OVERVIEW

The 28mm F2.0 Distagon is a rare lens compared to its little brother - the F2.8. The 28mm F2.0 Distagon’s optical formula is based on a Zeiss 28mm cinematic lens. The lens design was subsequently adapted for 35mm SLR use, so sometimes the 28mm F2.0 Distagon is referred to as the “Hollywood 28”. One of the key features of the 28mm F2.0 Distagon is the floating element design which provides significantly better near field performance and allows for a very short minimum focus distance.

The 28mm focal length is a very interesting discussion in and of itself. As a lens’ field of view (FOV) gets wider, more corrections are needed to convert the FOV into a rectilinear perspective. Depending on who’s opinion adopt, wide angle photography starts around 28-35mm on a full-frame dSLR. The 28mm focal length is at the upper bound of that range, so a 28mm lens does not require as much correction as 25mm, 21mm or 18mm lenses. Pictures with a 28mm lens have a wide angle feel, but still look natural without feeling overly corrected.

The Contax 28mm F2.0 Distagon excels at close-up photography. Compositions with a slight upward angle (taking advantage of the wide angle “feel”) produce a very bold perspective. The Contax 28mm F2.0 Distagon has a floating element lens design, so it resolves near subject matter very nicely. The three pictures on this page were selected because they illustrate the 28mm’s close focus abilities.

The 28mm’s end result is a natural looking wide angle FOV - especially compared to 21mm or 24mm. When it comes to shooting architecture or other subjects with straight lines and planes, 28mm can be an excellent choice due to its reduced distortion (compared to wider lenses). Compared to the Contax 28mm F2.8, the F2.0 version offers greater - the faster aperture provides more flexibility, the floating element design delivers excellent near field sharpness and by F5.6 the edge-to-edge (corner sharpness) performance is simply outstanding.

LENS PERFORMANCE

As stated above, adding a floating element improves resolution, sharpens corners and provides better frame illumination across the entire focus range. Most often a floating focus design is used to improve near focus performance. The use a floating element can helps minimize (possibly eliminate) focus shift. Focus shift is the shifting of the plane of focus as the aperture is changed. For example, the new Canon 50mm F1.2 L has a very nasty reputation for focus shift.

The Contax 28mm F2.0 has a shallow depth field (F2 or F2.8) with outstanding near field performance, thus the lens is ideal for full length portraits and close-up photography. Add in the drama created with 28mm lens, and F2.0 Distagon is without peer. Normally one would not think, “Ahhh 28mm, yes a good lens for product shots,” And they would be even less likely to think of CLOSE-UP shots. The 28/2 excels in this application. The Canon EF 35L F1.4 is better up to about F2.8, but past F2.8 the Contax 28/2 is unbeatable. The Contax 28mm F2 was about 10 inches from the flash tube for the above picture. The 28mm F2.0 Distagon also does very well with regular landscape pictures with the focus at 20 feet, 30 feet, infinity, etc. By F5.6 the lens is perfectly sharp from corner to corner and easily out-class lenses such as the Canon EF 35mm F1.4 L USM.

Soft corners and wide angle lenses go hand in hand. Photography forums such as DPreview or Fred Miranda have one post after another complaining about XYZ lens having poor corners. Soft corners are not always due to poor lens performance, in most cases the problem is adequate depth of field (DOF). As an extreme example, a 15mm lens on a full-frame 35mm dSLR focused at infinity at F4 will not have nearly enough DOF to have sharp lower corners. Wikipedia has a nice write-up (click here). To calculate DOF, this is a handy website: www.dofmaster.com/dofjs.html. Keep in mind DOF is not absolute - it varies with each lens design. For example, The Contax 100mm F2 Planar and the Canon EF 100mm F2 USM both may have different DOF at F2. A DOF table is a general estimate or guide.  (Continue to next page)