Do I get this? Flash/Ambient balancing

[Steve Smith]

I though a flash was already matched to daylight.


Steve.

[markbarendt]

I though a flash was already matched to daylight.

Steve.

To a point, as a baseline, yes.

Daylight's color though changes throughout the day. A sunset/late afternoon light is warmer than midday light, a flash matches midday light more that evening light. Gels can help fix that.

[Mainecoonmaniac]

i usually measure the scene and pick an aperture,the flash by itself would dictate. The shutter speed is irrelevant, aperture priority in a way.

Ralph is correct. However please be aware of the maximum synch speed especially with focal plane shutters or else your shutter might cut off part of your exposure in the shot. Aesthetically, I try to keep the flash about 1 stop less than the ambient light. Your taste might be different. Do some test first. On a Vivitar 285 you can set the auto mode on a fixed f/stop then let your camera set your shutter speed. I find Vivitar 283 and 285 guide numbers are pretty accurate. You can also set it on manual mode and read the f/stop calculator.

[robbalbrecht]

I love this thread. When I shot on 1s and 0s a lot of this stuff was easy to figure out thanks the the LCD on back of the camera. Now that I'm shooting on film all the time I like having to figure a lot of this stuff out on my own and visualizing, with a little help from my meter, how my shots are going to look.

[Steve Smith]

In the olden days before auto thyristor flashes and flash meters, all that was available was the guide number.

Divide this number by the distance and you get the aperture needed (usually for ISO 100).

Despite advances in technology, dividing one number by another still works! A little bit of Google searching will probably find the guide number for your flash.


Steve.

[robbalbrecht]

Despite advances in technology, dividing one number by another still works!

No way!!

[markbarendt]

Originally Posted by RalphLambrecht
i usually measure the scene and pick an aperture,the flash by itself would dictate. The shutter speed is irrelevant, aperture priority in a way.

Ralph is correct. However please be aware of the maximum synch speed especially with focal plane shutters or else your shutter might cut off part of your exposure in the shot. Aesthetically, I try to keep the flash about 1 stop less than the ambient light. Your taste might be different. Do some test first. On a Vivitar 285 you can set the auto mode on a fixed f/stop then let your camera set your shutter speed. I find Vivitar 283 and 285 guide numbers are pretty accurate. You can also set it on manual mode and read the f/stop calculator.

Ralph's idea works, but as you say there are real limits and for me it starts in the wrong place creatively.

Personally the flash is the last thing that I let dictate to me.

Aperture is typically my first choice, to get DOF right for the subject or style of shot.

Time limits are next in line, subject matter again dictates here but also sync speed. Typically for me it relates to age and activity, 1/30th may work for adults around a campfire with camera support, for youngun's or moving subjects or hand held I want to be up close to sync speed.

Aperture and time and background lighting (that I can't change) then dictates my EI.

Finally after all that is addressed then I start setting up the strobe for the subject. The reason I do strobes last is that they are adjustable and all the other choices are taken in my world.

With practice it can be easy and fast because we all find norms that work for us. Personally if I'm outside and there's a strobe attached to my camera the aperture is f/2.8, the shutter is between 60 and 125, the camera is on a monopod, the EI is judged by the situation, and my Nikon speedlites are on "A" or matrix TTL with no compensation.

[Mainecoonmaniac]

My Canon and flash system is so old there's no TTL. I've had to use the guide number system or the auto mode. I'm sure TTL are way more accurate that the system I use. Don't they shut the flash off as soon as there's enough light from the flash hitting the film? The auto sensors on the my Vivitar 285 shuts off the flash when enough light bounce off the subject.

[markbarendt]

The auto shut off is actually true for both auto and TTL. Power on flash units is adjusted by duration, luminance is typically fixed.

TTL, even balanced matrix TTL, isn't necessarily better, it's just a tool.

I use auto a lot especially where I can bounce the light. It lets me use slower films with faster shutter speeds, keeps me in the 400 EI range instead of 3200.

[jnanian]

i try to keep it simple
i measure and pick the aperture and speed for the ambient light and adjust the fstop or
shutter speed to under expose what the flash says. i have a electric eye for my lumedyne 244
and i can tweek the light from 2 ws to 200, so it makes it ez to tweek just a little bit...