Too MUCH light?!

[asha]

That's a problem I never thought I would have.

Using the S90 in the Ikelite housing, I recently upgraded my strobes to dual ys-01s connected fiber-optically. They're fantastic and provide so much light that shooting in Av, I had to use f/8 in order to not overexpose the shot. Whereas the photos turned out great, I'd like to be able to utilize other apertures. Presuming the solution was to shoot manual (so I could use a faster shutter speed), I struggled with the lack of rear dial access on the Ikelite housing before just resigning myself to f/8. So I suppose my question is twofold:

1. Am I missing something (strobe position? Camera settings?) that will make Av work for me, or is manual truly the answer?

2. Assuming I can get the s-button+L/R rear-dial workaround to work reliably for manual shooting, is there a trick to exposing the shot correctly? Presumably if I meter off available light, and then fire strobes, the result will be overexposed.

Thanks in advance!
A

 

[M_Bipartitus]

Most Canon cameras are made so that Av mode sets the correct exposure without the flash/strobe. The flash then adds on top of that. If your strobe is detecting a automatic flash duration from the camera, the idea is that the background is properly exposed by the camera, then the strobe adds light to the foreground. Unfortunately many times this is too much light.

To get around this I recommend setting the exposure compensation setting to around -2 stops. The photos without the strobe would be to dark, but adding the strobe on top of this dark image give a few nice perks. For example, open ocean behind your subject will have a deeper blue and look a little more natural than the light blue that can occur if the camera uses the background water for metering. Also, it will help your foreground subject stand out from the background as the subject will be brighter than the surroundings. This assumes the strobe is either manually set to the correct value, or some form of auto-exposure flash is used.

 

[Warmwater Wank]

Hey A. I'd be among the first to say (and apparently am) that yes, "Manual is truly the answer" but I say that about most anything. You do have a lot of options but let's clarify a few things. First, the shutter speed will have no real impact on the exposure for the areas lit by flash. You would notice the background getting blacker, back where the flashes don't cover but it would not help you avoid potentially over-exposing the subject. This is because the strobes fire at such a high speed the light is already on the subject before the shutter has closed (unlike how things work when it's available light only).

So, your main ways to control this, once you max the camera aperture out or want to use other apertures, is to have the strobes adjust themselves. You do this by either going to S-TTL or by switching the strobes to manual and adjusting their output (I believe the YS-01's have a 10 step adjustment). Double check your strobe manual (or go online for the PDF) for going S-TTL. Usually you would have one strobe fired by fiber optic from the camera flash and the other strobe hooked into the first strobe. When the camara shuts down it's flash the fiber optic connection shuts down the external strobes. You need to know some info to make the correct camera/strobe settings but the owners manuals should provide this.

As for manual camera exposure it's simple. You are correct, if you meter for the ambient light then toss a coupla external strobes at the subject you over-expose things. The big secret though is the exposure doesn't change all that much when doing flash work. Distance to subject is the big governing factor, not how much available light may or may not be present. What you find is you use a few basic settings and pretty much forget camera settings after that (ie--a basic camera setting for close work, another for wide angle etc.). You can then tweak exposures by manually adjusting the little output switches on the strobes to lighten or darken a shot. With 2 strobes you may want to adjust so one is more dominant for lighting effects but that is a topic to explore on it's own (which let's me plug Scott Geitler's great website if you want extra help: Underwater Photography Guide )

Play with the "S-button,left/right rear dial" biz above water a time or 2--it becomes very easy to use and you won't have to use it all that much if you do opt for full camera Manual exposure. Set it at 1/500th if you want a real black background and shoot slower speeds to begin to brighten up the bg to a more natural blue (or green if you get stuck in freshwater!). Adjust the f/stop as you desired then rely on the YS-01's manual output adjustment. If you opt for S-TTL do a bit more digging on the Sea & Sea site for details . You can experiment w/ any of this above water a bit to pin down what you want to try (though some UW strobes don't like to be fired a lot above water due to potential over-heating).

Check Scott's website for more help. If you don't want to mess with too much at least learn to use the strobe's output adjustment feature, it will avoid over-exposing. // ww

 

[Jorgy]

Another vote for manual control and vary the strobes themselves for fine tuning expousure.....

M

 

[Nemrod]

I would stay with Av mode and try going to Func Set button, set your camera strobe compensation +/- value to -2 stops for starters. Make sure your camera strobe is set to Auto under "Menu" and not Manual.

Set your camera exposure +/- value (overall) to -1.33 stops.

These adjustments should get you going and also get yourself a diffuser(s).

N

 

[asha]

Thanks so much for all the helpful information!

It's encouraging to learn that I likely won't need to be fiddling with the shutter speed constantly. I looked through Scott's website a bit and I'm looking forward to trying out the recommended settings and strobe positions the next time I can get in the water (tragically, not until Thanksgiving). I was previously using my strobes on minimum power, but I am thinking that some tweaking of positioning will help quite a bit.

Also, having looked back on the photos that "worked" on f/8, Av-mode was frequently choosing reasonably slow shutters (e.g., 1/60), so I imagine that Scott's prescribed speeds of 1/500 and 1/125 will help a lot! I'll be shooting manual soon enough

So far as TTL goes, I don't *believe* I can use it on the Ikelite housing... would love to be corrected!

Thanks again!

Ashley

 

[mitsuguy]

Thanks so much for all the helpful information!

It's encouraging to learn that I likely won't need to be fiddling with the shutter speed constantly. I looked through Scott's website a bit and I'm looking forward to trying out the recommended settings and strobe positions the next time I can get in the water (tragically, not until Thanksgiving). I was previously using my strobes on minimum power, but I am thinking that some tweaking of positioning will help quite a bit.

Also, having looked back on the photos that "worked" on f/8, Av-mode was frequently choosing reasonably slow shutters (e.g., 1/60), so I imagine that Scott's prescribed speeds of 1/500 and 1/125 will help a lot! I'll be shooting manual soon enough

So far as TTL goes, I don't *believe* I can use it on the Ikelite housing... would love to be corrected!

Thanks again!

Ashley

Its not really TTL as used in pro-photography with SLR's and such, and its not electronically controlled, instead it is optically controlled... You can use it on ANY housing that allows the internal strobe to function, regardless whether its an SLR or not...

The problem with shutter speeds up in the 1/500th ranges, is that it really cuts out pretty much all ambient light, to the point where if there are any unlit areas in the photo, it will appear as though the photos were taken at night. Its actually kinda neat, but only for a few photos, IMO...

When shooting close up stuff, I usually have to turn down my single strobe, use F/8, ISO 80, and 1/125th... My preferred settings for wide angle are f/8, ISO 80 or 100, and 1/60th...

F/8 is perfect (IMO) for underwater usage, and unless you are going for really shallow depth of field (more creative pictures), I can't imagine using anything other than F/8... About the only reason I stray from F/8 is if lighting conditions require more light than I can get at ISO 200 and 1/50th... Any slower and the images are more likely to come out blurry, and higher ISO and I'm not as happy with the graininess... Even then, I try to limit myself to F/5.6, but have gotten acceptable shots even at wider F-stops...

One other thing - I don't know if you are going for macro or wide angle shots and what lenses if any that you are using, but, you should try widening the strobes angle - instead of having the strobes fire directly at the subject, have the subject lit with the edges of the strobes output - this indirect light isn't as bright or as harsh...

 

[asha]

Thanks. I'm going to play with strobe positioning per Scott's website. I suspect this may be part of the problem. I'm using Inon UFL and UCL 165AD lenses for wide-angle and macro, respectively.

Re: TTL: I'm fascinated, but confused. Do I have to do anything besides set the strobes to TTL and go?

 

[M_Bipartitus]

TTL should work as long as the Strobe and the Camera are set to TTL. The basic idea for optical TTL is that the camera adjusts the length of the internal strobe based on how much light it detects during the photo. When the camera thinks that enough light has come back to the sensor, it stops the internal flash. The optical strobe, in the correct mode, Just "amplifies" the internal strobe. That is it fires as soon as the internal strobe starts, and turns off as soon as the internal strobe turns off. The camera doesn't know about the external strobe, it just measures the amount of light it receives.

 

[ozziworld]

I have encountered the same using my FIX s90 / Inon s2000. On Manual or sTTL and Av, TV or P. I find it definitely has to do with strobe distance and position.

On Macro 1/500 at F8 is the least amount of exposure on the sensor and it just seems the strobe over powers everything even at ISO 80 when the normal sTTL settings are used. When I tried to turn the power down (still in sTTL) it starts to help but not enough.

I then tried it on Manual and of course when the camera is also at 1/500, F8 and ISO 80 I have a little more control on the flash to turn the power down. Still not enough if the strobe is not at least 10 inches from the subject.

With 2 - ucl165s my lens distance to the subject is around 2-3 inches and I have to move the strobe out further or turn it away so it is not direct. Problem is not so bad when lens distance (4 inches and farther) and strobe distance are increased.

I find it definitely has to do with distance / position as the lowest power setting in Manual with the fastest shutter, smallest aperture and lowest ISO. I still manage to get blown out when strobe is direct and closer than 10 inches.

Seems for me it does not matter whether the power is turned down automatically (sTTL or Manual). And this is with one little s2000 strobe.

BTW - I also encountered same with my other P&S (Canon IXUS80) which does not have Manual, I also had to turn re-position or re-direct the beam.