580EX on ETTL and shutter speed problems.

[mattlaudergallery]

Hi,

 

I am shooting my first wedding tomorrow as the 2nd photographer for

a friend.

 

I have a Canon 20D and the new 580EX flash. I have done some

experiments with the flash and I keep getting slow shutter speeds.

It works great in good light, but I am finding it very limited in

lower light that you would get from being indoors with limited

overhead light. (Basically mood lighting found in reception centers)

 

I have the flash on ETTL with an ISO of 400 and I am getting a

shutter speed of 1/20sec at F5.6 (focal length of 50mm). When the

camera is set at AV.

 

I have put the camera on manual and the flash on ETTL and Im not

getting the results I want with the flash.

 

I don?t want to go manual on the flash as then I have to muck around

with NCORD or CORD readings from my Minolta light meter and this

impractical. I love the exposure you get from using ETTL, but surely

a flash this expensive cannot be so limited in this area.

 

Other than going to higher iso settings, is there anything I am

missing when using the flash in ETTL.

 

Thanks for any quick replies.

 

Matt

[gaius1]

In Av mode your flash is operating as a fill to get correct exposure of your foreground while also getting enough light for your background. It is operating correctly. In this situation, I'd leave the camera as it is and use an aperture of f/2.8 or f/2 instead, and use bounce flash.

[jonathon]

Yes, you're missing heaps! But don't worry its all laid out in a great article written specifically for YOU!<br>

http://photonotes.org/articles/eos-flash/<br>

There are three parts, part 2 the most important for this kind of stuff and you need to read the whole thing twice before the wedding. In summary Av and Tv mode will take the ambient light that's around and set the camera's aperture and shutterspeed to those settings as if there was no flash (there are some exceptions, but lets just use this as the rule). It then adds a little bit of fill flash to the scene. If you want the flash to add light to the scene so that your camera sets a faster shutterspeed you can either use P mode and let the camera do most of the work or use M mode on the camera. The M mode still uses the flash in ETTL so you don't need to meter. When its darkish, M mode is the best. Just set the shutterspeed, ISO and aperture you want and the flash will make the subject expose correctly (assuming the flash has enough power). But if you use those setting and then walk outside into the light, the shots will be overexposed.<br>

So here's you're next experiment. Tonight with a lighbulb only lighting a room, set to Av wide open aperture (if that's 5.6 then so be it) and see how the shots are. The background will be well lit, as will the subject. Then use M mode (say 1/60th, ISO 400, f5.6) and take some shots. The background will be darker, but the subject will be fine. Once AGAIN, read the photonotes article. Every answer is there.

[suzanne carey]

Thank you so much for bringing this up! Shew, this has helped me a ton. I was taking some pictures of my little one the other day in the bathtub. When set on AV mode, the pictures were too dark. (I was bouncing off ceiling). And the same thing as mentioned previously, the shutter speed was way too slow on f5.6. But then I put the camera on M, I was thinking to override the affects of AV mode, and the lighting worked out just fine! So yes, it was a happy "happen upon" for me, but glad to see it is something legit for me to keep in mind.

 

So during good lighting, you will use AV mode at the wedding but switch to Manual mode in low lighting?

 

This has been agreat concern for me too. Thanks for brining it up Matt! My first wedding is in April. EEEKKKK.

[jonathon]

Suzanne, if you are the main shooter at the wedding, I would advise you to tell the couple to get a regular wedding shooter to do the event. I'm not being mean, but you should come and keep and eye on the wedding forum where us event photographers hang around and people will all tell you the same thing. Untold number of friendships have been damaged by this very thing.<br>

That's right about Av and M mode. Outdoors I want to be able to use the ambient light to contribute almost all the light in the scene. I will then stick it on Av and the camera will add a tiny bit of fill flash. Indoors I can only hand hold the camera at maybe 1/30th depending on the focal length, usually 1/60th. I set the camera to what I'm happy as a minumum (in my case f2.8, 1/60th, ISO800) and let the flash make up the difference. The only catch is that if one area of a dark church has more light than these settings, my photos will be overexposed, so you need to be careful.