We only need 3 inches of focus. Yeah, we're that sharp.

Your personal photography and optics professor, PhotoCalc guides nearly any level of DSLR photographer. The calculator part of the tool produces depth-of-field data, flash illumination information, and relative exposure adjustments. The reference areas explain those and 100 more terms, give tips on filters, film stocks, advanced exposure techniques, and more. There’s even a location-aware area that displays your local sunrise, sunset, moon phase, and other natural light data. There’s so much useful information that we’re surprised the interface keeps everything organized.

We had functional fun calculating depth-of-field and flash data, the core of this app. We entered the distance to a subject, focal length, and other basics, and PhotoCalc returned details about how much of the area would be in focus or illuminated. Tweaks to our other numbers--such as the ISO rating--nudged the results until we found the right settings. It’s an intuitive process.

And deep reference materials help beginners along. Our favorite area explains the Zone System, telling how to override your camera’s suggested metering for better photos. With explanations of the Sunny 16 rule and so much more, we only found minor quibbles. Specifically, the moon phase shows a vague icon instead of stating the exact status, and we came across occasional typos.