Portraits in Av mode with flash in low light

sflemings

Hi all,

I have a Canon EOS 500D camera with the 18-200 glass on it. I've read a bit on the camera and photography in general.

Anywho here's my question. I was at a wedding at the wknd. After the dinner I was taking some portrait shots of some of my friends in a low lighted hotel function room. I had the aperture wide open and with the flash on but I was getting very slow shutter speeds of like 1/15 and slower and f3.5 with blurred effects. I switched to the portrait basic mode then and I got a shutter speed of 1/60 and f4.0 and a sharp image.

Can someone tell me how to get decent portrait photos on Av with it wide open and the flash on in low light? What am I missing? Thanks.

sensibleken

can you check the raw file and see what ISO was selected on the automatic portrait mode. is suspect that could have been higher than the AV mode

sflemings

sensibleken wrote: »

can you check the raw file and see what ISO was selected on the automatic portrait mode. is suspect that could have been higher than the AV mode

Just checked that there. The ISO in the auto mode was 400 with 1/60 and f3.5 and 18mm. In the AV mode I had it as 1600 with 1/8 and f4 and 28mm.

DaireQuinlan

It's probably because in Av mode the camera is only metering using ambient light, it doesn't take into account that the flash is on. Using one of the Program modes or putting the camera into manual is probably the best way to go about doing it.

The 'portrait basic' mode probably does exactly what you were trying to do, ie, opens up the aperture as wide as it'll go, and then either tries to shoot using only ambient or pins the lowest shutter speed to some handholdable value (in this case 1/60) and uses the flash to make up the difference.

sflemings

DaireQuinlan wrote: »

It's probably because in Av mode the camera is only metering using ambient light, it doesn't take into account that the flash is on. Using one of the Program modes or putting the camera into manual is probably the best way to go about doing it.

The 'portrait basic' mode probably does exactly what you were trying to do, ie, opens up the aperture as wide as it'll go, and then either tries to shoot using only ambient or pins the lowest shutter speed to some handholdable value (in this case 1/60) and uses the flash to make up the difference.

Ok so. Thanks for that. Is there any way to make the Av mode know when the flash is on?

Would it make any difference changing the metering mode? (I'm not very familiar with the metering modes btw!)

DaireQuinlan

sflemings wrote: »

Ok so. Thanks for that. Is there any way to make the Av mode know when the flash is on?

Would it make any difference changing the metering mode? (I'm not very familiar with the metering modes btw!)

Probably not, the function of the Av mode is to measure the ambient and come up with an appropriate shutter speed given the aperture set. As above, the various program modes are generally smarter so one of them might provide what you're looking for.

What I generally do if I'm shooting with flash as fill is shoot in Av, but if the shutter speed drops below what I'd consider an appropriate speed I'll switch to manual and just set the shutter speed manually, typically to some minimum speed that allows me to handhold while still allowing as much ambient in as possible. Then make sure the flash is on some TTL mode and let it do the heavy lifting light wise.

sflemings

Perfect. Thanks again. I've another wedding to go to in two weeks time so I'll try it out there again.

pixbyjohn

sflemings wrote: »

Perfect. Thanks again. I've another wedding to go to in two weeks time so I'll try it out there again.

Try this at home.
Camera in manual, F5.6 and shutter 160 with flash on, ISO 200 tell me how you like the results

dmg1982

pixbyjohn wrote: »

Try this at home.
Camera in manual, F5.6 and shutter 160 with flash on, ISO 200 tell me how you like the results

Good call... go with that and experiment with the shutter speed. The longer the shutter speed, the more ambient light you're going to get into the frame.

Also, in your cameras custom functions set the shutter curtain sync to 2nd-curtain sync. This will fire the flash at the end of the exposure rather than the start, so with longer shutter speeds the pop of flash at the end of the exposure will prevent the subject from blurring (as much as they would with a 1st-curtain pop).

oshead

pixbyjohn wrote: »

Try this at home.
Camera in manual, F5.6 and shutter 160 with flash on, ISO 200 tell me how you like the results

Just to explain... f5.6 will get you enough depth of field. Handy for small groups. Though f4 might be enough.
Shutter 160 will help with reducing camera shake. Your camera could go up to 200 shutter sync no problems.
ISO 200 will probably have to be put up higher. Try 400 and maybe up to 800.

As a general guide. Try and underexpose the ambient light by a stop or two. Any more than two and you will just get black backgrounds. This is fine, till every shot you take has a black background. If you loose the bg at the settings above, it might help to take the camera up to ISO 800 and increase the shutter speed to 1/60 sec.

sflemings

oshead wrote: »

Just to explain... f5.6 will get you enough depth of field. Handy for small groups. Though f4 might be enough.
Shutter 160 will help with reducing camera shake. Your camera could go up to 200 shutter sync no problems.
ISO 200 will probably have to be put up higher. Try 400 and maybe up to 800.

As a general guide. Try and underexpose the ambient light by a stop or two. Any more than two and you will just get black backgrounds. This is fine, till every shot you take has a black background. If you loose the bg at the settings above, it might help to take the camera up to ISO 800 and increase the shutter speed to 1/60 sec.

Thanks everyone. That's a great help. I tried out those settings and did a bit of messing around with the shutter speeds.

I did find alright that I had to increase the ISO to either 400 or 800. I felt 200 was a bit low. Also I found that a slightly slower shutter worked a bit better too. But it all depends on the kind of shot you're looking for.
I haven't tried out the shutter curtain sync custom function yet so I don't know what that will turn out like.

jaybeeveedub

Av mode is not any less "smart" than any other exposure mode, you just need to understand what you are telling the camera to do, as flash last for a fraction of a second (less than 1/125 of a second usually) what controls exposure to a great extent with flash is the aperture... in Av mode you are telling the camera that you want to let "this much" light in by selecting the aperture value, and the camera will select a shutter speed to give a correct exposure for the image.... Flash photography is probably the hardest thing to master... it's easy enough to get started, but to achieve exposures where a casual observer doesn't immediately say in their head "flash photo" is incredibly difficult....

thankfully digital is so quick and cheap its easy to practice.... get a mannequin head and start taking photos in low light... try tethered shooting with the 550 and see immediately the effect that your settings have....!!

good luck with it....

also, if you are bouncing flash in a church turn the flashgun to manual and full power or it'll never reach the ceiling to get back down!! and diffuse for catchlights....