Teacher: Kenji Tachibana Digital Photography I. Histogram (& EC) Exposure Graph & Bias 12 slides Copyright Kenji Tachibana

Teacher: Kenji Tachibana Digital Photography I Histogram & EC: Exposure graph & bias H istogram: Overview There are two (2) types. The better one is the (1) Active Histogram which shows the potential exposure as a graph. The more limited is the (2) Passive Histogram which only shows the exposure graph after capturing the image. In either case, Histogram can be a very useful tool if the graph makes sense to the user.

Teacher: Kenji Tachibana Digital Photography I Histogram & EC: Exposure graph & bias H istogram: Avoid with passion Something to avoid is a ‘serious’ over-exposure because when that happens, some of the lighter parts of the image will become pure white areas without any image detail. And those areas are referred to as ‘blown out’.

Teacher: Kenji Tachibana Digital Photography I Histogram & EC: Exposure graph & bias C ombat Blow Out: Turn on Zebra Striping Most DSLR and many high end compacts have a built-in feature called zebra striping which makes blown out areas of an image ‘flash’ when viewed in conjunction with the Histogram. That makes zebra striping a very useful feature or it could be very annoying to users who do not understand its meaning…

Teacher: Kenji Tachibana Digital Photography I Histogram & EC: Exposure graph & bias A void: Serious over exposure When an image is seriously over-exposed, the lightest areas of the image gets washed-out to more serious blown-out looking. Some washed-out areas can be brought back during the Photoshop basic processing phase. But blown-out areas can not be recovered because there is no pixel information to reclaim.

Teacher: Kenji Tachibana Digital Photography I Histogram & EC: Exposure graph & bias H istogram: Got one? Do it now. Cycle through the Display choices until you see something that looks like this. It is often found in the lower right quadrant of the LCD or viewfinder. It’s only drawback is its tiny size. Larger ones can be found on the DSLR cameras but, even then, they are still small.

Teacher: Kenji Tachibana Digital Photography I Histogram & EC: Exposure graph & bias E xposure assessment UnderNormal ExposureOver Way Too DarkBelievable Way Too Light This assessment will only work properly when you follow assignment requirement such as: 1.Use broad-source (soft) Skylight. 2.Don’t have a light source in the background. 3.Don’t shoot black, white, or shiny objects. This indicates blown out highlights. Lost detail can’t be retrieved. Avoid this at all cost!

Teacher: Kenji Tachibana Digital Photography I Histogram & EC: Exposure graph & bias E xposure Adjustment: EC The digital camera exposure can be adjusted to lighter or darker using exposure compensation (EC) feature of your camera. The EC has an adjustment range from -2 to +2 f/stops as shown below: | | | | | | | | | | | | | | | | | | | | | | | | | | Your camera may have a scale that looks like this… | | | | | | | | | | | | | | | | | | | | | | | | | |

Teacher: Kenji Tachibana Digital Photography I Histogram & EC: Exposure graph & bias A djustment: Bias changes Exposure can be lightened or darkened in 1/3 f/stop increments. Usually the adjustment change can be seen in the camera display. Corrective actions shown below: If UnderNormal ExposureIf Over Add “+”No changeSubtract “-”

Teacher: Kenji Tachibana Digital Photography I Histogram & EC: Exposure graph & bias T ry It Now: The EC button is usually in the back of the camera on the Cursor multi-button. Press on it once to get the scale with the center bar highlighted as a default Bias ‘0’ setting. | | | | | | | | | | | | | The highlight bar is moved using the cursor left or right buttons. Try it now… Press the SET button to accept the new bias. If you press the EC the second time. It will adjust the EC for the Flash. Try it now…

Teacher: Kenji Tachibana Digital Photography I Histogram & EC: Exposure graph & bias LCD Display: Histogram can be turned on or off as one of the Display options. When the EC is activated, sometimes the Histogram is also turned on. | | | | | | | | | | | | | | | | | | | | | | | | | | EC: There may also be a highlighted area with the exact bias written out as shown above. The example above shows that the next exposure will be ‘darkened’ by 2/3 f/stop.

Teacher: Kenji Tachibana Digital Photography I Histogram & EC: Exposure graph & bias S ummary: Knowing how your camera sees the photographic seen is very important to getting the exposure right. Being able to custom adjust the image brightness using EC and being able to interpret the Histogram are both necessary part of your job as the image maker. Another light source reminder – use Skylight which is mostly blue (cyan). And the cyan is mostly neutralized by the WB on Auto.

Teacher: Kenji Tachibana Digital Photography I x End