So far it has been a year with very few butterflies. I wonder if the draught last year plays a role in it. A few days ago one of my favorites showed up feeding in our yard, the Red-spotted Purple. They never sit still and it is a challenge to make a good click. It is always an act of balance what aperture to choose for this kind of an environmental image. If you open the lens all the way up to f/2.8 you may get a good shutter speed to freeze the action of the butterfly but depth of field is so shallow that only a small part of the insect is in focus. At the other hand if you stop down too much it's not just difficult to get a sharp image but also the background becomes way to distracting. If a butterfly moves around there are not too many choices for choosing the background. Now the technical geeks may say, why not pumping up the ISO into astronomical heights? Well, for me part of the challenge is to shoot in the basement between ISO100 and 200 in my wildlife photography. Of course, this doesn't work out always but on a sunny day I will stick with ISO100 for a maximum of detail. The alternative is not making the click at all, and this is not really an option... ;-)