Question on Metering and Autofocus points in natural light outdoors

[sun_p]

<p>Hello Gurus!</p>

<p> Hope you all had a great weekend!</p>

<p>I was doing my regular reading of photo.net forums to learn new things and I had a few doubts.</p>

<p>1. How do you all advice to meter outdoors in natural light when you do not have light/flash meter. I have been doing a lot of indoor flash photography so there I did not face much problem since there is only one or two light sources which are generally controlled by us. So I use my nikon D40 , generally set my shutter speed to to max sync, select my aperture etc etc and play around with them. In natural light however, someplaces are too bright, some places are dark, some have shadows, How do you advice to get the correct reading with just the dslr meter. Is it solely by histogram or do you advice to take the reading off the subject and then recompose and then shoot? Do I need to select any special metering mode like matrix etc.</p>

<p>2. What exactly is the advantage of autofocus points. I only have 3 on my D40. I was under the impression that if I select spot metering and then the spot highlighted will determine the metering parameters? .But does more number of autofocus points mean that many more points available to the camera to make a better decision especially if we have evaluative metering selected? Or are metering and Autofocusing completely different things,<br>

I shoot manual indoors with flash. but outdoors, I just select the P mode because, I am not sure how do I meter and what do I meter on. (I am talking natural light without any flash outdoors).<br>

3. Even if I have a light/flash meter. how do I use it to get the correct reading. I heard you need to expose the background coorrectly and then the subject etc.</p>

<p>Thanks in advance!!<br>

Regards,<br>

Sunil</p>

[chrisnielsen]

<p>Hi Sunil</p>

<p>I'm far from a "guru" but I will offer what I can.<br>

1) You have a meter. It's built in. If you use P, A or S modes it uses the meter to decide on the shutter/aperture to use. In fact, Nikon matrix metering is famous. Why not put it on matrix mode, select P,S or A mode and let the camera do it's thing? If you think the shot is too light or dark use exposure compensation to adjust it. If you have situation that is too contrasty then no matter how good the metering is, you won't capture it as it is, this is when you need to look at fill flash or reflectors or something</p>

<p>2) Autofocus and metering are completely different. Autofocus points are what the camera uses to decide where to focus the lens. Metering is the evaluation of the light to decide on shutter speed and aperture. The two are connected together in spot metering mode though, by metering off whatever focus point you've selected. This is just for your convenience though, and doesn't mean they are connected otherwise. If you use matrix metering it doesn't use the focus point though, so they are just used for focussing. And finally, when you're talking about P mode versus the S, A or M - it doesn't change the metering just how the camera uses the meter to decide shutter speed / aperture</p>

<p>3) Easiest way - put it in P mode, pop up the flash and fire. If you have flash exposure compensation use that to adjust how much flash it puts out. Or use regular exposure compensation to adjust the ambient. You might need to use slow sync mode depending on how much ambient you have.</p>

[Wouter Willemse]

<p>Another non-guru but to add some points:<br>

1. In camera metering is usually fine, but sometimes it does get fooled (i.e. highly reflective surfaces). Also, the matrix meter on some cameras can be a bit more difficult to predict (the D80 gets a lot of comments on that). In more complex situation, I often go to spot metering to take a metering exactly where I want it. For me, the easiest way to handle high contrast situations.<br>

2. Indeed for spot metering, there is a link between the active AF spot and where the metering will take place. "Evaluative metering" (which is Canon's term, Nikon calls it Matrix metering) is not tied to any AF spot since it will use the entire frame.<br>

3. I never used a light meter, I'm too newbie for that ;-) My cameras always have done a decent enough job of metering for my uses. For the camera light meter it's easy: P, S and A mode will give you a "proper" exposure. If you use flash, you may want to go to M (flash does not work well with S mode, and for the other 2 it will give a 1/60 shuttertime by default). The flash will compensate between your settings and the metered exposure.</p>

<p>In essence, there is no difference between indoors and outdoors. The amount of "ambient" light is different, but otherwise it all stays the same.</p>

[richard_driscoll]

<p>"flash does not work well with S mode, and for the other 2 it will give a 1/60 shuttertime by default"</p>

<p>I've used it in S mode with success. In A and P mode the shutter speed will be limited to 1/60 at the slowest in dim light unless you choose slow sync. In bright light on a D40 it will go right up to 1/500.</p>

<p>I'd try what Chris says. Put the camera in P mode and pop up the flash. To give the flash the best chance in bright daylight use the command dial to choose a high shutter speed.</p>

<p>If the background is too light or dark use exposure compensation and try again. If the foreground is too light or dark use flash compensation and try again.</p>

[pete_harlan1]

<blockquote>

<p>Do I need to select any special metering mode like matrix etc.</p>

 

</blockquote>

<p>I'm not sure, but I think I am seeing 3 different questions here.</p>

<p>1) Metering for outdoor exposures<br>

2) Using flash outdoors. Fill or primary.<br>

3) Use of multiple focus points.</p>

<p>Metering modes at best are the camera's attempt to "guess" what is the best exposure.<br>

Just like us photographers, it is interpretive. Meters are often fooled in many situations.<br>

Books have been written on this subject, so I will only give one example.</p>

<p>Outdoors..Bright sunlight..no shade..no flash.<br>

The photographer needs to determine what he/she wants exposed properly.<br>

Barring HDR imaging, you need to make a decision since you are not going to get everything is perfect exposure with one shot. (i.e) Pure white to pure black and everything in between ain't happening.<br>

If the subject is a person, you will want to meter off their skin tone. get close using Matrix to fill the frame, memorize the shutter/aperture combo, set to manual and shoot away. Or stand back and spot meter the subjects skin tone.<br>

The background will no doubt be blown out in this scenario, this is life.</p>

<p>Is there a way around it? Sure there is. Balanced fill.<br>

Perhaps another poster will tell you about fill flash..Or a good book would make for some nice light reading.<br>

Some camera's do a far better job metering than others as they rely on a database filled with many possible exposure combinations which is then compared to the scene you are metering. This still does not make them infallible.</p>

<p>When all else fail, you chimp.</p>

 

[dan_south]

<p>Hi Sunil,<br>

<br />You have asked some very good questions. I'm only going to answer your first one at this time. Perhaps I can come back later to help you with the other questions.</p>

<p>INCIDENT LIGHT METERS</p>

<p>You CAN use a light meter outdoors. If you are close to your subject, or if the same light that is falling on the subject is shining where you are standing, you can use an incident meter. Just don't use it on FLASH mode unless you also intend to add light from one or more flash units. The incident meter measure the amount of light that is illuminating your subject.</p>

<p>Advantage: The incident meter will not be fooled by the amount or reflectiveness of a surface. It will give the same reading regardless of whether you're metering white snow and a black road surface.<br>

Disadvantages: You can't separately measure the light and dark parts of the scene. You can't measure the light falling on distant objects.</p>

<p>REFLECTIVE LIGHT METERS</p>

<p>You can also use a REFLECTIVE light meter. A hand-held unit would probably be a spot meter. You can use this meter to measure the light that is REFLECTED from or being PROJECTED from various parts of your scene.<br>

<br />Advantage: You can take reading from distant objects. You can measure the light and dark areas of a scene separately.<br>

Disadvantage: The meter will be fooled by objects of high or low reflectivlty. Snow will give a much different reading than a black road surface in the same light. Note: You can counteract this problem by taking a meter reading from a specially-colored "gray" card that matches the reflectivity that your light meter expects.</p>

<p>IN-CAMERA METERS</p>

<p>The meter in your Nikon D40 (as in most modern cameras) is a reflective light meter, and it has the same advantages and disadvantages at the reflective light meter discussed above. The good news is that the meter will let you measure different parts of the scene. If the sky is much brighter than objects on the ground, you can determine the difference in the amount of light that each is reflecting (or projecting) and use this to determine the exposure values that you want to use.</p>

<p>If there isn't a lot of difference between the bright areas and the dark areas, your camera should be able to capture the scene faithfully. However, if there is a lot of difference (3 stops or greater), the camera might lose detail in the highlights, the shadows, or both. Here are some strategies for such high-contrast shots.</p>

<p>(1) Meter the part of the photo that's most important (e.g. a model's face) and let the rest of the photo be over- or underexposed.<br>

(2) Set your camera to shoot at about two stops slower than the brightest part of the scene and recover the shadow areas in post processing to the degree that you can. E.g. if the brightest part of the scene reads 1/500th @ f/8, shoot at 1/125th @ f/8.<br>

(3) Use fill flash, reflectors, or other light sources to brighten the darker parts of the scene and expose for the highlights.<br>

(4) Shoot multiple shots of the scene at multiple exposure values (this is called bracketing) and select one later or combine them on your computer (HDR processing).<br>

(5) Use a special filter to darken the brighter parts of the scene and expose for the shadows.</p>

<p>DIGITAL METERING</p>

<p>Digital cameras give you some extra tools to help you avoid metering errors. The histogram is a graphical representation of the amout of light captured along the continuum of bright and dim light. If the histogram curve touches the left or right edge of the display, you have (respectively) under- or over-exposed your image. The problem is that sometimes a peak of overexposure happens beyond the limits of your graph, and you don't see it in time to correct it.</p>

<p>Digital cameras also have an LCD screen where you can review how your photos look. However, it is dangerous to use the LCD screen to evaluate exposure. In bight sunlight, the LCD screen looks dim. The appearance of a dim image could convince you (erroneously) to adjust your exposure until the photo is over-exposed. The opposite problem can happen when you're operating the camera in dim light. The LCD screen will look very bright, and you'll be tempted to under-expose your photo.</p>

<p>SUMMARY</p>

<p>Exposure is a big topic. You'll spend years learning the fine points. If you manage to figure it all out, write a book someday, because all of the rest of us are still learning and we could use your tips! The best thing to do is experiment and see what happens. In time, you'll learn a lot about your camera and how it interacts with light.</p>

 

[dan_south]

<p>P.S. You camera's spot meter measures the light only at the active autofocus point. The matrix meter evaluates the entire scene, but it gives priority to the active autofocus point. (It assumes that this point is pointed at the most important part of your image.) Either can cause unexpected results. You need to try both types of metering under a variety of conditions in order to learn when they work well and when they give inaccurate results.</p>

[mark liddell]

<p>For you flash questions everything iy need is here http://www.planetneil.com/tangents/flash-photography-techniques/</p>

<p>Specifically on metering (section 7): http://www.planetneil.com/tangents/flash-photography-techniques/7-metering-techniques/</p>

[sun_p]

<p>Thank you all for such descriptive answers! Phew, this is super information and is likely to keep me busy for the next couple of days.</p>

<p>I was for the last couple of months doing a lot of indoor flash portraits using my Dlites and D40. the Dlites were generally controlled manually and I was shooting manually. I did learn quite a bit about shutter speed, aperture, ISO, etc, but thats pretty much it. Now, when I try to step outdoors, I think I am back to square one. :) . I hardly bothered about concepts like matrix, spot metering, flash compensation, exposure compensation etc.<br>

I have now printed this page and need to go through each of the points mentioned. Thankfully the next couple of weekends are long ones for me, so I intend to try these out on the ground. I will get back with any questions!</p>

<p>I have to say this again, just the fact that all of of you take the time out to help beginners like us especially who have not been to any photography school and explain things in such a simplified manner just says a lot about the kind of people you are!! </p>

<p>Have a great week!!</p>

<p>Thanks,<br>

Sunil</p>