Spot Metering with a Pentax K100D

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Spot Metering with a Pentax K100D

Post by sjj1805 »

Spot Metering

Other DSLR Cameras will also have Spot metering and other metering modes but you will need to refer to your camera manual for details of how to select the chosen metering mode.

Many DSLR users are aware of the various picture taking modes that are available such as:
Fully Automatic (Handy to be able to let a friend/relative take a picture of YOU with your camera whilst your out on a trip/holiday)
Program Mode - Next step up from fully automatic where the camera makes an educated guess at what kind of picture you are taking and adjusts itself accordingly.
Aperture Priority Mode - where You control the depth of field so that the "thing" you are taking a picture of (Person, plant, building etc.) remains in sharp focus whilst other things are blurred.
Shutter Priority Mode - where you control how fast the picture is taken so that a moving item is either frozen dead in its tracks - or you may deliberately induce some slight blurring to provide the effect of motion.

What many DSLR users may not be so aware of are the metering modes and also the focusing points. Some users may be aware of focusing points but be unaware of the different metering modes and (wrongly) assume they are combined with each other.

My two DSLR Cameras are both Pentax models and so I can only describe the settings in relation to these. Having peered into my sons Nikon D40 I could see that his controls are different but after demonstrating to my son how to use these modes on my Pentax he was later able work out how to use these modes with his Nikon.

Firstly let us peer inside the viewfinder:

Now let us examine those items


Automatic Focus
When you have set the lens to Auto Focus mode - with the switch at the front of the camera it will focus in accordance with your chosen focusing scheme.

You have 3 focusing schemes to choose from which you select from the Menu as follows:

These are:

Perhaps the most useful of these modes is

You then choose which part of the scene to focus upon by moving the small red dot to one of the eleven points by pressing the 4 way controller on the back of the camera.

If you are using Auto Focus the Camera will latch onto whatever object it finds in the area selected and focus on it. If however you are using manual mode - the focusing system will still help you to get that nice crisp sharp picture - when an item is "in focus" in the selected area :
1. You hear a beep.
2. The red "dot" for the selected area briefly blinks
3. A yellow indicator is illuminated in the viewfinder:

OK so now we know how to "Focus" - but what about "Spot Metering?"

Let us look again inside the viewfinder but this time we will see how the cameras metering system is arranged.

There are 3 possible metering modes (With a Pentax - other makes may have more/less)

1. Spot metering - the camera measures the light in the centre circle which I have highlighted in red.
2. Centre weighted metering.
Whilst this is a simplification it serves to describe this mode reasonably well. The camera measures the average amount of light in the centre square area - highlighted above in red and blue.
3. Multi segment metering - the entire scene is measured and the exposure is determined accordingly. This is the factory default setting.

To select which of the 3 available modes to be used you enter the Camera Menu:

and then select from the 3 available choices:

The factory default setting is Multi Segment Metering.
If a scene has a lot of bright areas and also a lot of dark areas then it may be better to switch to spot metering so that you can isolate the area that you wish to focus upon. What you then do is
1. Point your camera directly at the item you are interested in and zoom in. Half depress the shutter button so that the camera takes an exposure reading.
2. Press the AE-L button to lock the exposure setting.

3. Now adjust your focus and frame your picture.
When you take the picture the AE-L (Auto Exposure Lock) will clear itself ready for your next shot - so if you want to take a second picture you will need to repeat the process again from point 1 above.

(If necessary you can brighten or darken the picture by using the AV compensation button.)

Another handy use of the view finder frame is to use it to get the horizon level and also helps with the "Rule of thirds". Many expert photographers will advise against having an horizon which is straight across the middle of a picture. With this in mind I align the horizon either with the top or the bottom of the centre square in the viewfinder.