housing (= apply a vacuum) or push from outside (= apply water pressure). So the idea that the o-rings are "sucked in" is nonsense. And nonsense especially if you think about the relatively small degree of vacuum you apply with your pump.

Bottom line: If you want to avoid a flooding don't take your housing under water :-)

Just my two Euro-Cents
Jock

In Topic: Flash settings with Olympus E-M1

26 February 2015 - 08:37 AM

Hi Michael,

 

maybe you want to have a look here. I did some tests with the magnet in/out and TTL/manual:

http://wetpixel.com/...showtopic=51861

 

Generally I think it is not a good idea to mix different strobe brands and try to use TTL; even with two identical Inon Z240 TTL is not reliable - at least in my setup with an E-M5. Maybe the E-M1 is better in that respect? (I doubt...)

 

For wide angle TTL does not make sense, and for macro it is convenient (if it works!), but I shoot manual now. If exposure is a bit too bright or too dark, just use your RAW converter.

 

Jock

 

p.s. TTL="fill" in the camera and S-TTL on the strobe


In Topic: OM-D E-M5 II stabilization improvement significant?

21 February 2015 - 01:59 PM

There is a rule of thumbs for focal length and shutter time: If you shoot with 50mm, use 1/50sec or faster, if you shoot 140mm, use 1/140sec or faster etc. This is WITHOUT I.S. With stabilisation you can use longer shutter times.

You see, for wide angle like the Panasonic 7-14mm you can use relatively long shutter times and still get sharp pics. The advanced I.S. will be good if you shoot birds with a long lens like the Pana 100-300, but for u/w does not matter that much.

Jock

In Topic: Any news on the restrictions for 3 Sisters Springs?

13 February 2015 - 03:26 PM

Hi,

This link is a re-post from an article on the wetpixel main page, just in case someone will find this thread by the search function:
https://www.facebook...talRiverComplex
The Fish And Wildlife Service will annonce the status of Three sisters.

I was in their complex yesterday and watched a video which explains the latest rules for photographers and videographers, here are some key points:
As a "pro" you will need a permit, and you will have to wear a yellow vest.
Flash photography is allowed, you need to use a diffusor. You will have to wait some seconds before you take another flash photo, no rapid firing allowed.
You may submerge, but are not allowed to dive down head first onto a manatee.
And, most important, you will have to keep a distance of six feet to a manatee.

I hope FWS will put that video online, easiest way to avoid confusion and discussion....

Jock

In Topic: Metering for OMD-10

22 November 2014 - 09:50 AM

Hi ML,

What exposure mode do you use (P/A/M)? Do you use your strobes in TTL mode or manual? What lens? Maybe you can post an example?

If you use A with TTL the exposure is correct without strobes, and the strobes will submit only very little light - your pics are blueish.

If you are too far away from your subjects, the "warm" colours are filtered - your pics are blueish.