Dumb question about using flash

[Dazz1]

I am using a Canon 600D with it's inbuilt flash. When I try to take a photo in dim light using the flash, in Aperture priority mode, the camera chooses a very slow shutter speed. It seems as if it ignores the fact that I have the flash popped-up. This causes the resulting photo to look like 2 superimposed pictures, one nicely exposed via the flash, but the other image is like a ghost from when I inevitably move the camera a bit during the long exposure.

What is the right setup to take the photo?

[old dog]

I do this with my onboard or external. Set the camera up in S or speed priority, set the iso to 200, aperture 5.6 and pretty well works spot on all the time. I don`t know what is doing what in aperture priority but someone here will have the answer.

[Dazz1]

I do this with my onboard or external. Set the camera up in S or speed priority, set the iso to 200, aperture 5.6 and pretty well works spot on all the time. I don`t know what is doing what in aperture priority but someone here will have the answer.

I see. Thanks. Your method sounds very manual. I am thinking the camera should be smart enough to set itself up automatically for a flash shot, if only I knew what I was doing and put it in the right mode .

[MarkChap]

When using flash, in aperture priority shooting mode, the Canon system assigns the flash as fill light.
Therefore sets a slow shutter speed to achieve a correct exposure (as per the cameras meter).

When flash is used in Tv (time value/shutter priority) mode or manual, the canon system assumes that the flash is the main source of light and adjusts appropriatley.
The faster you set your shutter speed the darker the background is going to be
The higher your ISO, and the slower your shutter speed, the more ambient light will be recorded by the sensor, so you need to decide how much of that ambient light you want in your image and set the camera accordingly

[Ms Monny]

Well, that answers my question that Ive been asking myself for a long time. I didn't realise that Av and Tv made the camera work differently! Thanks from me too!!

[Dazz1]

When using flash, in aperture priority shooting mode, the Canon system assigns the flash as fill light.
Therefore sets a slow shutter speed to achieve a correct exposure (as per the cameras meter).

When flash is used in Tv (time value/shutter priority) mode or manual, the canon system assumes that the flash is the main source of light and adjusts appropriatley.
The faster you set your shutter speed the darker the background is going to be
The higher your ISO, and the slower your shutter speed, the more ambient light will be recorded by the sensor, so you need to decide how much of that ambient light you want in your image and set the camera accordingly

Thanks so much. I really could not figure that out from the manual (and I DID read it).

[Wandapics]

Thankyou I was having trouble with that also. Definately not a dumb question.

[old dog]

good explanation Mark. I too do not use flash a great deal so naturally you get out of practice, not as confident. Like anything really, the more you use it the easier it gets.

[leanneqld]

http://www.p4pictures.com/2012/04/fi...riority-modes/

[manohartvs]

When using flash, in aperture priority shooting mode, the Canon system assigns the flash as fill light.
Therefore sets a slow shutter speed to achieve a correct exposure (as per the cameras meter).

When flash is used in Tv (time value/shutter priority) mode or manual, the canon system assumes that the flash is the main source of light and adjusts appropriatley.
The faster you set your shutter speed the darker the background is going to be
The higher your ISO, and the slower your shutter speed, the more ambient light will be recorded by the sensor, so you need to decide how much of that ambient light you want in your image and set the camera accordingly

Interesting to know this. Does the Nikon system have any such nuances as well?

[ameerat42]

I'm only guessing, because I don't own one. But if you do own one, YOU could tell us after a simple experiment.
Now my guess is that Tv and Av modes would have to be basically the same for all cameras. When my batteries charge up I will also try it.
Am.

[Dazz1]

http://www.p4pictures.com/2012/04/fi...riority-modes/

In that link, it says it does fill-in flash for both Av and Tv, which is a bit different to what Mark posted.

- - - Updated - - -

Something extra I discovered today, in Tv mode, it won't let me set the shutter faster than 1/200 sec.

[leanneqld]

This is from another source....
http://photonotes.org/articles/eos-f...2.html#tvflash


"Tv (shutter priority) mode flash.

In this mode the camera lets you change the shutter speed. It then automatically chooses an aperture setting to expose the background correctly. Flash duration (flash output) is determined by the flash metering system. In other words, the camera always works in fill flash mode when it’s in Tv mode - it always tries to expose the background adequately, unlike P mode.

If the maximum aperture value of your lens starts flashing in the viewfinder it means the background of the scene you’re shooting is too dimly lit. If you want to try and expose the background then you should decrease the shutter speed to compensate. Otherwise the camera will just try and expose the foreground with flash and the background will come out dark. Naturally at slower shutter speeds you’ll need to use a tripod to avoid blurring caused by camera shake.

As always, the camera will prevent you from exceeding its built in X-sync speed unless high speed sync is available to you and engaged. If the minimum aperture value of your lens starts flashing then your scene is too brightly lit. You must then either engage high speed sync if it’s available or perhaps put a neutral density filter on the camera or use slower film or a lower digital ISO. Or turn off flash altogether and simply use a reflector of some type to bounce ambient light onto the subject. "