Flash lighting balance and related problems

Flash light balance related problems.

 

I am a newby here, so first of all allow me to apologise if this post

is replicating topics (although I did search and no relevant post

came up) or if I am involuntarily infringing any rules. Then allow me

to thank anyone who will spare his/her time to help me, it will be

greatly appreciated.

 

I use Nikon F5, SB80DX (master) on SC17 + SB24 (slave) on the SU4

wireless connector. AF-S 17-35 D, AF-S 28-70 D, or AF-S 80-200 D. I

use various films and various settings. The problem remains the same.

Exposure balance is poor.

 

I am an amateur and strobe photography is not my scene (clearly!) so

please help me from the fundamentals.

 

I have verified with Nikon Office in Shinjuku (main Customer Support

Centre in Tokyo, I live here) that my camera meter and equipment is

working fine.

 

I have switched off the MBFF (3d with pre-falsh) and gone to simple

TTL. But I still get problems. The greater the amount of light coming

from the flash array, the greater the under/over exposures. When I

use a lot ambient light, or shoot in sunlight, I get almost correct

exposure.

 

The Nikon guys have given me one hundred clues and I verified almost

all of them. Bottom line, I got them to come out and verify the

settings and set up (Yes, they are this kind in Japan to customers!).

Guess: Yes still exposure problems.

 

The UN-Offical answer was, with SU4 you better go manual. They will

not write this down, but a lot of head shaking and hummms...

(Japanese for: Yes, there is a problem here).

 

The problem is not solved with braketing either.

 

Apparently the SU4 will NOT cut off the light emission of the slave,

it will only pilot the beginning, so if the slave is too close or too

far away the result is not perfect.

 

I want to know if you have any similar experiences. What can I do? I

have been (strongly) advised to:

1. Go in manual mode and meter everything manually (Minolta V).

2. Use SC19+AS10 (I also have 3 cords and 2 units).

 

Just for reference this is one of the settings:

Shibuya crossing:

Af-S 17-35 D set at 35.

F5 in manual.

3D Pre-Flash off, normal TTL. SU4 as slave conroller.

Kodachrome 64 Asa and 200 ASA. (I can not go higher since I need a

120cmx180cm enlargment from slides (please don't ask why!) and I do

not own a medium format set up.

Environment is night, but some ambient light from brightly light

sorroundings.

Brightly light backgound boards, the largest of which is directly

behind the models and measures 60ftx200ft. This panel is 600ft away

from lenses, people are walking behind the models, the models are at

20ft from lenses (the lenses are almost on the ground),

Nikon light meter on matrix reads 6 seconds at F8 with 200 ASA and 25

seconds with 64 ASA.

On Spot (models) the meter reads much less.

Minolta Meter (V model with reflected light head 5°) gives an

average reading not too far off that of the camera meter when on

matrix.

I need the background to be correctly exposed and only slightly off

focus. So I figured I have to rely on strobes only to correctly light

the subjects as the background is too far.

I focus on subject, recompose image vertically and shoot in manual. I

tried different speed light positions but the result is not constant,

and small diffrence produces great difference (from under to over

exposire of main subject by moving the flash only 1 ft!)

I use diffusers when the flashes are closer than 15ft.

 

I ahd same problems in other setting (interiors with other lighting).

I can explain these other settings next time, if someone is willing

to help.

You need a 'more simple' set-up.

 

One flash umbrella, a studio strobe bounced into the umbrella, set your camera to 'M' for the shutter speed. Take a roll of print film, keep notes, and test a few shots. Then look at the density of the negatives: you should find the combination you are seeking.

 

The Nikon TTL system does not work well with cords and a mix of SB-80DX and SB-24 units. If you read the speedlight manual, it goes into detail about 'sometimes' needing to reset the flash units, etc.

 

If you can use the umbrella - studio strobe combination, you need only to use the SB-80DX (in manual, firing back to the umbrella) as a trigger for the studio strobe.

 

Good luck...

Set the SB24 to auto mode, not manual or TTL. Set the aperture value on the flash for one stop less than the camera. In other words, if the camera is set to f8, set the SB24 to f5.6. Just be sure the two flashes are NOT pointed at each other. Hmmmmm.....they aren't pointing at each other NOW, are they? THAT will surely result in underexposure.

My first instinct with lighting situations like this is to set all flashes on manual and use a flash meter.

 

HOWEVER, I'd like to think that the TTL system would all work. In fact, I've used my F100 with an SB-28 directly attached and an SB-24 on an SU-4 (all at near darkness like you describe), and the exposures were pretty darn close (although admitedly not perfect.) I thought the SU-4 DID cut off the light (I better check the manual). In fact, that's why I though my multiple flash scenario described worked.

 

Maybe I've just been lucky with my SU-4? Anyone else have any experience with it?

Thanks to all, for your advice.

 

Gerald, sometimes I do use studios. The reason I was trying not to use a studio set up was that I would actually like to learn how to use the portable strobe array I described. I am trying to learn how to use my equipment when in "portable" mode!

 

Scott, the flashes were not pointing at each other. But would you explain why the extra stop in aperture?

 

Thank you again to all.

 

Tommaso.