It was standing on one of our shelves and caught my eye. A gift from our older daughter who lived in Africa for some time. I tried using the Carl Zeiss Jena 58mm f2 Biotar, but didn’t get the results I was looking for. Where I was taking the picture was rather dark and I couldn’t quite get the manual focus right. So I switched to a Sigma 30mm f2.8 and much preferred the results.