GoingManual.com It's time to take control!    Home    Tutorials    Photography Forum  Photography Tutorial Introduction Part I – Gear The Camera  -  Focus  -  Resolution  -  MegaPixels Vs Print Size  -  Sharpening Semi auto settings  -  Aperture Priority (Av)  -  Shutter priority (Tv) Zoom and Focal Length  -  A Note About Sensor Size Other Camera Features  -  Viewfinders  -  Lens Hood  -  LCD screen  -  White Balance Extra Equipment  -  Tripod  -  Cable Release  -  Filter systems  -  Polarizer and ND filter  -  External Flash  -  Studio Lighting  -  Reflectors Part II – Capturing The Scene Your First Manual Photo  -  It's All About Exposure  -  The Light Meter  -  Exposure Explained  -  Controlling Exposure Creative Effects  -  Aperture and Depth Of Field  -  DOF Preview  -  Shutter speed Putting it all Together  -  ISO  -  Ap. & Shutter Relationship  -  Stop for a minute  -  So What?  -  The Bulb Setting Metering the Scene  -  18% of Everything Metering modes  -  Matrix  -  Average  -  Center weighted  -  Spot or semi-spot Taking Meter Readings  -  Expose for your subject  -  Sunsets and sunrises  -  Reflecting sun  -  Night Exposures  -  Moon  -  Green Foliage  -  Bright or White Scenes  -  Dark or Black Scenes Understanding Your Histogram  -  Flash Metering Composition Lead in The Viewer Eye  -  Point of Focus  -  Fill the frame  -  The Rule of Thirds  -  Moving Subjects  -  Print and frame Sizes Different Styles Learn by doing  -  Giving and Getting Critique  -  Portraits  -  Groups  -  Children  -  Shooting Outdoors  -  Silhouettes  -  Macro  -  Products  -  Landscapes  -  Sports and Action  -  Panning  -  Rear Sync Flash  -  Abstract  -  Long Exposures  -  Black and White A few Other Useful Things  -  Blown Out Skies  -  Neutral Density Filters  -  Polarizing Filters  -  Electronic noise You're Half Way There! Part III The Digital darkroom  -  Computer hardware  -  Card Reader  -  Printers  -  Mouse Post Processing  -  The Ethics of Altering  -  Choosing Your Program  -  Tutorials   Photoshop Tutorials   Photoshop Primer   Saving Your Image   Adding a Border   Using Levels   Using Curves   The S-Curve   Correcting White Balance   Improving Saturation   The Clone Tool   Correcting Lens Distortion   Blending Multiple Images   Black and White Conversion   Sepia Conversion   Reducing Noise   Cropping for Different Print Sizes   Sharpening   Working With RAW Files   The Gimp Tutorials   The Gimp Primer   Saving Your Image   Adding a Border   Using Levels   Using Curves   The S-Curve   Correcting White Balance   Improving Saturation   The Clone Tool   Correcting Lens Distortion   Blending Multiple Images   Black and White Conversion   Sepia Conversion   Reducing Noise   Cropping for Different Print Sizes   Sharpening   Working With RAW Files   << Taking Meter Readings Flash Metering >> Understanding Your Histogram The biggest advantage that digital has over film is instant feedback. You can see right away how well exposed your image is. High end digitals have a neat feature that is really useful to understand called a histogram. It's simply a bar graph of the different tonal values in your shot. The camera sees in shades of gray so it's brain is interpreting a black and white image. The histogram uses a scale along the bottom of the graph and goes from 0 black on the left to 255 white on the right. The vertical axis is the relative number of pixels in that tonal range. For the purposes of metering, think in shades gray, remember that's what your meter sees. Have a look at a few of the example histograms and see how they relate to their images. None of these have been processed in any way. This image has a wide tonal range but not many highlights. The orange and green show in the mid tone range. This image is basically 3 tonal ranges; the yellow building, the dark blue sky and the lights. In the histogram the yellow and blue tones are represented on the left and the highlights are the very thin line on the very right hand side. This image hasn't been converted to grayscale. This is the color of the tree and the sandstone head. You can see the tonal range more clearly when the colors are less distracting. The camera sees in grayscale and looks at tones in black, white and shades of gray. Again you can see the lack of highlights in the image are represented in the histogram by the lack of anything on the right hand side. Have a look at the post processing Levels tutorial to see how histogram information can be used to improve an image. Sometimes your graph will top out. This just means there is a disproportionate amount of pixels in that tonal range to represent on the scale. It's not necessarily a bad thing. If you graph stacks up on the ends that's not so good. If it stacks up on the left it means you have a large area of pure black in your shot. Common with night sky photos and as long as you would expect that kind of thing then it's no problem. If the graph stacks up on the right you've overexposed. Even snow scenes should only just touch the right end of the histogram, any more and the overexposed areas will loose their information and appear too white. This is called blowing out and is a common problem with scenes of high contrast. The highlights will receive too much light and blow out, loosing detail. You can use the histogram to great effect in scenes with snow or lots of white, like a wedding dress for example. Your meter will want you to underexpose, (too much above 18%) giving dull, gray whites. By consulting your histogram, after taking a shot, you'll see there are no tonal values on the very right hand side so there are no white pixels. You now know you have to increase your exposure a little and check again to see your histogram just touches the right hand side. This shows you are recording white pixels but not blowing out, by stacking up on the right side. Lots of black pixels in this image and no highlights. This might sometimes be your intention. Well exposed. The curve just touches the right hand side. Stacked up on the right means over exposed blown out areas. We rarely want this. We'll see histograms again later on, when we come to post process our images. << Taking Meter Readings Flash Metering >>

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