Allied Shipyards Death of a superzoom (2011-09-17) My friend gave me her water-damaged zoom lens:

Tamron 18-200mm f/3.5-6.3 XR Di II (EF mount). The lens worked, but with severely degraded autofocus and image quality. I decided to disassemble the lens before discarding it.

View of the EF mount

Assembled in China

Filter diameter is 62mm

Lens is fully extended at 200mm

At any focal length other than 18mm, there is an air space between the rear element and the physical mount point

Another view of the air space

Mount point is plastic with a metal foil ring

Water damage on the rear inner surface

Mount point and first barrel segment removed

Removal of first barrel segment reveals non-ultrasonic focus motor and belt-driven gears

Removal of second barrel segment, inner portion

Another view of focus motor and gears

Removal of second barrel segment, outer portion

Removal of combined second barrel reveals how tall the rear element air space is (minimum is approximately 30mm)

Severe mineral deposition on multiple surfaces

This horizontal structure apparently indicates focus wheel position. (This is most likely Gray code. Thanks to Redditor "Chroko" for this info.)

Removal of third barrel segment reveals vertical structure which apparently indicates focal length

View of both indicators/encoders

Removal of fourth barrel segment

Fourth barrel segment encases fifth barrel segment which holds all lens elements, including front and rear elements

Fifth and final barrel segment. It twists on itself to position all lens elements, resulting in zoom and focus.



All five lens elements, in order from front element to rear element, compared to a US quarter and other objects.

The middle lens element, with ribbon cable, is the iris assembly holding the glass and another tiny motor.

Front element from camera side. Image is upside-down; view is slightly distorted.

Element 2 from camera side. Image is normal orientation; view is distorted, fisheye-style.

Element 3 (iris) from camera side. Image is upside-down; view is slightly distorted.

Element 4 from camera side. Image is upside-down; view is almost undistorted.

Rear element from camera side. Image is normal orientation; view is almost undistorted.

All parts of the disassembled lens. If attempted reassembly was intended, this would have been organized.

Iris, aperture completely open

Iris, aperture partially closed

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© 2011 Allied Shipyards. Noncommercial use only.