C150 pilot reported descent below FAR minimum safe altitude resulted in a CFTT event.

Narrative

Today I assisted with a photo-op opportunity with another pilot over some rural farmland. The objective was to reveal the gender of a baby to be expected. There was a non-toxic smoke canister with the color blue that we carefully released out of the window. However; my intentions were to remain 500 feet above all obstacles; at all times. We accidentally sank a bit below that 500 ft threshold; and; due to density altitude took longer than expected correction to recover that altitude. The moment I realized we had gone below; corrective action to recover was taken. After checking ADS-B data; it is estimated that we got as low as 200 feet AG. This was; again rural farmland; basically over a pasture. And we did have permission from the homeowners to do a low pass for the gender reveal. However; I realized that I potentially may have violated regulation 91.119 in the process. I have debriefed with the pilot monitoring that this may have been the case. We both have learned the hazards of becoming distracted; and also the hazards of density altitude and how long it took to recover the altitude we lost.