New 40D user needs flash help

Hey folks,

I used previously an SB 800 with my Finepix S2. Now I am using a 40D w/ 580EX II. I was shooting in Av mode and got the attached result (blurred). When shooting indoor shots with movement, should I go to P mode or is there another option to prevent getting such a slow shutter speed? This was not an issue with my Nikon-based equipment. Thanks for any help you can offer!

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I've had people reccommend, and have had some success using shutter priority so that you limit your shutter speed from being too slow. I pretty new to photography and am finding that flag photography is a whole different beast. Try reading up on flash photography so you understand what the camera is doing in the different shooting modes.

The AV setting uses the flash as a fil flash and will set the eposure for the ambient light. Which can result in slow shutter speeds. It's best to use the manual setting, at maybe ISO 400, 1/125, F4. The flash will expose correctly. That's just a staring point. There is a custom function setting that allows you to always use a shutter speed of 1/250 for AV,

When I use flash I put the camera on M (really I use M most of the time anyway).

Start at something like ISO 400, f/4-f/5.6 and meter. Set shutter to underexpose 1 to 1 2/3 stops and let the flash do the rest. Add some FEC if needed.

The problem with your shot is that you had too much ambient light so you had a fairly bright ambient exposure and the flash exposure. By underexposing the ambient you won't get ghosting.

With 1/3” , hand hold in Av mode, you cannot expect to get the shot any better than this one.

Set camera to: Manual, f/5.6, 1/125”, ISO 200
Set flash to: ETTL, bounced at 45°-75°.

Adjust f-number and/or shutter speed to change lighting of the background.
Adjust FEC and/or bouncing angle to change lighting of the subject.
Show us the shot.

As shybull said, Av mode normally chooses a shutter speed that will expose correctly under ambient light and then the flash fires to fill in the shadows.

Your shot, at a focal length of 115 mm, was taken at a shutter speed of 1/3 second. That's guaranteed to be blurry.

The answer? Don't use Av for flash unless fill flash is what you want.

You could use Tv at a higher shutter speed, up to 1/250. The higher your shutter speed, the less illumination you'll see from ambient light. At 1/250 all the light will be from the flash.

For most flash use, M is the best choice. If you want flash illumination only, choose 1/250 and f/8 or so. If you want some fill, use a slower shutter speed and larger aperture.

The flash exposure will be correct no matter what aperture and shutter speed you select (within reason) because the 580EX will adjust its output automatically.

-js

Do Nikons work differently in aperture priority mode? How does one shoot fill flash with a Nikon if you want the camera to auto meter the ambient? So many people ask this question (Canon, Av and slow shutter speeds with flash on) that I start to wonder if other cameras do this differently or what?

Sorry if this is off topic but the last Nikon SLR I used was manual everything.

Yup, I shoot manual all the time with flash.

Thanks for the comments everyone, I really appreciate it! It's nice to post to a board where everyone is genuinely helpful.

Welcome to POTN, my friend!

You should also consider bouncing your flash off of a wall or ceiling. Welcome to the forums!

I agree on using M for flash is the best. You can make the exposure time as long or short as you want, but you have control of what you get.

Setting Av to always give 1/250 s when using a flash is rather pointless. Could just as well use M then, and leave Av for the moments when you do want fill flash. That works well outdoors, for example.

Setting the camera to P will save you from most of these issues, as it will select "safe" values.

JeffreyG wrote in post #6067272
Do Nikons work differently in aperture priority mode? How does one shoot fill flash with a Nikon if you want the camera to auto meter the ambient? So many people ask this question (Canon, Av and slow shutter speeds with flash on) that I start to wonder if other cameras do this differently or what?

Sorry if this is off topic but the last Nikon SLR I used was manual everything.

The answer is yes. Nikon works extremely well in Aperture Priority. I did a wedding and i was using canon 40D and the other two shooters had D300's. They shot aperture priority most of he night when i couldnt. I had to shoot manual.

magicman320 wrote in post #6076369
The answer is yes. Nikon works extremely well in Aperture Priority. I did a wedding and i was using canon 40D and the other two shooters had D300's. They shot aperture priority most of he night when i couldnt. I had to shoot manual.

But what does it do for fill then? Or did they simply have a function enabled to drive the shutter speed to the maximum synch?

This is a Canon function BTW. If you want to shoot in AV mode with the flash on for some reason there is a custom function that will hold the shutter speed at the maximum synch speed.

I personally don't see the point, as this isn't really Av mode anymore....just kind of M with only 1 shutter speed allowed.

I did my first flash gig using P mode ISO 100 while adjusting the FEC. Also make sure you at least have a fast lens (f2.8+). You can also try 1/60 f/4 iso 200, which is the speed the P mode uses most of the time. Try chimping around at nite and you will see how much fun the 580EXII can be.

I would also advise you to read the 580EXII manual a couple of times and do use re-chargeable batteries. I use duracell 2650 and they last for a good 700+ flashes. Always carry at least 4 extra batteries.

I did read however these great set of links found here.

https://photography-on-the.net/forum/showthre​ad.php?t=138907

Welcome to POTN.