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Low f stop with flash??

Jennine Hadfield , May 15, 2010; 01:29 p.m.

Hi everyone,
I have a couple of questions.
First, I am trying to accomplish taking portraits outside in aperture mode with a low f-stop such as 2.8 to get quite a bit of blur in the background for the shot. At this setting the camera automatically puts me at a shutter speed of 1/1000. When I don't use my SB 600 the picture turns out perfect. Great! However, with these shots I would like to have my SB 600 turned on for fill flash for shadows on their faces but as soon as I do that the shot is way over-exposed, naturally. Is there a way to get this shot at such a low aperture with a flash or is raising the f-stop my only choice with flash or maybe just deal with the shadows and keep the flash turned off? My SB is turned to the lowest exposure and zoom possible.
Secondly I have tried to do this in manual mode but when I have this aperture at 2.8 the camera only allows me to have the max shutter speed of 200. Why can't I get the shutter speed any higher in manual mode? I have a Nikon D90.
Any help would be greatly appreciated as I'm really confused after learning that using flash is good for fill flash on faces and that a low aperture is great for portraits.


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Dan M , May 15, 2010; 01:36 p.m.

Many cameras will not synch with flash at speeds greater than 1/200. Check to see if yours has a high-speed synch option. That might buy you a little bit more. Also, turn down the ISO as far as you can. However, once you are down to your minimum ISO and max speed (presumably, 1/200), there is no way to let in less light other than closing down the aperture.

You can get plenty of blur at apertures somewhat smaller than 2.8 if the background is a bit of a distance behind the people.

Kris Bochenek , May 15, 2010; 02:00 p.m.

You could try using a neutral density filters to cut down the amount of light entering the camera 3 stop filter would bring you down to 1/125s and that is within the camera's synch.

Jim Momary , May 15, 2010; 02:05 p.m.

Kris is korrect.
ISO to minimum (or slowest film speed).
Neutral density filter.
Case closed.

Steve Henry , May 15, 2010; 02:35 p.m.

Consider adjusting your flash output compensation to -2 or -3 stops. This should soften shadows, but not overexpose the scene in aperture priority. Also check the custom functions for high speed synch and turn on this option.

Michael S , May 15, 2010; 03:32 p.m.

Jennine -

You might want to consider working around the problem - if you can, simply move into a shadier area, and move the subjects away from the background. Also, if you have control over the timing, wait for a nice overcast day - you can make some really nice images using the SB600 & d90 when you aren't fighting the power of the sun.


Jeff Spirer , May 15, 2010; 04:42 p.m.

Doesn't the SB600 have high speed sync? The specs say it does.

Frank Skomial , May 15, 2010; 05:30 p.m.

Both, your camera D90 and the flash SB600 have FP flash mode.

Just read documentation that came with your equipment.

You can use any faster shutter speed, with SB600 is camera hot shoe, or as a remote FP CLS automatic exposure flash.

Jeff Spirer , May 15, 2010; 05:54 p.m.

Exactly. Ignore all answers that don't reference high speed sync (FP mode), they're wrong. You just have to set things right and you can do exactly what you want to do.

Hugo Poon , May 15, 2010; 10:56 p.m.

Stick an ND on
Turn the output of the flash down as low as you can, bounce it off white paper/card to further reduce output (and get softer light), get the paper closer to the subject to further soften the light (but you'll really need low-power flash for that)
Make sure you're using the diffuser
Minimum ISO

I find it amazing that you have too much light — I usually find myself lacking enough of it.

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