flash will freeze movement at low ss...not

[Dawgman]

Maybe I'm a little dense at understanding this. I want to take an indoor photo with only window light coming in and using my 430ex bounced and an index card attached. I tried ISO 400 to 800. (I prefer not to go to 1600.)

I've read that I should meter the background, set the shutter speed accordingly and all will be well. In fact it does produce a nice exposure. But the metering is asking for a shutter speed of 1 second and below at f4. Setting it there is too slow for hand held. But I've read that the flash will stop motion even at slow speeds due to the brief flash. This doesn't seem to be the case with me. I still get the blur.

I know I can bump up the shutter speed to 60 to 200 and the flash will adjust but the quality seems to suffer a bit.

Is there anyone out there that could clear this up for me? I'd greatly appreciate it.

Drew

[DarthVader]

That means your ambient light is still dominating...try to use M mode, drop the shutter speed to your max sync speed or at least 2 stops under correct ambient exposure, now your flash will be the main light. If the object still blur you need to drop the shutter speed some more.

John

Maybe I'm a little dense at understanding this. I want to take an indoor photo with only window light coming in and using my 430ex bounced and an index card attached. I tried ISO 400 to 800. (I prefer not to go to 1600.)

I've read that I should meter the background, set the shutter speed accordingly and all will be well. In fact it does produce a nice exposure. But the metering is asking for a shutter speed of 1 second and below at f4. Setting it there is too slow for hand held. But I've read that the flash will stop motion even at slow speeds due to the brief flash. This doesn't seem to be the case with me. I still get the blur.

I know I can bump up the shutter speed to 60 to 200 and the flash will adjust but the quality seems to suffer a bit.

Is there anyone out there that could clear this up for me? I'd greatly appreciate it.

Drew

[JeffreyG]

OK, the main misunderstanding regarding the flash freezing things is that in order to do so the flash needs to be the main source of light. Your problems are stemming from metering the background.

So you meter the background and come up with f/??, ISO800 and 1 second. If you take a picture like this (without flash) you will get an extremely blurry photo that is exposed by ambient light.

Adding flash to the above freezes nothing, as the main lighting will still be ambient. All the flash will do is fill in some shadows.

You need to adjust your settings to take down the ambient light further, and also keep in mind that unless your flash is lighting the whole room you also need to stay above your handholding limit or use a tripod.

Assuming a tripod, you could change the shot to use shutter speeds between 1/2 and 1/8, with the former keeping more ambient light but probably still showing ghosting and the latter showing little ambient light.

Or you could conclude that there isn't enough ambient light in this shot to bother trying to save (that sounds right to me) and simply take the shutter speed to 1/200 to kill off the ambient light. Then this shot becomes 100% flash lit.

[Dawgman]

Thanks for your input. But does that mean that the below post is incorrect?

http://photography-on-the.net/forum/showpost.php?p=2249463&postcount=6

[JeffreyG]

Thanks for your input. But does that mean that the below post is incorrect?

http://photography-on-the.net/forum/showpost.php?p=2249463&postcount=6

He is shooting in a nightclub, so he is setting his camera to 'correctly' expose the dark interior of the club and then lighting up the people that are near the camera with the flash. Since the difference in how they would look with and without flash is huge, the flash is able to freeze them.

This is the key.....the shot must be set such that the subjects are much dimmer without flash than with it. If they are at all well lit without the flash then it will not freeze them because you will see the ambient lit movement recoreded in the image.

As for the hand holding rule, my guess is that the poster in that thread is using a fast aperture and the background is OOF. He gets away with a slow shutter speed handheld becuase the background is OOF anyway and you cannot see the blur. And the foreground subjects are frozen by the flash.

[Dawgman]

Thanks Jeffrey. I think I got it now and can start semi-intelligently use my flash.

[DarthVader]

He will still get a motion blur on the object since it's a longer shutter speed. Only part that the get exposed correctly will be sharp. It's a compromise...you want the background not completely pitch black (that's why he's dragging the shutter to collect more ambient/background lights) but you want to get the object sharp enough even though there is still a small motion blur.

There is no exact theory on this compromise..it's a matter of taste. You can take some test shots.

Thanks for your input. But does that mean that the below post is incorrect?

http://photography-on-the.net/forum/showpost.php?p=2249463&postcount=6

[René Damkot]

http://photography-on-the.net/forum/showpost.php?p=6129682&postcount=3

[Jim M]

There is a lot of gray area (no pun intended) between a background exposed for "average" exposure and a background exposed to be jet black. A lot of people mixing flash and ambient light actually underexpose the background, but not so much as to completely eliminate it.