[1] Iwamiya was born on 4 January 1920 in Yonago, Tottori, the second son of parents running a shop selling traditional confectionery.
After graduation from high school he worked Hankyu Department Store in Umeda (Osaka), where he entered the Mitsuwa photography club (ミツワ写真クラブ, Mitsuya shashin kurabu), led by Bizan Ueda and Nakaji Yasui.
Following success in a photographic contest arranged by Asahi Shinbun, Iwamiya was invited to join the Tampei Photography Club and went on to become an assistant of Yasui's.
Iwamiya's photographs of Sado island were exhibited at the Osaka Fuji Photo Salon and elsewhere in 1956; these would later appear in book form.
From 1962, Iwamiya brought out a considerable number of books, mostly depicting Japanese crafts and architecture; several won awards.