Fill flash techniques

[j-dogg]

I got a regular Nikon flash was wondering what you all do for fill flash. Got the opportunity to shoot a drop dead gorgeous model so I have a feeling I'll be using that for a bit.

I used the search but couldn't find a definitive answer so I figured I would hear it from some people who have used this technique.

 

[Derrel]

Flash somewhere in the Minus 2.5 to Minus 2.7 f/stop range below the prevailing ambient light level in bright sunlight. In dim lighted situations, Nikon's TTL-BL (Balanced Lighting) can provide pretty good fill with the appropriate rendering of dark backgrounds as dark, due to it sensing the right shutter speed to keep the backgrounds dark-ish.

You can also shoot in an AUTO flash mode, and set the ISO just under three ISO settings HIGHER than the ISO in use by the camera...that is the old-school way to get under-exposed fill-flash shots when using a non-dedicated speedlight.

 

[j-dogg]

I should probably use this opportunity to tell you it's a Nikon flash in a Canon camera (and yes it works)

I usually fire in manual mode.

 

[Derrel]

Yeah, I've used Nikon flashes on Canon before. So...in Manual mode, it's easy to "lie" to the flash unit, so that it puts out LESS light than would be required for a full-flash exposure. SInce fill-in flash requires that the flash's output lighten only the darker, shadowed areas, the amount of flash exposure required is quite a bit less than if flash were going to make the entire,overall exposure.

THere are multiple ways to approach any problem. In Manual mode at full power, you could simply set the flash to an ISO value that is roughly 3 f/stops HIGHER than the ISO the camera is using, so ISO 100 on the camera, go to ISO 200/400/800= 3 stops.

You could also dial the flash power output LOWER, while maintaining the "correct" ISO value, such as full to half = 1 stop half to quarter 1 more stop and quarter to eight power= 1 more stop = 3 total stops' worth lower output.

You can also deliberately MIS-SET the AUTO f/stop on some Nikon flashes, and keep the same ISO value as the camera is set to, and in that way cause the flash to output less light than would be required for a full-flash exposure.

I hope this helps.

 

[j-dogg]

I have a Nikon SB-18, I have switches for off, manual mode and ttl. I don't see where I can change the ISO. Is this a camera setting? Kind of a bit of a flash n00b but I gotta learn this sometime.

From what it looks like I could just set the camera aperture and compensate with distance.

EDIT: So that's what the Flash Expsoure Compensation does. I thumbed through the menu on my Rebel and found this setting, tomorrow I'll shoot around my yard and see what turns up.

Thanks in advance. :thumbup:

 

[Derrel]

I went on-line and looked up the SB-18, which was an economy-level flash designed for full TTL control on older, film nikons like the FG and FG-20,so it goes back around 30 years. According to what I read here http://www.mir.com.my/rb/photography/hardwares/classics/nikonf3ver2/flash/sb1tosb21/index8.htm

the SB-18 is not capable of the more-sophisticated (and actually, more common!) method of normal AUTO flash control that was popular in the 1960's,1970's,and 1980's...so it's a Full-power Manual flash when used on a camera that it is not dedicated to...

Of course, on your Nikon FG, the SB-18 is dedicated; the SB-18 was sold only with the FG, as part of a package. I guess on the Canon Digital Rebel XT, you could work around limitations. The SB-18 has a guide number of 65, so at 10 feet, at ISO 100, the flash's output is f/6.5 roughly. So...that flash firing at full power is going to over-expose anything shot at f/6.5 or wider apertures at ISO 100...you'll need to get your aperture SMALLER in diameter by two and a half f/stops, or approximately 8 clicks using 1/3 stop aperture adjustment increments.

Outdoors, in bright, sunny conditions, at ISO 100, with the lens set to f/13 and the shutter at 1/200 second, this being November not July, at 10 feet, you'll probably have 'reasonable' fill-flash with the SB 18 right on-camera in the hot-shoe and aimed straight ahead at your subjects. If you have a polarizing filter, you could put that over the lens,and open up the lens a stop to stop and a half, and in that way, effectively weaken the FLASH's strength, and for a bit more control over things.

If you really want to MacGuyver things, you can also take cellophane and make cross-hatching on it as a way to cut down on the flash's effective power, or locate some neutral density film, or just literally block off some of the flash's lens as a way to throttle the power down a bit on close-range fill flash stuff.

When you have a very simple flash where the power is always,always FULL when used on non-dedicated cameras, you sometimes need to resort to all sorts of methods.

 

[j-dogg]

I had thought about putting something over the flash itself like some cellophane as you mentioned or something to diffuse it.

It came with a Nikon FG (surprise!) I purchased from my best friend and slapped it on my Canon to see what would happen and I was surprised to see it fire.

I think I know what I'll be doing and I'll give it a whirl tomorrow. :thumbup: