CannOffice:

Because if thats the correct exposure - it's the correct exposure however you set the camera. AV gives you more control over DOF while TV allows you to correct for subject movement.

Nope, sorry, they don't do anything different from each other at all.
  If you want a shallow depth of field and therefore you want, say, the full F2.8 from your lens, sure you can set this in Av (whereby it will give you,  lets say, 1/600) but you can set the DoF equally well in Tv by scrolling the shutter speed until it's forced to select F2.8, which you'll find is also 1/600, same thing, no difference at all, don't believe me do you?.
 Go pick up your camera and teach yourself something about the law of reciprocity, you see when you set the shutter speed in Tv it acheives this by opening and closing the shutter aperture and vise versa, want to freeze motion?, you're just as well served opening the aperture in Av as you are lifting the shutter speed in Tv.
 "P" mode is just automatically choosing for you based on the metering or basic scene recognition

You can, of course, get the same results but is'nt he word priority the key?

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   It's not actually prioritising anything it's pretty much only controlling which value is lit up in the viewfinder that's all, not as Canonoffice suggests, "Av to control DoF and Tv to freeze subject movement", which goes back to the OP asking "which do you shoot in", I was making the point that it doesn't matter.
 After all, if one or the other stops working it wouldn't make a jot of difference, it is, ridiculously, repeated as a function under another name.

Maybe it's just as well.
 I'm amazed by this, do people really think they are seperate, independant controls then?, frankly I'm gobsmacked if you haven't noticed that the only difference swapping between the two options is the light moving in your viewfinder from one value to another.

  This is day one, class one, stuff, the next lesson after "this is a camera and this is the front"


If I'm wrong, fer gawds sake tell me, I've been shooting sports in Aperture pririty for years now.

Stinkyfinger:

CannOffice:

Because if thats the correct exposure - it's the correct exposure however you set the camera. AV gives you more control over DOF while TV allows you to correct for subject movement.

 you can set the DoF equally well in Tv by scrolling the shutter speed until it's forced to select F2.8,

Well I'm steering well clear of this argument other than to say that there is no way in the world would you find me f*rting about setting Tv and then scrolling around until I eventually found a suitable aperture to give me the DOF I'm looking for. Far quicker to set Av and choose the correct aperture from the word go. And if 'time' is an issue here - well I've been doing it this way for over 30 years myself, without complaint and quite successfully I might add.

My closing comment is only to say that statements like This is day one, class one, stuff, the next lesson after "this is a camera and this is the front" are not very constructive - in retrospect I'm sure you'll agree.

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I give up
. You don't have to "randomly fart about" in Av, just scroll to the shutter speed you want, same as in Tv, it really does just light up a different part of the same display, nothing more, go and check before you accuse me of being unconstructive, I actually think it's been very helpful because, obviously, there are people on here who don't understand this very fundament of the relationship between the shutter speed and aperture and without understanding that, and how "exposure compensation" alters this how can you move on?.
   I would have thought with 30 years under your belt you would have known that the shutter speed has a corresponding aperture size, it'll certainly help with those "snap" shots that someone aware of this would get while you are still twizzling round to Tv and resetting the value.

 I'll leave it at that, the fact that a different part of the display has lit up in red has seemingly convinced you you are carrying out an entirely different and somehow more accurate task, and if you are happy with that, good on you.

Stinkyfinger:

I give up
. You don't have to "randomly fart about" in Av, just scroll to the shutter speed you want, same as in Tv, it really does just light up a different part of the same display, nothing more, go and check before you accuse me of being unconstructive, I actually think it's been very helpful because, obviously, there are people on here who don't understand this very fundament of the relationship between the shutter speed and aperture and without understanding that, and how "exposure compensation" alters this how can you move on?.
   I would have thought with 30 years under your belt you would have known that the shutter speed has a corresponding aperture size, it'll certainly help with those "snap" shots that someone aware of this would get while you are still twizzling round to Tv and resetting the value.

 I'll leave it at that, the fact that a different part of the display has lit up in red has seemingly convinced you you are carrying out an entirely different and somehow more accurate task, and if you are happy with that, good on you.

Er, did you actually read my post or did you simply decide to jump in both feet first? I would suggest you note the points I have highlighted in red and then go back and read my post again (or for the first time if applicable). I think you'll find my views are entirely opposite to what you are suggesting and to assist you in this I have actually gone back and highlighted the relevant parts in my original post.

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"Being a Pro doesn't mean you're better. It means you get paid" - David duChemin

Don't you think I gave the precise opposite example to further underline my point that both Tv and Av are the same parameters by different names?, they are, you may not believe me, and I confess I'm beginning not to care, but they are. It is as easy to change the aperture and affect depth of field from within Tv as it is to change shutter speed from within Av to get that fast moving shot, not nearly as easy, EXACTLY as easy, you simply rotate the wheel until the value you want is achieved, for that matter you rotate the wheel the same amount. If you were colour blind or the light was faulty  in your viewfinder, you wouldn't be able to tell which mode you were in...it's the same.

Stinkyfinger:

   It's not actually prioritising anything it's pretty much only controlling which value is lit up in the viewfinder that's all, not as Canonoffice suggests, "Av to control DoF and Tv to freeze subject movement", which goes back to the OP asking "which do you shoot in", I was making the point that it doesn't matter.



If I'm wrong, fer gawds sake tell me, I've been shooting sports in Aperture pririty for years now.

Your wrong.

Yes in theory you can achieve the same settings with both, but if for example you shoot in TV and set the camera to give you  F/8.  what happens when you move the camera around.  The shutter will stay set, and the aperture will alter to give what the camera says is the correct exposure.  IE giving priority to the shutter setting.  Your in control of the shutter, and the aperture will do its own thing. (shutter priority) 

If you shoot AV and set the aperture F/8. what happens when you move the camera around.  The aperture will stay set, and the shutter will alter to give what the camera says is the correct exposure.  IE giving priority to the aperture setting.  Your in control of the Aperture, and the shutter will do its own thing. (aperture priority) 

 

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Lurkalot:

Stinkyfinger:

   It's not actually prioritising anything it's pretty much only controlling which value is lit up in the viewfinder that's all, not as Canonoffice suggests, "Av to control DoF and Tv to freeze subject movement", which goes back to the OP asking "which do you shoot in", I was making the point that it doesn't matter.



If I'm wrong, fer gawds sake tell me, I've been shooting sports in Aperture pririty for years now.

Your wrong.

Yes in theory you can achieve the same settings with both, but if for example you shoot in TV and set the camera to give you  F/8.  what happens when you move the camera around.  The shutter will stay set, and the aperture will alter to give what the camera says is the correct exposure.  IE giving priority to the shutter setting.  Your in control of the shutter, and the aperture will do its own thing. (shutter priority) 

If you shoot AV and set the aperture F/8. what happens when you move the camera around.  The aperture will stay set, and the shutter will alter to give what the camera says is the correct exposure.  IE giving priority to the aperture setting.  Your in control of the Aperture, and the shutter will do its own thing. (aperture priority) 

 

You're right, I am perhaps being a bit pedantic, in purely technical terms, for any given exposure they are in effect identical (reciprocal law), however, as you say which one is automatically controlled will vary depending on metered light will be down to which priority it is set to, I confess I hadn't thought of that, I still shoot sport in Av mind, I'm generally as concerned with depth of field as I am with shutter speed and don't run into problems because I generally leave a bit of a margin if the conditions are changeable.

OR you could set your camera to manual and do exactly the same thing lol

Once you set you camera up in manual as long as the light doesn;t change then you have no need to worry about your aperture or shutter speed changing. SO on days or at locations where the light is constant it's easier to set it once in manual and leave it. the problem for me with av and tc modes is as lurkalot said is the camera will tell you your under or over exposing depending on what the camera is being metered on.

So as I said, for something like portraits I spot meter on the brighest part of the face generally sellecting an aperture I want and over expose that by one stop by adjusting the shutter speed. this should give a better and more realistic representation of the skin tones. This should also allow me to shoot anything else in the relative same light withought having to meter the exposure again. Obvioulsy then if you want a faster or slower shutter speed or bigger or smaller aperture you have to adjust the other accordingly in steps up or down. And now I'm confusing myself lol

Yep, Stikyfinger is wrong.  Whilst both AV and TV are connected, you cannot set the lens to it's optimum aperture in TV mode any more than you can control the shutter speed in AV mode.  To separate the two from each other gives the photographer a great deal of choice over how he wants an image to be photographed.  If you shoot in A/V and it sets 1/000 of a second @ f8,  you might be wanting a shutter speed much slower to capture movement blur.  To do this manually you'd need to be in TV mode.

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What Stinkyfinger has been saying is

You can change the aperture if AV mode to get the shutter speed you want
AND
you can change the Shutter speed in TV mode to get the Aperture you want

This is TRUE

If you dont want to give PRIORITY to the shutter speed or the aperture the mode to use is surely the P (Program) mode which allows you to change either while making the corresponding adjustment to the other.

There is a place for all three modes on the camera to suit the needs of different users and for those really independent users there is also "M".

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