Strobe Technique Tips...

Hi all,

I'm getting ready for an awesome trip and am going over my gear and pouring over thousands of images over the past decade of working on my photography and I seem to have one issue that haunts me. Strobe wash-out. There are tons of photos that I feel look good u/w, only to download and discover that I continuously get washed out photos when in TTL mode. (yes, I've tried several different cords in case of cord failure, but TTL works)

I read the forums, I talk with folks, I scour the internet and of course practice incessantly. It seems that in TTL mode, I'm always getting the same result. (in manual I don't, but if something is happening quickly, do you have time to go adjusting strobes?)

ok, so you probably want to know what I'm shooting with these days.. Nikon D700 with assorted lenses in a Seacam housing, with two seaflash strobes on some ULCS arms.

I thought before my trip, perhaps picking the collective brains of theWwetpixel community might be a good source of ideas and encouragement.

Thanks!

in hindsight I probably should have put this in the techniques and tips catagory, sorry about that.

You may post a washed out picture so that we can see what you consider as washed out!

TTL don't prevent pictures to be under or over exposed if you are too near or too far.

Washed out pictures can depend on several factors:
- your strobe is too powerful and you burn out the picture --> try to use a lower power setting

- your strobe is too weak --> crank up power setting or move nearer
- a lot of backscatter --> control your strobe position
- auto iso setting --> use manual iso setting and if possible not higher than 400

- dirty sensor --> have your camera sensor professionally cleaned

Keep in mind that you rather underexpose slightly the overexpose and burn the whites.

A perfect exposed picture should not be washed out, but TTL is not always perfect...

Chris

I think it's common... TTL mode has been miss more then hit for me. I do also find it giving me more light then needed. Check with a friend and the saying is that it's better to shoot in manual.

With regards to things happening really fast. Then it's a matter of knowing the strobe and distance from subject. Plus. Doing test shots.. Esp for wide angle. For Marco.. Usually have more time...

I've moved this to the techniques forum.....

Your problem is probably using TTL! Are you having the problem on wide-angle or macro imagery?

If it is the former:

When the camera meters the scene, it does not know what your subject is. Hence it will try and illuminate the entire scene, which means that the strobes will apply full power. Of course, this "washes out" or overexposes anything close to the camera.

For macro, we often deliberately underexpose the background in order to get black or other colors (blue/green) that will enhance the subject or stop up in order to enhance DOF. In TTL, again, the camera will try not to let this underexposure happen and will apply full power.

Manual strobe control is actually fairly easy to get right!

Adam

There are tons of photos that I feel look good u/w, only to download and discover that I continuously get washed out photos when in TTL mode.

How did you ascertain they were OK under water?

Which Seacam strobes do you have? Only the D models work in TTL with a D700 and if you use both you need a special circuit board.

I tend to agree with the majority here. Many photographers look for TTL as a feature to make life easier, but I never shoot TTL and I find that the well exposed image ratio is much better when shooting manual and simply minding your distance from the subject, and making minor adjustments on the strobes when needed.

Quickly closing your aperture with the dial, if you don't have time to adjust anything else is also a good method to save a shot from over exposing.

Oh, and of course, shoot RAW. It can bring photos back from the dead

To get the most from TTL you still need to be in the right ballpark with your fstop settings to get decent results, try this with ISO 100

1 foot or less from subject = f16-f22

1-2 ft = f11-f16

2-3 ft = f8-f11

3-4 ft = f5.6 - f8

Like Mike pointed out above, better be in the ballpark even with TTL - or at least understand the relationship between your strobes GN and distance and aperture.

Check what the guide number of your strobe is. GN = distance × aperture. So for example, if your camera is set to ISO 100, say your GN is 32, your strobe (not front of camera) is 4ft from the subject, you would get the correct exposure at f 8. When I started shooting underwater many moons ago, I used to carry a little laminated cheat sheet table with me. However, you will quickly get used to / memorize the setting and you can of course adjust in many ways, for example, cut strobe to half power to if you want a one stop bigger aperture, or move strobes closer for a smaller aperture. But just start with one setting with camera set to ISO100 and strobe(s) at full power, paying attention to your strobe to foreground subject distance. This will tell you how accurate your GN in-water is. You might find that the GN given by the manufacturer is a little "optimistic" and find that perhaps it is a stop or so smaller, but in that case just "adjust" your calculations to that number. Practice this until you feel that you have it down solid and you can "trust" that the light is always behaving the same (it is, but it helps to "get it" ). Then you can start adjusting according at desired effect, while keeping exposure correct, by adjusting you iso and aperture ( but not time, except to change the background brightness).

I have never used TTL. When I see amazing shots it is often due to the creative way people have lit them. So to the above I would ad, be creative with your strobe positioning. Here is an old Powerpoint presentation I did. https://www.youtube.com/watch?v=ldCw80PSugY

It's the shots at Wetpixel that make me think "wow how did they light that?" I find inspiring.