The Electroblog
Queen's Park Looking South
Posted by Damon Schreiber (Toronto, Canada) on 5 August 2007 in Cityscape & Urban and Portfolio.
Sakamoto/Schreiber - Toronto 1977-2007 series starts here.
On the importance of focal length
Yes, the first part of reverse-engineering a photo like this is to use the same focal length. Some small variation probably won't hurt, but you can't for example substitute a telephoto (e.g. 100mm lens) for a wide-angle (e.g. 28mm lens). Telephoto lenses make distances look compressed, whereas wide-angle lenses have the effect of exaggerating distances. Also, perspective can change a lot, so you really must try to stick to the same focal length.
Which brings up an interesting problem: These were taken in 1977 with a 35mm camera. Although today's digital cameras may look similar, and provide similar results, the sensor is usually much smaller than a frame of 35mm film. I could have used a film camera, it's true. But I think in reality I wouldn't have had the money or the patience to see the project through. I have gone on so many trips to the same locations to try to improve the results, that I believe it just wouldn't have been possible using film. But having said that, a 35mm film camera with a 28mm lens would have produced a more technically pure simulation of the original photos all else being equal.
But I like digital too much. And while I could have used a Canon 5D (which uses a sensor the size of a frame of 35mm film), it's not really a camera I could afford or would even want if I only could have one DSLR (I got the one I wanted).
So I'm using an APS-C sensor which is small enough that one does a 1.5 factor conversion to see what a given focal length would approximate in a 35mm camera. Thus a 19mm lens would approximate a 28.5mm lens in 35mm terms. My Sigma 17-70 lens will of course offer me the right length if adjusted just so, and my camera will tell me what length the lens is set to currently, so it all works out apart from some small details: The camera isn't completely precise about displaying the exact focal length. It goes from 17mm to 19mm to 21mm, so I have to guess. In fact, I recently thought to test it against an actual 35mm camera with an actual 28mm lens, and it looks pretty much the same at least through the viewfinder - although the 35mm SLR certainly has a larger viewfinder.
One caveat about the conversion between APS-C and 35mm is that although the 19mm approximates the angle of view of a 28mm lens. it's really only a cropped version of what you'd see through a 19mm lens on a 35mm camera. Thus the geometry of that view won't actually be exactly the same. Still, as my high-school math teacher used to say, "Close enough for government work".
Sorry if all this number talk is confusing - I'm probably just rambling. The important thing is to see that it's hard to be completely exact, but it pays to try to come as close as possible. In reality, framing just a touch wider than the original photo gives you more options when processing, so I reluctantly recommend it.
Note: Not a lot to say about this photo, but I was kind of amazed that the flower bed looks so similar after all these years. I don't even think they're the same flowers (likely impatiens in 1977) but the colour scheme is exactly the same. And the trees yet again have grown taller and block out more scenery from this viewpoint, although they also provide more shade and habitat for birds and such.
Top image copyright Shige Sakamoto - 坂本政恵
High-res here (my image) and here (1977 image). The entire 1977 series can be viewed in context starting here.
[University & College, Toronto]
