Dragging The Shutter

[Higham]

Hey Guys I did my mate a favour and took photos his daughters christening, I used his 580 EX ll (which i'm saving for) on the day for the first time.

It was in a church around mid morning, using 2nd curtain rear sync in AV mode i was shootting with a shutter speed of around 1/15 (lens was a 18-200 f/3.5-5.6) should i have changed to manual mode and up'd the shutter to hand held speed (1/60th) or not used rear sync at all with the generous amount of ambient light.

I'm a little upset as although I nailed shots, of course they have a motion blur.

[ricktas]

Rear sync will cause motion blur, it is designed fairly much to create that effect.

If you didn't want motion blur, yes you need to have used a faster shutter speed.

[Scotty72]

Dragging is particularly useful when there is a big seperation between subject and the background and the ambient light is not brilliant or worse.

Eg. a subject in front of a city-scape.

If you set at 1/60th and use flash, the subject is well exposed but the city-scape is too dark.

By dropping to say 1/20-30th, you are allowing the background light in and the flash should be enough to freeze the subject pretty well. So, long as there isn't too much ambient light that lights the subject enough to cause blurr (which at 1/20th you will have). So, a reasonably still subject (your subject standing and waving), a subject not too wel lit by ambient light - and a background that is perfectly static (or too far away that a bit of movement won't be noticed)

In a church, the background and foreground are generally too close together and the flash will light both (but unnevenly) - there is likely to be far too much movement around the frame too.

Maybe someone has a better explanation over a wider range of uses, but, I hope this helps.

Scotty

[Higham]

Thanks for the feed back guys. So really rear sync should onlt be used when its fairly dark or you want the effect of motion, or use manual mode and up the shutter to something over 1/60th depending on how dark i want the background.

Does this pretty much sum it up?

Dave

[Cadnium]

Dave,

Firstly - don't be upset because you did take some good photos. It was my bub's christening after all! We do need to get together and practice this all some more though. It would probably have helped if I had a proper diffuser so you didn't have to bounce flash!

I haven't used it much yet, but I would only use 2nd curtain (rear-sync) when the foreground (subject) is atleast a stop or more darker than what you are exposing in the the background, unless of course you want the blur effect. For example - as mentioned above, if you use rear sync with a city scape background you should be able to get some nice effects from the lights before flashing and freezing the subject.

Also, I would not use bounce flash when trying to drag the shutter (by design, bounce flash will increase the exposure of a much larger area meaning indoors you won't be able to isolate your subject and background sufficiently).

I haven't had a chance to work out the exact requirements yet, so indoors I usually just set manual, 1/80th, the lowest aperture that will give me good DOF. I then set the ISO based on what my metering says; but don't like to go above 400. It works ok for now.

[Cadnium]

So i guess to sum it up, I think that rear-sync requires you to isolate the exposures of the background and the subject.

An even better suggestion - let's catch up on Saturday and test the theory.