Fill flash creates blowouts

[robert_g.2]

<p>With my Canon T1i, 50mm 1.8 prime & Speedlite 430EX II I shot a few outdoor pics of a subject who was just about 6 feet away. She was standing in partial shade. There was LOTS of blowouts and the picture seemed really overexposed. Sunny day. Here's my settings: Av, Flash Comp -1, AWB, ISO 100, Exposure -1, 1/200, f1.8. Any ideas why? Thanks.</p><div></div>

[rffffffff]

<p>most likely your camera doesn't support high speed sync... your shutter would have been, lets say, 1/1000 for this shot if you were using no flash in av mode. Because it detected the flash present, it lowered the shutter speed to 1/200, the max sync speed, and the shot was blown out... the way to rectify that is to close the aperture down so that 1/200 is acceptable, use high speed sync (which might not be possible) or don't use flash.</p>

[robert_g.2]

<p>I believe it does. It's a Canon Rebel T1i. Would the fact that it was in Av mode make a difference?</p>

[Matt Laur]

<p>How did that exact same exposure work without the flash?</p>

[Matt Laur]

<p>Meaning, you're probably pretty close to over exposing even without the flash - so perhaps use the flash in manual mode, and set it at its lowest possible output level ... AFTER you get the camera set to meter happily for the overall scene. You really have to take control of this sort of situation, and not let the camera/flash "help" you with any cruise-control stuff at all.</p>

[rffffffff]

<p>I bet its just a matter of turning high speed sync mode on.. I am a nikon user, so I dont know how to do it on your camera, but in certain nikons it is off by default.<br>

the shutter speed being at 1/200 and the blown out background are strong indicators that the camera wanted to be at a higher shutter speed but essentially wasnt allowed to because the high speed sync wasnt on.<br>

av mode should provide better results than this.</p>

[michael_madio]

<p>"Sunny day" + "ISO 100" + "1/200" + "f1.8" is the problem ... it's over-exposed. There's nothing for the flash to "fill". In direct sun you should be at about ISO100, 1/125s, f/16 and in open shade at about f/5.6.</p>

[steven_f1]

<p>The sunny 16 rule of thumb says to set the lens to F16 and then set the shutter 1/(iso). So at 1/200 shutter and F1.8 you over exposed the background. For F1.8 your shutter should be 1/8000 of a second. For regular flash photography the shutter cannot be used at a speed faster than 1/200, which is known as the flash sync speed. </p>

<p>The difficulty in this type of photography is that you must use a shutter aperture setting to correctly expose the background while allowing enough flash to fill in the shadows. Sunny conditions generally call for stopping down the lens. However flash power drops rapidly as the lens is stopped down. Finding the correct ballance can be difficult.</p>

<p>From the looks of the photo you were maybe 10 feet away. So the first thing you do is to stop down the lens. The 430EX flash in auto will then increase power to compensate. You probably could have used F8, 1/200, at iso 100. At F8 the needed shutter speed is 1/400. Not quite enough. However if she was lit better than I am thinking and or closer to the lens then a setting of 1/200, F11, iso 100 would correctly expose the background with just enough flash to correctly expose her. </p>

<p>Another option is to use high speed sync. For canon this is an option that is built into the flash. You must activate it in the flash. It won't turn on automatically. My 5D MkI does support this and since the T1i is a more recent camera, it should also support it. HS sync does allow you to use a shutter speed faster than 1/200. However HS sync does tend to reduce the power output of the flash. The only way to know if it would have helped is to try it. </p>

[allardk]

<blockquote>

<p>For canon this is an option that is built into the flash. You must activate it in the flash.</p>

</blockquote>

<p>On a 40D you can set it from the camera via the external flash func. settings menu. Second item in that menu.</p>

[paul_russell1]

<p>The camera has a custom function to lock the shutter at 1/200th in Av mode, it is set as this as default but can be over-ridden, so that the shutter is set as per the cameras metering (then when the flash kicks in it can also easily over-expose, even with E-TTL!)<br>

A few options to consider:<br>

Smaller aperture<br>

Same aperture (not the lenses best in any case, setting it to f2.8 or f4 makes a huge difference) but with an ND or polariser to bring down the shutter. <br>

Even f2.8 or f4 with an ND or polariser...<br>

Come out of Av mode.<br>

Go into manual mode.<br>

Set a manual exposure for the background that is 0EV to +1EV. If the shutter is still above 1/200th the use the high speed mode on the 430EX.<br>

Place the centre area over the subject, use the FEL function (small star under thumb) take the picture.<br>

If the smaller aperture is affecting your depth of field too much then you can try altering the perspective:<br>

Move closer to focus closer and throw the backgrond out, or move the subject so that the background is further away, again, throwing it out of focus.</p>

[carlwakefield]

<p>Hello Robert, I agree with what Steve wrote and would like to add the following. As above when your using times above 1/200th sec turn on the high speed sync button on the flash. You can then use speeds upto 1/8000 sec the camera maxium speed. The flash left to its self tries to exsposure as fill but is often a touch strong. Flash compensation and exsposure compensation are not linked. So if the flash looks hard as fill just use flash compensation -2/3 or maybe a little more. But if you want to use Flash as keylight you need to over power the sunlight and there highspeed sync comes to work. Try this. Set AV mode 2.8 ISO 100 exsposure compenstation -2/3 and flash compenstion to + 2/3rds and meter the background area that is out of the flashes effective range. Press the star button to lock the exsposure reading. Recompose on your subject and take the shot. the flash will meter the subject for correct exsposure and the background should be slightly darker. Can look very good. But fill light from a reflector backinto the shadows is also great. Fts clear your shot is over exsposed and this are is out of the range of the flash its just over exsposed. Regards Carl</p>

[robert_g.2]

<p>According to their website (http://www.usa.canon.com/consumer/controller?act=MultiMiscPageAct&key=EOS_Advantage_System&fcategoryid=139#b)</p>

<blockquote>

<p>Integral to the EOS System, Canon Speedlites are the ideal flash source for EOS SLR cameras. They are technologically advanced to provide<strong> perfect exposure and<a title="Search Twitter" href="http://search.twitter.com/search?q=ntegral%20to%20the%20EOS%20System%2C%20Canon%20Speedlites%20are%20the%20ideal%20flash%20source%20for%20EOS%20SLR%20cameras.%20They%20are%20technologically%20advanced%20to%20provide%20perfect%20exposure%20an" target="_blank" title="Search Twitter" > </a> <a title="Search Google" href="http://www.google.com/search?q=ntegral%20to%20the%20EOS%20System%2C%20Canon%20Speedlites%20are%20the%20ideal%20flash%20source%20for%20EOS%20SLR%20cameras.%20They%20are%20technologically%20advanced%20to%20provide%20perfect%20exposure%20an" target="_blank" title="Search Google" > </a> <a title="Search Wikipedia" href="http://smarterfox.com/wikisearch/search?q=ntegral%20to%20the%20EOS%20System%2C%20Canon%20Speedlites%20are%20the%20ideal%20flash%20source%20for%20EOS%20SLR%20cameras.%20They%20are%20technologically%20advanced%20to%20provide%20perfect%20exposure%20an&locale=en-US" target="_blank" title="Search Wikipedia" ></a> illumination with just about any subject</strong> , yet operation is remarkably simple. Whether you’re an amateur or an expert, Canon Speedlites make it easy to obtain professional results. </p>

</blockquote>

<p>Doesn't that imply that you just turn the flash on and it will do the rest? Am I hoping for too much?</p>

[rffffffff]

<p>as long as you turn high speed sync on, it should do the rest! =o)</p>

[robert_g.2]

<p>So should I always leave it on to be safe? Or just in well lit outside shots?</p>

[andrewg_ny]

<p>Yes, you're hoping for too much. In this case, "Remarkably simple" doesn't mean "just turn the flash on and it will do the rest".</p>

<p>Looking at your image, even the background that is not illuminated by the flash is overexposed. Most likely you would find that without the flash turned on, the recommended shutter speed would have been higher than 1/200. Once you turn on the flash, without HSS enabled, your shutter speed is limited to 1/200. With HSS, shutter speed can be raised to allow better exposure.</p>

<p>The next question is why shoot at f/1.8? If you had stopped the lens down a bit, perhaps this would not have been a problem. Plus, f/1.8 has additional issues with severely limited depth-of-field and lens performance.</p>

[robert_g.2]

<p>Thanks. I think I will avoid 1.8 for the most part. I will review all your suggestions. Thanks!</p>