Which curtain is which?

<p>So I can't seem to get a straight answer anywhere. Does anyone know for sure which shutter curtain is first, and which is second? Which one is closer to the film or sensor, and which one is closer to the lens?<br>

Thanks!</p>

<p>Huh? Look here for explanation what a focal plane shutter is and how it works:<br>

<a href="http://en.wikipedia.org/wiki/Focal-plane_shutter">http://en.wikipedia.org/wiki/Focal-plane_shutter</a></p>

<p>They aren't in front or behind of each other in terms of being more distant from the film or sensor.</p>

<p>There are two curtains that make up the one shutter unit, and as far as I know in EOS Canons the first curtain goes up, followed by the 2nd curtain going up from the same direction. Older FD-mount cameras have cloth or metal shutters that start on the right and travel left, one right after the other.</p>

<p>I expect it depends on the camera. In my Nikon FM2, the first curtain is closer to the lens and the second is closer to the film. It's kind of hard to get a good enough look at the curtains in my DSLR since I can't open the back and I can't advance it slowly by hand. With some shutters, neither curtain is closer to the film or the lens, they both lie in the same plane.</p>

<p>Does it matter?</p>

<p>It would appear on the Elan7 the first curtain is closer to the film.<br>

http://www.smugmug.com/gallery/8945351_aVDzo#594144440_Fc6W5-A-LB</p>

<p>Why do you want to know? As far as I can tell the knowledge will not help you improve your photography skills.</p>

<p>I was going to refer you to photonotes.org but then that wouldn't have done us any good.</p>

<p>All the film EOS bodies I've looked at, and that's most of them, have the first curtain nearest the film, and they both go down from top to bottom to make the exposure.</p>

<p>The only odd one is the EOS RT, where both curtains are closed in the rest position to give better light proofing necessitated by the absence of the light blocking properties of the mirror.</p>

<p>Henry</p>

<p>If you look at the video for the 50D you could assume that since you can see the holding arms (?) for the second curtain and not the first that the holding arms (?) for the first would have to be on the other side. If you use the video from the Elan7 as a reference that the curtain closest to the viewer is the one where you can see the holding arms you can deduce that the 50Ds shutter has the first curtains shutter closer to the sensor.<br /> http://www.smugmug.com/gallery/8945351_aVDzo#597156427_zmRzW-A-LB</p>

<p>Same with the 20D<br /> http://www.smugmug.com/gallery/8945351_aVDzo#597152520_cdrHK-A-LB</p>

<p>And the XT<br /> http://www.smugmug.com/gallery/8945351_aVDzo#597165552_BYPEm-A-LB</p>

<p>http://www.smugmug.com/gallery/8945351_aVDzo#594124511_2CUHh</p>

<p>Thanks for the comments and suggestions.</p>