Digital Diversity

Learning how to expose photos in anything but automating modes can start to get confusing. When I got my first digital camera (Ixus 75) I didn’t know much about cameras in general, let alone metering modes and correct exposure.

When I upgraded to a superzoom (panasonic fz28) I switched to aperture priority mode. My main reason for this was that I could choose the aperture and change the ISO and exposure compensation to alter my shutter speed. This served me well and a lot of people use this method. I pretty much stayed clear of manual mode as it just sounded to fiddly to be of any use.

Since I got my DSLR (Canon 500D) I have started to think about this more. The only problem I would get with aperture priority was inconsistent exposure. What I mean by this is that say I was photographing my dog. As he runs passed different colour backgrounds this will in turn effect the exposure settings and lead to an over / underexposed shot. This would in turn have effected the shutter speed and can cause unwanted blur. I would also have to use exposure compensation and sometimes I may forget to change it back which would ruin the next shot. Another problem I had was that the exposure lock button never seems to lock the exposure for very long and getting the exposure back to what is was can be a pain.

To escape these problems I needed to step into the realm of manual mode.

This was a little daunting for me at first. I thought it would take me a lot more time to get correct exposure and that I would be spending a lot of time changing settings… Well I was wrong. It has in-fact made photography easier for me and in many cases faster. Why? well I will explain.

If you are in a situation with consistent light then your exposure rarely needs to change once it is set. For example I got to the park on a sunny / overcast day. The light is fairly consistent on the surrounding subject matter. Say I then want to take pictures of my dog. All I need to do is spend a few seconds getting the exposure correct for him and once its set I don’t have to worry about it again. Every shot will come out exposed the same.

As long as the lighting stays the same I don’t need to touch any settings. This allows me to find the perfect aperture, shutter speed and ISO. In the shot above you can see Oscar running and general looking pretty pleased with him self. If I had my camera set to Aperture priority mode and evaluative metering and then Oscar runs past a dark object I would likely get a very over exposed shot with a shutter speed that was to slow and would come out a blurred mess. However with your camera in manual your shutter, aperture and ISO is consistent and your subject will remain perfectly exposed no matter what he runs passed.

Manual is also a godsend when inside. In a room the lighting tends to also be fairly consistent. If you don’t want to use a flash then getting the right shutter speed is all the more important. Inside I used my Canon 50mm 1.8 lens. Set the camera to manual. With the aperture at between 1.8-2.5 and an ISO of 800-1600 I tend to be able to get a shutter of between 1/50 and 1/100 with no flash. Once I have the exposure set I can snap away and not worry about it to much. I may need the odd tweak here and there if there is a bright window somewhere but for the most part I get consistent results. If I do get home and the shots are slightly underexposed I can adjust the first shot and then simply repeat these exact exposure adjustments to all of them as all the shots are consistent in exposure. It just makes things more accurate.

How do I set up the exposure in the first place?

This is the key. When shooting in AV mode I tended to use evaluative mode and then spot for tricky situations. In manual mode you can use either of these as they are used to get you a starting point. To use this you need to understand exactly how your camera meters something.

Your camera has no idea what you are actually photographing. For example in the picture above the camera doesn’t know that there is a white and brown dog sitting there. What your camera does depends on your metering mode. If you use evaluative then it reads the whole scene assuming there is a full range of tones. It will use that to determine what part of the scene should be a mid-tone grey (12-18% grey) and set the aperture, shutter and ISO to expose that as such. The problem is your camera doesn’t know what in the scene actually is a mid-tone grey. Its all just best guess. When using spot metering it assumes what ever you point the spot meter at is a mid-tone grey and alters the exposure settings to make it so. What this means is that in spot metering, if you point the camera at a black dog it will come out a grey colour and give you an over exposed shot. When shooting a white dog it will underexpose the shot turning the white to a darker grayish colour.

To set your exposure manually using spot metering you need to pick out a mid-tone from your scene, point your camera in spot metering at it and look at your light meter.

When the bar is in the middle (where the 0 is) that means what you have targeted is now exposed as a mid-tone grey. Common things to use as a mid-tone are grass and skin. You can often use your hand to set this.

If you use evaluative then compose a shot with varied tones from dark to light and adjust the shutter so that the meter is centred.

After that you take a test shot and then tweak the settings till exposure is correct.

So my process for setting exposure when at the park would be the following.

1. Set camera to manual mode

2. Choose the metering mode (spot, evaluative/matrix etc etc)

3. Set my ISO. If shooting fast moving subjects I will set it to 800 or 1600 depending on light. For static subjects I will set it to 100-400, again depending on light.

4. Set my aperture. For landscape I would set it between 8 – 11. For portraits / action I would have it fairly wide open.

5. With the camera set up all I need to do is set the exposure. If using spot I would point my camera at the grass and alter the shutter speed till it is metered correctly. If using Evaluative I would compose a shot with varied tones and set the shutter.

6. The last thing to do is take a test shot. Once I have taken this shot I look at the histogram. This should tell me the balance of exposure over the scene and if there are any blown highlights or not. If its slightly over exposed I will increase the shutter. If its slightly underexposed I will reduce the shutter. Once its set I can now fire away and not worry about exposure unless the lighting changes.

I tend to even use manual in situations where light may vary now and then. For example moving from light to shade. The key is simply learning how your preferred metering mode works and understanding your histogram. It only takes a second to re-adjust your settings and your ready to go again.

If I was in a situation where I really didn’t have time to set the exposure or lighting conditions change a lot and often I will go back to aperture priority mode using either evaluative or centre weighted metering. This will give me the most accurate settings when in a hurry and should keep the shadows and highlights balanced in most situations. The problem is each shot will vary slightly in exposure and if I want them to look similar then they will need extra care in post processing.

To summarize: using manual mode gives me accuracy and consistency. It takes a little longer to set up in the first place but is faster and more accurate once you are shooting. It also gives you precise control over both the shutter and the aperture so that the shutter wont change mid shoot. I really was worried manual was going to be a pain but after a while it becomes second nature.

Tags: aperture priority, blur, centre weighted, evaluative, exposure, highlights, lighting, manual, metering, panasonic fz28, panasonic lumix fz28, partial, photography, portrait, shadows, spot, thoughts

This entry was posted on Monday, January 11th, 2010 at 12:31 and is filed under photography. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.