Shutter speed 1/180 is not there on XT2

[Sueco]

As I say in the topic, I received my XT2 a couple of days ago, and I noticed something strange on the SS but till day I haven´t realized it does not have 1/180th.

Has anyone noticed that or is it my XT2 and should I send it back and get a new one??

Thanks

[deva]

No reason to have it... shutter sync is 1/250th

[Jürgen Heger]

May be an explanation helps to understand why 1/180 is not needed.

 

Typically shutter speed steps are in a way that the time when the shutter is open is cut in half with every step. So typical steps are 1/60, 1/125, 1/250, 1/500 and so on. You may have noticed that the 1/120 is rounded to 1/125 same as 1/16 becomes 1/15.

 

You see that 1/180 is not part if the standard steps. But you have it on the T1 as there it is the shortest shutter speed where the shutter is completely open. In fact the shutter consist of two curtains. Curtain 1 is fixed on one side of the sensor window. It is closed before you press the shutter button. So no light will reach the sensor. Curtain 2 is fixed on the other side and is open.

 

When you press the shutter button curtain 1 will open, thus letting light to the sensor. After the selected shutter time curtain 2 will close. If a very short shutter time was selected curtain 2 will start closing before curtain 1 has fully opened. In this case the window is never completely open. This way you can provide very short exposure times with relatively slow moving curtains. But in this case when you are using a flash which typically has a very short duration it can never illuminate the complete sensor.

 

So the highest speed where the window is completely open is the fasted shutter that you can use with a flash besides with those modern flashes that provide High Speed Shutter (HSS) function.

 

Obviously the curtains of the T1 are not fast enough for 1/250s so the 1/180s was introduced between the standard steps as the fasted speed for flash synchronization. The T2 has faster moving curtains and therefore can provide 1/250s as flash sync speed.

[jack1758]

In manual mode ...you can use the rear command dial to fine tune shutter speed ...faster or slower shutter speed.

[FujiNut]

and... you still can get to 180 -- well, not quite!  -- by setting your shutter speed on 125 or 250 and then using the dial in back to get to 160 or 200th.

 

close enough, i would guess?