===== Pentax SMC 17mm f/4 Fish-Eye =====
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==== Summary ====
The SMC Pentax 17mm f/4 Fish-Eye is a compact, manual-focus ultra-wide lens introduced in 1975 and produced until 1985, designed for full-frame K-mount film cameras. It delivers a 180° diagonal field of view while filling the frame rather than producing a circular image. With an 11-element/7-group optical design, Super Multi-Coating (SMC), and a 6-blade automatic diaphragm, it was Pentax’s only K-series diagonal fisheye prime, later succeeded by the A 16mm F2.8. The lens has no front filter thread due to its bulbous front element, but includes a built-in rotating turret with four internal filters: Skylight, UV, Yellow, and Orange—a feature especially useful for black-and-white film photography. It also accepts rear-mounted gelatin filters. The minimum focus distance is 20cm, offering 0.1× magnification, and the lens weighs just 234g, measuring 64.5 × 34mm—remarkably small for a full-frame fisheye.
==== Tech Specs ====
| Manufacturer |Pentax|
| Series |K Series Fish-Eye|
| Model |SMC|
| Focal Length |17mm|
| Max Aperture |f/4|
| Min Aperture |f/22|
| Format |Full-Frame|
| Image Circle |-|
| Minimum Focus |20cm|
| Focus Rotation |°|
| Iris Blades |6|
| Optical Design |11/7|
| Squeeze |none|
| Front Diameter |64.5mm|
| Filter Thread |none|
| Focus/Zoom Rod |none|
| Native Mount |Pentax K|
| Data Protocol |none|
| Length |34mm|
| Weight |234g|
| Body Telescope |-|
| Body Material |-|
| Focus Drive |-|
| Iris Drive |-|
| Zoom Drive |-|
==== History ====
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Release Date: 1975 \\
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==== Service ====
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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==== Notes ====
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