Lens testing resources Index Publications

• Lens test sites
• Lens testing information and procedures
• Lens testing resources
• Optical theory references
• Photographic links
• Disclaimers and other information

Lens test sites

Many members of the of the Pentax Discuss Mail List (PDML) have been active in the establishment of both subjective and quantitative lens test sites. Some of following links appear to be the most successful of their type in the on-line photographic world.

Pentax biased:

• Pentax Lens Gallery A subjective display of lens performance under real world conditions.
• Yoshihiko's PHOTO site A quantitative test site backed by excellent subjective commentary.
• Ralf's Photography Page Quantitative tests of Pentax 50mm prime lenses by Frederick Wasti.
• Pentax Lens Review by Peter Spiro Subjective lens performance tests.
• Pentax medium format vs 35mm lens test A relative comparison of MF and 35mm lenses.
• Jostein Øksne - Test of 645-A 120mm f/4 macro and 35mm converter A subjective view.
• Stan's Pentax Photography Subjective lens performance comments by PDML members.

General:

• WWW PHOTO ZONE A survey style compilation of subjective lens ratings.
  
• Photodo! A commercial lens test site, a good source of quantitative tests including MTF plots.
  

Lens testing information and procedures

The following links provide lens testing procedures and perspectives, some authors argue that lens testing is an absolute waste of time and others provide entertaining arguments for the exercise.

• Bojidar Dimitrov's Pentax K-Mount Equipment Page The definitive reference for Pentax K mount.
• The Unofficial Asahi Pentax Spotmatic Home Page Screw mount information by Peter Jonkman.
• Large Format Lens Test Review Discussion of testing methods and theoretical limitations.
• Lens Tester A sarcastic commentry on the value of lens testing by Stephen Gandy.

Lens testing resources

The following links provide lens testing guides, utilities and charts.

• USAF test sheet An aproximation of the USAF test sheet (A4 210mm x 297mm) for printing (Adobe Acrobat pdf ~11kB generated from the PostScript program by David Jacobson). When printing using Acrobat Reader ensure that the print box "Fit to page" check box is unchecked. For accuracy the largest test pair at the bottom right of the test sheet (with the "1" adjacent to it) should measure exactly 16mm between adjacent line pairs.
• USAF lens testing worksheet Translates USAF test chart measurements to lpmm for each lens and test distance (Excel 5.0/95 ~9kB zip).
• USAF lens target to lpmm Translation table of USAF test chart targets to lpmm for a specific lens and test distance. (Excel 5.0/95 ~4kB zip).
• Optical worksheet by Bob Walkden Hyperfocal distance, depth-of-field, image size, subject distance and focal length calculations.
• f/Calc A Windows utility for photographers that calculates various lens formulæ; "f number", depth of field, hyperfocal distance, field of view, angle of view, magnification and spot meter angles.

Optical theory references

The following links represent some of the best optical references available on the Internet.

• Photographic Lenses Tutorial A summary of optical facts for photographers.
• Frequently Asked Questions Regarding Lenses A FAQ about lenses intended for photographers.
• Lens FAQ A FAQ about lenses for photo.net photographers.
• Optics pages Excellent notes and illustrations of optical aberrations by Paul van Walree.
• Merklinger's Magazine Articles 91-97 Excellent white papers on "Bokeh" etc.
• Quality Criteria of Lenses A white paper by Schneider Optics (Acrobat pdf).

Disclaimers and other information

The text contained in this document represents my opinions only, and as such I will not be held liable for detrimental consequences that arise from the application of any information within or relating to this document. All references to trade marks and or trade names are acknowledged as belonging to their respective owners.

This complete document may be copied, re-posted, linked-to or used within other publications providing that permission from the author is sought and granted and that there exists a visible reference to Rob Studdert as author in any referring text.
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Rob Studdert
Digital Image Studio
distudio@swiftdsl.com.au
28th February, 2000

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