Why are all my photos overexposed?

[fire.fly]

<p>I don't understand what went wrong? I lowered my shutter speed to lose the graininess with my Nikon D40. Now, the shot is useless. Help!!</p>

[wade_roth]

<p>I shot a few dozen frames of my niece right after she was born in the hospital and couldn't figure out why my exposure would be good for one and then bad for several. I turns out that I had turned exposure compensation bracketing on. Did you do something similar?<br>

--Wade</p>

[Matt Laur]

<p>If you lower your shutter speed (which means that it's open for <em>longer</em>) then more light gets in. To make up for that, you have to either close the lens aperture (raising it to a higher f-stop number), or lower the ISO setting on your camera to make it less sensitive to light in the first place.<br /><br />Shutter speed, lens aperture, and ISO all combine to make the right exposure. If you change one, you have to consider changing one or both of the others. <br /><br />I take it you're using the camera in manual exposure mode?</p>

[vrankin]

<p>If you shoot in Auto or Program Modes without setting exposure compensation factors, you should be okay.</p>

[nathangardner]

<p>if you're shooting in manual mode, you have to use the light meter to match up the shutter and f stop to get a correctly exposed image, so changing one without the other will cause a bad exposure (if you started with a good one). If you shoot in Av or Tv modes, you may have accidentally bumped the exposure adjustment so that the camera overexposed everything. Let us know all the details and we can pinpoint the problem. Tell us the shooting mode you shot in, shutter, aperture, ISO, and the conditions (indoor, outdoor, lighting). And the image to accompany the data would be even more help.</p>

[ron_steedman]

<p>+1 to Matt response.</p>

<blockquote>

<p>I lowered my shutter speed to lose the graininess with my Nikon D40.</p>

</blockquote>

<p>Besides ISO, aperture, and shutter speed consider changing the lighting.<br /><br />To reduce noise while maintaining the same exposure, reduce your ISO at the same time you reduce your shutter speed. Eg, 1/120s @ ISO800 => 1/60s @ ISO400.</p>

[steven_f1]

<p>Graininess of an image is mainly caused by the iso setting. High ISO setting have more noise or "grianiness". Low ISO settings have less. changing the shutter speed alone will not effect ISO noise. So if you are in manual mode and want to reduce high ISO caused noise you should</p>

<ol>

<li>Reduce the ISO setting</li>

<li>Lower the shutter speed so more light reaches the sensor.</li>

<li>If reducing shutter speed is not enough then open up the aperture (reduce the F number) to allow more light to pass through the lens.</li>

</ol>

[anthony_montecillo]

<p>if you mean by "lowering your shutter speed" as adjusting from 1/125 sec to 1/60 sec then you will definitely overexpose your pictures because the shutter is open for a relatively longer time i.e. 1/125 sec is actually 0.008 sec while 1/60 sec is actually 0.0167 sec<br>

i know the d40 auto-iso feature kicks-in during dark situations but does it also lower the iso in very bright situations?</p>

[mark_drutz]

<p>While you are learning to use the camera you should keep it simple when shooting important pictures. So like Howard said, shoot in program or auto mode. Exposure is subject that fills books. That's why I suggest that all newbies get a good basic photography book. Any good bookstore should have a few to choose from. In the meantime you got good advice above, but I still recommend you get the book.</p>

[paul_harris16]

<p>Mercedes,</p>

<p>Fundamentally, there are two ways to measure light: reflected and ambient. When measuring reflected light you measure light that has bounced off the subject. When measuring ambient light you measure light that is falling on the subject. Obviously, if, under the same conditions, you measure light bouncing off a white wedding gown and a black tux, you will get two different readings; however, if you measure light falling on those two subjects, the readings will be identical.</p>

<p>Think about it, which reading, reflected or ambient, will give you the desired result? The reflected light reading will cause the wedding dress to look darker than it is and the tux to look lighter than it is; that is, unless the photographer doesn't fudge the readings some. But, the ambient reading will result in a white wedding dress and a black tux.</p>

<p>Cameras with built-in light meters measure reflected light. So, the photographer has to use his or her noodle when using a camera with a built in light meter. For a buck two ninety-eight you can buy something called "an 18% gray card" in almost any camera store. If you place this card such that the light falling on it is the same as that falling on the subject and take a reading off it, you will get a reading that approximates an ambient light reading. If you are willing to spend 25 to 50 bucks, you can buy a used Sekionc Studio DeLuxe light meter that does an excellent job of measuring ambient light. That's the way the pros do it. Try it, you'll like it.</p>

<p>Happy shooting.</p>