Understanding Exposure

Quaker

Quaker

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Not long since bought the book Understanding Exposure by Bryan Peterson and I love it. really good read.

One thing that I can't get my head around though and was wondering if anyone could help me out.

On a few occasions in the book when referring to images he has taken he says something like:

"I took the metering from the sky and recomposed"

What does he mean and how do you do it?

Cheers
 
Point the camera at the sky to get your light reading and do your settings, then position the camera to get the shot.
 
I'm not sure what it's called on a Nikon but Canon called it 'AE Lock'.
Basically you press the lock button, point camera at the sky, press the shutter button halfway, recompose on the object you want to shoot then press the shutter button.
This takes a meter reading from the sky then locks the meter reading, when you recompose the meter reading does not change.
As an example, this is a good method to reduce the sky from over exposing.
 
I prefer to set my camera in Aperture mode so if I was to meter from the sky for instance I would set my Ap at whatever I wanted, (say f8) point the camera to the sky and whatever shutter speed was indicated (for eg 250) , this is what I would set the camera at to match my aperture. I would then recompose at these settings and shoot.

Am I reading this right?
 
Quaker said:
I prefer to set my camera in Aperture mode so if I was to meter from the sky for instance I would set my Ap at whatever I wanted, (say f8) point the camera to the sky and whatever shutter speed was indicated (for eg 250) , this is what I would set the camera at to match my aperture. I would then recompose at these settings and shoot.

Am I reading this right?
Click to expand...

Yep. But you would either have to use Exposure lock (how ever that works on a Nikon) or switch to Manual mode to input the Aperture and Shutter speed.
 
Quaker said:
I prefer to set my camera in Aperture mode so if I was to meter from the sky for instance I would set my Ap at whatever I wanted, (say f8) point the camera to the sky and whatever shutter speed was indicated (for eg 250) , this is what I would set the camera at to match my aperture. I would then recompose at these settings and shoot.

Am I reading this right?
Click to expand...

The thing is, if there is a slight difference in the light, say cloud movement giving more light, by the time you have changed the settings in either aperture mode or manually, the light reading may have changed.
I've notice when doing multiple exposure shots that include the sky, sometimes you can see a slight cloud movement in next to no time.
Actually, I'm probably barking up the wrong tree as people have probably using your method long before focus lock became available.
 
I would much rather do it manually at first so I can get to understand it, When I have cracked it manually then I will use the AE Lock. I just want to understand the mechanics of it first.
 
Quaker said:
Not long since bought the book Understanding Exposure by Bryan Peterson and I love it. really good read.

One thing that I can't get my head around though and was wondering if anyone could help me out.

On a few occasions in the book when referring to images he has taken he says something like:

"I took the metering from the sky and recomposed"

What does he mean and how do you do it?

Cheers
Click to expand...
Not sure about Nikon but on Canon you can point your lens at the sky and press the * button this will lock your exposure you can then re-frame and take the shot with the locked exposure.
There might be a button the same on yours or not?
 
Nikon camera's do have an AE-lock button (well, the ones I have used).
 
sdb123 said:
Nikon camera's do have an AE-lock button (well, the ones I have used).
Click to expand...
Yes you are right Nikon do have an AE Lock function but like I said, I think its best I understand the mechanics of it before I use it.
 
Quaker said:
Yes you are right Nikon do have an AE Lock function but like I said, I think its best I understand the mechanics of it before I use it.
Click to expand...

I wasn't aiming it at you in particular - I was informing the Canon shooters who have posted on the thread who were unsure of whether Nikon bodies had an AE-lock button. :)
 
Quaker said:
Not long since bought the book Understanding Exposure by Bryan Peterson and I love it. really good read.

One thing that I can't get my head around though and was wondering if anyone could help me out.

On a few occasions in the book when referring to images he has taken he says something like:

"I took the metering from the sky and recomposed"

What does he mean and how do you do it?

Cheers
Click to expand...

It's an interesting and entertaining read, but as a practical instruction manual it falls short.

I think you're referring to the chapter on The Sky Brothers where he talks about Brother Dusty Blue Sky and other weird stuff, where you can only really undertstand what the heck he's talking about if you understand it in the first place.

It gives you a good feel for the kind of issues invloved in exposure control but I also think he makes too much of a meal of it, being originally a film shooter. A lot of that stuff is just irrelevant with digital.
 
HoppyUK said:
It's an interesting and entertaining read, but as a practical instruction manual it falls short.

I think you're referring to the chapter on The Sky Brothers where he talks about Brother Dusty Blue Sky and other weird stuff, where you can only really undertstand what the heck he's talking about if you understand it in the first place.

It gives you a good feel for the kind of issues invloved in exposure control but I also think he makes too much of a meal of it, being originally a film shooter. A lot of that stuff is just irrelevant with digital.
Click to expand...

I agree with this totally. It also has to be said he used center-weighted metering nearly all the time. I tried following his instructions with matrix metering and it was very hit and miss. There's simply no need for most of it if you take a shot and check the histogram.
 
Quaker said:
Care to enlighten me?

I may ask for a tutorial :)
Click to expand...

Loads of stuff on google re histograms, like the Luminous Landsacpe link above, or this one http://www.sekonic.com/images/files/HistogramsLightmetersWorkTogether.pdf It really is God's gift for optimum exposure.

Some purists will hate me for this, but I really think exposure metering is so easy with digital. You don't need to write a whole flippin book about it! Use evalutative/matrix metering (it's very clever) and it will get you pretty close under all but the most unusual situations. Much of the time it will be spot on. Enable blinkies - that is the flashing warning on the LCD of over exposed highlights. Learn to read to histogram. Use +/- exposure compensation to bring the exposure level in line with an optimum histogram. That's all there is to it.

Bear in mind that the sensor can only handle a limited range of brightness from light to dark. Rule of thumb is about 7-8 stops, ie 1:256 ratio maximum. Many typical scenes will be more than this, very much more if you have the sun near the frame, or even within it, and maybe some dark foregound shadows.

No camera can cope with these extremes (called the dynamic range) so you have to choose which range of tones is most important - the bright ones, the darker ones, or a compromise in the middle - and adjust the exposure level to slide the histogram left or right so that the 256 most important tones fall within its range.

Some people also believe that if you use spot metering, or an incident light reading, or some other technique that might have been useful shooting film, that you will somehow get a 'better' exposure. This is not true - they are just different ways of measuring the light in order to get as close as possible, as easily as possible - the result is the same. Digital shooting techniques make this unnecessary, but whatever works for you, use it.

In extreme situations, it is possible to compress the dynamic range, eg to darken a bright sky that would otherwise blow to pure white. Popular methods for that are a polarising filter, or a graduated filter, or HDR technique (High Dynamic Range) which inloves shooting several frames at different exposure levels and combining them in post production.
 
sdb123 said:
Nikon camera's do have an AE-lock button (well, the ones I have used).
Click to expand...
:thumbs:
the ones i used you would push timer lever towards the camera to hold the shot
later ones you did as suggested..or push on a button on the timer boss to hold the reading
these were 35mm bodies but i think some of the technology may have filtered through
the call to set the manual settings are best i think and monitor the sky readings accordingly
then you are free to shoot without using any pre-conditioned thoughts

i have just photographed a collection of antiques doing this...
set the cam on manual and then shoot everything so that any highlights and shadows are not commanding differing exposure settings
it was a whiz... set up the piece..shoot then.. on to the next piece or view of
assuming a constant light source...diffused daylight which may be what light cloud exposure is

cheers
geof
 
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