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Apperture priority vs. Manual


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#1 beto

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Posted 06 July 2004 - 03:43 AM

Hello,

I know there is no "magic recipe" that works for all pictures, however I would like to get some settings I could use as a starting point and learn from there. I have a Canon 300D with an Aquatica housing and Inon Z220 strobe.

My specific question is What would you recommend: shoot with apperture priority or Manual mode? If it is Manual mode, do you change f stop and speed for every shot, or should I set speed to 1/125 (or something else) and play only with f-stops?

I don't dive very often so my learning curve with u/w photo is very long. :D I would like to get an idea of some settings I should use in my next trip.

Again, I am not looking for a magic recipe, but some of your advice based on your experience.

Thanks :)

#2 herbko

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Posted 06 July 2004 - 09:13 AM

Manual always. It's possible to shoot aperture priority but it very easy to have the shutter speed out of useful range unless you paid close attention.

I usually make my setting choices in the following order.

1) choose aperture for the DOF
2) set strobe power for forground exposure
3) set shutter speed for background exposure

If you can't do step 2 or step 3 because of your choice in step 1, go back to step one. After awhile you'll get calibrated and will usually get it done in one past.

To get started, I recommend shooting a 50mm lens, find a medium size subject like a foot long fish that isn't moving much, or coral of similar size, start at F/8, 1/125 and -2 on your strobe. Vary the setting and take lots of shots. You should catch on quickly.
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Canon 5D; Aquatica housing; 2 Inon Z220 strobes; Canon 100mm macro, 17-40mm ; Sigma 15mm FE, 24mm macro, 50mm macro

#3 scorpio_fish

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Posted 06 July 2004 - 01:45 PM

What would you recommend: shoot with apperture priority or Manual mode?


Yes :D

I've shot all three modes; aperture, shutter and manual (yes, even shutter priority). Depends on what you are shooting and what you are trying to accomplish.

You don't mention what lens. It could make a difference. If you are shooting with manual strobe power, then manual works fine.

For macro:

1) Pick a shutter speed, any shutter speed. Well, OK, between 1/60 and 1/125.
2) Pick an aperture for DOF, say f/22.
3) Set manual strobe power to something under full.

Fire. If its underexposed, bump strobe power or open up aperture. If overexposed, reduce strobe power or stop down aperture. I try to not stop down past f/29.

You get pretty good, pretty quickly at judging what the exposure is going to be just by judging strobe to subject distance.

For wide angle:

There are several techniques that work well. Everyone has their preference. Mine is different and isn't great for a fist timer. My alternative approach is even wackier. I'll defer to others' suggestions.

#4 critter

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Posted 06 July 2004 - 04:01 PM

Do you change power or since you are using dslr do you sometimes use exposure compensation on the camera to compensate? This works well for me on the surface does it work underwater as well?

Tony
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#5 james

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Posted 06 July 2004 - 05:42 PM

Exposure compensation tells the camera to look at the reading from its light meter (What's used when you shoot in Aperture or Shutter priority) and either adjust up or down.

The exposure comp of course doesn't work underwater unless you are shooting A or S, but for some situations, you can shoot, review histogram, and adjust for background exposure. That is best done using A mode, because the f-stop is fixed, so you can adjust strobe power to suit. I would try adjusting by - 1 stop if you intend to try it.

I still second Herb's recommendation - when I started shooting manual, my shots got a LOT better.

Cheers
James
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#6 critter

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Posted 06 July 2004 - 07:29 PM

Thanks James that makes sense to me. So basicly just like film bracket with the fstop and leave the shutter speed fixed or reduce power on strobe. I plan on using the ys120 strobe for now and has only two settings full and 1/2 power. I suppose you can also adjust by moving the strobe back a bit.

Tony
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#7 MikeVeitch

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Posted 06 July 2004 - 11:29 PM

One basic rule of thumb i like to tell my students for wide angle and manual.
For an average sunny tropical day:

Before 9am and after 3pm shutter speed 1/60
Between 9 and 3 1/125 to 1/250

These will give you nice average blues as long as you are not pointed up to the sun. Shooting toward sun a whole different story.
Once you set the shutter then you can worry about subject exposure by playing with your f-stops. This is all to do with distance, YS 120 Full power and diffuser exposes correctly 5.6 at around 3 ft.
For a new camera this is a great starting point until you are more comfortable.

Have fun and experiment!

#8 beto

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Posted 07 July 2004 - 08:14 AM

Thanks for your comments. I am still a little confused. Herbko suggests setting the f-stop and strobe output, and then slect the shutter speed; review the results and re-adjust the shutter speed and strobe output based on results produced. However Critter suggests selecting a shutter speed and the bracketing with the f-stop. So, any recommendation over the other?

In the Canon 300D you need to press Av button while you turn the dial to select the f-stop. Just turning the dial adjusts the shutter speed. To press the Av button with the Aquatica housing you need to screw in the control, so it is not as easy or quick as said. Herbko, since you have the same camera and housing, don't you think it would be easier to select the a shutter speed and then leave the screw in, so the dial adjusts the f-stop (similar to what Critter mentions)? Do you usually "bracket the shutter speed" instead of the f-stop?

One more question, with the Z200, do you usually use any (which) of the difussers?

Thanks again

#9 paninaro

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Posted 07 July 2004 - 11:45 AM

I adjust the aperture only, and typically leave the shutter speed alone (set to 200) unless I'm taking shots with lots of available light, since most of the UW photography I do here in Puget Sound is macro or at least close in, primarily strobe-lit. The Ikelite housing makes it easy to leave the av button pressed in (or switch between them), so I can switch between them, but of course you have to be careful not to move the shutter speed faster than your strobe can sync.
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#10 james

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Posted 07 July 2004 - 12:22 PM

I think the best approach is to set your aperture and flash power for the foreground exposure FIRST, then adjust the shutterspeed to get a good background exposure.

The reason I recommend this is that once dial in the right aperture and strobe power, you can leave it alone as the shutterspeed changes won't affect the foreground exposure.

If you fix your shutterspeed, then you will have to adjust TWO things everytime you make a change - aperture AND strobe power.

Cheers
James
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#11 beto

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Posted 07 July 2004 - 12:45 PM

That makes sense. Thanks guys for the advice :D

#12 herbko

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Posted 07 July 2004 - 01:29 PM

Thanks for your comments.  I am still a little confused.  Herbko suggests setting the f-stop and strobe output, and then slect the shutter speed; review the results and re-adjust the shutter speed and strobe output based on results produced.  However Critter suggests selecting a shutter speed and the bracketing with the f-stop.  So, any recommendation over the other?  

In the Canon 300D you need to press  Av button while you turn the dial to select the f-stop.  Just turning the dial adjusts the shutter speed.  To press the Av button with the Aquatica housing you need to screw in the control, so it is not as easy or quick as said.  Herbko, since you have the same camera and housing, don't you think it would be easier to select the a shutter speed and then leave the screw in, so the dial adjusts the f-stop (similar to what Critter mentions)?  Do you usually "bracket the shutter speed" instead of the f-stop?

One more question, with the Z200, do you usually use any (which) of the difussers?

Thanks again


The easy question first :D . I always use the 0.5 stop diffuser, except when I use the "Craig Jones" color fiters on the strobes. Don't worry about the color filters at this point, just use the 0.5 stop diffuser.

Which of the three, shutter speed, aperture, or strobe power I vary depends on the subject. The outline I wrote earlier is just the simple version to get you started.

For macro shots, where I need small aperture for good DOF, I'll set the aperture to between F/16 and F/22 and shutter to 1/200 and only vary the strobe power.

For wideangle shots, like large fans or soft coral, with a bright background (sometimes including the sun), I'll turn the shutter all the way up to the max speed of 1/320, and start with a aperture of around F/8 and strobe on full power and tweek the aperture. Here, I place a higher emphasis on getting the background right and will settle for a slightly underexpose foreground if I have to.

There are different strategies for other situations...
Herb Ko http://herbko.net
Canon 5D; Aquatica housing; 2 Inon Z220 strobes; Canon 100mm macro, 17-40mm ; Sigma 15mm FE, 24mm macro, 50mm macro

#13 james

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Posted 07 July 2004 - 01:44 PM

Sounds like you need some more powerful strobes Herb...;-) Just kidding of course, 'cause I know you will appreciate the joke.

Cheers
James
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#14 davephdv

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Posted 07 July 2004 - 06:17 PM

I almost always shoot M. I use 2 shutter speeds. 125/th for macro or close-ups and 1/250th if I want to freeze motion or sunlight rays. I also will change the ISO setting as necessary if the light is low for wide angle. This helps me attain the Aperture settings I want to use for the desired depth of field.

I only use aperture priority if the action is so fast I don't have time to think. But I have been some what disappointed by the results and may use M for those times as well.
Dave Burroughs, Nikon D300, D2X, Subal housing, DS160 strobes

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