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Chasing a Comet, Finding Much More

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My good friend and exceptionally talented astrophotographer, Phil Hart invited me to go with him last weekend, to a country observing site to photograph Comet Lulin, and test out the 5D2 as an astrophotography camera. As you can see above, we were successful!

Below are a selection of my favourite photos and multimedia from the night, with descriptions. There are two embedded movies and two panoramas, which require Flash 9 to be installed [Download Flash]. Make sure you look at the panorama at the very bottom. I’m very proud of that one! :)

Top: The comet image was taken with Phil’s camera and lens, but I chose the composition and setup, and merged the images before processing. I guess you could call it a colaboration! Canon 40D, 200mm f2.8, 8 x 120sec exposures stacked and processed.

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Above: A beautiful young moon watched over us as we set up our equipment.

Above: Phil carries his telescope, used only for astrophotography, from the car to the tripod. Watch this movie in High Def at YouTube.

Click here to view a larger version of this panorama.

Above: A spherical panorama of our observing field, at the Leon Mow dark sky site, near Heathcote, owned by the Astronomical Society of Victoria (ASV). There were another dozen or so people observing on a different field, dedicated to telescopic observation, rather than astrophotography.

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Above: For much of the night, Phil used my new 5D MkII on his telescope, as seen above, to photograph the comet and to test the capabilities of the camera. I was content to let him use it, as I’m very curious to know its astrophotography capabilities. First impressions from Phil is that it is a very capable astrophotography camera. I entertained myself by continuing to shoot with my 350D.

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Above: Phil uses the 5D2 on his 530mm f3.3 telescope to photograph Comet Lulin, which can just be seen as a tiny green dot to the left of the bright blue Altair, above Phil’s hear near the top of the photo.

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Above: Phil and I weren’t the only ones photographing the comet. Another ASV member is seen here controlling his telescope from an attached laptop. All of these photographs with foreground elements and the stars behind were captured in single exposures, and not composited. They were typically 30 second exposures at 18mm f3.5 and 1600ISO on the Canon 350D. It’s amazing how good a dark sky can look in camera.

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Above: While the 5D2 was clicking away shooting an automated sequence, we visited the observation field, and were able to observe Comet Lulin through a gigantic pair of binoculars, 100mm (4in) in diameter. It was truly an incredible sight.

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Above: I also turned my 350D to the iconic Southern Cross for a 30 second exposure with my 50m f1.8. The stars are incredibly dense and beautiful in this area of the sky.

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Above: Once Phil had completed his tests with the 5D2, I was itching to get the fisheye lens onto the camera, to take advantage of the full frame and photograph the whole sky in a single shot. I did a sequence of almost 200 photos to create a time lapse, but for the photo above, I stacked 14 of the exposures together to minimise the noise and increase the brightness of the stars.


Night Sky Time Lapse by Fisheye.

Above is the full time lapse sequence built from the nearly 200 photos taken. Unfortunately the compression in the video at Vimeo doesn’t look great, but it’s better than the dreadful quality of the version at YouTube.

Click here to view a larger version of this panorama.

Above: Finally, I experimented with the all-sky photograph, as seen above, and turned it into an interactive panorama that you can click on and drag to look around the whole night sky. It’s really worth seeing this one bigger, so please click the link above. This has inspired me to try an photograph an all-sky panorama with my 50mm lens, and stitch all of the image together, to make a highly detailed interactive panorama of the night sky!

[Update] Phil just posted his own blog entry on the evening. Go check it out and see how a REAL astrophotographer shoots a comet – his photo is *gorgeous*: http://www.philhart.com/node/127

Inside the oven – P365 Mar06

A part of a series of photos exploring different views of everyday objects, this view from inside our oven is a three exposure HDR taken with the fisheye lens. Although it’s obvious our oven needs a clean, I love the gritty, grungy industrial look, and the dramatic perspective of the bars on the oven trays, pointing towards escape through the door.

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These the other photos in the series:

The washing machine.

Behind the steering wheel.

The dishwasher.

The fridge.

The microwave.

About macro extension tubes – P365 Nov03

This humble aluminium tube has opened up a whole new photographic world for me. The world of the small.

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A series of tubes

creek-071020-209All lenses have a limit to how close they can focus. A typical lens, for example, may not be able to focus on anything closer than 30cm. This is because as objects move closer to the lens, the focal point moves further back, eventually beyond the plane of the film or sensor. An obvious way around this problem is to move the lens further away from the camera. That’s what macro extension tubes do.

The macro extension tubes that I use are very cheap and simple. As you can see from the second photo above, it comes in five sections. At each end is a bayonet ring for mounting the tube to the lens and camera body (in this case Canon EOS). In between those any combination of three threaded tubes of varying length can be used to change the extension by varying degrees. That’s all there is to these tubes, nothing more.

Pros and cons

As with all compromises, there are trade-offs to the solution. This is especially true of a cheap, bare-bones solution like mine. Here’s the costs/benefits of tubes like mine:

Weaknesses

  • Moving the lens out from the camera sets an upper limit to how far away you can focus the lens.
  • There is no auto function control over the lens, such as aperture or focus.
  • The threads can be accidentally overtightened and thus become very difficult to seperate.
  • The centre of gravity is moved forward and there is no tripod mounting collar, putting greater stress on the camera body’s lens mount.
  • Moving the lens out and focusing closer makes the light rays more parallel at the focus point. This causes increased chromatic abberation which is much more obvious in high contrast macro photos.
  • No aperture control means that in order to change it, the lens has to be set to the desired aperture while on the camera body, then with the camera on, removed from the body while holding the depth of field preview button to keep the iris at the desired aperture.
  • Using the DOF preview hack to control the lens aperture, along with the fact that small scenes have less light on them, makes for an exceptionally dark view through the viewfinder.
  • With no autofocus and a dark viewfinder, focusing manually can be extremely difficult.
  • A natural and unavoidable effect of macro photography is an extremely small depth of field. This increases the need for a small aperture and the resulting dark viewfinder even more.
  • Extreme close-up macro photos put the lens so close to the subject, lighting it can be very difficult. Side or back lighting may become your only options, as the lens gets in the way of the light.
  • As there is no data connection between the camera and the lens, the camera has no idea what lens is attached, and as such much possibly useful information will not be stored in the images’ EXIF metadata. (Thanks to whipartist for this point, found via this discussion thread.)

Strengths

  • Photographic opportunities otherwise unavailable (without very expensive specialist lenses) are possible.
  • Dirt cheap! (Mine cost $30AUD including shipping)
  • Works with most lenses, except for those with very short focal lengths.
  • A light and compact addition to your gear. I carry mine with me everywhere.
  • Useful even with telephoto lenses. A long lens is great for making things bigger, but they can’t focus very close at all. An extension tube can allow you to enlarge with the telephoto but still maintain a good working distance.
  • Mechanically simple. There’s not much that can go wrong with these.
  • They’ll get you thinking about new ways to take photos. Extension tubes make your lenses a whole lot more flexible, and don’t just have to be for photos of insects or flowers.

Alternatives

creek-071010-044There are, of course, ways around many of these problems. The most obvious one (and one to which I one day plan to graduate) is using official brand name extension tubes. They most likely have the needed connections to allow full control of the lens from the camera, and each tube is bayonetted, making swapping and stacking them far simpler. Of course this makes them more complicated and more expensive solutions. The ability to keep auto focus and apeture control is a huge advantage likely worth the cost, however. Here’s an example of one Canon extension tube. Note the cost for a single extension, compared to that of my five piece no-name tube.

If you have a bigger budget, or enjoy macro photography enough to justify the cost, you can buy specialised macro lenses. These are great for macro photography. They eliminate many of the problems, especially chromatic aberation, and can get you extremely close to the subject. Also, extension tubes can even be fitted to these, resulting in the possibility of some insanely huge macro magnification. They are specialised optics, however, and can be quite expensive, especially when compared to extension tubes.

Lighting for macro

This can be an extremely tricky and frustrating issue. In fact it’s worthy of a detailed post in itself, so I’ll only mention it briefly here. There are many possible solutions, including:

Final thoughts and links

creek-071016-086Ever since I got these tubes, I’ve loved shooting macro photos. It’s a lot of fun and gives so many new opportunities. It’s a challenge to be sure, but that’s part of the fun. I plan to upgrade to “real” extension tubes in the future, but when the entry level gear is so cheap, there’s no reason at all not to try your own hand at macro photography.

Here’s some useful and inspirational links about macro photography:

View some of my macro photos at Flickr

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