Argh...this is gonna be a tough one to write. I should just post a few images:P
Not sure about you, but when i look at a macro shot, I look at not just the technical aspect of it but also the artistic/aesthetic side as well.
- Is focusing spot on?
- Sufficient DOF and enough details for me to ooh and aah at?
- Is the pose good? Let's face it...butt shots are normally frowned upon, even though it might work once in a while :D If you catch a bug in flight or about to take off, extra brownie points!
Now a couple of images for a short break.
Most of the images below were shot with a Canon 40D, Canon MP-E65 1X-5X Macro Lens and Canon MT-24EX Twin Flash.
- Composition. This can be very subjective though so let's not discuss it too much here :-D. Common portraiture rules/guidelines apply in macro as well. For example, active space, head shot, shoulder shot, half body shot, full body shot - you need to know where to crop/frame even if the subject is a bug. But of course...the bugs are always on the move and it's not always easy to shoot, much less frame them nicely.
- Background clutter - try to avoid them as much as possible.
OK..another short break.
- Quality of light, whether you shoot with natural lighting or full flash, the light has to be good. If you're shooting natural light, shoot in the morning or evening or when it's overcast. Clouds are the best diffusers for sunlight.
If you're shooting full flash, bring your light as close to the subject as possible, and make the diffuser as big as possible - apparent light size. It's been discussed in this post.
How to tell if the light is bad?
Look at the specular highlight and see if they're easy on the eyes. Any blown highlight with lost details?
Look at the shadow. Hasrh aka poorly diffused light will result in hard i.e more defined shadow.
Something like this..but of course this one is not bad at all:D
Notice the shadows of the legs are quite defined? Not bad but can be better. But it's shot with a 100mm at quite a distance, with snoot-diffuser. Bigger distance = poor apparent light size so this is to be expected.
Do bear in mind that if the subject is very leggy, you can't expect to see much shadow. For example, look at this shot of a stilt legged fly:
Almost no shadow.
- of course when you see a shot of a rare bug, all the rules above can be relaxed a little :D