Monday, July 24, 2006

Using a hammer to drive a screw

Close-ups with a rangefinder

Fixed-lens rangefinder cameras aren't really made for macro or close-up work. Most, as is the case with my various Olympus RFs, have a lens in the normal range (40-55mm focal length) and their closest focus is about 1 meter. Compare that to a normal lens on a 35mm SLR which typically can focus down to about 1/2 meter, and there's a difference of an order of magnitude.

As I told one friend, "if it's hard to do I figured I should try". Another interpretation of that, of course is, "Sheesh, why not use an SLR ... you've only got SEVERAL ... not to mention bellows and lenses more suited to macro." Like I said...

Well, the results were pretty pleasing. A slower speed film would have been somewhat better, IMO, but Fuji NPH 400 Professional did really well.

How I did it...

I used an Olympus MCON 40, which is a macro/close-up lens intended for use on some of Olympus' digital cameras. I attached it to the 35 SP by using a 49-55 mm step-up ring; the 35 SP's diameter for threaded attachments is 49mm, and the MCON 40 has a 55mm filter thread.

With the camera empty of film and the MCON 40 mounted, I opened the back of the camera. I had cut a piece of frosted acetate into a 24x36mm rectangle (actually, a tiny bit larger), which served as a type of "ground glass" for focusing. The frosted side was mounted toward the lens, i.e. the smooth side facing the back of the camera.

Moving the shutter speed dial to the 'B' setting and the aperture to f1.7, the lens set at closest focus and in bright sunlight, I moved the camera forward and backward until an object came in sharp focus. Upon achieving focus, I measured the distance from the film plane to the object with a ruler.

The above procedure gave me the correct focus distance for this particular camera. It's not an easy process, but once determined, I can use the ruler to set camera/subject distance with this camera/close-up lens combination. This does not compensate for parallax, which is the phenomenon of the image not be centred in the lens' field of view because the rangefinder mechanism is off centre from the lens axis. (Parallax is only of concern at close focusing distances.) To compensate fo parallax, I simply approximate the offset by eyeballing it. To calculate the actual offset would require more exacting experiments, which I'm not really interested in doing.

Tuesday, July 11, 2006

The Nature of Scientific Work

My major in university was biology, with a minor in chemistry. Initially I had been interested in going on to medical school, but for various reasons decided against that. As it turns out, my various jobs and career development meant that while I never direclty worked in either field, training in the scientific method has always been a benefit. Through various stints in information technology areas, being able to create hypotheses, valid test plans and being able to analyze results has been an enormous advantage. For example, my current gig as a sales engineer supporting sales reps seeling Voice-over-IP (VoIP) systems requires that I quickly evaluate assumptions, proposed "solutions" (both as conceived by sales reps and prospective customers,) based on my company's system architecture and the true capabilities of network protocols, etc. (Note: Most of the time both sales reps and prospects are wrong.)

The nature of scientific rigor is that experimentation where variables are controlled are at the vary heart of fact-finding and the development of accepted scientific theory. Experiments, hypotheses and formulae are open to peer review, that is, repetition and testing by other parties.

All this seems very simple, yet it is subject to complexities in the "real world".

A vocal group who either deny global warming is a real phenomenon or who at the very least dismiss the human contribution to climate change invariably declare (normally in breathless, apoplectic language) that nothing is "proven", that there has been no definitive scientific proof of global warming as a trend attributable to human activity.

The problem with this, of course, is how do you conduct a controlled experiment with planet Earth as the subject? Since there is only one Earth available for observation, and we obviously cannot control all variables so as to change only one and observe the results, we can never "prove", to the satisfaction of those who deny global warming that it truly exists or is a human-influcenced/induced problem.

The proper response to this, of course, is that the question, while in the scientific realm, is not one that can be subjected to controlled observation and experimentation. In other words, it is a different, if not special, case of scientific study, just as there are special cases in all realms of study.

This is a long way of introducing a brilliant article by Showey Yazdanian, a Torontonian who is currently a PhD student at Cornell University. If I were like Bill O'Reilly and the other neo-con know-it-alls, I would tell them to "shut up". But I'm not, and I believe in open discussion, so recommend the article to you to provoke thoughtful dialogue.

No one can deny we only have one home .... one planet ... and that how we handle this issue is of enormous import.