Picture Guidelines

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Low cost lighting setup, consisting of a tripod and two 5000K CFLs

Having quality, detailed pictures of supported devices is an important part of the sigrok project. It enables users to easily identify their device, and in many cases, provides a plethora of information on the inner workings of the device. We are a hardware community as much as we are a software community; no detail is unimportant.

A few notes on taking good pictures

The idea behind mugshots is that they will be placed on a transparent background in the Supported hardware page. It's surprising how small imperfections in an image become stringently obvious when used in this manner. These guidelines presented below are just that, guidelines. If you have a better way to take mugshots (and there are many better ways), feel free to use your method. While these hints are geared toward mugshots, they apply equally well to all pictures.

Light setup

  • Use a matte (non-reflectve), neutral background; usually white is the best choice. A piece of paper or a poster-board works wonders. Do not use a colored background, as light tends to reflect from the background, giving the device edges a color hue. This hue becomes stringently obvious when the mugshot is placed on a transparent background.
  • Use midday light on a clear day, but avoid sunlight hitting the device directly to prevent reflections. This is by far the easiest setup to work with.
    • Alternatively, use 5000K to 6500K CFLs. Do not use incandescent bulbs or 3000K CFLs.
  • Avoid using the built-in camera flash. Any front flash can easily create unwanted reflections on the device.

Setting your camera

  • Set your camera to the highest resolution.
  • Set your camera to record image metadata. Metadata is very useful in applying lens correction filters, most notably, reducing distortion. A plethora of automated corrections can be done if metadata is present. It is OK to strip EXIF data before uploading the final image to the wiki, but if you are giving it to someone for post-processing, they will need to spend a lot more time making manual adjustments if they do not have the EXIF data.
  • If your lens exhibits severe lens distortion, consider taking the shot from further back, and/or dial down the zoom until you get a more acceptable result. Although the resulting image will have "more background" and the cropped image will be of a lower resolution, a lower resolution image still provides better clarity than a higher resolution image with aggressive lens correction applied in post-processing.
  • If your camera supports it, take pictures in RAW format. Images in RAW format are much less prone to artifacts when applying color corrections.
  • If available, place an 18% gray card somewhere in the frame. This helps establish correct color balance. This is helpful only if shooting in RAW mode.
  • If lighting conditions permit, set your camera to ISO100 and aperture between F8 and F11. For most lenses, this provides the sharpest picture.

<gallery> File:NI_GPIB-USB-HS.png| Excellent picture, with good contrast, no obvious lens distortion, no color hue, and no halo from cropping the background File:Tp4000zc_front.png| Acceptable picture, but with uneven lighting. The lower right and upper left corners recieve more light than the rest of the device. This is a result of poor choice in positioning the lights. File:Tp4000zc_232_optoisolation.jpg|Part of 18% gray card still visible in the frame. When color balancing is done, the value of the pixels should be 50% red, 50% green, 50% blue. Further post-processing, such as contrast-enhancement and exposure correction may alter these values slightly. File:Braintechnology_usb_interface_v2x.png| Color hue from non-neutral background is visible after background is cropped out File:Minila_mockup.jpg| Severe lens distortion File:Mastech_va18b_device_front.png| Blurry image due to too agressive post-processing corrections File:Robomotic_buglogic3.jpg| Poor lighting required the iso sensitivity to be set too high, resulting in poor contrast. Color balance is also off. <gallery>

Contact mrnuke on #sigrok for more details.