General Considerations:
Most current consumer digital cameras will probably produce images that will function with the InspectorG software. The factors affecting the camera choice are resolution, lens accuracy, and ease of use. Resolution is the easiest to address. It has been established that a resolution of about 20 pixels per cell provides the most reliable operation so it is easy to calculate the resolution requirements given the sample size and grid spacing. Of course, larger samples and denser grid spacings may require a higher resolution camera then minimally available, though not beyond the choices readily available. Related to resolution, a zoom setting that allows the largest sample area to nearly fill the frame at a distance of 4 meters is required.
The second consideration, lens quality, is much harder to judge. Choosing a reputable manufacturer is one consideration. As larger samples and grids are used, the field of view becomes larger and the potential for lens artifacts such as "pin-cushion" and "barrel" distortion also increases. In some higher end and more expensive lenses there are mathematic formulas and computer programs that can correct for these distortions in the final image. The physical equiptment required for the use of this software provides an excellent opportunity to measure lens accuracy by comparing an image of the grid board with the expected rectangular array of gridlines. This is not currently done, but it is being investigated and may likely be incorporated in the future.
The ease of use consideration means how well the camera can be triggered to capture images and transfer them into the computer for analysis. It is a great convenience to have the camera rigidly mounted in the testing fixture and be able to initiate the capture through software in the computer that runs the InspectorG software. Many have used USB cables to attach the camera to the computer which, with appropriate software, allow both of these actions. Newer cameras with wi-fi capability may be a good solution for this but we have not tested this approach.
Brands:
Approximately ten years ago when the first version of InspectorG software was being introduced the specifications of a number of different cameras were examined and a few tested. The major consideration of connectivity and availability of triggering software led to a recommendation for Canon digital cameras. Both Powershot and various DSLR models came with software that provided the capability for remote triggering. Testing of lens accuracy was positive although admitedly rather qualitative. Certainly, other major supplies such as Nikon, Sony, and others would probably serve for this purpose.