Few n00b questions...

Kryptix

Kryptix

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I understand pretty much every setting on my 450D now except a few things which I'm about to ask.

First one is the exposure... -2, -1, 0, +1, +2

What does this actually do? I know what exposure does, but surely the shutter speed, the aperture and the ISO all control this? Is the 'exposure' setting a 4th control or is it meant just as a guide or what? Can someone explain it simply to me please and how I'd use it?

The second one... Tv mode (or Av mode). When shooting motorsport, I normally put it on Tv (shutter priority) mode with a shutter speed of 1/60 (ish) for panning. I put the ISO onto Auto and the aperture is adjusted for me (as is the ISO).

But what adjusts first, aperture or ISO? Ideally I'd like a Shutter-then-aperture priority mode. I know I can set the ISO to 100 but if it's way to dark I'd sooner it increase the ISO than miss the shot. That seems logical, but sometimes I'm shooting and it'll use ISO 1600 and like f/20. :thinking: I'd much sooner it use f/4 and ISO 100 (for example).

Can anyone explain why, and if it's possible to alter this?

Hopefully I've explained myself properly...
 
Kryptix said:
I understand pretty much every setting on my 450D now except a few things which I'm about to ask.

First one is the exposure... -2, -1, 0, +1, +2

What does this actually do? I know what exposure does, but surely the shutter speed, the aperture and the ISO all control this? Is the 'exposure' setting a 4th control or is it meant just as a guide or what? Can someone explain it simply to me please and how I'd use it?
Click to expand...

That is called exposure compensation - it allows you to compensate for the cameras metering which makes assumptions.

Essentially a camera takes a light reading and then decides what the 'correct' exposure for the scene is depending on your metering mode. You can then tell the camera to under or over expose by up to 2 whole stops (custom functions allow you to change from 1/3 to 1/2 stop increments) to either bring out details in the shadows or the highlights.

Some people like to under expose by 1/3 of a stop to make sure they don't blow any highlights as shadow detail is easier to recover



Kryptix said:
The second one... Tv mode (or Av mode). When shooting motorsport, I normally put it on Tv (shutter priority) mode with a shutter speed of 1/60 (ish) for panning. I put the ISO onto Auto and the aperture is adjusted for me (as is the ISO).

But what adjusts first, aperture or ISO? Ideally I'd like a Shutter-then-aperture priority mode. I know I can set the ISO to 100 but if it's way to dark I'd sooner it increase the ISO than miss the shot. That seems logical, but sometimes I'm shooting and it'll use ISO 1600 and like f/20. :thinking: I'd much sooner it use f/4 and ISO 100 (for example).

Can anyone explain why, and if it's possible to alter this?

Hopefully I've explained myself properly...
Click to expand...

Can't help you with this as I always set the ISO myself and don't know how the auto function works
 
On the 450D when in Auto ISO mode I've never seen mine go about ISO 800, and never seen it go below ISO 200(And I've been trying to shoot in nigh on darkness before, and really bright sunshine, but it still won't go outside that range)

It goes for the lowest ISO setting it can get away with.

That's how mine works anyway.....
 
I quite often use exposure compensation on the 450D - mine has a tendancy to over expose even if I spot meter on something. The histogram should give you an idea of what to 'dial in' when shooting. I use a combination of the histogram and the flashing thing that shows you where you've clipped the highlights.
 
Exposure control makes perfect sense. So it's only really used when using AUTO or P? It's not a 4th control as such?

...and still no-one really knows about the other question. :(
 
Kryptix said:
Exposure control makes perfect sense. So it's only really used when using AUTO or P? It's not a 4th control as such?

...and still no-one really knows about the other question. :(
Click to expand...

I usually use Exposure compensation when using Aperture Priority but it can be used with the other modes with the exception of Manual (Not 100% sure about Auto).

As for the second question, It's one of the reasons I don't use Auto ISO if I can help it as it does seem to select smaller apertures and higher ISOs than you want. I know with my camera the minimum ISO on Auto is 200 and I can choose the maximum to be either 800 or 1600.
 
Kryptix said:
Exposure control makes perfect sense. So it's only really used when using AUTO or P? It's not a 4th control as such?(
Click to expand...

It's available in A-Dep, Av, Tv and P modes, and it's come in really handy this month while shooting for this months competition - Contre Jour!

Sorry - can't help on the auto ISO issue
 
This is what the 450D manual says about the auto ISO.

About Auto ISO

This mode sets the ISO speed automatically between ISO 100 - 800 to
suit the shooting mode and ambient light level.

For flash and (manual) exposures, ISO 400 is set. When you press the shutter button
halfway, the automatically-set ISO speed is displayed in the viewfinder
and on the LCD monitor.
 
Oh now I really get it, sometimes Tv/Av is too dark as it's guessing wrong so you higher the exposure. Bingo! :)

Cheers mate.
 
So Auto ISO is a big no-no really? I use manual shutter speed for panning, but I don't want ISO 400 on all my pictures!
 
Kryptix said:
except a few things which I'm about to ask.......First one is the exposure
Click to expand...
Blimey.
Some pretty rudimentary, noob[your words] questions being asked considering on your FB site you claim to offer 'professional services....including photography' ! Or just is that marketing hot air!?
 
Merovingian said:
Blimey.
Some pretty rudimentary, noob[your words] questions being asked considering on your FB site you claim to offer 'professional services....including photography' ! Or just is that marketing hot air!?
Click to expand...

Quite an old thread to bump with that post, hopefully not posted to just 'stir' :nono:
 
On the contrary.

I noticed the commotion in that 'other' thread, but it didn't seem to be that heinous a crime to me - people say daft things in the heat of the moment on the net. However, it did prompt me to dig a little further out of interest, and his site links are there for all to see.

More concerning to me, is those passing themselves off as professionals when they bought their first dslr a few months ago.

I recalled this thread from memory after reading his site comments, but my comment could easily have applied to his current 450v40v50d thread.

So the [genuine]question seems a fair one to raise, don't you think.
 
Jimmy_Lemon said:
Quite an old thread to bump with that post, hopefully not posted to just 'stir' :nono:
Click to expand...

I would say this was the conclusion I came too when I saw the post and then the age of the thread. Witch hunt? :nono:

I would say that a quick flick through his flickr gallery shows that he is of a good enough standard to be offering work out as professional. Especially on the car rig shots. Whether it be just a hobby/part time cash. Granted that is hard at the moment with his signature missing!
 
Merovingian said:
Blimey.
Some pretty rudimentary, noob[your words] questions being asked considering on your FB site you claim to offer 'professional services....including photography' ! Or just is that marketing hot air!?
Click to expand...
Not really. I always shot on Manual so I had no-idea what exposure composite did.

Anyway, if people are prepared to pay for your services you must be doing something right... and they do. :)
 
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