Exposure Problems

<p>Hello Everyone,</p>

<p>I am shooting with a Canon 40D, 28-135mm f/4-5.6 with a 430 EXII on camera flash. I seem to be having problems shooting in moderately low light, even with the flash. I'm in Aperture Priority mode at the maximum aperture (f/4) and direct ETTL flash and the camera sets the shutter speed to almost a second. I feel like the flash fires very early and then the shutter stays open a long time after that.</p>

<p>Is there something I am doing wrong? I can go into full manual mode and get the exposure I want, but the camera isn't doing it right on its own. Any advice would be great.</p>

<p>Thanks in advance.</p>

<p>I'm not familiar with Canon, but it feels like a flash or in-camera flash related setting is off, something like sync speed, or flash exposure compensation or something.</p>

<p>Can you post what manual settings are successful for you?</p>

<p>Chris,</p>

<p>I was shooting at 135mm f/5.6, manual shutter speed of 1/250 sec. In Av mode I was getting a shutter speed of 0.8 sec. I had my Speedlite set to Auto sync, 1st curtain with no flash exposure compensation.</p>

<p>I just changed my flash sync speed to 1/250 sec. fixed (in camera setting) and this seemed to help, giving me a shutter speed of 1/250 sec. in Av mode. Thanks.</p>

<p>Hi Jason,</p>

<p>Something you should know about Canon cameras, is that the default settings for flash in Av mode is 'Auto' which means using the same (or similar, not 100% sure if it's exactly the same) speed/aperture combination as you would have without flash. That's useful for when you are using fill flash. But if the flash is the main light source, this does not work well. Setting to 1/250 cures this, but it leaves you with very little control over foreground/background ratio. Using M is the way to go if the flash is the main light source, IMHO. Go <a href="http://photonotes.org/articles/eos-flash/">here</a> for everything you ever wanted to know (and more) about Canon flash systems.</p>

<p>Jason, the problem seems to be Aperture Priority mode. I believe that Aperture Priority mode still considers the ambient exposure as the primary objective, and if a flash is used, it is treated as simply a "fill" to the ambient exposure. Thus, you're still getting slow shutter speeds. If you need to control your aperture, but need a faster shutter speed for hand-holding the camera, you might simply switch to manual and set your aperture and a shutter speed of 1/60 or so and let the flash do the rest.</p>

<p>Read this ... at least two times ...<br /> http://photonotes.org/articles/eos-flash/</p>

<p>Have a special look on this section:<br /> http://photonotes.org/articles/eos-flash/index2.html#confusion</p>

<p>Wow, thank you all so much, this is exactly what I was looking for. I understand what my camera is thinking now, so I think this will go a long way in making me a better photographer.</p>

<p>Thanks!!</p>