Wow
Nicely captured.
Nice and sharp Brian, well done.
Beautiful critter and nice shot Brian You are lucky to have that garden which has lovely plants and interesting critters
Very nice! You have made huge progress in recent months.
Everything is working well with that shot.
Lucky? 20 years of dreaming and 16 years of creating! I am a natural lighthouse keeper, small village pastor sort of person. I don't like cities or crowds so stay home a lot. Myra loves her work but needs a place to come and be herself in. We created the place we need.
If the weather cooperates the new pond (center piece of the garden/temple) will be filled with water today. Then there will be lots of new beasties, birds, frogs and fish to shoot.
In my limited experience, how much of the mosaic structure of the compound eye that resolves in an image depends on many factors;
Precise focus distance and Depth of Field - e.g. the depth of the eye is significant, at wider apertures, more than the DoF available - so, within the limits of diffraction (mitigated by other factors below), the narrower the aperture, the better.
Shooting distance and physical scale of compound mosaic for species being shot - e.g. the closer you are, or larger it is, the better.
Colour contrast of eye; think black bee or wasp eye vs paler colours often seen on butterflies and dragonflies.
Lighting angle must also play a part; particularly on facets with less contrast to their divisions; side lighting may help reveal the 'texture' of the facets on the surface of the eye, while flat frontal lighting (e.g. on camera flash) will reduce this.
Anything that allows you to get the eye bigger in the frame will help, so yes, extension tubes may help, but only if you're already shooting with the lens at minimum focus distance (mfd) and your subjects are allowing you to get closer than that (which is 1:1). If they're not, because you're further back to fit the whole dragonfly in the frame, then extension tubes won't help.
The other factor is that a dragonfly is many times bigger than your sensor, so you probably won't reliably see more detail in the eye while simultaneously trying to get the whole critter in shot - you'd have to do a portrait of its head only and be able to get closer than mfd for extension tubes to be of benefit.
All extension tubes will allow you to do is achieve a greater than 1:1 magnification by means of getting closer to the subject, by shortening the mfd - they are not a magic 'resolution booster' and other factors may thwart your desires.
Geoff, Jim or Dan, do correct me if I am off-kilter here.
Cheers, Dave
Last edited by Dave Humphries; 29th July 2016 at 01:38 PM. Reason: updated (mainly) with thoughts on lighting angle
So if I get as good with the 90 as I was with the kit lens I could see some improvement.
A couple of other points about extension tubes.
You may need to add a little bit of positive exposure compensation when using them; also, they give a fairly narrow workable distance. If you want to back off a bit you totally lose the ability to focus.
I sometimes use a 25 mm tube to get a little closer, but that is with a suitable approachable subject.
There are super quality macro lenses available but with a price to match and more useful for really close very detailed photographs than for general purpose use.
Possibly you are now approaching the stage where you will want to think about focus stacking for some subjects. There are a number of stacking software options and some do let you have a free trial.