Do you TTL or Manually Set your Strobes?

[Mike Veitch]

now that is a good point!

never thought of it that way...

i'm sticking with video....

 

[HowardE]

I would have to say that I have had better results with my WA shots with Manual. It's really easy to switch to Manual on my ike housing.

Question for WA shots - Do you (if you're a WA shooter) set your strobes to FULL, and keep a more open F-stop 5.6 or so? I'm still getting used to the WA thing... Macro shots seem pretty easy to get the desired result.

 

[RonFrank]

I would have to say that I have had better results with my WA shots with Manual. It's really easy to switch to Manual on my ike housing.

Question for WA shots - Do you (if you're a WA shooter) set your strobes to FULL, and keep a more open F-stop 5.6 or so? I'm still getting used to the WA thing... Macro shots seem pretty easy to get the desired result.

I'm new to the whole UW shooting thing, but here is one way to think about exposure with WA when using flash. Use the aperture setting to control the foreground exposure, and the shutter speed to control the background (the BLUE!). So if you have a shot where you include a subject three feet away, and one shoots and previews and the background is very dark, then slow the shutter down. This will not impact the foreground exposure, but it will lighten the overall exposure. Common sense, and an understanding applies. If you increase the shutter by a factor of 3X say 1/250 to 1/60 you may just open up the foreground exposure as well depending upon how much flash one is using, and the available light.

This can be done regardless of if your flash is set using Flash TTL, or manual.

Recongnize that if you have great lighting conditions on a shallow reef, one may have to up the flash power to balance it with ambiant light. Since flash allows us to create daylight WB, both UW and Topside, having the flash balanced against the ambiant light helps create more natural colors where lighting is not daylight.

Another thing to remember, WA provides built in DOF.

HERE is a cool hyperfocal distance calculator. If one enters a focal length of 18mm (12mm on a 1.5X sensor), a focus distance of 5 feet, and an aperture of f5.6, the DOF is from 3.28feet to 10.5feet. The hyperfocal distance is 9.45 feet at that aperture, and that is fixed based on the FStop, not of the focus distance.

Change the focal length to 105mm using the same settings, and the DOF drops huge, from 4.93~5.07 feet. And now look at the hyperfocal distance, off the charts at over 320feet. Understanding the hyperfocal distance is generally more useful for topside shooting as UW we rarely (never?) need to have DOF through infinity. However knowing what DOF a lens is capable of based on the focus distance is invaluable.

I look at TTL as just an easier way of controlling the flash. The exposure compensation is on the back of the camera, and when one changes aperture, the flash automatically is going to change to follow the camera settings. So now rather than having one knob on the flash to control the output, one has the output controlled by the aperture, and it's rather easy to dial in exposure compensation when need on the back of the camera, up to four stops seemless increments which is as much or more than many flash systems allow.

As I indicated, I don't currently have Flash TTL, but I'll get there because I think it will allow me to spend less time thinking and messing around with my flash settings, and more time thinking and messing around finding cool stuff and enjoying the dive.

These discussions take me back to a time when I was arguing pro the use of Autofocus, and incamera exposure meters with photographers who based their entire way of shooting on hand held meters, and using distance scales and hyperfocal distance calculations (landscape shooters). One thing I always attempt is to recognize that this is not a religeon we are discussing, these are tools. Nikon, Canon, and now (lagging behind) Ikelite, and others recognize how useful Flash TTL can be, and have spent considerable effort developing the hardware. The market obviously feels strongly about TTL as I can (and did) pick up an SS200 for $250 almost new on Ebay, and a new DS200 sells for $1000, and close to that used IF you can even find one.

Learn to use the tools available, and you are not guarenteed to be a better photographer, but you at least will get exposure, focus, and DOF more in line! The end results is really what we are all after, and it's easy to loose site of that in the discussion over how to get there.

 

[Larry C]

Some people may consider it cheating but shooting digital in raw format, exposure compensation of about +/- 1 stop is not really a big deal

Best thing about shooting RAW. Since it is easier to correct a slightly underexposed than overexposed shot, I like to err on the low side. With ttl, that means backing off the strobes a little extra and maybe correcting with the fill lighting bar.

 

[HowardE]

Ron (or anyone else) - do you think that the iTTL of the newer Nikons has made advancements over previous versions of TTL?

 

[ssra30]

Question for WA shots - Do you (if you're a WA shooter) set your strobes to FULL, and keep a more open F-stop 5.6 or so? I'm still getting used to the WA thing... Macro shots seem pretty easy to get the desired result.

Depending on the lenses that you have. For 12-24mm, I generally stay at F9 most of the time for a couple of reasons. One is that f8-f11 is pretty much where the lens is at its sharpest. Secondly, since you are taking a virtual image formed by the domeport, you want the depth of field to be deep enough to get the entire virtual image from the dome in focus. On 12-24mm, I find anything from f7.1 or larger aparture to have too narrow a depth of field so the peripheral of the pictures are a bit out of focus. At f8-9, the corner softness is not very obvious behind a dome. Does that make any sense?

Depending on the strobes that I have and if I actually have any subject in the foreground that I want to light up, strobe power will be different.

If I have something in the foreground about 2 ft in front, on DS 125, I would start at around 1/2 power, with DS200, even less power. If no sunball or strong background natural light, around 1/80-1/100. If I have a sunball in the background, the strobe is usually at full power, F11-F16, 1/250s-1/320s on my D2X.

 

[RonFrank]

Ron (or anyone else) - do you think that the iTTL of the newer Nikons has made advancements over previous versions of TTL?

iTTL is a big improvement over dTTL. I would say from an exposure perspective the old film flash TTL was a lot better than dTTL, and I think that iTTL is as good as the OTF (film) TTL, with some huge improvements based on wireless technology.

I can control my SB800 flash with the built in flash on my D200. I can set my in camera flash to master no fire mode, and slave one or many SB800's and control the exposure compensation, and ratio for each flash. That is SOOOO cool. Unfortunately I don't have multiple SB800 flashes.

The downside of all this technology is that with flexibility and features comes built in complexity.

Howarde, you have an awesome setup, good diving from you back door, a wife who is into diving and photography, and the desire to learn. I look forward to seeing more great images, and diving with you in FL again in the future where you can maybe teach me based on your experience!

BTW, for those who shoot Nikon, if you REALLY want to get down and funky with your hardware here is THE BOOK IMO: http://www.bythom.com/d200guide.htm

Thom Hogan is THE master (other than the folks that engineer these complex things, who are under disclosure!) when it comes to understanding Nikon camera's, flash systems, optics, and how it all works. He also responds to questions on dpreview at his discretion. He seems like a fantastic guy, and runs with some of the elite like late outdoor legand Galen Rowell. http://www.mountainlight.com/