Black Rapids Lock 13 - Rideau Canal taken during Blue Hour

[Manfred M]

Blue hour is the period between sunset and the end of civil twilight. The sun has dropped below the horizon, but there is still enough light to see. At this time of year, civil twilight lasts about 40 minutes, and this shot was taken about half-way through that period.

The subject is the Black Rapid Lock (Lock #13) on the Rideau Canal, just south of Ottawa, on the Rideau River, taken in the winter.



The south gate of the lock can be see, as well as the lock walls. One of the old winches that used to operate the gates can be seen on the left; this is no longer used as this lock has been converted to being operated using hydraulics.

The shot was taken with the Nikkor f/2.8 14-24mm lens using a focal length of 15mm. I shot with a tripod at f/16 to ensure the tuft of grass, which was around 30 cm / just over 1 ft in front of the camera and everything in the distance was in focus.

[chauncey]

Manfred, I've got a problem, I really like that image...but I can't figure out why.

[Mike Buckley]

Wonderful composition and detail in the snow!

[Suzan J]

Hello Manfred: I have never heard the term "civic twilight". At first I thought it must be something new for the Ontario government to tax... This image looks really good in lightbox as everything is very crisp as you had intended. I think you have captured that "winter feeling" quite well.

[Manfred M]

Hello Manfred: I have never heard the term "civic twilight". At first I thought it must be something new for the Ontario government to tax... This image looks really good in lightbox as everything is very crisp as you had intended. I think you have captured that "winter feeling" quite well.

Thanks Suzan - there are three separate official definitions of twilight, and all are related to the position of the sun below the horizon.

Civil twilight is the period after sunset when on a clear day, we land dwellers can still see without resorting to artificial light. The end of civil twilight occurs when the sun is 6° below the horizon.

Nautical twilight is the period where sailors can still make out the horizon on a clear day for navigational purposes. The end of nautical twilight occurs when the sun is 12° below the horizon.

Astronomical twilight occurs when the sun is 18° below the horizon and is when astronomers can start serious observations of even the faintest light sources in the sky.

[Shadowman]

Very nice.

[NorthernFocus]

Manfred, this shot is a good demonstration of the effects of an ultra-wide angle lens. Am I correct in assuming this was shot with the D800? So you got the full effect of he UWA lens. It's amazing that the grass is that close to the camera. I've never worked with anything wider than 24mm(effective) and that rarely. Every year I plan to get an UWA lens to try shooting mountain flowers but it never moves high enough on my priority list.

You mention the civil twilight. It is an odd phenomenon in northern latitudes. Ours is currently getting shorter every day and will do so until the equinox. Then it starts getting longer. I've never taken the time to study the spherical geometry to understand that. Then for nearly a month from early June through early July, from sunset through to sunrise meets the definition of civil twilight. When one goes hiking that time of year there's no risk of getting caught out after dark

[Polar01]

Great shot Manfred and you got it on a day without wind, I use to do a little sailing loving the wind, this winter and I like winter a lot but the wind starting to hate wind.

Cheers: Allan

[Manfred M]

Manfred, this shot is a good demonstration of the effects of an ultra-wide angle lens. Am I correct in assuming this was shot with the D800? So you got the full effect of he UWA lens.

Correct. D800, f/2.8 14-24mm Nikkor and my heavy duty tripod (this was a 4-second exposure). I'm actually quite surprise by the amount of CA in the shot (easily corrected for, of course).

The shot also demonstrates the "trick" when using UWAs. You need something in the foreground to break it up; which is why the tuft of grasses is the shot. If one doesn't do this, the risk of a shot that is all foreground and sky is quite high. Even moving by a couple of inches / cm can make or break the shot.

The following shot shows how drastic this can be when using a UWA.






This image was taken 45 minutes before the other one, during "golden hour". On my way back to the car, I decided to take another few shots and dropped my tripod legs in the same holes in the snow that marked my previous shot and shot at a 15mm focal length, rather than at 14mm. A 1mm focal length difference when shooting a UWA makes a lot of difference compositionally.

[NorthernFocus]

An interesting exercise in the use of UWA, Manfred. Thanks for doing that. I'm becoming more convinced to delve into UWA if for no other reason than the learning adventure. But I really like many images that are made with UWA technique. Yet another piece of kit....