Nikon CFI Super Fluor Objectives are designed using ultra low dispersion fluorite elements (also know as flurspar) correct chromatically and spherically for two colors (red and blue). The superior correction of fluorite objectives, as compared to achromats, enables these objectives to be made with a higher numerical aperture, so they have better resolving power than achromats and provide a higher degree of contrast, making them better suited than achromats for color photomicrography in white light.

This article will give you information you need to know about using this objective for photography with specifications, price and availability, general information, set-up, and some comparison tests.

NIKON SUPER FLUOR 4X 0.20 OBJECTIVE SPECIFICATIONS

Nikon Part number: MRF00040

Official name: Nikon CFI Super Fluor 4X 0.20 Microscope Objective

Objective type: Biological microscopy

NA and Nominal Aperture: NA of 0.20, nominal aperture is f/2.0 and the effective aperture is f/10

Focal length: 50mm

Working Distance: 15.5mm

Mount: M25 x 0.75 mount

Parfocal length: 60mm

Chromatic Correction: Super Fluor objectives use fluorite or fluorspar elements to compensate for chromatic aberrations so they are correct chromatically and spherically for two colors (red and blue). The superior correction of fluorite objectives compared to achromats enables these objectives to be made with a higher numerical aperture, so they have better resolving power than achromats and provide a higher degree of contrast, making them better suited than achromats for color photomicrography in white light.

Tube lens length: 200mm. An infinity-corrected optical system consists of two parts – the objective and the tube lens system.

Chrome Free Infinity (CFI): The Super Fluor 4x is designed with the CFI160 optical system so aberrations are corrected within the objectives so there is no need for correction in the tube lens.

Country of origin: Japan

OFN: 25mm

Image circle coverage: Good for photography. The Nikon Super Fluor 4X field of view is specified as 25mm but it will cover an APS-C sensor with a 26-28mm diagonal.

Note: Fluor objectives are well know for having more than average field curvature that is not really a problem for photography since you will be stacking image anyway.

COMPARABLE OBJECTIVES

The more well known Nikon Plan APO 4x 0.20 objectives have the same numerical aperture and magnification as the S Fluor but they are not really suitable for macro photography due to the poor sensor coverage, where the S Fluor will cover a APS-C sensor without a problem.

Nikon-Super-Fluor-and Plan-APO-4x-Objectives-Robert-OToole-Photography-2018.jpg

PRICE AND AVAILABILITY

These objectives are not common on the used market but they are unknown so they can be bought for an excellent prices on Ebay if you are patient. In 2017 I got lucky and found an auction for mint Nikon S Fluor 4x came for only $399 where I was the only bidder. There are no S Fluor objectives available currently as I write this but earlier this month an S Fluor 4x sold as a Plan Fluor 4x for only $250 with only one single bid, so there are excellent deals to be found.

Full retail price: $2295.00
Typical Ebay used price: $400-500
Typical online dealer price: $1100

WHAT YOU NEED TO KNOW

What I like about the lens
Excellent sharpness over the entire field
Chromatic aberration correction

Things I don't need
This objective is not plan corrected so you will need to focus stack flat subjects. Field curvature is usually the most severe optical aberration that occurs in fluorite objectives.