Wednesday, November 17, 2010
Hey, look at that, you all got lucky today! Just when you had given up on your dreams of seeing a new post on this lovely Wednesday, a picture of a rose appears. I of course took this one across the street, in the Woodland Park Rose Garden, earlier this summer. I took it using the old 105mm Kiron macro lens (with a Minolta mount!) that I picked up (very) used on Ebay earlier this year. It’s a tough lens to use, for a number of reasons (which I’ll detail out here in a bit), but every time I come across a picture I took with it, it just takes my breath away. I keep trying to justify not using it, and instead using a lens that’s easier (again, see the list below), but man, this lens takes nice shots.
So, what’s so tough about using this guy? Well, mostly stuff that I’ve mentioned several times before. First of all, it’s manual focus. Which I know, is a lame thing to complain about. But, seriously, it’s really easy to get wrong. Especially when you factor in part 2, which is that the aperture control is totally manual. Meaning, it has a physical actuator that can be used to automatically control the aperture (so that it’s wide open while you’re focusing, but then it steps down when you hit the shutter button), but new, modern, electronically controlled cameras don’t know what to do with a little spring-loaded knob that you need to push aside to open the aperture. So, you have to deal with trying to focus with the aperture stepped down, which (obviously) greatly reduces the amount of light you have to, you know, focus with. Also, (somewhat less obviously), stepping down the aperture has the expected effect of lengthening your depth of field, so whereas it’s really easy to see exactly where the point of focus is when the aperture is wide open, it can be really tough when just about everything LOOKS in focus through the view finder, especially when everything is also very very dark.
Then, to top it all off, the range of stuff you can even focus on with this lens is pretty limited. Meaning, you can’t focus to infinity. Why that is has to do with the difference between the lens that uses an old Minolta mount, and the camera that uses a Canon EF-S mount. So, you see, the lens expects there to be a very specific distance between the rear of the lens and the sensor. If you have a lens that has the same mount as your camera, this isn’t an issue, since the mount points are designed to put the lens at exactly the right distance. But, different mounts require different distances. Some longer, some shorter. Canon’s EF mount is generally pretty convenient, because it requires a shorter distance than most others. Meaning, the mount points on the camera will put the lens CLOSER to the sensor than most non-Canon-mount lenses want. Why is this convenient? Well, because you can’t just attach a non-Canon-mount lens to a Canon. You need an adapter. So if the lens wants to be further away than the camera wants the lens to be, then you just make the adapter the correct width to make everybody happy. The camera doesn’t actually care about how far away the lens is, it just has it’s mount points at a certain location. But the lens DOES care, so you can make the adapter the right width. But, as I mentioned, that only works if the lens wants to be FURTHER than the camera’s mount wants it to be. If the distance is the same, or the lens’s ideal distance is shorter… well then it doesn’t quite work. And the way that the “not quite working” is manifested is that the range of stuff you can focus on moves closer. To completely make up numbers, let’s say a lens would normally be able to focus on anything between 10 feet away and infinity. If you mount it (using an adapter) on a camera who’s mount needs a shorter distance, you’ll instead be able to focus on things that are (again using made up numbers) 5 feet away to 20 feet away. It moves the window closer, and makes it smaller. It’s exactly the same thing that happens when you use macro extension tubes. In fact, that’s the whole idea behind macro extension tubes – you move the nearest focus distance much closer to the camera at the expense of being able to focus on things that are more than a couple inches away. So, the old Minolta mount is one of those few exceptions to the “Canon EF is a convenient mount” rule. It actually wants a shorter distance than the Canon EF/EF-S mount. So, if you’re using it as a macro lens (and you’re thinking about tossing an extension tube on anyway) it’s not really an issue. But if you want to use it as a general-purpose lens, well, then you’re out of luck.
Phew, that was a lot more words than I was intending to use today. That wiped me out.
On a completely unrelated note, I’ve started reading more and more the blog of a guy named Bill Hess who lives in Wasilla, Alaska. He’s been a professional photographer for quite awhile, and his blog is regularly updated and is a joy to read. Today’s post in particular was about being invited onto the set of a film they’re filming up in Alaska, so if you haven’t visited his blog before, it’s a great time to start. Click here to visit.
Notes: Canon EOS Rebel T1i, Kiron 105mm macro lens. 1/200s, aperture unknown. ISO: 400.