D90 problem with shutter speed

[lufeb]

Hi everybody!

I'm having problems with my D90, when it's on Manual mode, when I pop the flash out the shutter automatically goes to 200 and I can't put it faster... don't know if it's something I touched in the menu or if It's a camera problem and I have to take it to service or something.

Thanks!

[zona5101]

Originally Posted by lufeb

Hi everybody!

I'm having problems with my D90, when it's on Manual mode, when I pop the flash out the shutter automatically goes to 200 and I can't put it faster... don't know if it's something I touched in the menu or if It's a camera problem and I have to take it to service or something.

Thanks!

with the built in flash the top shutter speed is 1/200...so when you pop up the flash it stops you at 1/200 (but you can go slower)

[OsmosisStudios]

It's called the flash Sync Speed. Most cameras hover around 1/200s, though some are higher or lower.

Your shutter is actually two sets of curtains that chase each other. At 1/200 or slower, there's enough time for the first curtain to get completely out of the way and expose the sensor entirely before the second one comes down. At higher speeds, the second curtain starts coming down before the first one is done moving, so the ENTIRE sensor is never exposed at once.

When you use flash, the flash burst is VERY short (in thousandths, if not less). As such, to have the flash light your entire image properly, the sensor has to be completely exposed for a portion of time. If it isnt, you end up with a big black bar across a portion of the image: that's one of the shutter curtains still in the way.

In short what it means is that, barring some playing around with an external flash, you cant use a shutterspeed faster than 1/200s. If you NEED a faster shutter speed (to, say, freeze action), then you have to find yourself a flash that can do High Speed Sync, which is where the flash duration is longer (but weaker) and allows you to use a faster shutter speed.

[lufeb]

thanks a lot for the answer!

it's the first time I post something and it surprised me the fast it got an answer.

truly grateful