Why is this exposure so bad? (canon 20d)

juliejules

Why did the camera expose this picture so badly? I know the ISO is high (I'm always forgetting to check it :uhoh), but it should have been able to do better than this. I actually didn't take this picture, I handed the camera to my SO. I'm the character on the right. There are 4 shots in a row that he took that are like this.

The EXIF data says:
Aperture priority, f5.6, 1/250s (wayyy too slow), ISO 800
Canon 20D, 24-105mm F4L lens.

Here's a link to the EXIF.



Here's one I took of him, 2 minutes before. It's a little over exposed, but the shutter speed went to 1/4000 so at least it's close. Here's the EXIF.



What's happening :scratch?

Thanks!

Swartzy

I suspect that the shot was taken
without using the button pushed halfway down before exposure. In other words, simply pushed straight through to exposure before the camera could calculate...just my guess.

Jeffro

The flash fired on the first one, and the flash wasn't on highspeed sync, so it fired at 1/250th which caused the overexposure.

No flash on the second, so it was ok.

PS...Why you shooting at ISO 800 anyway...it looks plenty bright, which would allow lower ISO.

pathfinder

juliejules

Jeffro wrote:

The flash fired on the first one, and the flash wasn't on highspeed sync, so it fired at 1/250th which caused the overexposure.

Aha! I didn't notice the flash. I didn't hand him the camera with the flash up, and I don't remember pushing it down after I got the camera back. I don't understand why having the flash up would cause it to force the shutter speed to 1/250th.

PS...Why you shooting at ISO 800 anyway...it looks plenty bright, which would allow lower ISO.

I know! Like I said, I set the ISO for a scene, like the previous day, then forget I've done it. It's always biting me in the butt. I wish I could see the ISO in the viewfinder. It kills me.:bluduh

gpphotos

i could be wrong but your 20d probably syncs at a max of 1/250th

im sure you could look it up to make sure, just a guess

Jeffro

gpphotos wrote:

i could be wrong but your 20d probably syncs at a max of 1/250th

im sure you could look it up to make sure, just a guess

You are correct. 1/250 is the sync speed and the 20D will go to that, unless you have high speed sync turned on, on lets say a 580EX flash, for example.

SteveM

I was a victim to this in August at an airshow. Sunny day, no reason for my Speedlite, or so I thought. I took some ground portraits of some WWII actors with my pop-up flash for some fill. What I didn't realize was the flash sync speed was locked at 1/250, when I was shooting around 1/8000 in AV. Around 15+ posed shots were absolutely blown out. I managed to salvage one or two through RAW, and a couple with the popup flash DOWN. I was SO disappointed, cuz they were some great shots. Live and learn!

Here's one that made it

mercphoto

You already know the problem was with the flash sync speed, but....

juliejules wrote:

The EXIF data says:
Aperture priority, f5.6, 1/250s (wayyy too slow), ISO 800

Can I ask why you think 1/250 was wayyy too slow? Apart from the obvious, that at ISO 1800 and f/5.6 in light that bright you need a much faster shutter. But did you think you needed a fast shutter, in general, to capture that particular shot?

To answer your question about flash synch speeds requires a brief lesson in how shutters work in the first place on this camera. Maybe do a google.

juliejules

mercphoto wrote:

Can I ask why you think 1/250 was wayyy too slow? Apart from the obvious, that at ISO 1800 and f/5.6 in light that bright you need a much faster shutter. But did you think you needed a fast shutter, in general, to capture that particular shot?

Nope, I simply expected the camera to select the proper shutter speed, and it didn't.

Now I know why, thanks to my fellow digital grinners.