Do you ever wonder what your life would be like if you lived, say, a few hundred years ago? I think it’s kind of romantic to imagine myself living in a victorian manor house or as a medieval artisan but the longer I dwell on it the more I realize that, 200 years ago I would probably be considered blind.
Now, today, in 2010, I’m not blind. I have big thick glasses. Without them anything more than an inch or two from the tip of my nose is a blurry blob, but when I have them on I can see just fine. I pass my driver’s test, I catch things people toss to me, I do carom off furniture but that’s just because I’m clumsy. Vision wise I’m just fine.
The one caveat is that, to correct for my astigmatism, my lenses have a pronounced cylinder rating. This means that when I look directly on at a straight line like the corner of a room or the edge of a table it looks as it should, but as I turn my head and look at the line askance it begins to curve away from me as if the wall bowed outward.
When I first get an updated prescription the difference can be pronounced and things can look a little strange. For example with my glasses on it looks to me like I’m at least 4 inches further from the ground than without. But, after an hour or so my brain adjusted and everything looks ok again. After that I don’t notice the effect unless I consciously look for it. It’s not that I get used to things being curved but that my brain tells itself that the curved things are straight, which is pretty amazing.
I often wonder how this distortion effects the way I draw what I see. I don’t seem to have any trouble drawing things in perspective and as far as I can tell the straight lines I draw are actually straight. Still, it’s hard to say what the effect might be
It also makes me wonder what other optical effects my brain is screening out of what I think is the real world.
The lens in your eye focuses light on the back of the inside of your eye in an area called the fovea where the majority of your optical receptor cells are. However stuck in amongst those receptors in your optic nerve, which has no receptors on it. This causes a blind spot in your vision, an area where you see nothing. Everyone has this spot, but you don’t perceive it because your brain edits it out.
When you fix your vision on something your eyes don’t stay still. Instead they’re continually making tiny jerking movements called saccades. This is because your brain will begin to ignore signals coming from your optical receptors that don’t change. If your eyes didn’t move then you would swiftly find yourself unable to see what you’re looking at.
Makes you wonder what you’re really seeing, doesn’t it?
Well this all brings me to what I’ve been drawing. I’ve been working on some backgrounds and interiors for my animation project and since it’s been a little while since I last did some real perspective work I was feeling a bit rusty. To sharpen things up a bit I parked myself on the floor in my studio on Sunday night and took a stab at drawing the room.
I have to admit I goofed off a bit, but after about 2 hours here’s what I came up with:
I’m pretty happy with it.
Part of that goofing off I mentioned was listening to things on my phone. When I was all done it occurred to me that the phone has a camera too and that got me wondering how my drawing and reality compare.
To draw the section of the room I did, I had to turn my head a bit. To cover the same area with the camera I had to take a few shots and stitch them together in the computer. Here’s what I ended up with:
I should say a few things about this image to begin with. First, it’s awful. The light in my room at night is not very good. Sorry. Second, in camera terms your field of view is determined by the focal length of the lens. For a 35mm camera normal human vision is in the neighborhood of 50mm. Lenses around 35mm or below would be considered wide angle (think fish eye) and higher around 100mm would be telephoto. My phone’s camera is equivalent to a 30mm lens. This means that there’s a degree of spherical distortion in the image. This is intensified by the fact that this image is stitched together from 6 pictures moving across the room.
So here’s the moment of truth. I’ve superimposed my sketch over the photo (deep breath):
It’s interesting to see what I got right and what I didn’t.
- The general perspective lines (angles of the walls and ceiling) are pretty darn good.
- I started the drawing in the back corner where the two walls meet, and based measurements of features near that location. As you move away from that center you can see that the differences increase.
- Most of the things I measured carefully were rendered pretty well (windows, desk, back table with radio, computer monitors). Things I drew free hand did not fair so well (notice how big the lamp is compared to it’s photo).
- Some things (the stuff pinned to the wall for example) I drew without regard to reality, so they can be ignored.
Keep in mind that there are three distorting factors here:
- The distortion of the camera.
- The fact that the drawing is in 2 point perspective, but reality (camera reality anyway) is in spherical perspective. This causes a lot of distortion towards the far right edge for example.
- General “mistakes” in my drawing.
I put “mistakes” in quotes because I still think the drawing is pretty successful as a drawing. I also think it’s interesting to consider how my subconscious may be responsible for exaggerating the size of some objects like my lamp and radio while others nearby were basically the right size. I do interact with the radio and lamp a lot, and if I were doing an imagined drawing and wanted to emphasize certain elements in a room I might exaggerate their size. More food for thought.
To round things out I colored the drawing. I always wanted a green room. Here’s the final piece: