Is my camera faulty

[GarfieldLeChat]

also to add that i have found that av doesn't work well in bright sunlight, you need tv for this, i think the technical reason is that the av mode is the aperture-priority mode and the tv is the shutter-priority mode (some one will tell me that they are the other way roudn in a min i'm sure...)

basically it means that either the shutter speed or the size of the hole you create with your lens to let light in (the aperture) controls the other aspects of the shot, which means if the aperture is to large then you will get over blowing on your shots (which is why you need to stop down) however if you stop down to much then you will find the images are too dark...

From personal useage outdoor shots are best done on tv or m setting (m for manual...) and night time /bad light/ indoor clubby shots are best taken on av...

 

[cybertect]

also to add that i have found that av doesn't work well in bright sunlight

First time I've come across this idea.

IMO, it shouldn't make any difference to the metered exposure whether you're in shooting aperture priority or shutter priority mode.

 

[GarfieldLeChat]

First time I've come across this idea.

IMO, it shouldn't make any difference to the metered exposure whether you're in shooting aperture priority or shutter priority mode.

i'm not saying it's correct i'm saying the camera in av mode doesn't appear to work terribly well ... as in it doesn't work well in bright sunlight...

and of course it will make a difference as a shutter will like under expose where as an apeture will likely over expose... which ever is given priority will therefore give you either an under or an over exposed shot.

http://en.wikipedia.org/wiki/Aperture read this...

more over the OP advised they were using Av in their shooting with this camera, which in my opinion has this defeicit if not used and stopped correctly (some thing which is not easy to do with this model) as a result you get many over blown images, knowign this i commented...

would you care to explain why this shouldn't be the case...

 

[cybertect]

The reason it shouldn't make any difference is twofold

- physical: except on antiquated SLR designs, when you're framing the shot and the metering occurs, it's done with the aperture diaphragm wide open to ensure the brightest image in the viewfinder.

That's why you need a depth of field preview button, which stops the aperture down to the one you've actually selected for the shot.

Consequently, it makes no difference from the point of view the amount of light falling on the meter whether you've got Av or Tv mode selected. The sensor is exposed to exactly the same input.

- logical: there's a direct and linear inverse relationship between aperture and shutter speed. Double the exposure time and you have to reduce the aperture by one stop to ensure the same exposure value. Double it again, and the opening is two stops smaller. There's no particularly complex mathematical relationship that could go wrong if you've established the light level (see above).

 

[blackadder]

Cheers Garf, I've just been experimenting with the stops, you have to keep the AV+/- button pressed down whilst you turn the dial, but I'm getting more used to it.

 

[GarfieldLeChat]

The reason it shouldn't make any difference is twofold

- physical: except on antiquated SLR designs, when you're framing the shot and the metering occurs, it's done with the aperture diaphragm wide open to ensure the brightest image in the viewfinder.

That's why you need a depth of field preview button, which stops the aperture down to the one you've actually selected for the shot.

Consequently, it makes no difference from the point of view the amount of light falling on the meter whether you've got Av or Tv mode selected. The sensor is exposed to exactly the same input.

- logical: there's a direct and linear inverse relationship between aperture and shutter speed. Double the exposure time and you have to reduce the aperture by one stop to ensure the same exposure value. Double it again, and the opening is two stops smaller. There's no particularly complex mathematical relationship that could go wrong if you've established the light level (see above).

and...

if you didn't stop down what would be the result???

an over exposed shot which is what we have... tadah!!

what was my intial advice...??

stop down..

tadah...



B'ladders: no probs let's see the results posted up here it'll become second nature to you once you have gotten used to it (btw in preview mode you can also use that little wheel to scroll through the images... )

 

[Paul Russell]

Hi there

BTW, you won't need the AV-/+ for most shots -- it's just for situations where the cameras automatic metering has been "fooled" by an unusual situation.

Say you're indoors taking a photo of someone standing in front of a window and it's bright sunlight outside -- the automatic exposure will usually mean the person is very dark in your photo. In this case you would whack the AV-/+ thing up to +1 or something. There will be blown highlights (the bright light) but in this case you don't care -- you're interested in being able to see the person.

Or if you look at the histogram of a shot you took and the trace is going nowhere near the right-hand side of the graph the photo is going to be a bit dark, and the photo might benefit from dialing in a + value.

If you're outside on a bright day, if the histogram is spilling right over the right-hand side of the graph, you will have a load of blown highlights, and the photo might benefit from dialling in a negative value. (You can lighten up the dark bits later in an image editing program to some degree, but the blown highlights are gone forever -- there's no detail to get back.)

I'd chose aperture priority when you want to control aperture, and shutter priority when you want to control shutter speed!

Cheers Garf, I've just been experimenting with the stops, you have to keep the AV+/- button pressed down whilst you turn the dial, but I'm getting more used to it.

 

[cybertect]

Hmm... the 'stopping down' you're referring to is exposure compensation against the metered Exposure Value, but the EV is measured the same regardless of whether you're using aperture priority or shutter priority.

I'm not saying that the meter will get it right every time and expose every scene perfectly. Of course it can't and that's why, amongst other things, it's worth spending the money on a camera that will allow you to adjust the EV to bring out the detail in the areas you want to for that particular shot.

In aperture priority mode, that will increase or decrease the time the shutter's open for, and in shutter priority mode, it will adjust the aperture compared with the metered value.

If you look at the OPs second posted pic, it's clearly backlit. The shadows are pointing toward the camera - shooting into the sun. That's going to pose a major challenge to obtain a properly exposed image, especially for any system which meters based on an average the entire scene.

The only options in that situation are to spot meter on the feature you want properly exposed, if your camera allows that, or to compensate with a manual adjustment of the EV, both of which amount to the same thing. In either case, you're either going to over expose the cobbles (which are bouncing sunlight straight into the lens) or under expose the shadows.

The problem is nothing to do with the total amount of light or the shooting mode, but the disposition and relative values of light and dark in the scene.

 

[Paul Russell]

In a nutshell:

To get a correct exposure you need the right total amount of light hitting your film/sensor.

Two things govern that

1. How long you expose the film/sensor to light (shutter speed).

2. How big the hole is that you use (aperture).

For a given scene, there is a combination of shutter speeds and apertures that will let the right amount of light in.

Either

Big hole, fast shutter speed.
Small hole, slow shutter speed (so the light has more time to hit the sensor).


And all the combinations in-between.

If you select aperture priority, you are choosing the aperture, and the camera will give you the correct shutter speed.

If you select shutter priority, you are choosing the shutter speed, and the camera will give you the correct aperture.

Most times the camera will get it right -- if it doesn't, using the AV -/+ thing can help.

But if there is a huge difference between the brightest and darkest bits, your camera won't be able to handle it -- come back 2 hours' later/give up/re-frame/or combine two shots!