Aperature @ 2.8 & fill flash?

[samckitt]

This weekend I was taking (trying) to take some family pictures for some friends & I had the Aperature set at or near 2.8 to give a shallow depth of field. But the pictures kept coming out dark for the people. I don't remember what the metering mode was on. Probably should have used center right? I was trying to use the 580 flash as fill, but all I kept getting was overexposed pics. Once the flash was installed the shutter speed went down to 1/250 & aperature stayed at 2.8. Camera was set on aperature priority. Any suggestions what I should have done?
Thanks,
Scot

[cdifoto]

You need to enable high speed sync (2nd button from top right) so you can use faster shutter speeds and prevent overexposure.

[Curtis N]

first you say the pictures kept coming out dark, then you say all you got was overexposed pics. So maybe you can clarify that?

In the meantime, take a look at flash facts #6 and #7 in Flash Photography 101 (http://www.photography-on-the.net/forum/showthread.php?t=171657).

High Speed Sync is the way out of this if you need a wide aperture. Otherwise, the safety shift custom funtion on your camera (#16 I think) will prevent blowouts in situations such as this.

[Wilt]

This weekend I was taking (trying) to take some family pictures for some friends & I had the Aperature set at or near 2.8 to give a shallow depth of field. But the pictures kept coming out dark for the people.

I was trying to use the 580 flash as fill, but all I kept getting was overexposed pics. Once the flash was installed the shutter speed went down to 1/250 & aperature stayed at 2.8. Camera was set on aperature priority.

I presume you were shooting outdoors? In the sun at ISO 100, your camera should have used 1/100 f/16 (or about 1/250 f/ 8.5) for proper exposure (Sunny 16 rule). As cdi-ink says, if you had HSS enabled on camera and flash, the camera could have increased its shutter speed higher.

It would have had to use about 1/3200 in direct sun with f/2.8, though, and the effectiveness of flash is reduced signficantly when having to support HSS for very high shutter speeds, so at your shooting distance it may not have had much real effect!


First you say 'too dark' then your say 'overexposed'...the antithesis of each other! Please post two examples or explain with more detail, so we can help you sort this out.

[samckitt]

Curtis - Underexposed without flash, overexposed with the flash. Without flash sutter speed up around 1/1000 with F2.8, with flash sutter at 1/250 & f2.8.

Yes it was outside. I didn't have HSS set. Forgot about that.

Thanks,
Scot

[Wilt]

Curtis - Underexposed without flash, overexposed with the flash. Without flash sutter speed up around 1/1000 with F2.8, with flash sutter at 1/250 & f2.8.

Yes it was outside. I didn't have HSS set. Forgot about that.

Thanks,
Scot

We need a bit more scenario description here, because (as I said in my earlier post) ISO100 in sunny condition outdoors is 1/100 f/16 or 1/3200 f/2.8, and you gave about +1.5EV more exposure with 1/1000 f/2.8 so it should not come out too dark!

[samckitt]

the 1/1000 was a number I used, I am not sure what it was. The people were too dark & the background looked fine. I was not in the sun, but was outside, in under the shade of trees. I am thinking I need to use the center meetering mode & set the flash to HSS to get the shallow depth of field & proper exposure on the people.

[cdifoto]

the 1/1000 was a number I used, I am not sure what it was. The people were too dark & the background looked fine. I was not in the sun, but was outside, in under the shade of trees. I am thinking I need to use the center meetering mode & set the flash to HSS to get the shallow depth of field & proper exposure on the people.

The problem was your camera was metering for the background (non-shaded area) so the people were underexposed. Overall the scene was properly exposed. Fill flash is the order of the day if you don't want to blow out your background. Just remember that high speed sync reduces your working distance.

[tim]

Sunny 16 is a rule of thumb, a meter will give you more accurate results.

[Wilt]

Sunny 16 is a rule of thumb, a meter will give you more accurate results.

And in this particular case, i was merely using the rule as a sanity check of the claims of camera settings vs. the obtained underexposure.

The OK background and dark people in foreground does sound to be the root cause of the problem...exposure biased for the background, leaving foreground underexposed. The fix, as described by cdi-ink is fill flash. (or simply let the background be blown out and overexposed instead)

[Wilt]

the 1/1000 was a number I used, I am not sure what it was. The people were too dark & the background looked fine. I was not in the sun, but was outside, in under the shade of trees. I am thinking I need to use the center meetering mode & set the flash to HSS to get the shallow depth of field & proper exposure on the people.

scott, a kind suggestion for the next time you pose a problem: fully describe the circumstances you are in, your camera settings, etc., as otherwise it is a game of 20 questions to figure out your circumstances!

[In2Photos]

scott, a kind suggestion for the next time you pose a problem: fully describe the circumstances you are in, your camera settings, etc., as otherwise it is a game of 20 questions to figure out your circumstances!

And I will add to that:

The old saying "A picture is worth a thousand words."

Posting one of the underexposed images and one of the overexposed images, both with EXIF, could have resolved this in one post.

[Wilt]

And I will add to that:

The old saying "A picture is worth a thousand words."

Posting one of the underexposed images and one of the overexposed images, both with EXIF, could have resolved this in one post.

In defense of the OP, this forum does not make it easy to post photos...I probably participated for 6-8 months before establishing use of a photo sharing web location so I could include illustrations! To someone just joining POTN and having a problem, they would have to figure out how to do that, too! Ergo, my request only for a full description (although I wanted to ask for photo, too).

[PacAce]

In defense of the OP, this forum does not make it easy to post photos...I probably participated for 6-8 months before establishing use of a photo sharing web location so I could include illustrations! To someone just joining POTN and having a problem, they would have to figure out how to do that, too! Ergo, my request only for a full description (although I wanted to ask for photo, too).
Photos can be attached (via the PaperClip icon), too, without the need for a separate photo hosting server.

[Note: This is just an aside FYI. Nothing related with the actual discussion in progress. :) ]

[In2Photos]

In defense of the OP, this forum does not make it easy to post photos...I probably participated for 6-8 months before establishing use of a photo sharing web location so I could include illustrations! To someone just joining POTN and having a problem, they would have to figure out how to do that, too! Ergo, my request only for a full description (although I wanted to ask for photo, too).

I joined this forum in December and posted shots shortly(within a few days) after joining. I had never really had any interest in cameras and was not familiar with the software for editing but I made it work. I think the forum's photo sharing capabilities are great.

[Wilt]

Photos can be attached (via the PaperClip icon), too, without the need for a separate photo hosting server.

[Note: This is just an aside FYI. Nothing related with the actual discussion in progress. :) ]

We're drifting off topic, but the instructions are not clear enough...I tried the 'insert link' and it pointed to a URL, I tried the 'insert image' and it pointed to a URL, too. I had never thought of 'attachments' as a way to insert a photo, but a way to include an ancillary file! Might pass on the comment to Pekka that the explanation he provides makes use of terminology which is different than the tools in message creation, so oblique and not easy to understand. I had tried reading it multiple times before I gave up and simply set up a photo sharing account online! And then the paperclip icon only appears if you have selected the 'Go Advance' button...I never noticed it until you mentioned the paper clip!

[samckitt]

If I have the camera (30D) set on Aperature Priority & there is a flash(580) on the camera, does set the sutter speed to the available light as if there was no flash on it, or will it set it for the light from the flash?

Thanks

[In2Photos]

If I have the camera (30D) set on Aperature Priority & there is a flash(580) on the camera, does set the sutter speed to the available light as if there was no flash on it, or will it set it for the light from the flash?

Thanks
The camera will act just like it does without a flash. The only difference in the shot with the flash is that a pre-flash will fire before the shutter opens for the camera to determine flash output. Then the shutter opens, flash fires, and your exposure is created. Try it out. Put your flash on your camera but leave it turned off. Set your camera to Av, set your ISO and aperture. See what the camera determines your shutter speed to be. Turn on the flash. Does the shutter speed change?

[René Damkot]

Does the shutter speed change?

If it's dark, it probabely will ;)
That's called NEVEC (http://eosdoc.com/manuals/flash/NEVEC/). Rather silly, and it can't be shut off. One of the reasons to use M with flash...
Apart from that, you are off course right...

[In2Photos]

If it's dark, it probabely will ;)
That's called NEVEC (http://eosdoc.com/manuals/flash/NEVEC/). Rather silly, and it can't be shut off. One of the reasons to use M with flash...
Apart from that, you are off course right...
Thanks Rene. I have never heard of that. Good read. Of course I normally use M for flash in dark situations but for fill flash in good light I use Av.

[Curtis N]

If I have the camera (30D) set on Aperature Priority & there is a flash(580) on the camera, does set the sutter speed to the available light as if there was no flash on it, or will it set it for the light from the flash?Scot,

Keep in mind that the camera can't predict how much light will be gained by the flash. When you use Av or Tv mode, you're telling the camera to meter for ambient light. What happens depends on conditions and how you have your camera and flash set up.

1) If you choose an aperture/ISO combination in Av mode that requires a shutter speed faster than 1/250 for proper ambient light exposure, the shutter speed will revert to 1/250 (flash sync speed on your camera) when you turn the flash on, and the result will be overexposure from too much ambient light.

Exception A: If your flash unit has high speed sync enabled, it will not change the shutter speed and should work fine.

Exception B: If you have custom function 16 set to 1 (safety shift) but high speed sync is not enabled on the flash, the camera will revert to Tv mode with a 1/250 shutter speed and change the aperture for proper ambient exposure.

The scenarios above usually happen outdoors in daylight. Indoors or at night, you're more likely to encounter the NEVEC phenomen that Rene' referred to.

It's never simple. :D

[samckitt]

The shutter speed does change if it isn't TOO dark. Evidently I was trying to take a pic of my 6mo son in a room that was too dark. Once I turned the light on & did the same scenario, the shutter speed did change.
THanks,
Scot

[Curtis N]

Scot, can you tell me more about the camera settings where you saw the shutter speed change? And what were the shutter speeds before/after turning the flash on?

I could be that you saw the NEVEC thing happening, but I'm more concerned that you're using Av at all indoors with flash. It's likely to give you shutter speeds slow enough to introduce motion blur.