Wide angle options
The image above is 11 minutes, ƒ/16, ISO 50 with in-camera noise reduction, using an Olympus Zuiko 21mm ƒ/3.5 lens on the 5D with a Cameraquest adapter. The center sharpness of this tiny prime lens is on par with Canon’s wide angle zooms, but the Zuiko walks all over the Canon 17-40mm ƒ/4L and 16-35mm ƒ/2.8L in the corners of the frame. The only significantly sharper lens at this focal length is the fabled Contax Zeiss 21mm Distagon, which currently runs $2500-3500 on the used market. Some people have also resorted to using the Nikon 17-35mm zoom on their EOS cameras with an adapter. Blasphemy!
If you use a 20D, 30D or other Canon dSLR with a smaller sensor, don’t throw your zoom on the junk heap quite yet. This problem is with the edges of the frame, which are not utilized by 1.6x crop cameras. But if you are a 5D, 1DS or 1DS MkII owner who has looked at your wide angle images at 50% or 100% in Photoshop, you’ll know what I’m talking about. Canon wide angle zooms show a loss of sharpness and smearing of detail near the edges of the frame, even when stopped down at ƒ/8 or ƒ/11. I would like to thank Mark over at 16-9.net for his extensive lens testing and comparisons. His site is a great resource.
Olympus Zuiko 21mm
Using aftermarket lenses on Canon EOS cameras can be an expensive and time-consuming rabbit hole to go down. Fortunately, the Zuiko lenses made for the Olympus OM system are quite small, light, and reasonably priced in most cases. The Olympus 21/3.5 usually sells in the $300–500 range. There is also a Zuiko 21mm ƒ/2 lens that will give you a brighter viewfinder image, and has an additional lens element for close focusing. This lens is usually $800–1000. Extensive specs and technical information on Olympus OM lenses can be found on the MIR website. The Olympus 18/3.5 and 24mm shift lens are both stunning performers that do not fall into the “reasonably priced” range.
The Zuiko lenses are manual focus, and the aperture needs to be stopped down manually. Manual focus lenses are great for night photography—unlike modern zooms and even high end prime lenses, most manual lenses have a decent manual focusing scale. Before shooting anything critical with manual focus lenses, I recommend taking test shots at different focus settings and analyzing the results.
Do not focus by only using the markings on the lens, or with an online depth of field calculator. The old trick of setting infinity on the focus scale one aperture wider than you are shooting may or may not work. You’ll get the best results by taking test shots at different focus settings to calibrate how the lens focuses on your camera.
For night photography exposure calculation, it’s easiest to pick an aperture and stick with it. I usually like to shoot at ƒ/8, both for sharpness and exposure time.
Perhaps the night photographer’s addendum to the "ƒ/8 and be there" axiom is "ƒ/8 and be there for 10 minutes."
I tested the Olympus 21/3.5 in the daytime at 5 or 6 different focus settings and made notes about where the focus ring was set. After analyzing the results in Photoshop, I determined I get the best results by shooting at ƒ/8 with the focus set at 3 meters.
Night photographers, do you see where I’m going with this line of thinking? No more fumbling with a flashlight and praying that your wide angle zoom focuses where you want it to. No more having someone stand in the photo holding a cell phone so you have something to focus on. No more taking 4 test shots at high ISO to gauge your focus accuracy before shooting. I just set the lens to the 3 meter mark, stop the aperture down to ƒ/8, and take the shot.
This focus setting also works just fine at ƒ/11 and ƒ/16, which is useful if you need a longer exposure. I wanted longer star trails in the above image—due to strong tungsten street lighting, I stopped down to ƒ/16 to get an 11 minute exposure.
I realize after finishing this article that it really could be entitled "in praise of the Olympus 21mm lens." It really is the full frame wide angle shooter’s best friend.
For more information on Zuiko lenses, have a look at Gary Reese’s extensive Olympus OM System Lens Tests. Adapters to use Olympus lenses on EOS cameras can be purchased from Cameraquest or Fotodiox.
Posted by: JOE REIFER