How do u decide on shutter speed the metering exceeds preset levels ?


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marcwang

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Jan 9, 2003
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#1
I face this problem.... on night shoots. I use an F80, and the inbuilt metering max out at 30seconds. Anything more required would be labeled "LO" , as in low light and no suggested shutter speed is advise. I would have to guess then, which is highly highly inaccurate.
 

Shadus

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Jan 17, 2002
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#2
not really.
At 30 sec, +1 stop is anr 30 sec. +2 stop is 2 minutes liao. Usually film and even slides can take 1,2 stops latitude. So no problem at all.

Moreover, you hv to understand that @nite, as meters take average light reading, it tends to be wrong. you hv to rely instead on spot metering to meter off the brightest part of your pic (usually street lamp) and add 1 or 2 stops to brighten up the surroundings.

(NB: Above is usually wht I do and not indicative of proper photograhy techniques)
 

Tweek

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Jan 17, 2002
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#3
First of all, for night shoots sometimes the in camera metering may not be accurate. It will be good to do some bracketing.

Since most cams max out at 30s, any longer you'll have to use bulb mode. First of all, set a wide aperture like f4, and see what's the metered shutter speed, say it is 4s. Then select the aperture you want to snap at, and calculate the number of stops to compensate. Say you want to take at f11, so f4 to f11 is 3 stops difference. From 4s, 3stop difference will be 32s. So just take with bulb mode and time for 32s.

And then, there's reciprocity failure of film too. Typically for long exposures, you may have to compensate 1/2 stop to 1 stop more, depending on the film you use. Say you need to compensate 1 stop more, so you'll have to expose for 64s.

I'm not exactly experienced in long exposures, but above is the knowledge I have so far. Any misconceptions or fallacies, please do correct me!
 

Ian

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Feb 20, 2002
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#4
A couple of methods:

Method 1

The easiest way to measure out of range low light levels is to try the old ISO kludge.

Manually set the camera ISO as high as it will go, then meter the scene and count back the stops, doubling the metered exposure each time you move one stop of ISO speed.

eg: f2.8 at 6400 ISO gives 1 second reading
then by translantion:

2 seconds at ISO 3200
4 seconds at ISO 1600
8 seconds at ISO 800
16 seconds at ISO 400
32 seconds at ISO 200
64 seconds at ISO 100
128 seconds at ISO 50

Once you have this base figure you can then make any adjustments for desired aperture etc.

Method 2

Use a quality external light meter, such as the Gossen Luna Pro that can meter to 8hrs under moonlight.


Notes:

Always take in to account reciprocity failure of the film being used. The figures vary from film to film and there is NO average figure that can be applied. Additional colour compensation filtration is usually regured and specified such as a CC20M filter (20 Units of Magenta). See the technical data sheet for the film being used.

In order to avoid reciprocity failure keep your exposures inside the film's rated exposure tolerances.

 

Jed

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Jan 19, 2002
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#6
Fast and clean.

But not very efficient, expensive, and it doesn't help you to learn about exposure and understanding things.
 

jasonpgc

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#7
1) If you want to have the street lights in detail during a night shot,
Point the spot meter towards the light source and give a +2 or +3 exposure compensation to the reading given by the meter depending on the brightness you prefer.

2) If you want the streets to have more detail during a night shot, exclude any light source from your composition. Point your spot meter towards the pavement, if the pavement is light grey give +1 , or if the pavement is red give 0, or if the pavement is dark grey give -1, exposure compensation to the meter reading.

3) If you require to have both the light source and detail in your picture, then point your meter at the pavement and give -1 exposure compensation regardless of what color your pavement is, this will help to prevent the light source from burning out too much and also render visible detail in the scene.

The above is base on my personal taste, treat it only as a basic guide, please go out to try and experiment yourself, preferablely with slide film

I never bracket, One Shot One Kill :bsmilie:
 

clive

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Oct 9, 2002
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#8
LOL..jason's 1 shot 1 kill method is even much cleaner but yeah Jed has a point; sometimes its better to go thru all the rigorous detail, esp for the initial learning process. hopefully as marc progresses he will be able to bracket with greater precision
 

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