OK, back to our macrophotography discussion. This will be a particularly long post, so get comfortable. It is crucially important information for macrophotography using any camera system, though.
Getting so close to your subjects changes quite a bit about how you can take your photos. Without getting into specifics, the closer you get to your subject - either physically or with the focal length on your lens- the less light will reach your camera's sensor (or film, for you dinosaurs out there ).
What this means for you is that the closer you are or the closer to a 1:1 ratio you are, the longer your shutter speeds will need to be, the larger your aperture (lower the f-stop) will need to be, the greater your ISO, or the more light you'll need to shine on your subject. I personally don't like using a flash - that's my preference and not a commentary on those that do - so most of my macro shots are with a low f-stop or long shutter speed. In fact, frequently with my macro shots, even with my camera stopped down as far as it will go (decreasing my f-stop as much as possible), the shutter speed will still be too slow for me to hand-hold the camera. This is even frequently the case when I raise my ISO to 800 or 1600 and/or with moving subjects such as a crawling insect or a flower swaying in the breeze.. As such, a tripod is absolutely crucial for my macrophotography.
|Even if I did dump a bunch of light on my subject, a tripod would still be necessary because hand -holding and keeping a specific part of the image in focus is extremely difficult. On distant shots, being off on your focus by a millimeter or two will make no difference whatsoever in the resulting image, but in a macrophotograph, it can mean the difference between getting what you want in focus and having it be an out-of-focus mess. This is because as you get increasingly close to your subject, the depth of field at a given aperture or f-stop will decrease. At a 1:1 ratio, the depth of field at your lowest f-stop will be razor thin. Even at your largest f-stop, your depth of field will be measurable in only centimeters if you are very close to your subject. A tripod will hold your camera where it needs to be to get the image you want, whereas hand-holding takes a lot of patience, skill, and - mostly - luck. There is a way around this using specialized computer software that composites multiple shots to create an image where a greater amount is in focus, but this is the only way I know of to get around this issue with today's cameras. From what I've seen of camera research, this may be an issue of the past in 10-20 years.
For those of you who do use flash frequently, keep in mind that your lens will get in the way of your flash at very close distances and cast a shadow on your subject. This is true with both P&S and SLR cameras with smaller focal length lenses. There are ways around this with specialized flash equipment, but that is getting into a realm most of you will never go. If you are that interested in macrophotography that you want to know more, feel free to ask and I'll talk about it more later, but otherwise I'll leave it there..
I know some of this might have been confusing, so if you have any questions at all about this, please ask now.
