Flash is simply not the same with digital as many are accustomed to with conventional photography. The simple fact is that the CCD does not reflect the same as film so TTL is really not TTL. If you’re coming from shooting an F5 or an F100, you’re used to the TTL flash system functioning like this: You depress the shutter release, and the camera fires. The light leaves the flash, heads towards the subject, and strikes it. The light from the flash then bounces off the subject and heads back to the camera, goes through the lens, and then bounces off the film to hit a sensor in the bottom of the mirror box. This sensor meters the light, and when the exposure for the flash is correct, the camera tells the flash to turn off. Before and during this process, two other pieces of exposure information are gathered by the camera: a measurement of light from the Monitor Pre-Flash, and distance information from the lens. These three elements combined are what make flash exposure with the F5 or F100 so foolproof. That is true TTL flash metering. Such is regretfully not the case with the D1!
The F5, F100, and D1/X/H all have an 18% “gray card” gray shutter. This is for the Monitor Pre-Flash, which is really the first part of the flash exposure calculation. OTF, or “off-the-film,” is the second crucial part of TTL flash exposure. This is present in the F5 and F100 but not in the D1/X/H. While the D1/X/H has the gray shutter for the Monitor Pre-Flash to bounce off of, it doesn’t have film in order to make the OTF calculations.
The reflectance value of the D1/X/H’s CCD and shielding filter, which have taken the place of film in the D1, is not the same as film, and therein lies the root of the D1/X/H’s problem with foolproof flash exposure. With the traditional off-the-film TTL flash metering component missing from the D1, flash exposure is relying on the Monitor Pre-Flash, which has huge limitations! However, by understanding these limitations and working within them you can take perfect flash images with the D1.
The Monitor Pre-Flash has a range of just over 20 feet. Keeping the Monitor Pre-Flash distance constant, and therefore exposure performance constant, is important and requires the use of a high-voltage battery such as the Quantum Turbo, Turbo Z, DigitalCameraBattery, or perhaps Nikon’s SD-8a. Relying on AA batteries of some type alone can vary the pre-flash and the flash exposure by as much as 1/2 stop from frame to frame! The external battery cuts that degree of inaccuracy to a maximum of 1/10 stop between frames. While the pre-flash can be relied upon for many aspects of photography, it doesn’t work for wildlife photography because of the pre-flash’s limited distance. This is kind of a step backwards in flash technology because you need to start being aware of the distance between the subject and the flash again. You also need to be watching the background, as it directly affects flash exposure as well (oh brother, all that money and you get a rotten flash system!).
There is a difference between the flash exposure of the D1 and the D1X/H. Put simply, you must work within 20 with the D1 to get any reasonable flash exposure. Because of this, when I’m shooting with my favorite type of background (one that’s darker than the subject), the D1 and SB-28DX combo in 3D Balanced Fill-Flash isn’t up to the job the majority of the time. Under these conditions you can dial in +/–3 stops compensation on the SB-28DX and it still blows out the subject! There is simply nothing you can do with this setting and get the right flash exposure. On the other hand, you can have a subject indoors in front of a brightly lit window with the D1 and SB-28DX in the exact same mode and it nails the exposure every time! These are just the limitations of the D1’s flash technology, so we have to recognize them and learn to work with them.
Like so many other D1 shooters, I use the basic approach to flash exposure with the D1 that I chant to myself when shooting flash: “Background Bright, TTL Is Right. Background Dark, Use A for a Lark!”
The D1X and D1H DO NOT have this problem. Why? The software was fixed, it’s that simple! The “TTL” flash of the D1X/H closely approximates the performance we’re use to with the F5. I like using bounce flash, using the small built-in white card of the SB-28DX. Here’s my formula for correct exposure using the white card to bounce light from the SB-28DX.
When the flash is the main light, I set the flash to DTTL and exposure compensation to -2/3. When the flash is fill, I set the flash to DTTL Matrix with exposure compensation -2/3. You might want to try this as a baseline for your own exposures. One other thing I do, when the flash is fill, I set the tilt of the flash to the default click of the flash. When the flash is the main light, I lessen the angle and set it somewhat halfway between the default bounce setting and normal flash head position.
I hope this helps your digital flash photography! --Moose Peterson
David adds: This may seem like a lot to remember, but it is well worth it. For example, if you have flash as the main light and leave your SB-28DX on Matrix you will very often get too little flash output and be left with either useless underexposures or maybe some images you can save through hard work in Photoshop. Better to get it right the first time in the camera! If you're curious about the SB-50DX and whether you can use it to replace the SB-28DX, check out our review on nikondigital, at http://www.nikondigital.org.