Coburg Street Lights

Coburg Street Lights

The lights of Coburg Street and passing cars in a long exposure shot of the street from the traffic lights at the junction with Bridge Street.

This was a 15 second exposure at f/22. The lovely star shape of the street lights is because the opening in the lens was so small (at f/22) and the diaphragms of my lens. It takes a long time to get the exposure but it’s worth it!

This appears to be a beautiful example of Fraunhofer diffraction. It is due to the wave nature of light. The effect depends on the wavelength (that is, the color). It is most pronounced when bright light from a practically infinite distance passes through narrow slits, causing the light to spread perpendicular to the slits. This spreads a point-like beam of light into a pair of streaks.

Using a small aperture creates slit-like situations at the corners formed by adjacent blades. Thus, when you have a combination of relatively intense, pointlike, monochromatic light sources in the image and a narrow aperture, you should see a streak (of the same color) emanating from the points in two directions perpendicular to the blades…

…Finally, length of exposure is related to the occurrence of this effect, as you have observed, but only because exposures with bright points of light are almost always made much longer than needed to record the lights: you’re trying to see the rest of the scene, which is much darker. The brightness of the diffraction streaks decreases so rapidly away from their sources that if you used a sufficiently short exposure to properly expose the lights themselves, the streaks would be practically invisible.

Aperture ƒ/22
Camera Canon EOS 6D
Focal length 19mm
ISO 100
Shutter speed 15s

False dawn of the city

False dawn of the city

As you may have already guessed, that’s not the dawn. It’s the lights of Cork City (and Blarney) shining and into the sky in a long exposure shot I made last August.

I had meant to mention this sooner but 2 weeks ago I was shocked to hear about the death of Debbie Metrustry (@debbiemet), a wonderful person I had the pleasure of conversing with by tweet and by email over the course of the last year or so. She even won a print on this blog last year, but between this and that I never got around to sending it to her. I hope I can get in touch with her family at some stage and offer it to them instead.

Debbie’s blog on is still there and will be as long as the service is there (which is forever, right?), I’ve seen to that.

If you knew Debbie you might like to read the reaction from other people who knew her.

RIP Debbie.

Aperture ƒ/4
Camera Canon EOS 40D
Focal length 10mm
ISO 100
Shutter speed 384s

Call of the evening

A bird atop the light outside my house calls into the glowing evening sky heralding the end of 2007.

After walking Oscar I had to grab my camera and shoot the beautiful evening sky. The background was this colour, there’s no trickery here except a little vignetting and sharpening.

Shadows on Slea Head

Shadows from the broken clouds above play over the landscape on Slea Head in Co. Kerry. Every moment was a different photo until the rain eventually caught up with us!

Press the button and walk

A pedestrian traffic light on St. Patrick’s Street, Cork. The green man is strutting his stuff and people are walking across.

Does anyone else have a dislike for the design of this button? Sure, there’s a big arrow pointing to a large white dot, but it took several years for people to realise that they press the white button instead of the light at the bottom of the unit. The problem is that people are used to pressing a physical button, something that sticks out and can be pushed in. The white dot is flush with the surface of the unit, and people go to press the only thing that looks vaguelly button-like, the light. I still see people do it, and yes, this is one of my pet peeves, thanks for reading!