Camera Accessories

The Lensbaby Composer fitted to Photo Review's EOS 40D showing the adjustment of the front of the lens to shift the focus 'sweet spot' off-centre.

Each Lensbaby comes with a set of Waterhouse stops for adjusting aperture settings. These interchangeable discs range from f/2.8 to f/22 in full-stop increments. They are stored in a circular 'pill box' receptacle with a pull-of cap that looks like a 35mm film canister lid. It's about 7mm thick and attached to the magnetic 'wand' that is used to extract and replace the discs, as shown in the illustration below.

The Lensbaby Composer kit showing the optic, interchangeable apertures, attachment wand (plus aperture container) and lens cap.


Using the magnetic 'wand' to change apertures.

The apertures are held in place magnetically and, by default, provide a depth-of-field preview of each shot for each aperture you fit. Although the viewfinder image remains reasonably bright with apertures up to about f/5.6, it darkens progressively and becomes very dark with the smallest apertures. It's difficult to compose shots and adjust focus by f/11 and almost impossible at f/16 and f/22.

In practice, you probably won't use the smaller apertures much as the blurring effect of the lens (which is the reason for purchasing it) is most pronounced with the widest aperture settings. Best results are obtained with apertures between f/2.8 and f/5.6. This happens because the lens achieves the selective defocusing through the optical system's inherent severe spherical aberration.

Unfortunately, this aberration makes accurate focusing difficult when the front section has been slewed off-axis so best practice is to compose the shot and focus with the f/2.8 aperture in place and then stop down by substituting a smaller aperture, if a greater depth-of-focus is desired.

The Lensbaby Composer consists of a ball and socket housing with a doublet lens installed in the front (ball) section. The lens pivots on the ball assembly, allowing it to be swung up, down or to the right or left (or anywhere in between). You simply push the front element of the lens one way or the other. Friction holds it in place and adjustments can be made with one hand.

The tightness of the ball joint can be adjusted by turning the black ring near the lens mount, which can also be used to lock the joint in place. This joint may require some adjustment until you find the right balance between tightness and ease of movement for your requirements. After that, you may never need to adjust it again.

Twisting the focusing ring at the front of the lens sharpens the image in the viewfinder. The Composer was usable with the 40D's live view system but we found the viewfinder provided a clearer view that enabled greater precision.  Focusing the Composer can be challenging, although the logic behind the system is quite straightforward. The further out the lens is from the camera, the closer it focuses; pushing it back towards the camera body shifts the focus towards infinity. Fine-tuning requires the focusing ring.

Interestingly, you need to turn the focusing ring through a wider angle as you approach infinity. This makes it easier to focus on mid-range and distant subjects. Close-up focusing can be tricky as finer movements are required. (The Composer's focusing limit is around 30 cm.) Unfortunately, the position of the focusing ring makes it easy to move inadvertently when changing the angle of the lens and the focusing ring moves very easily. Consequently, you usually need to re-focus if you've moved the lens at all. 

Compared to Tilt/Shift Lenses
Superficially, the Lensbaby Composer appears to achieve a similar effect to tilt/shift lenses for a fraction of the cost. However the two lens types are quite different. Lensbaby lenses have a curved plane of focus, while in tilt/shift lenses the plane of focus is flat. This means the areas of unsharpness are much more controllable and the gradations between sharp and unsharp areas are smoother and more natural looking.

Optical quality is significantly better with tilt/shift lenses and the plane of focus is more controllable. Modern tilt/shift lenses also possess electronic contacts that enable them to communicate with the camera's microprocessors. This means autofocusing is supported and you can meter at full apertures as the camera will stop down automatically to the selected aperture setting. Exif metadata transfer to image files is also supported. Tilt/shift lenses are also faster to use.

Optic Swap System
Introduced at Photokina 2008 with the new Lensbaby models is an interchangeable optical system that increases photographers' options. While each Lensbaby ships with one lens installed, the Optic Swap System enables them to change lenses and achieve different effects.  Four swappable lenses are currently available:
- Optical glass doublet (two lenses). This lens is supplied with the Composer and has a focal length of approximately 50mm on a 35mm camera. RRP is $135 when purchased separately.
- Optical glass singlet (one lens). An uncoated 50mm focal length like the original Lensbaby. RRP is $62 when purchased separately.
- Plastic lens. A high-diffusion single lens that can make your $1500 DSLR simulate the effects of plastic cameras like the Diana, Holga and Lomo. RRP is $62 when purchased separately.
- Pinhole/Zone plate. An optic cup with an f/177 aperture for pinhole photography and an f/19 Zone plate opening.  Users can slide a toggle to change between Pinhole and Zone plate mode, RRP: $62.00,

The Single Glass, Plastic, and Pinhole/Zone plate optics will be sold individually as well as in an Optic Boxed Set that will retail for $169. Each lens comes with an Optic Swap Tool that doubles as a cap to the carrying case. This tool is used to pop the installed lens out and lock the new one in. 

Performance
For our test shots, we took two series of shots covering the full aperture range, the first with the Composer focused centrally and the second with the 'sweet spot' moved to the left hand edge of the frame. Blurring outside the focus 'sweet spot' could be seen in all shots, although it was much stronger at large apertures and by about f/8 looked more like a defect in the lens than a deliberate effect.

Adjusting the focus 'sweet spot' was easiest when it was closer to the centre of the frame. Swinging it towards the periphery of the frame made it difficult to determine exactly what was in and out of focus and very hard to find the actual 'sweet spot' - even with the f/2.8 aperture.

Using Waterhouse stops provides plenty of potential to experiment with making your own set of lens apertures, using shapes like starts, hearts and other geometrical forms. You can also try different filters for additional variations since the Composer's lens cap clips into a 37mm filter thread.

Running Photo Review's standard Imatest tests across the full aperture range of the Lensbaby Composer provided an excellent way to demonstrate the inherent spherical aberration in the optical system. All test shots were taken with the 'sweet spot' positioned on the test target closest to the centre of the field of view to maximise the chances of obtaining high resolution figures.

When the test shots were analysed, blurring was such at the periphery of frames that Imatest could not recognise the selected area as being able to be evaluated and no readings were possible for apertures from f/2.8 to f/5.6.  The results of our tests are shown in the graph below.

Three key factors can be derived from this graph. The first is that overall resolution at the focus 'sweet spot' isn't particularly high. By way of comparison, the results of our Imatest tests for the EOS 40D with the EF-S 17-85mm f/4-5.6 IS USM kit lens produced line widths/pixel height figures of 2246 for centre and 2152 for edge with a test shot taken with a 35mm focal length and aperture of f/8.  In contrast, the Composer yielded figures of 1857 and 345.8 respectively.

You can also see a steady increase in resolution as the Composer is 'stopped down'. We suspect this is largely a result of the increased depth of field, which makes progressively longer sections of the test target appear sharp. Finally, the abrupt loss of centre resolution at f/22 is likely to be due to the effects of diffraction since edge resolution continued to rise at f/22.

Interestingly, lateral chromatic aberration was consistently low or negligible for all our Imatest assessments on the Composer.

Photo Review's assessments of this lens have concentrated on its technical aspects, rather than its creative potential.  If you'd like to see some of the creative effects other photographers have achieved, go to www.flickr.com and search on Lensbaby Composer. When we searched there were 1,335 images to view.

Buy this lens if:
- You love experimenting with special effects.
- You need selective focusing but can't afford a tilt/shift lens. (See above for the differences between them.)
- You're happy with a slower-paced style of photography and can cope with the time required to change apertures and take test shots plus the need to use a tripod for most shots.

Don't buy this lens if:
- You require optimal image quality from your camera.
- You need to shoot quickly.
- You don't have/use a tripod.
- You tend to mislay small items of equipment. 

IMATEST GRAPHS

SAMPLE IMAGES

Centre focus, f/2.8, 1/90 second, ISO 200.

Centre focus, f/22, 1 second, ISO 200.

Edge focus, f/2.8, 1/30 second, ISO 200

Edge focus, f/22, 1 second, ISO 200.