Photographing the Paris skyline at dusk would seem to be pretty straightforward. The rooftop observatory on top of the Tour Montparnasse is open late, and there are gaps in the plexiglass allowing one to shoot without worrying about reflections. With a camera on a tripod, what then could be the big technical issue?

Not so much if all you need to do is display your images at a small size, but plenty it turns out if a large reproduction (print size 60″ X 40″ or 150cm X 40cm and up) is the requirement.

In the spring of 2013 I shot Paris City of Light and Les Lumières de Paris from the top of the Tour Montparnasse. By the way, the Tour Monparnasse is a hideous high-rise built in the 1970s that doesn’t fit in with the elegant Paris skyline in the slightest. The joke is that the best thing about the Tour Monparnasse observatory is that you can’t see the Tour Montparnasse from it. Bus loads of Chinese, Korean and Japanese tourists ride the elevators up to the Tour Montparnasse observatory, but most of them stay on the floor below the plein air top deck.

Anyhow, my 2013 shots were good enough for a couple of publications, but there was “trouble in Paradise” when an art publishing client of mine ran some really large test prints. These images just weren’t sharp enough.

What can cause lack of sharpness under these conditions? First, in any landscape shot that includes a distant vista diffusion due to atmospheric conditions is always a factor, and there isn’t much you can do about it except wait for a really clear day (not always possible). Paris is often moist, and has some pollution from cars and other sources, so this limiting factor is a real consideration.

From the viewpoint of photographic gear and the craft of photography, the issues are camera motion, optical sharpness, resolution (sensor size) and sensitivity settings.

As I’ve noted, my camera was on a tripod. But my observation and analysis was that the real problem was slight camera motion, caused by the wind coming through the gaps in the plexi, even using my tripod. Absent the ability to come back with a heavier tripod, which wasn’t possible, the fix in 2014 seemed to be to use a faster shutter speed.

So in the two images of Paris Sunset (far above, above and also shown here) I shot at 1/100 of a second for a relatively short duration shutter speed. This implied bumping the ISO, to 1250 in each case.

The good news: my files this time stand up to the blow-up that is required!