=====Mamiya-Sekor A APO 300mm f/2.8 ===== 
{{ :lens:apo3001.jpg?400|}}
==== Summary ====
==== Tech Specs ====
| Manufacturer    |Mamiya-Sekor|
| Series          |645|
| Model           |A APO|
| Focal Length    |300mm|
| Max Aperture    |f/2.8|
| Min Aperture    |f/22|
| Format          |645|
| Image Circle    |-|
| Minimum Focus   |138 in.|
| Focus Rotation  |-|
| Iris Blades     |8|
| Optical Design  |9 / 8|
| Squeeze         |n/a|
| Front Diameter  |n/a|
| Filter Thread   |rear 43.5mm|
| Focus/Zoom Rod  |n/a|
| Native Mount    |Mamiya 645|
| Data Protocol   |n/a|
| Length          |9.3 in.|
| Weight          |2660g|
| 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 ====
<nodisp 8>
Service Manual: (Insert link to manual here) \\
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Full CLA: **5-6 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: **6-7 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>\\
</nodisp>
==== Cine-Mod ====
<nodisp 8>
Focus Ring O.D.: \\
Zoom Ring O.D.: \\
Iris Ring O.D.: \\
De-click Y/N: Yes\\
<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>\\
</nodisp>
==== Notes ====
==== Media ====