Hi,
So I wanted to try out my Canon 100mm macro lens and here's my first shot...critique please as I want to improve the quality of my macro shots greatly.
Good start Shak, and good advice from Ian.
I found it difficult to work with DOF.
A couple of thoughts.
The DOF will always be thin, and tastes differ as to how to deal with that. A lot of people make a merit of the thin DOF, and focus on a part of the subject, like an insect's head, or eyes, or a spider's eyes and mouth parts. That can work well if the out of focus parts of the subject make for a nice composition where it seems natural to focus on the one area of interest.
Another approach is to try to get all of the subject, or most of it, in focus. For example, if taken from the side I like to try to get all of an insect's head and body in focus, and if possible also the wings and/or legs on the side nearest the camera. There are a several issues - the angle between you and the subject, where to place the centre of the DOF, how to maximise the DOF.
For subjects that are more or less "long and thin", the more that you can get the subject side on (or top down) the more of it you will be able to get into focus. (Actually it doesn't have to be side on or top down, it can be anywhere between, including sometimes more or less underneath, just as long as the camera is pointing somewhat towards the middle of the subject and at right angles to the line between the front and back of the subject.)
For the DOF positioning, remember that there will be an range of distances that will be in focus, some nearer to the camera than the focus point and some further away. If you focus on a part of the subject that is nearest to the camera you will "waste" the region of sharp focus that is nearer to the camera. So you need to find something to focus on that is at a suitable distance so that all the available DOF is put to good use.
It depends on how the subject lines up, but I often use the "shoulder" or "neck" for insects. I find it sometimes helps to look at the subject "real world" as well as through the viewfinder or on the LCD to work out which bits are actually closest etc, as sometimes the subject is at an angle that isn't obvious looking at it only through the camera, especially I find for flowers.
It is obviously important to get the "important" bits in focus (e.g. typically an insect's eyes), but keep in mind that doesn't necessarily mean that is the best place to put the focus point.
There are a couple of ways to maximise the amount (front to back) of the subject that is in focus. One is to use a smaller aperture (e.g. f/16, f/22). As you get into these smaller apertures the sharpness will drop off because of
diffraction, but for my taste at least the increase in DOF more than compensates for the loss in sharpness.
Another approach is to make the subject smaller in the frame and then crop the image to the composition you want. This will increase the amount (front to back) of the subject that is in focus, but because of the cropping (essentially "magnifying the image") you will lose detail. With the camera and lens you are using you can do a fair amount of cropping and still get a good quality image.
Can't remember if I used flash on this or not...
Apologies if you know this already, but you can find that out from flickr. On the
photo page click on Actions, View Exif data. If you have installed it, Canon's Zoombrowser will also give you all sorts of information about an image. (I'm still waiting for Lightroom to arrive, but that might tell you too.)