In 1869, Sealy helped von Haast with the exploration of the Tasman Glacier. By then, von Haast was suffering from rheumatism and the exploratory work was left to Sealy. Other glaciers explored that year were the Classen and Godley glaciers. On this latter trip, Sealy took his camera with him. His photos did not come out well and he decided to switch from dry to wet plate. In 1870, he went back to the Tasman Glacier and the Rangitata glaciers. He took photos of Mount Darwin and Hochstetter Dome; this is the first time that these mountains were seen from the east side. Sealy exhibited landscape photos at the first art exhibition in Christchurch in early 1870. In 1871, he gave 44 photo plates to the Canterbury Museum, where his friend von Haast was the curator. Some of Sealy's photos were exhibited as part of a map prepared by von Haast at the 1873 Vienna World's Fair, and Sealy won a silver medal for some of his photos. It is estimated that Sealy's gear that he carried onto the glaciers for photography weighed .