Minor Adjustments

Hi chaps!

This is a silly question I know and I'm sure many will laugh, however I have always been a firm believer that 'if you don't know, ask'.

I am no pro, I am very amateur but having had what I consider nice results in the past with my 400D and that I will very soon be helping out at a wedding with my new 60D it's time to ask a few questions.. This being the first!

When looking through the viewfinder and also on the screen there is a dial, I'm unsure of the correct name for it, but you am compensate in increments the F stop + and -

My question is, what exactly is this for? I've played with it and know what it does, but why would you choose this function over altering the ISO (as this is what I have always chosen to do).

Please don't laugh...

Do you mean exposure compensation? I'm not too familiar with the 400D, but basically in AV and TV modes, you set your ISO and either your AV/TV depending on which mode you're in.

Then based on the metering mode, the camera will then guess which AV/TV setting to use to get a good exposure. The + and - then means you can manually compensate whether you want more or less light the actual picture to take. Does that make sense?

Also, let me know if you're talking about something completely different...

welcome to POTN!

I believe that the last poster is correct.

In case you need it, and it sounds as though you might, here's the manual, it has any and all that you will need to know, I'm sure.

Canon 400D/XTi Manual

Randy

Thanks, I actually now have a 60d :-p

The replies are great and yes, I meant the exposure compensation...

I just don't understand why I would need to adjust that? In my eyes (which I know are wrong..) all I can see if that the ISO and exposure compensation do the same thing...?

You don't have to adjust exposure compensation if you don't want to. It is a there because the camera tries to expose everything as 18% grey, and if you (the creator of the photograph) wants to override it, it allows you to. ISO and exposure compensation are not the same, they change your exposure differently.

The meter is nice and all, but it's not perfect. There are many lighting conditions that can fool the meter and thus ruin your shot. For example, shooting a subject against a bright background or shooting in a snowy environment. The built in meter tries it's darnedest to get everything exposed so it comes out a nice even 18% gray. EC allows you to apply a bias one way or another to compensate for this.

Stuuk1 wrote in post #14883244
Thanks, I actually now have a 60d :-p

The replies are great and yes, I meant the exposure compensation...

I just don't understand why I would need to adjust that? In my eyes (which I know are wrong..) all I can see if that the ISO and exposure compensation do the same thing...?

Somehow the 60D part didn't sink into my (evidently tiny) brain...

Randy

Stuuk1 wrote in post #14883244
I meant the exposure compensation...

I just don't understand why I would need to adjust that? In my eyes (which I know are wrong..) all I can see if that the ISO and exposure compensation do the same thing...?

Because adjusting the ISO wont make any difference when you are in Av or Tv mode; exposure compensation is the only way to alter the exposure.

In Aperture priority mode you set the aperture and the camera sets the shutter speed based on the meter reading*. However, as mentioned above, the meter can be fooled under certain conditions. Metering of a large black object can cause it to overexpose, while metering off a lot of white may cause it to underexpose, so you need to be able to compensate for this. Altering the ISO won't help because the camera will simply adjust the shutter speed again to get back to what it, incorrectly, thinks is the right exposure.

This is where exposure compensation comes in. It allows you to increase/decrease the exposure without the camera trying to compensate.

* and vice versa when in Tv mode.

This is why you need it in Av & Tv: Post #47

More: Correct Exposure