Incident metering technique


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e905591s

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Sep 15, 2002
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#1
hi all,

I was fortunate enough to acquire a handheld meter from a fellow clubsnapper recently. The only problem is that, there wasn't any manual that came with the unit. So I hope someone can help me with some questions below.

I have difficulties getting readings that agree well with my existing "lightmeter" (an Oly C3040z), in incident mode at least. I tried to follow instructions on incident lightmetering from the internet, i.e. put the meter near to the subject and point the golf ball to the camera lens and take a measurement. I almost always get readings that are half a stop to one stop more than what the digicam says, resulting in overexposure. I trust the readings from the digicam since I can get properly expose slides, so I would tend to believe that my metering technique could be at fault.

e905591s
 

Astin

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#2
Most lightmeters require the user to set the ISO rating and the shutter speed before measuring the light.

Also I normally point the ball at the same direction as the model face point at, because I want a correct exposure of the face. Not sure why you need to point the ball to the camera lens.
 

e905591s

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Thanks for the info, Astin.

I actually found out about this method of incident metering by pointing the golf ball to the camera from various online sources, including Sekonic's or Kodak's official website, such as

http://www.sekonic.com/IncidentVsReflect.html
http://www.kodak.com/global/en/consumer/products/techInfo/af9/
http://www.scphoto.com/html/exposure.html
http://homepage.newschool.edu/~schlemoj/film_courses/sekonic_light_reading.html

I guess your method will be what is suggested by these sources when your model happens to look to your camera, hence the golf ball points towards camera.

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Lemon

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Nov 23, 2002
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Can you you elaborate on the subject matter that you are shooting?

A point to note is that incident meter only measure the amount of light falling onto the subject, but it doesn't take into account the reflectivity of the subject. Therefore, if the suject is highly reflective (e.g. glass, smooth reflective metallic surface etc) or it tends to absorb more light (dark cloths, black velvet, dark matt surfaces), you might need to compensate for that matter.

Alternatively, the meter may not be properly calibrated, just another point to note.

Maybe you can post some sample pics so that we can give you further suggestions.
 

Astin

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#5
Wait a minute! I am assuming you are taking photographs of people, am I correct? And I am assuming you want to have a correct exposure of the person's face.

If above is correct, then you should walk to the person, stand next to him/her, then check where you want his/her face to look at, then put the lightmeter on the forehead of the person, point to the same direction, and take a reading. If you want to be more accurate, then also take a reading on the left face, another reading on the right face, another reading on the chin, another reading on the nose tip. You then compute the optimized (or average) reading and set the aperture on the lens accordingly.

And if you shoot outdoor, the light condition changes very fast, you will need to repeat to take your readings again and again.
 

Newman

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#6
Get Jim Zuckerman's book Perfect Exposure. Excellent book on getting the right exposure using lightmeter or cam's built-in meter.
 

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#7
how in the hell yr " existing lightmeter" (an Oly C3040z) can do a incident reading,The metering in yr camera is a reflected -light reading not an incident-light reading. even if u are using reflected light reading on yr light meter,are u using the correct acessory to use with it.

Most of the Minolta meters need a reflected-lighted attachment to be use for reflected light reading.if yr meter is a Sekonic or Polaris u will not need acessory
 

e905591s

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Thank you all for the kind pointers.

Astin:Actually I haven't progressed to meter people yet. I was just trying out the meter with some objects I found on my dining table. It's better to screw up the metering on apple and oranges than a human face....

xfathom69: You are right ! The digicam obviously only does reflected metering. I was comparing the built in metering (somekind of evaluative metering ?) of the digicam and the incident metering of the handheld meter.

I tried again yesterday. The handheld meter will still give me half a stop to 2/3rd of a stop overexposure compared to the digicam reading. Can't seem to get them to agree well yet.

e905591s
 

V

vince123123

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#9
I've read somewhere that you can actually convert ur camera into an incident light meter by placing a semi translucent white (like that golf ball thing) cover over the lens mount. accurate or not...hehe go try it out :)
 

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