I went to an orchid show yesterday to take flower photos. My picks are posted at Nashua Orchid Show 2-13-2016. I used the Panasonic 14-140 lens on a 10mm Fotasy extension tube. Everything worked very well and my shooting distance from the flower averaged around 18". What was interesting was that if I zoomed in, I had to move back. If I zoomed out, I had to get closer. This resulted in the flowers always being about the same size in the viewfinder - within the distance that could be focused. Perhaps someone can explain this phenomenon to me.