Help Using Aperature : LUSENET : Konica 35mm SLRs : One Thread

I am just beginning photography this year and got am using a FS-1. My mom had it around the house, and I thought I would use it for taking pictures of my brother Wakeboarding this year. How can I determine what aperature to use? Do I need to get a light meter?


-- Anonymous, March 13, 1998


Selecting apertures

Hi Pete,

The FS-1 camera has shutter-speed priority exposure automation, which means you manually select which shutter-speed is appropriate for the amount of action in the scene - and the camera's light meter will select and set the appropriate aperture value automatically.

First, set the film speed ISO number in the little window which is inside the shutter-speed dial. Make shure the aperture ring (f/stop scale is set to the "AE" or "EE" position. After you've done this, whenever you press the shutter release button the camera's light meter will switch on and select the appropriate f/stop automatically. The f/stop the camera chooses will be indicated by a lighted, red LED on the aperture scale inside the viewfinder. If a red LED doesn't light up when you press the shutter button, your camera may need repair.

I must confess that I don't know what wakeboarding is, but I'm assuming that it is like waterskiing on a surfboard. If this is done outdoors in sunlight, you won't need a hand-held light meter. If your camera's built-in light meter is functioning correctly, it will work fine in selecting the appropriate apertures.

If your camera's shutter is working but the light meter seems to be inoperative, you can still take good pictures outdoors by observing the "Sunny 16" Rule. The Sunny 16 rule simply states that on a bright, sunshiny day you set the aperture scale to f/16 - and set the shutter speed to the nearest reciprocal of the film speed. For example if you are using ISO 200 film, set the shutter speed to 1/250th sec. With ISO 400 film, set the shutter speed to 1/500th sec.

When using the Sunny 16 Rule, remember to increase your exposure by 1 f/stop each time the amount of light is cut in half. For example, if the sun passes behind a cloud, change the f/stop from f/16 to f/11. Near sundown or in dark shade, use f/8.

Keep in mind that single-use, disposable cameras make acceptable exposures outdoors in sunlight with no light meter or exposure controls at all. The exposure latitude of color negative film is sufficient to render a negative of printable density within a range of about 5 f/stops, so your exposure calculations can be over or under by 2 f/stops without noticeable problems.

All in-camera light meters are calibrated to assume a reflectance of 18%, because the light reflectance value of all objects found in nature averages out to 18%. This works amazingly well in most situations, except when the majority of the picture scene is very bright or very dark. For example, if you are photographing snow skiers in bright sunlight or a black cat sitting on the hood of a black car - a reflected light meter will be "fooled." The meter assumes that 18% of the light is being reflected from the scene, but in reality the snow field may be reflecting 90% of the light - and the black cat is reflecting only 10% of the light.

When the scene you are shooting is reflecting substantially more or less light than "average," the situation calls for an incident light meter. These have a translucent, hemispherical dome which measures the amount of light actually falling on the subject - instead of the light being reflected from the subject as is the case with built-in camera meters.

However, except when a professional level of precision is required, one can get by nicely without bearing the expense of an incident light meter. Camera stores sell a product called an 18% grey card, which is simply an 8 X 11 inch piece of cardboard which is coated with a grey surface which reflects precisely 18% of the light falling on it. When you take a close-up meter reading of the 18% grey card with your camera's built-in light meter, you are essentially duplicating the effects of an incident light meter. This is the only way to get an absolutely accurate meter reading with the built-in light meter of any camera. But as mentioned earlier, with color negative film absolute accuracy isn't necessary.

Instead of enduring the inconvenience of carrying an 18% grey card around with you, you can much more easily take a close-up reading from the palm of your hand. Caucasian skin reflects about 35% of the light striking it. This is about twice as much reflectance as an 18% grey card, which equates to 1 f/stop. So if you take a meter reading from the palm of your hand and the light meter indicates f/11, you need to give the scene you are actually photographing 1 f/stop more exposure and set the lens aperture to f/8. If you don't compensate for the higher reflectance of the palm of your hand, the darkest areas of your scene may be underexposed outside the film's range of exposure lattitude and will look sandy and grainy in the final print. If there are no dark areas in the scene, then the average reflectance of the scene is above 18% and you need not worry about underexposure.

The film's ISO rating is calculated on the assumption of 18% average reflectance also. But if your camera's light meter is working properly, you needn't worry about any of this stuff - unless your main subject is a field of snow or a mound of coal.

One of the main benefits of an SLR camera with built-in light meter is than it automatically compensates for the light reduction when using filters. When shooting outdoors in bright sunlight, using a polarizing filter will reduce or eliminate the glare of reflected light. This will increase color saturation in most cases, making the colors more vivid - like a picture postcard. The polarizing filter can also make blue skies a much deeps shade of blue and white clouds more distinct. It can also make blue water a deeper shade of blue. For wakeboarding pictures, a polarizing filter might be ideal.

Lens flare has the opposite effect of the polarizing screen. Lens flare causes the colors to look washed out, and may be visible as ghost images in the scene. Lens flare is caused by light which is outside the angle of view of the lens entering the lens and bouncing around on the interior lens elements.

Multicoating on the lens elements helps reduce lens flare, but not nearly as much as using a proper lens shade. On some lenses, the front element is recessed deeply enough that adequate shading is provided by the front of the lens barrel. Of course, this goes out the window if you attach a filter to the front of the lens - so you should never use a filter unless you are using a lens shade also. I suggest that you always use a lens shade, and never use a filter unless you need it to accomplish something specific. Some people suggest that you keep a UV filter or a skylight filter on the lens all the time - to provide "protection" for the lens. This is all well and good, if you are willing to tolerate more lens flare and reduced picture quality in order to "protect" the lens. I suggest that if the lens needs protection, use a lens cap. And use shaded filters only when they're needed to do something specific.

Good luck,


-- Anonymous, March 14, 1998

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