Update 2018
The Nikon CFI Plan 10X was part of a objective test with the Mitutoyo 10x, Nikon MM 10x, and Nikon 10X LU Plan.
Be sure to check it out how this objective does against the other Nikon lenses and the excellent Mitutoyo.
Nikon CFI Plan 10X Achromat Objective MRL00102 OBJECTIVE SPECIFICATIONS
Part Number: MRL00102
Official name: CFI Plan Achromat 10x MRL00102
Objective type: Clinical Laboratory and photography
NA and Nominal Aperture: NA 0.25, Nominal aperture: f/1.8, effective aperture: f/20
Focal length: 20mm
Parfocal length: 60mm
Working Distance: 10.5mm
Retail price: $255
Mounting Threads: M25 x 0.75.
Coverage: Very good, APS-C and up to full frame sensors
The CFI Plan Achromat 10x is probably one of the best Nikon objectives for photography with a big image circle and consistent image quality across the entire frame, rare qualities in my experience for a Nikon objectives. Nikon objectives, unlike Mitutoyo M or BD Plans, usually perform well, sometimes very well in the center, but most fall off quickly towards the corners. Also this Nikon objective is available for a reasonable price, about $225 new at most retailers, or less on the used market, the low price is also a little unusual for Nikon objectives. This is a highly recommended objective for someone just starting out at 10x or someone on a strict budget.
Links for more info:
The 10x Plan Achromat series on Nikon’s website:
The Nikon Plan 10x discussion on Photomacrography.net: