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Where can I find a discussion of techniques used to get the best from my lenses?

Download Issue Number 4 of the Carl Zeiss Camera Lens News newsletter from the Carl Zeiss Lenses link at Links on this site.

Why are there no depth of field markings on the Contax G lenses ?

The markings are useful only if there is a manual focusing collar on the lens. Five of the 6 Contax G lenses do not have a manual focus collar.

With no Depth of Field Markings on the lens, how do you know the Depth of Field?

The G cameras owners' manuals have Depth of Field tables. There is a circular Depth of Field Calculator available at The Contax G Users Pages, http://www.novia.net/~jlw/contax/ . There are also Depth of Field products for sale through camera stores.

What is Depth of Field?

Depth of Field is the near to far distance where objects will be more or less sharply focused for a given focus distance on a given lens at a given aperture.

Without a manual focus collar on the Contax G Lens, how do you set a lens to its hyperfocal distance?

Switch your camera to manual focus and set the Hyperfocal Focal distance by turning the manual focus dial and reading the distance from the LCD screen on the top of the camera.

What is Hyperfocal Distance?

The Hyperfocal Distance is that focus distance set on a given lens at a given aperture where objects from one-half the Hyperfocal Distance to infinity are focused as sharply as is technically possible.

Are there any third party lenses manufactured for the Contax G cameras?

No.

What are the principle differences between Carl Zeiss G lenses and Leica rangefinder lenses?

Leica offers a greater selection of lenses as well as lenses which have a greater maximum aperture size; e.g., faster, than does Carl Zeiss. In a like to like comparison using each manufacturer’s data, the lens offerings from each manufacturer are comparable optical performers. Both manufacturers offer outstanding optical quality lenses.

Where do I find the Hyperfocal Distances for the G camera lenses?

They are listed under Miscellaneous.

There are two Hyperfocal Distances listed for each lens aperture, which one should I use?

Use the larger of the two numbers if you intend to print your frame to 8”x10” or larger print. Use the smaller of the two numbers where maximum depth of field is important, but your enlargement will be limited in size.

Why does the lens always return to a rest position rather than stay focused?

The lens must return to a known position in order to be focused again as there is no mechanical linkage between the camera body and the extent to which a lens is turned out. In addition the lenses are interchangeable. For both reasons, using a last known turn out distance could result in out of focus photographs.

Are the data for MTF plots for Carl Zeiss lenses generated from design standards?

How is the total Depth of Field distributed about the plane of focus?

Approximately one-third of the total DOF lies before the plane of focus and two-thirds is after the plane of focus.

There is a filter stuck on my lens. How do I get it off?

Place a rubber band around the filter ring, grasp the rubber band tightly, and unscrew the filter. If this does not work, camera stores sell plastic wrenches that can be used to remove stuck filters.

Is there an adapter that will allow me to use the Voigtlander Heliar 15-mm. lens on my G camera?

No.

Which focal length lens is the most useful? 

Aaron Sussman* collected the focal length and shutter speed given below data from 700 prints displayed by Leica in their New York City exhibitions. While the data may not apply to your style of photography, the data are the only data available that give any insight into focal length, aperture, and shutter speed choices.

Of the total of 700 prints, 78% were taken with a normal focal length
lens, 10% were taken with a wide-angle lens, and 12% were taken with a
telephoto lens. Of the total, 89% were taken at an aperture of 3.5 or
numerically larger, and 65% of those were taken at an aperture of 6.3 or
numerically larger. Eleven percent of the total were taken at an aperture
numerically smaller than 3.5.Fifty-three percent were taken at shutter
speeds of 1/40 sec. or faster, and 27% were taken at shutter speeds of 1/100
sec. or faster.

Overall, almost 80% of the photographs displayed by Leica were taken with a normal focal length lenses set at apertures of f/3.5 or numerically greater and using shutter speeds of 1/40 sec. or faster.

What is the definition of “T*” as it is used in Carl Zeiss T* Lens?

T* is the symbol Carl Zeiss chooses to use for its lens element coating technology. The coatings serve two purposes. First, the coatings reduce reflections from the internal lens element surfaces. The reduction in reflections increases the transmission of light through the lens thereby reducing internal flare. Carl Zeiss claims that their transmission standards are unsurpassed.

Second, the coatings are used to maintain a constant chromatic transmission between different Carl Zeiss lenses. Carl Zeiss claims they are the only lens manufacturer to do this. A constant chromatic transmission insures that the color spectrum produced by the CZ G 28-mm. lens, for example, is the same as those produced by any other CZ G lens. For that matter, the color spectrum is the same chromatic spectrum as that produced by any other CZ lens irrespective of lens mount or number of lens elements. No other lens manufacturer claims such a result.

*Sussman, Aaron; The Amateur Photographer’s Handbook, Eighth Revised Edition, pg. 115, Thomas Y. Crowell Company, New York, NY

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