Friday, October 9, 2009
Another bee, another daisy, whatever. Awhile back I said I had a feeling in my gut that taking pictures of bees on flowers just may become my new obsession, and that turned out to be right on the mark. I have so many of these pictures that if I don’t spread them out, I’m going to scare away my whole audience. Well, “scare” isn’t the right word. “Annoy” is probably better.
If you’ve been reading and paying attention to this blog for awhile, you’ll know that the word “macro” can mean a lot of different things. As in, there are several levels of macro. I think the word itself (at least in the context of photography) generally just means focusing on things that are close (ie, “macro mode” on a point-and-shoot). In practice, it generally means taking pictures of little things – usually flowers – and having those little things be the big star of the show. There are a lot of camera lenses you can buy that say “Macro” on them, and it’s not entirely clear what exactly that means. I mean, there are true MACRO lenses, on in particular that I know about that has a magnification ratio of up to 5:1….
Hold up, let me take a step back. This confused me for awhile, so it’s worth talking about. Magnification ratio. I think we all know what the term is ABOUT (making things look big), but what does, say, 5:1 mean, exactly? Good question, let’s address that.
Right, magnification, magnification.. Let’s start with the easy case. A magnification ratio of 1:1. So, you all know basically how cameras work, right? You have this lens that focuses the light into a spot inside the camera, onto the sensor (or the film, in the case of a non-digital camera). In the case of a traditional 35mm camera, the target is, yes, 35 mm across. In most digital cameras, it’s a little bit smaller. (Although there are digital cameras, usually the higher-end SLRs, that have a full-size (meaning 35mm) sensor. I’m not going to go into what differences that makes here.) Regardless, there’s a target where the light coming through the lens is focused. With me so far?
Normally, when the light that will be making your picture is shining on the target/sensor, it’s quite a bit smaller than the real thing. If you’re taking a picture of a mountain, or a person, the real thing is almost certainly less than 35mm across. Let’s say that you are taking a picture of your buddy, and for simplicity let’s say that you’re using a 35mm camera, and, also for simplicity, let’s say your buddy’s face is exactly 350mm across. If you take a picture where the edges of your buddy’s face exactly touch the edge, then you’re working with a magnification ratio of 1:10. Make sense? The number before the colon is the size on the target, the number after is the size in real life. So, 1mm on the sensor represents 10mm in real life. Let’s say you get a bunch closer, and zoom all the way in, so that now you can only fit in half of the face. Well, now the ratio is 1:5, since you’ve got a 175mm (350mm divided by 2) object that’s 35mm across on the sensor.
So, following that pattern, we can get to the idea of 1:1 magnification. Meaning, something that’s, say, 10mm across (like a bug) will be exactly 10mm across in the image being shined on the sensor. 1:1 is actually a very LARGE amount of magnification as far as cameras are usually concerned. Because if you then view that image on your computer screen, that 10mm bug (that’s a centimeter) will take up a third of the frame. That’s BIG!
So, to take it one step further, imagine what happens when you get to, say, 2:1, or 3:1. Now the image on the sensor is BIGGER than real life, and the results will be more and more ridiculous. This is the part that got me for awhile, there is a **HUGE** difference between a magnification ratio of 2:1, and a ratio of 1:2. (Well, there is a 4x difference, to be precise.)
Camera lenses that supposedly do “macro” usually specify a “maximum magnification ratio”. What that means is, through a combination of zooming in and getting to the closest point that the lens will focus, that is the *maximum* ratio that you can get with that lens. In my experience. any lens that will get you to a 1:1 ratio or beyond will cost a LOT of money, as in, at least a thousand bucks generally. And they’re hard to find. But lots of lenses still claim that they do “macro”. Most of those lenses will usually get you to a 1:4 ratio, sometimes 1:2. That’s a big difference from 1:1, but it as long as you’re taking pictures of things that aren’t TOO small (like, a flower, for example), you can get a great image. If you’re hoping to shoot images of the little hairs on a fly, then you’ll need something more.
So, this image, while still in the “macro” realm, clearly isn’t at the extreme end of the spectrum. This one was taken with the lens that I recently settled on to be my primary mid-range lens, the Tamron 28-75 f2.8. (Amazon link: http://bit.ly/z7D8t ). It’s got its maximum magnification ratio listed at 1:3.9. So, definitely not extreme, but enough to get some nice flower shots. And actually, I don’t believe I was at the maximum end of the spectrum either.
There are a variety of methods I’ve used to get in further, which have been covered in some detail in earlier posts. If you want to read more about those, just go back into the archives, or ask me, I’m happy to talk about it at length. But, here’s a quick list: I have a big telephoto (70-300 mm) lens that has a macro mode that gets in to about 1:2, I’ve got a “macro kit”, which is basically a set of magnifying lenses that you put on your lens like any other filter, that help you focus closer and magnify the image a bit, and I have a reverse-mount that I put on my 18-55mm kit lens. THAT gets you some ridiculous magnification. Well beyond 1:1, although I’m not sure how far beyond. Fun stuff to play around with, and all quite a bit more affordable than a $1000+ macro-specific lens.
So there you go. Please do let me know if you want to know more about my macro explorations. I’m still an extreme beginner, but there’s a lot of fun ground to cover. So, have a great weekend!
Notes: Canon EOS Rebel T1i, Tamron 28-75mm f/2.8 lens. 1/320s, f/7.1, ISO 100. Focal length: 75mm.