Need help with Nikon flash!

If I were to believe the propaganda, I might believe that I own

the most sophisticated consumer flash package on the market: an F80

coupled with an SB-50DX and a D-type Nikkor. The problem? Shooting

with this arrangement leaves my negatives mostly underexposed. Even

my finest are thinner than ideal. I've tried to decipher the SB's

manual, but it's no use. Here's what I'm confused about:

Say I'm indoors and my camera's meter is telling me that if I

shoot at f/1.4 at 1/45 sec I'll be underexposed by 3 stops. Since I

usually work handheld, I opt for my flash. I set it to shutter

priority mode so I can drag the shutter if need be and since,

according to the manual, the flash will select the correct aperture

for my chosen flash-to-subject distance. But my meter gives me the

EXACT same reading. What's more, focusing on points from several

feet to infinity seem to have no effect on the camera's choice of

aperture. Am I overlooking something that should be blatantly

obvious?

TTL flash doesn't use the flash-to-subject distance to determine aperture. On TTL, the flash fires at full power and the camera cuts it off when the meter tells it to. That's why the distance makes no difference to the aperture.

 

Your meter will continue to give you exactly the same reading because it is metering the ambient light. If you set shutter priority at 1/45s then you will get f/1.4 because that's as wide as the lens can open. The background will remain 3 stops underexposed.

 

Use aperture priority. If you want to, use slow or rear-sync flash, but watch your shutter speeds.

Yeah. Why are you shooting in shutter priority? If you want to drag the shutter go to manual. The metering will indicate what you need to do to get the ambient lighting properly exposed. Choose a shutter speed and aperture based on that just like you weren't using a flash. The flash will do the rest. Make sure that you have selected 3D Matrix Balanced Fill Flash on the flash for it's mode. If the flash is too hot, dial in some minus flash compensation. That's all there is to it. <p>

With the most sophisticated flash system in the industry I don't know why you are having a problem.:-)

Mike, the meter reading you are seeing before and after pressing the shutter is your ambient reading, not the flash's. TTL flash exposure is measured "real-time", while the mirror is up. So you won't see any change to your reading just by varying your focus points (or focus distances). That said, the lens's focus distance will be considered by the TTL flash circuitry during actual flash exposure.

 

The main thing you should be ensuring is that your physical flash-subject distance is within the range indicated by your flash distance indicators (shown on your flash LCD panel). The flash distance indicators vary according to your chosen aperture, i.e. longer for wider apertures and shorter when stopped down. Stay within these limits and TTL flash circuitry will take care of the rest. (Note there are times I deliberately stop down my aperture or dial in fractional flash-power that will give me a distance on the LCD which is shorter than my flash-subject distance, but those times are only for manual fill-flash. Doing so for other occassions will result in guaranteed flash underexposure).

 

Regards,

The flash will select the correct aperture? You misunderstood something. You are using flash because of handholding, yet want to drag the shutter. That's a little contradictory. You've left out flash-to-subject distance. If your flash pictures are underexposed at f1.4, something is dreadfully wrong. If you could provide all the details, the problem and solution should be blatantly obvious.

Actually a D100, D1x, F100 or F5 combined with an SB-80 and a Nikon AFD,

AFS or G mount lens is a more sophic=sticated package but never mind.<P>

Okay; camera meter tells you that 1/45 @ f/1.4 is 3 stops under. You decide o

use flash. using flash basically means that aperture is king. So you should

first try aperture priority. This will tell you (duh!) hat your exoure is now 1/60 @

f/1.4. But you want more ambient light so you switch to either rear sync mode

so the flash fires at the end of the exposure, or slow sync so you get an

equally long exposure butthe flash fires at the beginning of the exposure. A

non under exposed shutter time should be 1/6 sec at f/1.4. Now if the subject

is far enough away from the camera & flash You might be operating outside

of the range ofthe flash to effectively boost the light level. <P>Basically what i

think I see here is user error caused by too much over thinking on the user's

part. But maybe iam wrong and the case is too little thinking on the user's part.

These are just machines; it is up to the user to underastand the fundamentals

of exposure.

Thanks for the info everyone. And Ellis, I said the most sophisticated CONSUMER flash set-up. You're listing pro gear. But now I'm nitpicking. Thanks again all.