Experiments with aperture

On Wednesday 9th February 2011 RHS Wisley ran a half-day course in he New Glasshouse to allow photographers to develop their skills in shooting butterflies. The glasshouse 'tropical zone' was made available from 8.00 for photographers' use, and then the upper part only from 10.00 (when visitors arrived) till 11.00. The tutor was Adrian Davies whose courses I have attended several times and whom I like. He is the author of several useful books, too.

The technical scope of the course was close-up and macro photography applied to these pleasant and fairly cooperative subjects. It took half an hour for cameras to warm up and get rid of the last traces of condensation, and to let the light - on a grey February morning - develop a little. Most people were using 90 - 105mm macro lenses, or zoom lenses in the 70 - 300 mm range with macro facilities. Due to the gentle breezes which waft around the glasshouse, and the slight twitches around the mouthparts of even a torpid early morning butterfly, it was necessary to shoot at ISO 400 to keep the exposure times below 1/15 second at reasonable apertures. A few people tried flash, but there was really not enough room to get clever with off camera stands and reflectors, and most were happier using natural light. All of the examples below were shot on a Sony A55V SLT at ISO 400 in natural light; a Manfrotto tripod provided all sorts of weird angles.

The following pairs of shots emerged from the 30 or so 'worth keeping' images as examples of the effect that aperture has on depth of field and I though they might be of interest. The smallest aperture used is f 8.0. It would have been interesting to try f 11 or f 16 but there was not enough light in the jungle to keep the exposure times down. In all cases the focal target was the eyes and mouth parts; the sharp point was selected using manual focus and the 'electronic loupe' provided on the A55V quick view screen. This was a novel camera feature for me, but worked pretty well from the first attempt. I will try flash on a bracket next time and see if I can get closer with a short exposure at f 16, hand-held, and looking at the quick view 'loupe'.

Idea leuconoe (Tree Nymph) f 4.5 & f 6.3.

Morpho peleides (Blue Morpho) f 4.5 & f 8.0

Papilio lowi (Asian Swallowtail) f 4.5 & f 8.0

(Do not entirely trust the identifications . . . )

What I did not have time to do was to try image-stacking; it was a choice between shots of lots of butterflies and lots of shots of one butterfly. Also I have not yet got this working to my satisfaction - see the work-in-progress example below using Helicon Focus - but I will keep at it on this method.

All (constructive) comments and suggestions are welcome!

-- JohnAshford - 11 Feb 2011