There are no hard and fast rules for "settings" when using flash, other than don't exceed maximum sync speed (which is not a hard rule if your flash has a high speed sync capability)..
If you are shooting a DSLR, it is often best to get a dedicated flash that can communicate with the camera. Between the two of them, they do a pretty good job overall. There will be, however, many situations that they will screw up horribly. It does give you an opportunity to get a flash in use, and if you pay attention to what the camera and flash are doing while you shoot, you can learn a lot. You can also see what pictures come out wrong, and learn even more from them! It is very important that you understand the way the flash and camera work together, and what to watch for in your scene that can create problems. Things like highly reflective materials or large flat dark colored areas.
The flash will also behave differently if used in PASM mode, compared to green box full auto. It will probably act differently in A mode, from any other. This is one of the things that new flash shooters never catch at first, and think the flash or camera is defective. It isn't, it is designed to work differently using Aperture Priority over the other modes..
The specific brand and model of flash will determine a lot of what you can do and cannot do. The camera body can also change the available options..
If you tell us what you are using, we can be a little more specific..
Crime Scene PhotographyA small gallery of personal work: http://picasaweb.google.com/PID885..
There's a huge range betyween hard and fast and guessing..
Rules, and guidelines, and options, vary first of all between adding light to predominat dayliongt or other ambiant light fill flash and having flash be the dominent light sounce, light inside int he dark..
Science is pretty straightforeward. Divide the guide number by the distance, and you get the aperture to use..
A guide number of 110, a distance of ten feet, and shoot at f 11..
The real challenge is trying to understand the words in the instuction manuals when you use flash automation..
Starting with your manual is helpful. fortunately, there are good books about flash. unfortunately (as my experience will tell me), you still have to go out there and experiment with what you have read to fully understand it. just like anything else, experience and practice are the best teachers here (with aid of manual and a good book). you can a read a good book from cover to cover (and read the threads here in dpreview till your eyes hurt) but unless you experiment/practice what you read, you will never understand/learn what you read. yes, flash photogrpahy is a totally different world in itself.
My apologies. I realized that I should have posted that information shortly after posting, but by then I had already shut down for the evening..
Anyway, I am currently shooting with a Nikon D40. While I am looking at getting a SB600, I am currently working with a borrowed Sunpak Softlite 1400 M. I mainly alternate between M and A modes...
What I am going to say is based on using a Canon dedicated flash, but I am sure that a Nikon dedicated flash (or on-board flash) is not too different. The Sunpak that you are borrowing may work slightly differently..
If you are using fill flash, then your aperture and shutter settings determine the overall exposure of the image and the flash automatically lightens darker areas..
If you are using full flash, then the exposure of the image is controlled by the length of the flash burst and not generally by the shutter speed and aperture settings. The flash burst length, which is something like 1/50000 of a second, is calculated by the camera - called ETTL in Canon cameras. You can adjust the flash burst by using Flash Exposure Compensation..
Provided your flash has enough power for the scene that you are trying to light, and provided your shutter speed is not shorter than the x-sync speed (too long to explain this - do a forums search), your shutter and aperture settings do not affect the exposure. If you use manual exposure mode, you can use the aperture to control depth of field and the shutter speed to control the balance between objects lit by the flash and background objects lit by ambient light. The latter can very very useful if you have a bright window or lamp in the backgound, or if you want the background to be as well lit as possible (or the reverse)..
On my Canon, if you use the flash on automatic mode it simply sets the shutter speed to 1/60 and the aperture to f5.6. If you don't use manual mode you are giving up the ability to control depth of field and background lighting..
I hope that this is of some sue to you.Chris R..
James AEB wrote:.
My apologies. I realized that I should have posted that informationshortly after posting, but by then I had already shut down for theevening..
Anyway, I am currently shooting with a Nikon D40. While I am lookingat getting a SB600, I am currently working with a borrowed SunpakSoftlite 1400 M. I mainly alternate between M and A modes..
The SB600 will do matrix balanced fill flash, which is probably what you're after, and it'll do it in TTL or iTTL mode just fine. I generally have to dial in about a stop to a stop and a half of negative exposure compensation for balanced fill on my SB-800 to not get that "over-lit" look. If you're serious about flash, you should consider the SB-800 for commander mode should you decide you want to use a couple of SB600's in conjunction as fill in the future- though you could always get the SB800 as the second flash, one advantage is that you could use the SB800 slaved to the built-in flash and just dial one up or down to get whatever lighting ratio you want..