I have made it pretty clear in the past that macros are one of my favorite subjects for photography. I have been meaning to pull together some advice on macro photography for a while and I am finally getting started. I have a list of ideas and questions that I plan to cover over the course of a few posts, but feel free to comment with any other questions or ideas and I will add them to my list.
Question 1: What makes a macro a macro?
There is some debate on what makes an image a macro or a lens a macro lens. I tend to use the term rather loosely and call shots that are probably just "close-ups" macros. But the true definition I go with is that for a lens to be a macro lens it needs to allow you to shoot something life-size on your sensor. So if you sensor is 36mm x 24mm like the sensor in my 5D mark ii, you could capture a flower that is 36mm across filling up the entire width of the sensor. I don't always shoot everything at 1:1 since that really can limit your composition options. How can you tell if you can shoot at 1:1, or how close you can get with the lens you have or with a lens and extension tubes? Find out the size of your sensor, and then grab your camera/lens and a ruler.
As I said the sensor in my 5D mark ii is 36x24mm, here is a shot of a ruler with my 100mm L macro lens.
You can see that I fit about 34.5mm on the sensor meaning that I actually shot just a little bigger than life size.
I got the idea for this experiment from one of my favorite photographers and a post on his blog here. You can see that he had a similar result.
In comparison when I use the "macro" end of my 24-70 at 70mm.
I only could get close enough to have 112.5mm on my sensor, so that is about 1/3 life size, pretty far from a true macro.
I also dusted off my old XT which has a sensor size of 22.2 x 14.8mm to see what that gives me with the 100mm macro. I didn't bother to upload it since the result was pretty similar to if I had just cropped the 5D picture down. I fit about 22mm on the 22.2mm sensor, so again life size, it would look larger if you put two 4x6 prints next to each other but on the sensor they are the same.
Question 2: What lens I should use?
My first answer would be "whatever lens you have", but ideally I would recommend a dedicated macro lens around 100mm in focal length (depending on the manufacturer they seem to range from 90mm to 105mm) as that is what I have personal experience with and have been very happy with. If you can afford a lens with VR/IS or similar to help stabilize your shots while handholding that will be a plus.
The only ones I can recommend from personal experience are the two Canon 100mm macro lenses.
Canon Telephoto EF 100mm f/2.8 USM Macro Autofocus Lens
Canon EF 100mm f/2.8L Macro IS USM Lens
Between those two I would go for the L version if you can afford it, I am very happy with my upgrade, but the non-L version is also a darn good lens.
As for ones I have heard good things about but haven't used.
Nikon Telephoto AF Micro-Nikkor 105mm f/2.8G ED-IF AF-S VR (Vibration Reduction) Autofocus Lens
Sigma 105mm f2.8 EX Macro 1:1 Lens
Tamron SP AF90MM F/2.8 Di Macro 1:1
Question 3: What settings I should use... which apertures you like best.
Well you know the answer to the first part is always "it depends on the light and your camera/lens", however I will tell you that I try to keep my shutter speed at 1/200 at least, though with the IS now I can go as low as 1/100 if there is no wind. I will sacrifice ISO to get more DOF or to keep the shutter speed up.
I actually tend to shoot wide open a lot, which probably isn't best considering how shallow your DOF is with macro photography (a topic for my next macro post) but I am addicted to creamy dreamy bokeh.
Bonus Question: Who inspires you?
I have a huge list of photographers who work I really admire. A lot of these are links to flickr streams.
Next time I will try to have some pretty example pictures to spice up the post.