The Trouble with TTL

by Alex Mustard Saturday, January 14th, 2006

TTL. It’s just three letters. But, boy, has it caused some trouble in these digital days. Underwater photographers, unlike our land-loving counterparts, invariably use flash in almost all our shots and this makes us very demanding when it comes to flash performance. Ever since TTL strobe control was introduced with the Nikonos V in 1984 the vast majority of images have relied on it.

TTL works on digital, but do we really need it?
Taken with Nikon D100 + SB80DX dTTL speedlight. Photo © Alex Mustard

TTL is tricky with digital because sensors don’t reflect light in the same way as film. Camera companies have been forced to develop new TTL protocols for their digitals, usually determining the required power output using pre-flashes. Unfortunately, traditional underwater strobes were not compatible with these pre-flash systems. Fixing this problem is exasperated because there are now so many different types of camera being taken underwater, and many have bespoke TTL flash metering protocols. Even within one brand there can be several different flash protocols. Ten years ago our camera choice was limited: Motormarine, Nikonos or a handful of housed SLRs. Today, according to the website Digideep.com, there are more than 600 digital cameras models with underwater housings.

A number of companies have worked hard to crack these codes. Indeed I imagine that right now we are benefiting from more R & D effort in underwater photography than there has ever been. For example Ikelite now has systems that allow TTL with some Olympus, Canon and Nikon cameras, and INON’s innovative new D2000 strobe is capable of TTL with almost every digital compact camera, yet its only connection to the camera is a fibre optic cable. And several European strobe manufacturers off Nikon and Canon digital TTL compatible strobes, often making use the of the electronics developed by photographer Matthias Heinrichs.

The author shooting with an INON D2000 TTL strobe. Photo © Joe Hoyt.

I do accept that TTL is a useful tool, and well worth having in the box (a TTL strobe can always be used in manual). Digital TTL also sells strobes. But many experienced digital shooters are now calling for underwater strobe companies to put their effort into other areas. Canon users want second curtain flash synch in an underwater strobe, and high-speed flash synch. Nikon users want to be able to realise the potential of their Creative Lighting System underwater.

The irony of the situation is that most digital photographers tend to cast off the crutch of TTL as their digital experience grows. They rapidly realise that not only is manual strobe control ridiculously easy with the instant feedback of the cameras LCD screen, but it also empowers them with more creative control. The sticking point is that each photographer who converts from film to digital cannot believe that they do not need TTL. TTL is such an essential part of film shooting. Each photographer has to go through the learning process for himself. They cannot be told. Nearly all film converts demand TTL and, driven by the market, the R & D effort is misdirected.

How do I know? I am part of the problem. When I first got my first digital SLR, a Nikon D100 back in 2002, I went to the expense and effort of housing a normal Nikon land flash so I could have TTL. I told everyone I needed it. But, like the reformed smoker I am now one of the most vehement critics of the necessity of TTL. This is not because I believe the new TTL protocols don’t work. They do. I have just seen my mistake repeated by so many, wasting time and money because the must have TTL with digital. Then half way through their first trip they turn off TTL and never turn it on again. Digital shooting is different from film. But it seems we can only learn that the hard way.

—
Dr. Alex Mustard
Talking Megapixels

Digital has ushered in many changes to underwater photography. The aim of this column is to discuss both the important and more frivolous consequences of these changes to the status quo of our consuming pursuit.

Practice makes perfect. Not everybody has the time or inclination to become perfect before their big dive trip. And so, not having the flash to worry about is a good thing. I am sure, with many dives under my belt using my setup, I will consider not shooting TTL. But something is going to motivate me to do that, and that something is going to be, "gee, my flash isn't doing what I want it to do" and until that happens, I doubt I'll go off of ttl.
Posted by DavidScubadiver on 2008-07-04 08:06:09 Well, if you do it correctly, it is NOT easy. When you think it's easy, you're doing something wrong... Don't take it personally. Yes, TTL works for maybe 85%, but you still have to know what you're doing for the other 15%. And that might also explain why 85% of the pictures taken are worthless...
Posted by ScubaSapiens on 2007-04-13 07:17:18 "It is not intended to be easy when done right". That has to be the most condescending comment I have ever heard. The implication is that if you find an easier way to do it, it must automatically be wrong. What it really says is if you make it easy, you have devalued my expertise; when everyone can do it, they won't need me. I think "professional photographers" have been lamenting every invention since the light meter because it let's the common man do what they do. I understand that wide angle presents problems for TTL, but as James said, for 85% of the shots most people will take, it works.
Posted by bandit on 2006-10-19 15:10:20 I've never relied on TTL even in film days. Could have on some occasions by preferred manual for same reasons as Mauricio, Alex & others. In my workshops I explain to people that if they can remember 4 numbers they can shoot manual. 3 feet, f/8, f/11, f/5.6 .... this is how I taught my best half to leave TTL (which was not performing well in w/a). Once she realized that manual exposure and bracketing was no rocket science she agreed to leave TTL at home! A small exposure table velcroed on her housing allowed her to make images bewyond her wildest dreams. This taught me that TTL-addiction was something one can get out of... providing that someone helps the victim! With digital... as someone pointed out: you've got the best light-meter/esposure table: THE LCD SCREEN ! I agree that TTL will continue to improve in digital photography. However, controlling the behavior of TTL strobes for more creative images is harder, for the beginner, than learning how to use an exposure table. One thing not enough people do: Pool practice before leaving for the $ 10,000 trip! My $ 0,02 Michel
Posted by manatee19 on 2006-01-26 12:04:20 This is a great quote- Mauricio Handler: "you... really learn to control [light] manually if you are to progress into the creation of images that transcend time. Underwater photography is an art form when practiced as such. It is not intended to be easy when done right." Alex
Posted by Dr. Alex Mustard on 2006-01-23 15:01:41 In my uw photography workshops I have always taught manual exposure and manual control of all lighting. As Alex, I am a firm believer in the process of photography. Finding the subject, establishing the working distance, and then working on composition and lighting control using all light sources available to me at the time. From the sun to strobes to cinema lights. Manual control of all of these allows for your image to become much more than a snap shot. On land TTl works great because of many variables that allow for the measurement of light and quenching of the strobes accurately. Underwater the blue column of dark water that surrounds most of out medium to wide-angle images is the cause of many failes accurate TTL reading. To be able to balance the foreground image (lit by strobe) and the natural ambient light is much easier and rewarding in the manual process. Overiding all the elements, from aperture and speed to the power output of the strobes and the mixing of all these elements is what in the end creates an interesting image.. Use TTl (if you must ) for macro, as it is here and primarily here that it works effectively (no large black column of water to through the reading off). For wide, you will have to really learn to control it all manually if you are to progress into the creation of images that transcend time. Underwater photography is an art form when practiced as such. It is not intended to be easy when done right. You will have to learn to feel it, gestimate distances, exposures and spend mor time on composition and expressing yourself through the medium beyond the snapshot that is accurately exposed. Mauricio Handler
Posted by handlerphoto on 2006-01-23 14:10:33 I think having the choice of TTL or not is a good thing. I was forced to go manual when I switched from Nikonos V to a housed Canon F1 and was really surprised how simple manual was once you learn how to shoot that way. For macro it was a matter of learning how to judge distance and adjust strobe power accordingly. Then brackett your f-stop. I think for general macro snap shots, TTL worked great but manual really takes you to the next level and forces you to think about how the light will interact with the subject. TTL is akin to shooting "P" mode in my opinion. I'm not too much of an electronics wiz but how about a Franken Flash: Why can't you gut a 550EX flash, take the board(s) out and uses it with a subtronic or ikelite capacitor and flash tube to get ETTL II? I guess if it were easy or doable, it would have already been done.... Keith
Posted by kcf955 on 2006-01-21 11:30:52 Alex, Eric and others I have been shooting TTL macro for the past ten years with excellent results and I really trust TLL (on macro, with compensation sometimes). Wide angle I always shoot manual. So with digital, how do you manage macro without TTL as the strobe to object distance is often short and sometimes hard to judge. Do you develop a "gut feeling" over time and check the histogram after initial shot to correct the exposure or how do you achieve consistent results ? And do you find it difficult to get to the same shooting position after viewing the histogram. In extreme macro we are talking about fractions of inches. BR, Pekka
Posted by ptuuri on 2006-01-19 15:54:35 When Sarah and I went to Bali for our honeymoon, we brought along the Ikelite 20D housing with eTTL2 circuit. For the mainly-macro shooting that we were doing in Bali, this was great! It allowed Sarah to concentrate on your composition and finding subject, not having to change strobe power herself. When shooting on black sand, the flash exposure compensations of +1 stop worked well. Now when we shot wideangle on a few dives, she just used the manual power settings on her strobes - usually 1/2 or full for bright sunny dives. One of the best experiences for me was shooting TTL with the Fuji S2pro. Since this camera has an EXCELLENT ttl system, I could depress the Flash +/- button, (using the "stay depressed" control on the Aquatica housing) and I could do flash bracketting by simply rolling the command dial up or down. Need a little more flash, turn the wheel one click. Need a little less, turn it the other way. It was a fingertip flash control, excellent, but only needed for those rare situations where TTL gets "tricked." Now that I shoot a Canon 1DmkII, I can no longer shoot with TTL flash, and I miss it sometimes. It was a good tool when it worked - and it worked 85% of the time for macro and about 0% of the time for wideangle. Cheers James
Posted by James Wiseman on 2006-01-17 13:18:15 Hi, To say that TTL is not needed on digital cameras it's a bit like saying that autofocus is not needed on SLR cameras (except for the fact that to find the right exposition is a slower process than to focus manually). I do not have a all Alex skills (Unfortunately!) and experience, and for me to increase the probability to have the correct exposition, sometimes would be really a plus. Encounters with rare fast moving animals, or to freeze a moment than a second after vanishes away. I trusted expert opinions like Alex'one, and I bought a complete system that does not give me the possibility to use ettl. I regret my decision. But I have to admit that the possibility of using flashes only in manual mode is pushing me to think more on how to light a subject, since 'point, compose and shoot' just doesn't work.
Posted by Havskatt on 2006-01-17 11:45:30 TTL is a tool like any other [autofocus, metering, bracketing] use it when you need it, don't when you don't. It is the result that counts not how you did it.
Posted by giftie on 2006-01-17 10:13:31 Alex Right on!!!
Posted by Tank513 on 2006-01-17 08:30:47 Hey Alex, great article. It exactly matches my view on it. we recently had a similar discussion on it in our German forum.
Posted by Andi Voeltz on 2006-01-17 07:21:50 Tools are just that, but I am amused by the argument that you can always look at the lcd display (and perhaps the histogram) and make adjustments. This is true if you are shooting a nudibranch perhaps, but I am pretty sure that the lionfish that was used to illustrate the article wasn't just sitting still and waiting for you to reset the power ouput of the strobes. Often there is a single chance to get the shot you want ( for a variety of reasons) and you want it to be close to right as you can be. I use TTL above water when I am using either a ringflash or a Canon flash and I use a flashmeter when doing portraits or studio work where the flowers aren't usually moving. Both have their place but there are lots of times that I wish that I had TTL underwater to capture a scene that is changing even if slowly. Bill
Posted by bvanant on 2006-01-16 17:19:39 Hi Alex, It is also very beneficial for those of us trying to come to grips with new equipment and getting back into an old past time. I for one believed all the "information" out there and chose my equipment around TTL availability and then find out from those with experience that it is not necessary. So good to have someone out on the limb with me for a change. If your tutorials are going to be based on actual findings, then bring 'em on brother! Good way to shorten my learning curve.
Posted by bruceterrill on 2006-01-16 02:24:56 We plan to publish a series of these editorials, periodically here on Wetpixel. I'd like to add that they are a column expressing my editorial bias - and are not indended purely as dry statements of fact. Although I do hope you find them interesting and accurate. Also it is very useful to readers when counter or supporting views are added as comments underneath. So keep 'em coming.
Posted by Dr. Alex Mustard on 2006-01-15 18:11:22 TTL is about as necessary for underwater photographers as light meters. The best light meter is the lcd display on the back of your camera. That instant feedback, along with the latitude of digi sensors on the down side, make ttl unnecessary. I was a reluctant convert to ttl toward the end of my film shooting days, but never missed it when switching to digi.
Posted by ehanauer on 2006-01-15 10:38:28 This article does a great job of summarizing the echo chamber of Wetpixelian thought on TTL: 1) TTL is unnecessary with digital (partially true), 2) TTL doesn't allow creativity (straw man argument), 3) real photographers don't need or want TTL. I've never shot underwater digital with TTL, yet I still want it available. Just curious, top side do you always use your Nikon speedflash in full manual mode? TTL is no more a "cructch" than Aperture or Shutter Speed priority. Use it for effective and quicker results. If it doesn't work in some circumstances, then switch to manual.
Posted by scorpio_fish on 2006-01-15 02:30:32 oh alex ... i remember telling you as well ... such an amusing piece for me to read ... how is your SB housing ? I havent seen it in years !
Posted by Giles on 2006-01-15 00:44:53