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Spot Metering Help
If I understand correctly, spot metering takes asmall portion of the frame and meters from it. But where on the frame does this spot come from?Daniel..

Comments (14)

The centre, usually the central focus point, although I think some cameras allow you to set the spot to a different off-centre focus point. If you haven't explicitly changed it - which may well not be possible - it will be the centre..

Best wishesMike..

Comment #1

For most DSLRs it will be the active focus point. On the D80 I have 11 of them to choose from..

Your question by infrerence also wants to know what should you choose to spot meter off. There appear to be two broad ways to use spot metering.

The ways pro's do it:.

Spot meter off something mid grey in the frame - grass, blue sky or the like (I have a link to a list somewhere). Then set aperture and shutter manually based on those settings (or lock the aperture).

Sometimes those using this system will meter off the darkest , the lightest and mid tones of a scene than determine which manual settings to use..

A more casual approach.

I use Matrix metering but have my FUNC button on my D80 set to take me straight to SPOT so that if I have concerns that a highlight will be blown I can check my aperture and shutter speed. Anything more than 3 stops above my matrix reading (I would say 2.5 or less above for the Olympus you are considering) will mean I need some negative exposure compensation or I risk blowing the highlight..

Chris Elliott.

*Nikon* D Eighty + Fifty - Other equipment in Profile.

Http://PlacidoD.Zenfolio.com/..

Comment #2

Chris Elliott wrote:.

For most DSLRs it will be the active focus point. On the D80 I have11 of them to choose from..

So within the camera you define which one to use..

Your question by infrerence also wants to know what should you chooseto spot meter off. There appear to be two broad ways to use spotmetering.

The ways pro's do it:Spot meter off something mid grey in the frame - grass, blue sky orthe like (I have a link to a list somewhere). Then set aperture andshutter manually based on those settings (or lock the aperture)Sometimes those using this system will meter off the darkest , thelightest and mid tones of a scene than determine which manualsettings to use..

How can you meter off more tha one thing? Maybe I dont understand metering. Metering is how a camera interprets colour via exposure. If I spot meter off a black rock on a red mountain, the camera assumes that the frame is too dark and brightens it. Or maybe I am getting confused with exposure, even though I know what exposure is or at least thought so....

A more casual approachI use Matrix metering but have my FUNC button on my D80 set to takeme straight to SPOT so that if I have concerns that a highlight willbe blown I can check my aperture and shutter speed. Anything morethan 3 stops above my matrix reading (I would say 2.5 or less abovefor the Olympus you are considering) will mean I need some negativeexposure compensation or I risk blowing the highlight..

Chris Elliott.

*Nikon* D Eighty + Fifty - Other equipment in Profile.

Http://PlacidoD.Zenfolio.com/.

Daniel..

Comment #3

Profborg wrote:.

Sometimes those using this system will meter off the darkest , thelightest and mid tones of a scene than determine which manualsettings to use..

How can you meter off more tha one thing? Maybe I dont understandmetering..

You do them one at a time, not simultaneously .

... take spot readings off different parts of a scene and determine the exposure on that basis:.

Http://www.normankoren.com/zonesystem.htmlhttp://en.wikipedia.org/wiki/Zone_system.

A simple way to do it is find the darkest part of the scene that you want to show significant detail (i.e. not a deep black shadow) and measure it's exposure; then find the brightest part of the scene that you want to have significant detail (i.e. not a bleached-out highlight), and take a reading from that; and then average the two..

The clever thing about this - despite it's simplicity - is that YOU decide which parts of the scene are the most important so that the exposure will be optimised for those, and things that might confuse a light meter - like a bright sky in the background, or lots of black suits which make a scene look dark - are ignored..

In practice matrix metering does a good job most of the time, especially if you shoot raw which gives you plenty of scope to rescue under or overexposed pictures when the matrix metering is fooled. It's fun (and instructive) using careful manual metering when you aren't in a hurry..

Best wishesMike..

Comment #4

Now I am even more confused! Is metering the camera measuring colour or light?Daniel..

Comment #5

Light MeteringTechnique - Technique.

LIGHT METERINGTopics:The basics of metering systemsAll around metering modesExamples for:Spot or Partial MeteringCenter-weighted MeteringMatrix or Multi-zone Metering.

Http://www.photozone.de/Technique.

Bill,Jr'I kind of like the Earth, it's where I keep all my Stuff.'Website; http://www.pbase.com/wboth125 Lake Wylie, SC..

Comment #6

Now I am even more confused! Is metering the camera measuring colouror light?.

It is measuring the intensity (brightness) of the light reflected off the subject. Colour has nothing to do with it: a mid-red and mid-blue, if they are of the same brightess, will give the same meter reading on the camera..

Best wishesMike..

Comment #7

I think you can spot meter with matrix metering and center weighted by zooming in on the spot you want to meter so that the spot covers the entire frame. I believe you'd have to then lock exposure and recompose or just meter on the spot, set the exposure manually and then recompose..

Someone correct me if I am wrong..

Mary..

Comment #8

Profborg wrote:.

Now I am even more confused! Is metering the camera measuring colouror light?Daniel.

Metering is about light and dark (black and white in other words). In between light and dark are middle gray tones that the meter is on average trying to achieve with the exposure it calculates. When photographers meter off of blue or green they are able to determine thru experience which blues and greens represent a mid tone value. (They do a black and white conversion of the scene in their mind.)..

Comment #9

Profborg wrote:.

Chris Elliott wrote:.

For most DSLRs it will be the active focus point. On the D80 I have11 of them to choose from..

So within the camera you define which one to use..

Exactly. A couple of years ago DSLRs only had one AF point. Now even the most basic of cams has at least three. I can frame a shot on a tripod and spot meter off any of the 11..

..How can you meter off more tha one thing? Maybe I dont understandmetering. Metering is how a camera interprets colour via exposure.If I spot meter off a black rock on a red mountain, the cameraassumes that the frame is too dark and brightens it. Or maybe I amgetting confused with exposure, even though I know what exposure isor at least thought so....

Mike has already given you an answer. You take meter readings and do the maths in your head. (Most good pros can manage without a meter. They can predict settings within a stop or so just looking at the scene with their eye. So they are really just fine tuning).

One final rather confusing point. Most matrix type metering is colour blind and determines metering based solely upon tones. Nikon matrix metering meters off either a 420 or a 1005 RGB sensor and thus colour (chrominance) and not just luminance helps determine the exposure. The metering is also linked to the AF system to factor in distance to give a very sophisticated matrix metering read out and computer model which the cam compares against it's bank of 30,000 odd tone map images. But neither of these features is typical for all DSLRs.

Chris Elliott.

*Nikon* D Eighty + Fifty - Other equipment in Profile.

Http://PlacidoD.Zenfolio.com/..

Comment #10

MaryGierth wrote:.

Profborg wrote:.

Now I am even more confused! Is metering the camera measuring colouror light?Daniel.

Metering is about light and dark (black and white in other words).In between light and dark are middle gray tones that the meter is onaverage trying to achieve with the exposure it calculates. Whenphotographers meter off of blue or green they are able to determinethru experience which blues and greens represent a mid tone value.(They do a black and white conversion of the scene in their mind.).

I'm sorry I am taking so long to understand this, so I thank you all for your patience. Mary,should I be thinking about your explanation in terms of light reflected off an object? Or maybe on a histogram, where right is white, left is black and middle is gray. There, midtones are gray, but I dont really understand what midtones are! If highlights are white and shadows are black then midtones are what colour? This must be related to 18% gray, which has always eluded me. Help!.

Daniel..

Comment #11

Profborg wrote:.

I'm sorry I am taking so long to understand this, so I thank you allfor your patience. Mary,should I be thinking about your explanationin terms of light reflected off an object? Or maybe on a histogram,where right is white, left is black and middle is gray. There,midtones are gray, but I dont really understand what midtones are! Ifhighlights are white and shadows are black then midtones are whatcolour? This must be related to 18% gray, which has always eluded me.Help!.

Try reading these:.

Http://www.fredmiranda.com/A16/.

Http://www.cambridgeincolour.com/tutorials/histograms1.htmhttp://www.cambridgeincolour.com/tutorials/histograms2.htm.

Http://halley.cc/photo/histogram.html.

Http://www.luminous-landscape.com/...ng-series/understanding-histograms.shtml.

Chris Elliott.

*Nikon* D Eighty + Fifty - Other equipment in Profile.

Http://PlacidoD.Zenfolio.com/..

Comment #12

Profborg wrote:.

MaryGierth wrote:.

Metering is about light and dark (black and white in other words).In between light and dark are middle gray tones that the meter is onaverage trying to achieve with the exposure it calculates. Whenphotographers meter off of blue or green they are able to determinethru experience which blues and greens represent a mid tone value.(They do a black and white conversion of the scene in their mind.).

I'm sorry I am taking so long to understand this, so I thank you allfor your patience. Mary,should I be thinking about your explanationin terms of light reflected off an object? Or maybe on a histogram,where right is white, left is black and middle is gray..

My explanation was referring to the use of the in camera reflective light meter. However you certainly could and should think about this in terms of the histogram.. The light meter measures light and the histogram is a graphical representation of that measurement based on the picture you've taken..

There,midtones are gray, but I dont really understand what midtones are!.

Tones refer to the brightness of the scene or how much light is being reflected..

Ifhighlights are white and shadows are black then midtones are whatcolour? This must be related to 18% gray, which has always eluded me..

Midtones are not a color, but I do think about tones on a scale ranging from black (almost no reflectance) to white (high reflectance, 36%) with many shades of gray in between. In the middle of this scale would be midtones - parts of the scene with an average reflectance considered to be around 18%. On this scale these midtone brightness values would appear as a shade of gray but again, it would not be correct to think of this gray as a color, rather it is a brightness value..

I don't think this is an easy subject. Chris has provided you with very helpful links for more in depth discussion of this subject...

Comment #13

In your Olympus DSLR it meters from the centre cross focus point.Here's a couple of articles for you to read..

Http://backroom.renderosity.com/...ials/thomas_haynes_%20spot_metering%20.pdfhttp://www.normankoren.com/zonesystem.html..

Comment #14

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