Lighter-than-air, unmanned, tethered platforms for small-format aerial photography include balloons and blimps. Hot-air and helium blimps have been developed and tested successfully in the field. Both provide stable platforms for lifting camera equipment in calm or low-wind conditions. The operating range for blimps overlaps that of kites, so a combination of a blimp and kites spans wind conditions from calm to 40 km/h. A helium blimp is smaller, substantially lower in cost, and easier to operate compared to a hot-air blimp with equivalent lifting capability. However, helium is not readily available in many regions, and in such places a hot-air blimp would be the only practical lighter-than-air platform for small-format aerial photography under low-wind conditions.