[Joe_G.]

Originally Posted by RUKen

Given that the necessary exposure times then were much longer than today's (no "point and click") and the likelihood that the photographer was using a strong light, it would have been difficult to keep looking directly at the camera. The long exposure time is also why the early photographic portraits do not feature people smiling.

By the late 1880s, "instantaneous" photography was commonplace. Exposure times were often a fraction of a second. This made it possible to capture galloping horses in great detail etc. Some Old Judge cards show the player peering directly into the camera, others do not. The rare smile has more to do with what was deemed acceptable and appropriate vs a concern of holding a steady face during the exposure timeframe.