CLS Questions

[rob_piontek]

I shot for the first time today a few portraits with an SB-800 on camera and an

SB-600 off camera. A couple of things weren't quite clear to me.

 

If the camera is in full manual, and the flash in TTL, does the aperture/shutter

setting affect the flash output?

 

What is the easiest way to balance ambient with flash, when I want the flash to

be the primary light for the subject? Until now I've been shooting manual flash

and camera, and it's easy to just change the shutter speed to bring up or down

the ambient light. Or change the aperture/shutter together to keep the ambient

the same, but change the flash exposure. How do I do this with CLS?

[zippy_doda]

Only aperture and distance to subject effect flash output, the smaller your aperture or the farther the distance the harder your flash has to work. To balance ambient with flash just keep an eye on your meter in the view finder, it?s metering ambient light. If it says your 1 stop under expect your background to be 1 stop under and your subject will be exposed properly by the flash (hope that made sense)

 

Not sure what body your using but on the D200 output of individual flashes can be made from the menu. I have never used the SB800 as a commander so I?m not sure but I think you also have those options on the speedlight.

[tom_luongo1]

I do a lot of that kind of thing.

 

I usually set manual exposure to underexpose ambient light by 1 or 2 stops. ISO, shutter speed, and aperture are determined by the limits of available light and what I want to do to eliminate camera shake and subject motion. i.e. Higher ISO with slower shutter speed and wider apertures if it's dark.

 

I put the flash in TTL-BL mode and everything comes out right.

 

If I were outdoors, I'd normally want ambient light exposed the same as the flash on the subject. Aperture priority on the camera with TTL-BL on the flash.

 

The photo below was probably direct flash with a diffuser and a low white ceiling. So the flash added something to the background but more to the foreground. This is most noticeable in the different color balance between foreground and background but it also demonstrates about 1 stop underexposure of the background/ambient.

[tom_luongo1]

Forgot the example!<div></div>

[tom_luongo1]

In this example, the far background is all ambient light.<div></div>

[rob_piontek]

Actually since you mention it I'm not sure I really understand TTL BL. This means that camera controls ambient and subject exposure, or so I think the manual says. To me this must mean that the camera changes the shutter or aperture to expose the background at a similar level as the subject. Is there a difference between dialing in exposure compensation on the camera or on the flash when in TTL BL? What about in normal TTL? In normal TTL the flash exposure compensation controls the subject, and the camera exp. comp. the background?

 

It's funny that shooting manual flash and camera seems so much simpler!

[lex_jenkins]

TTL flash works regardless of camera exposure mode. (If I'm recalling correctly my D2H has limits in spotmetering mode, tho', but I'm too lazy to check the manual.)

 

The BL option is best reserved for situations with bright ambient lighting: outdoors in daylight or, rarely, indoors with unusually bright lighting. On my D2H with SB-800 the BL option works very well in no-brainer Program for quick grabs outdoors in daylight when I don't have time to fiddle at all with any settings.

 

Indoors and in dim outdoor light use the non-BL TTL mode. You'll get more consistent results. I also use this outdoors in daylight when I have the time to manually choose my exposure settings.

 

You can easily experiment for yourself at home. Set the shutter speed to 1/30-1/60 to enable a reasonable level of ambient lighting to affect the photo. Set the aperture based on the desired DOF. Take identical photos, one with the flash set to TTL, the other set to TTL BL. Shoot a variety of situations, including against backlighting, white walls, non-reflective dark backgrounds, etc. I'm betting you'll see more consistency in regular TTL mode.