=====Mamiya-Sekor C N 45mm f/2.8 ===== 
{{ :lens:45533_6-1114x1160.jpg?400|}}
==== Summary ====
==== Tech Specs ====
| Manufacturer    |Mamiya-Sekor|
| Series          |645|
| Model           |C N|
| Focal Length    |45mm|
| Max Aperture    |f/2.8|
| Min Aperture    |f/22|
| Format          |645|
| Image Circle    |-|
| Minimum Focus   |1.5" / 0.45m|
| Focus Rotation  |-|
| Iris Blades     |6|
| Optical Design  |9 / 7|
| Squeeze         |n/a|
| Front Diameter  |2.752"|
| Filter Thread   |67mm|
| Focus/Zoom Rod  |n/a|
| Native Mount    |Mamiya 645|
| Data Protocol   |n/a|
| Length          |2.8 in.|
| Weight          |475g|
| Body Telescope  |-|
| Body Material   |-|
| Focus Drive     |Manual|
| Iris Drive      |Manual|
| Zoom Drive      |n/a|
==== History ====
Country of Origin: Japan \\
Release Date:  \\
Launch Price:  \\
Design Revisions:\\

==== Service ====
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Service Manual: (Insert link to manual here) \\
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Full CLA: **6-7 hrs.**\\
<wrap note>Enter relevant notes here</wrap>\\
Spray and bake threads: **+1 hrs.**\\
<wrap note>Enter relevant notes here</wrap>\\
Haze / separation in doublets\\
<wrap note>Do not offer to correct. Cost and risk is too high. Replacing with a donor lens/element is recommended.</wrap>\\
PL/EF mount conversion\\
<wrap note>PL or EF mount conversion is available for most Sekor C primes that are in the original Mamiya 645 mount. Conversion not available for lenses with an integrated shutter system or the Mamiya RZ mount system.</wrap>\\
Re-anodize exterior: **7-8 hrs + $50/part** (typically 5-7 parts)\\
<wrap note>some focal lengths may have helical attached to rear housing, if so, additional lapping is required after anodizing. Sekor C lenses have plastic housings. Be careful offering anodizing!	</wrap>\\
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==== Cine-Mod ====
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Focus Ring O.D.: 2.912"\\
Zoom Ring O.D.: \\
Iris Ring O.D.: 2.75" (see notes)
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De-click Y/N: Yes\\
Additional Notes: \\
<wrap note>Additional Notes:Iris gear is possible but not generally recommended since the surface area is very slim, the gear will cover the stop numbers (unless a custom segmented gear is made and attached via screws into the iris ring) and the iris rings on some Mamiya-Sekor lenses, specifically the C N variants, is plastic, which can flex. Generally, iris rings on the C versions are aluminum, while the iris rings on the C N versions are plastic. The quickest way to distinguish between a C and a C N variant (besides, of course, looking at the engraved serial ring — the C will always be green, while the N will be white) is the texture of the rubber focus grip. If the grip has a diamond texture, it is a normal C version. If the grip has an elongated bar-type pattern, it is a newer C N version.</wrap>\\

Mamiya Focal Reducer Project Synopsis (Failed):
The goal of this test was to bring the Mamiya Sekor-C lens from 645>FF. While the focal reducer did indeed reduce the focal length, the optics in this particular model of reducer are designed for FF>S35.
While we are technically able to achieve a proper image, the coverage doesn't quite resolve a proper Super 35mm image, and the part we would need to fabricate would look ridiculous.  It sticks out so far a custom PL cap would need to be designed as well.

{{:lens:mamiya_focal_reducer.jpg?direct&400|}} \\

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==== Notes ====
==== Media ====