===== Pentax-A 645 SMC 80-160mm f/4.5 ===== 
{{ :lens:pentax-a645smc80-160mmf4.5.png?200|}}
==== Summary ====
The SMC Pentax-A 645 80-160mm f/4.5 is a manual-focus telephoto zoom lens introduced in the mid-1980s for the Pentax 645 medium format system. Covering a focal range equivalent to approximately 63–126mm in 35mm terms, it was designed to bridge the gap between standard and short telephoto primes—making it a flexible option for portraiture, landscape, and general-purpose photography. Though later replaced by the autofocus FA version, the A-series model remains popular for its optical quality, mechanical precision, and affordable price on the used market. Optically, it features an 11-element, 11-group design with Super Multi-Coating (SMC) and an 8-blade automatic diaphragm, stopping down to f/32. The lens focuses as close as 1 meter, delivering a 0.17× magnification ratio, and uses a 77mm filter thread. It weighs 1010g, measures 82.5 × 131mm, and includes a manual aperture ring with an “A” setting, enabling full program and shutter-priority modes on compatible bodies. There’s no internal focusing, and the front element rotates during focusing—making polarizer use a bit cumbersome. A screw-in RH-A hood and S90-160 soft case were typically included.
==== Tech Specs ====
| Manufacturer    |Pentax|
| Series          |Pentax-A|
| Model           |645 SMC|
| Focal Length    |80-160mm|
| Max Aperture    |f/4.5|
| Min Aperture    |f/32|
| Format          |645 film|
| Image Circle    |-|
| Minimum Focus   |100cm|
| Focus Rotation  |°|
| Iris Blades     |8|
| Optical Design  |11/11|
| Squeeze         |none|
| Front Diameter  |82.5mm|
| Filter Thread   |77mm|
| Focus/Zoom Rod  |none|
| Native Mount    |Pentax 645|
| Data Protocol   |none|
| Length          |131mm|
| Weight          |1010g|
| Body Telescope  |-|
| Body Material   |-|
| Focus Drive     |-|
| Iris Drive      |-|
| Zoom Drive      |-|
==== History ====
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==== Service ====
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Service Manual: (Insert link to manual here) \\
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Full CLA: **TBD hrs.**\\
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==== Cine-Mod ====
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Focus Ring O.D.: -\\
Zoom Ring O.D.: -\\
Iris Ring O.D.: -\\
De-click Y/N: -\\
Additional Notes: \\
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==== Notes ====
==== Media ====