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A mode with 7D

aperture priority 7d

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#1 billywinter

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Posted 09 July 2013 - 05:51 AM

I just came back from my first dive trip using my new setup:  7D/Nauticam w/dual ike 125's.
I was previously using a G-series setup.  It took me 3 dives before I started getting decent pictures.
I was first using all Manual settings and my pictures were coming out a bit dark (strobes were
1/4),  I then tried aperture priority and the pics came out poor due to very slow shutter speeds (1/5 - 1/30). 
Finally,  I set speed to around 180-200, ISO = 160-200, stobes on full and Fstop between 10-15 and the pics

started to look pretty good.  

 

My question is why the Aperture priority was so far off?  Was there a setting I was missing?  It makes sense

to me that it would slow shutter speeds down to increase light, as I presume it does not know I would light the

scene up with the strobes?  Is A mode just not suitable for underwater or do you also need to have some ETL

going on to get a proper meter?

 

 



#2 Steve Williams

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Posted 09 July 2013 - 06:34 AM

Hi Billy,

Where were you diving in what conditions?  What camera settings on manual were you using that gave you "a bit dark"?  What were you shooting? Macro, wide angle?

 

Aperture priority is especially tough on WA because of the broad exposure range in a underwater wide angle image, from f22 at the surface to f/4 lower in the water column.

 

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#3 bvanant

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Posted 09 July 2013 - 07:38 AM

As Steve says, A mode is not really set up for underwater for several reasons. In a housing the camera doesn't know that the strobes are there and so will set very low shutter speeds even at large apertures. In TTL mode for strobes, in A mode the 7D will also run fill flash since Canon aims the camera more at portrait/wedding guys than UW guys.  I would go back to manual mode and up the strobe power a bit and use the aperture to control exposure since that is where you more or less ended up.

 

Bill


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#4 Aquapaul

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Posted 09 July 2013 - 08:26 AM

Manual is the way to go.

 

What you need is a starting point. Assuming clear blue water, I have my camera set at ISO 200, Shutter @ 1/180 and F/8 and dual strobes set at half power for fisheye wide angle. I adjust my shutter speed taking an exposure reading from the clear blue away from the sun ball to 1/2 to 1 stop under exposed and adjust strobe power for my foreground. It's usually just that simple unless you are shooting in a dark hole or at the sun ball then you will have to adjust further.

 

Macro ISO 200, Shutter 1/200 to your maximum sync speed and an appropriate aperture F/8 to F/36 and strobe power accordingly, F/8 probably not much power and F/36 maybe all you got.

 

It helps to think of it this way, Shutter speed to control the color of the water, want darker water faster shutter. Aperture to control depth of field and strobe brightness. It's not quite that simple but thinking in that way helps.


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#5 billywinter

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Posted 09 July 2013 - 04:43 PM

Thanks for the replies.  I was shooting all macro (60mm) in Aruba with decent viz.  In the past I was using A mode with my old G10 and did not have these problems,  however as has been pointed out manual is the

only way to go with this setup.  Just wanted to make sure there wasn't some setting I didn't know about that helped with this.



#6 twinner

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Posted 09 July 2013 - 07:58 PM

Especially when your shooting macro you want to use manual. Think about what your camera is doing when you take a typical macro shot in any auto mode. Typically your shooting something close to the reef so your getting none to little ambient light. The light meter sees black so it wants to increase the iso, open up the aperture or slow down your shutter speed so it can get a ambient exposer. Most macro shots are 100% strobe lit so you don't really care what your light meter sees. I would suggest setting a low iso 100-200, shutter speed doesn't really matter but you don't want camera shake so 1/125-1/250 and a f-stop that will give you your desired depth of field. With your ikelite strobes and nauticam housing your going to be shooting manual strobes so just dial in your exposer using your strobe power settings and strobe distance from your subject. It's not going to work for every macro shot it it will work for most. Hope that helps.
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