Darren’s Guide to Blue Hour Long Exposure Photography

June 18, 2010 at 2:10 pm (Howto, Photography, Software) (, )

Exposure: 8 Aperture: f/16.0 Focal Length: 11 mm

Picking your spot

Blue hour generally starts about 30-45 minutes after sunset. This will vary depending on your location on Earth, and the time of year. If you are a morning person rather than a night person, there is of course another blue hour which starts 30-45 minutes (or more) before sunrise. You probably want to plan to get to your spot just after sunset, to give yourself enough time and light to set up and try some test shots. I have found the best subject for blue hour photos is a well lit building or other structure such as the steamship above. You can also do scenics, but a well lit structure tends to come out better.

Camera Settings

I use a Nikon D90, and these settings tend to work for me. Your camera may be different, so these settings should be used as starting points. First of all, you’ll be on a tripod, so turn the AUTO-ISO off, and set ISO to the lowest available to your camera. This will likely be 100-200. Nikon cameras have a low ISO setting called Lo 1 Lo 0.7. You can try these settings if you like, but they are digital hacks, and I find I get great results with ISO 200. If your camera has a mirror lock-up feature, turn it on to ensure the sharpest shots possible.

Now if you are shooting RAW format (which you should be) you don’t need to worry about white balance. Just set it to ‘AUTO’ fire away, and you can easily adjust colour temp in post with your RAW editor. If you are shooting JPG, then you will need to know something about the type of light in your scene. There may be many types of lights which make it difficult to select a ‘correct’ white balance setting in camera. My advice: Try a few different setting for some test shots, and see what looks best. The most common lighting will probably be sodium arc, common in most street lights. Sodium lights will leave a pronounced red cast to your picture which will need to be corrected. Again, if you shoot RAW this will be trivial in post. If shooting JPG you will just need to experiment in the field and try to pick a white balance setting that looks good.

Exposure: 8 Aperture: f/11.0 Focal Length: 20 mm

Taking a shot

So you’ve mounted your camera on a tripod, framed your shot, and you’re ready to go. At the start of blue hour, there is still a considerable amount of light. Now don’t be afraid, put your camera on full manual (‘M’ on the dial on Nikon cameras) and set your aperture to about f13 or so. Set the shutter to 4-6 seconds. Now, you should always be using either a remote shutter release or the timer setting. The simple act of tripping the shutter is enough to cause camera shake, and a blurry picture. So: Frame, focus, fire, and review. Too bright? Cut the shutter time or choose a smaller aperture (ie: higher f-number). Too dark? Increase the shutter time or use a wider aperture (ie: lower f-number). Always review your shot and make corrections.

Now as the light gets darker, you will want to ramp up your shutter times and open up your aperture. I like to keep the aperture in the f/11 area for best depth of field, and also, you get nice starbursts from lights in frame with a smaller aperture. Keep taking shots. When you get to 30 seconds at f/11 you will need to start opening your aperture. I keep shooting until I am at 30 seconds at f/3.5. By this time, most of the blue in the sky is gone anyway. You can ‘prolong’ blue hour by shooting on nights with close to a full moon. The moon will light up the sky and reveal blue pretty much all night. I’ve been able to pull blue out of the sky very late at night using a 30s+ shutter and my largest available aperture.

Your AF system may have difficulties focusing at night. A well lit building will probably work fine but a scenic may cause problems. You may have to focus manually, or if your lens has a distance meter, set it to infinity, and everything farther than the lens’ hyperfocal distance will be in good focus.

Exposure: 30 Aperture: f/14.0 Focal Length: 26 mm

Doing some post

Now you should have several pictures on your camera, and you should be able to see pronounced blue even on the little LCD straight out of camera. Basically, first you want to adjust white balance/colour temperature. Use your RAW editors slider and see what looks good. Basically, you want to remove any colour casts created by ambient lighting sources. Again, the most common will be red. Move the slider until the red cast is gone, and points of light appear ‘white’. Play with saturation and contrast if you like, and also, raising the gamma a bit may help introduce a better dynamic range to your shot. Last step, run an unsharp mask and you should be good!

Hand-holding blue hour

If you don’t have a tripod or don’t want to use one you can also try to hand-hold a blue hour shot. While you will not get as sharp an image as if you were on a tripod, you can capture other things such as people, who will appear ghosted if at all on a long (2-3 seconds +) exposure, and moving vehicles which will likely show as a car-shaped blur rather than disappear completely leaving just the streaks from their lights as in a longer exposure.

To do this you will need as fast a lens as possible, probably at least an f/1.8. You will also have to crank up your ISO settings which will introduce some noise. The amount of noise is completely dependent on your camera’s high ISO ability. Full-frame camera’s such as the Nikon D700 always do better in this regard. You will also have to deal with relatively long shutter speeds, such as 1/30 of a second or longer. To ensure the sharpest shot possible I recommend placing your back against a wall or other solid surface, bracing the camera stiffly against your face, and slowly exhaling while pressing the shutter. Here’s a blur hour hand-held shot I captured in Edmonton:

Exposure: 0.033 sec (1/30) Aperture: f/1.8 Focal Length: 35 mm


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Homebrew Sabbattier Effect

December 29, 2009 at 2:57 am (Computers, Howto, Photography, Software) (, , , , , )

In photography, the Sabbattier Effect is a technique originally described by H. de la Blanchere in 1859 whereby some of the images tones are reversed. It is also commonly called solarisation. The technique seems to have been ‘invented’ many times over by many different people, the common thread being that it was introduced by inadvertently turning on lights during darkroom processing. After many years, the effect can be created while processing negatives, while creating prints, or in our case, digitally using a computer.

In any event, the effect creates a high contrast look that is especially well suited to architecture and other man-made subjects. In my opinion, the effect does not work all that well and looks rather unpleasant on human subjects and scenes from nature. Of course, given the right picture to begin with, there are always exceptions. Your best bet is to experiment.

Many photo editing software titles include a solarisation filter, however, if yours does not, or if you want more control over the final look I will describe a method for creating the sabbattier effect using only the curves tool and a desaturation filter (ie: convert to black and white).

The first step is to choose your subject, and to convert it to black and white. I choose a picture of the Erickson Building in Penticton BC, that I had cropped square. Here is the original shot:

Now after converting to greyscale open up your curves dialogue. Basically what you want to do here is create a ‘sine wave’ shape. Hard to describe, but easy to show…here’s what it looks like in digikam, including a preview of the result:

This step is wide open to experimentation. Try different shapes and levels on your curves. The more ‘oscillations’ you use in your sine wave, the more pronounced the effect will be as you can see here:

You’ll notice that abusing the curves tool in this way has introduced some colour artifacts back into the picture. Not a problem, just convert to greyscale once again, and that’s about it. Again, experimentation is the key here. Twist those dials and see what you can come up with. Now here’s the final results, first the mild version, and then the more extreme version:

So there it is. Please leave a note if you found this useful or not, or have any other concerns, questions, or comments. Thanks!

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December 8, 2009 at 11:48 pm (Camera Gear, Computers, Linux, Photography, Software) (, , , , , , , , , )

So I get lots of inquiries on flickr and other places where I post my pictures on how much ‘photoshopping’ (terrible verb by the way, Photoshop doesn’t exist on my chosen platform) I do if any, and people want to know what software I use and all that. So: rather than repeat myself every other day, I am just going to write a detailed account of my workflow here, and link folks who ask directly to it.

When it comes to hardware, it’s pretty simple. I built my photo editing and main desktop rig myself. A few main stats:

  • AMD Athlon 64 X2 Dual Core Processor 5200+
  • 4x 1GB 800 MHz DDR RAM for a total of 4096MB memory
  • 3x Hitachi HDP72505 500GB SATA HDD for a total of 1.5 terabytes of disk space

I have it running dual-head and have two identical Acer 20″ flat screen LCD monitors. As far as camera gear, I have a Nikon D40 body, and a Nikon D90 body. For more info on my camera gear please see the about page, there is more info on lenses and all that.

On the software side of things, I should mention that I don’t run Windows, no, not Mac either. I’m one of those crazy software hippies that use Linux. This has, of course, shaped my digital photographic workflow to a large extent, as most commercial software available to Windows and Mac users is not available to me. To be perfectly clear, I am just fine with that fact as I much prefer to use open source software if it is available.

So: say I’ve been out for a long hard day of shooting. I should mention here that I always shoot RAW format, in my case, producing Nikon’s ‘.nef’ files. Upon returning home the first thing I do is import all my files to my photo organizing software of choice: digikam. My directory structure goes like this -> ‘Raw Photos’ -> ‘year’ -> ‘month’ -> ‘day’. If I was shooting with both bodies, each will get its own directory suffixed with the body model. So pictures I shot on December 4, 2009 look like this:

My Albums/Raw Photos/2009/12/2009-12-04-D40/
My Albums/Raw Photos/2009/12/2009-12-04-D90/

I put the full date in the last directory name as the full path is not always visible, and I find the exact date to be useful information. I will immediately tag all photos in digikam with the geographic location of the shots, and with any other tags which may apply. Now I will begin with my inspection and culling of all the shots. I will ‘star’ any exceptional shots, and delete the obvious duds. All others, which make up the large majority, remain status-quo.

Next, after deleting the crap and identifying the pictures I wish to publish to flickr, I open my RAW editor, Raw Therapee. When I first started shooting RAW, I tried both Raw Therapee and UFRaw. Nothing wrong with UFRaw really, I just prefered Raw Therapee, so I standardized on it. You would do well to try both if you are looking for a RAW editor.

Raw Therapee screenshot

Above is a screenshot showing a typical view of Raw Therapee. Now as for actual editing, there’s a few things I do by default, and you can see from the capture on the left side that I have saved them as a preset called “Darren’s Default”. Basically it is only two things, and increase in contrast, and an increase in saturation (Raw Therapee calls this ‘color boost’). If the photo in question has some poorly exposed areas, I will try to lighten them using the ‘Highlights and Shadow’ tool in the ‘Exposure’ tab. Generally a small tweak here will lighten up the dark areas nicely. I find you don’t want to be too heavy-handed here, as it will make the photos a bit too tacky and HDRish. Yes, I have been guilty of this a few times. For some long exposures I will also do a white balance adjust at this point, for example, if street lights are creating an ugly orange/yellow cast on the photo.

That’s it for Raw Therapee. At this point I save the picture as a 16 bit TIFF file straight into the same directory in digikam that the RAW file came from.

So digikam has a few handy editing features built right in. At this point I will open the TIFF file for (lossless) editing. I use digikam to perform any black & white conversions and crops. I also use it to straighten the horizon if I flubbed it in camera. Obviously the previous steps only apply to a few photos. At this point however, almost every photo I take gets run through an unsharp mask. If the picture requires more drastic editing at this point such as cloning or selective desaturation (very few do) I would open the TIFF file with The Gimp at this point, and save back into digikam when finished.

So now I save each TIFF file I intend to publish to flickr as an 8-bit JPG to save on space and bandwidth. Here’s a screenshot of digikam, with the main window filtered to show only JPG files ready for upload to flickr:

digikam screenshot

So that’s about it. I use FlickrUploadr which is built right into digikam to upload my pics to flickr. This is also where they get resized to 1600px on the long side. I wish I didn’t have to do this but I was finding it took way to long to upload the original sizes. Perhaps if I ever get a superfast OC3 internet connection I may reconsider this 😉

To recap, the large majority of my shots, probably about 85% of them only have the following ‘photoshopping’ done to them:

  1. increase contrast
  2. increase saturation
  3. unsharp mask

That’s it!

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