[Slicker]

Hi there,

I have an EOS 400d and I am a little confused between the difference of the modes P, Tv and Av.

It seems that if I set the camera to P it will select a shutter speed and apeture which I can change. If I set the camera, to Av, then I can set the apeture and the camera will select a shutter speed, Tv sets that shutter and the camera will select the apeture (is that correct).

Whats the purpost of this. If I can set the shutter in P, surely this is the same as setting the shutter in Tv mode? Similar with Av?

Can someone give me some advise on this please.

Thanks
Paul

[stepheno]

Yes, you've got it. But -

P - you can't change anything other than Aperture and Shutter (all else is on Auto)
AV and TV - you can change other settings like WB
Manual - you set everything yourself.

[Slicker]

I thougt I was able to change ISO on P as well...?

[Dave]

Tv Mode - Video Tutorial
Av Mode - Video tutorial

[stepheno]

Originally Posted by Slicker

I thougt I was able to change ISO on P as well...?

You might be able to - since I've never used it I could be wrong

[Slicker]

ok, but I am still not sure what the advantage of use P over TV or AV since P I can change the shutter/apeture accordingly

[Angela]

The advantage will depend on what situation you are shooting in. If you have all the time in the world to take a shot then using full manual is no problem but if you are shooting in a more fast-paced situation and perhaps you need a fast shutter speed - yoi can set that and let the camera take care of aperture and vice-versa. It gives you one less thing to have to think about.

[Dave]

My understanding is P mode is halfway house between fully Auto & using AV & TV mode. In fully Auto mode the camera automatically sets AF mode, Drive mode & built in flash, in addition to Shutter speed & Aperture. In P mode only the latter 2 are set automatically, allowing you to change the other settings. (This is relevant to 40D)

I've never used P mode, as I use AV mode almost exclusively, checking shutter speed & compensating accordingly with either ISO or the aperture.

[Dave Canon]

I also use a Canon (not the 400D) but it is probably the same. My advice would be to read the camera manual as that will tell you the precise difference between the different modes. Most of the other posts here are certainly not correct for my camera and probably not correct for yours either.

For my Camera Canon EOS 20D, in the P mode you can change just about everything but the exposure is automatically set (both aperture and shutter). In the AV mode, you set the aperture and the Camera sets the shutter. In the Tv mode you set the shutter and the Camera sets the aperture. I use all three modes at different times.

If you need to set a large depth of field, you need a small aperture so it would be best to use AV (similalry if you needed a small depth of field you would set a large aperture in AV). I you wanted to capture high speed action, you will need a fast shutter speed so should use Tv mode. For many routine shots it is quite OK to use P mode and let the Camera decide both shutter and aperture. I find it is useful to leave my camera in P so, if I have to grab a quick shot, it is likely that the camera will set something sensible. If you have more time you can then consider whether TV or AV is better.

Don't forget that there is also a Manual mode M which is also very useful where you set both aperture and shutter. Unless you have a separate meter, you may need to measure the exposure using and automatic mode then transfer the settings to manual.