Nikon Rayfact GF 82mm f/4 Line Scan Lens
Updated March 2024
Tochigi Nikon designed the Rayfact GF lens line for industrial use, fine pattern inspection and defect detection, within the production process of FPDs (flat panel displays), and PCBs (printed circuit boards) using AOI (automated optical inspection). Designed for use with high-resolution industrial line scan cameras with a pixel pitch down to 4.7 μm and a 43mm line width the GF should be just a about a perfect match for full frame digital cameras.
On paper the GF specifications are just about ideal for a full frame camera and when you consider the cost for a used copy is close to or lower than a plain Nikon enlarging lens the lens is really hard to ignore. Rayfact lenses have been been pretty much ignored by collectors and resellers thankfully. The high-end specs and low price seem too good to be true so our goal here is to find out if the GF lens image quality meets our high expectations.
The model tested used for this test is the GF 0.47X version, which is the most popular model found on the used market, but there are a total of 4 lenses in the GF series lineup for reference in case you come across one of these on the used market.
Nikon Rayfact GF 82mm f/4 0.2X QVM0235023MF
Nikon Rayfact GF 82mm f/4 0.47X QVM05041MF
Nikon Rayfact GF 83mm f/4 0.70X QVM07052MF
Nikon Rayfact GF 83mm f/4 1.0X QVM10065MF
Key Features of the GF lens
Fast f/4 maximum aperture
0.47X magnification forwards and 2.0X in reverse
Apochromatic
Diffraction-limited
43mm image circle means coverage for full frame sensors
Standard thread mounts
Flat image field with no corner shading
All metal barrel with locking aperture ring
80mm FL requires less extension
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GF 2.1x Test: APS-C sensor
In this test the GF was compared to two other high-performance lenses at 2.1X.
Canon MP-E 65mm 1-5x Macro Lens
Nikon Rayfact GF 82mm f/4 0.47X QVM05041MF
Schneider 85mm Macro Varon CAS Line Scan Lens
2.1x Test results
Silicon Wafers are perfect targets for testing a lens. They have lots of sharp details in different shapes and sizes and they are completely flat and will not warp or twist in the middle of a test like naturals subjects like to do. Most importantly they have a lot of ultra fine detail, some, like the one below, have tiny micro-letters and numbers etched into the wafer.
All of the images below are from a single file and were chosen out of a stack of images. The images were made at sharpest aperture for each lens, wide open for the Rayfact, and Schneider, and stopped down to f/4.5 for the Canon MP-E. For consistency all of images were made on a MM-11 microscope stand with two Godox TT-350 flash units and X1T wireless trigger.
Click on any image below to launch a new window with a larger version. You can right click, or two-finger click with a Mac and select the open in a new tab or new window options.
Nikon Rayfact GF 80mm F4 line scan lens image at 2.1x
This is the full wafer test area resized down to 1500 pixels, click on the image for a larger version.
The test wafer on the left, the blue outlines indicate the crop areas.
Clicking on the image below will open in a new window, or right click, or two-finger click on a Mac, and select open in a new tab or new window to see the full size version.
This is the central area at 100% view in Photoshop. The Canon MP-E on the left, the Rayfact in the center, with the Macro Varon on the right. Rayfact has the advantage in sharpness.
All the lenses do a good job here resolving plenty of sharp details. The Canon MP-E was the weakest of the three and was stopped down to f/4.5 for better CA control.
Clicking on the image below will open in a new window, or right click, or two-finger click on a Mac, and select open in a new tab or new window to see the full size version.
This is the edge area at 100% view in Photoshop. The Canon MP-E on the left, the Rayfact in the center, with the Macro Varon on the right.
All three lenses resolve the lettering and numbers well, which I think is amazing, but the bright pink lateral chromatic aberrations in the Canon MP-E crop, obscure details, making it appear to be less sharp than the others. The Rayfact and Macro Varon are very close with a slight advantage going to the Rayfact.
Clicking on the image below will open in a new window, or right click, or two-finger click on a Mac, and select open in a new tab or new window to see the full size version.
This is the corner area at 100% view in Photoshop. The Canon MP-E on the left, the Rayfact in the center, with the Macro Varon on the right.
The Rayfact has a clear advantage in sharpness, contrast and the best CA suppression with the cleanest blacks. The Canon image details are sharp but the red fringing makes the image appear to be less sharp and the blacks are less neutral and with less contrast then the others. The Macro Varon shows a slight drop in performance at 2x in the corners where the GF shows no drop off in image quality across the field.
All of these images were made with the identical lighting, camera settings, and processing. The Canon has an obvious issue with lateral chromatic aberrations.
GF 2.1x Test Final Verdict
The Nikon Rayfact GF 82mm 0.47X deserves our highest recommendation for use on full frame cameras. The GF produced clean, sharp true high-end image quality that Rayfact lenses are known for.
For now GF lenses are one of the best price vs performance buys you can buy selling for ridiculously low prices, lower than a standard Nikon 50mm enlarging lens on eBay. This is ironic since the GF lens was extremely expensive new. A couple of years ago Tochigi Nikon actually refused to quote us a price for a single GF lens, instead recommending a much less expensive lens, the less expensive lens was a Rayfact 2X (95mm F2.8) selling for $7368 USD!
GF tips: Look for GF lenses sold under the Kubotek label, these tend to be the lowest cost. Avoid GF lenses on eBay from sellers in China, unless its from a recommended seller like Chendata.
GF PROS AND CONS
What I really like:
Standard thread mounts for easy installation in forward and reverse
Very uniform sharpness and contrast from the center to the far corners
Very strict color aberration correction
Aperture is one-half stop faster in reverse
No distortion
Locking aperture ring
Solid all metal lens barrel and iris mount
What I dislike:
Very hard to find used
Ultra expensive new
2.1X APS-C sensor TEST SET-UP
Camera: Sony α6300, model # ILCE-6300, also known as the A6300
Sensor size: 23.5 × 15.6 mm. APS-C. 28.21 mm diagonal. 3.92 micron sensor pitch
Flash: Godox TT350s wireless flash x 2 with one Godox X1s 2.4G wireless flash transmitter
Vertical stand: Nikon MM-11 with a Nikon focus block
A series of images was shot with each lens in 10 micron steps, and the sharpest image was chosen at Photoshop at 100% view. The single RAW file was processed in PS CC with all noise reduction and lens correction turned off, all settings were zeroed out (true zero) and the same settings were used for all of the images.
longitudinal chromatic aberration test
It's easy to see three distinct amounts of chromatic aberration suppression in the crops below. On the left, the Canon MP-E crop shows a particularly bad case of LoCAs neon pink fringing. In the center, the Rayfact lens shows a slight hint of green LoCAs. On the right the Schneider Macro Varon is very clean.
LoCA crop examples, L-R, Canon MP-E 65mm f/2.8 macro lens, Rayfact GF 80mm f/4, and Schneider Macro Varon 85mm CAS lens.
Longitudinal chromatic aberrations or LoCAs are ugly pink and green fringing seen in the out of focus areas in front of and behind the focus point of an image. LoCAs are common, especially with fast lenses, so chances almost all of your lenses have at least a trace, you just never noticed. The problem is that LoCAs are extremely difficult to correct with complex designs using special glass to fully correct the aberration.
The optical glass used in lenses disperses or separates light in varying degrees. This is bad for image quality because it causes chromatic aberrations or CAs, where the different wavelengths or colors end up being focused at different points. This causes unsightly fringing that will reduce sharpness and resolution. Chromatic aberrations, or CAs, are produced by a lens that was not able to bring all the different wavelengths or colors of light, to focus on the same point. A low dispersion lens element, with a lower the dispersion ratio, will scatter less the light which makes it easier for the designers to correct for chromatic aberrations.
GF TECHNICAL SPECS
Nikon Rayfact GF 80mm f/4
Part Number: QVM05041MF
Type: Industrial Large format 12K Line-scan Lens
Focal length: 81.90
Optical Design: 7 elements in 5 groups
Magnification range: 0.4X ~ 0.5X, 2X ~ 2.5X in reverse
Opimized magnification: 0.47X forward and 2.1X in reverse
Focus range: infinity ~ 0.48m
Aperture range: f/4 - f/8
NA: 0.04
Maximum aperture (Rayfact specification): f/4
Measured aperture at indicated f/4 forward: f/4.2
Measured aperture set wide open forward: f/4.1
Measured aperture at indicated f/4 in reverse: f/3.5
Measured aperture set wide open in reverse: f/3.4
Image size: 36mm φ at 0.47X, 43.6mm φ at 2.1X
Compatible CCD sensor pitch: 4.7 μm
Vignetting: 0% at f/4
Distortion: 0.09 % at 0.47X
Wavelength range: 400nm - 700nm (546.07nm ref)
Resolution: 8μm at 0.47x, 4μm at 2.1x
Resolving power:
180 lp/mm center, 100 lp/mm edge at 0.47X
100 lp/mm center, 56 lp/mm corners at 2.1X
Relative Illumination: 90%+ at 0.47X
Illumination in % from the optical axis to the maximum image height
Working distance: 248.1 ~207.1mm (0.4X ~ 0.5X)
Lens mount thread: M40.5 P=0.5
Front accessory thread: M30.5 P= 0.5mm
Dimensions: φ 63.4mm X 90.5mm
Weight: 440g
Source: Tochigi Nikon plant, Japan
Introduced: February 4, 2005
Discontinued: December 26, 2014 made to order only. Still listed in the Rayfact catalog in 2019.
GF part numbers:
Nikon Rayfact GF 82mm 0.2 QVM0235023MF
Nikon Rayfact GF 82mm 0.47x QVM05041MF
Nikon Rayfact GF 83mm 0.70 QVM07052MF
Nikon Rayfact GF 83mm 1.0x QVM10065MF
Notes:
Aperture ring will move beyond the marked f/4 aperture, this is normal for Rayfact lenses, we measured the aperture at the marked f/4 and at the aperture ring’s wide open position.
All of the specs above are directly from Tochigi Nikon and you will not see this information anywhere else online, even on the official website.
When it was introduced in 2005, Tochigi Nikon estimated production of 500 units per year.
Nikon Rayfact GF 82mm Line Scan Lens with Sony A6300
SETTING UP RAYFACT GF LENS FOR MACRO PHOTOGRAPHY
The GF lens seen in the setup above is mounted in reverse for 2.1x magnification. The front of the lens, here facing backwards has a M30.5 x 05mm thread so I am using a M30.5 to M52 step-up adapter and a 52mm male-to-male coupler to connect the lens to my standard M52 Studio setup. More details on the Thorlabs M52 studio setup is available here on Closeuphotography.com: https://www.closeuphotography.com/52mm-setup
Nikon Rayfact GF 82mm Line Scan Lens with Sony A6300 Setup
Left to right, Nikon Rayfact GF lens, M30.5 to M52 step-up adapter, 52mm male-to-male coupler, M52 studio set up with a variable tube in the middle to set the magnification, Raf Camera M52 to E-mount adapter and Sony A6300 body. M30.5 adapters are easy to find on Ebay for more than resonable prices.
THE GF LENS IN THE RAYFACT LINEUP
This chart gives you information of the sensor pixel size requirements vs subject side lens resolution at a glance. Tochigi Nikon lists the GF series for industrial inspection of display, and printed circuit board manufacturing designed to be used with sensors in the 4.6 μm pixel pitch range, a slightly smaller pixel size than the Rayfact Series 1x and 2x, also know as the Eco-Glass Printing Nikkor 105mm and Printing Nikkor 95mm lenses.
The MJ, and IL series are designed for general inspection and not for high resolution imaging purposes so I would avoid these two series of lenses.
Nikon Rayfact GF Compared to Rayfact VL and the Rayfact Printing Nikkor 95mm
The Nikon Rayfact 95mm F2.8 2x is the eco-glass version of the Printing-Nikkor 95mm F2.8.
Nikon Rayfact Focus Helicoid Adapter
Tochigi Nikon ships the GF lens with a special industrial Nikon F-mount focus helicoid. The unit I have came with a focus helicoid with M40.5 P=0.5 threads, the same as the rear of the lens. The heavy duty helicoid is really rigid and very smooth.
TOCHIGI NIKON
Looking at the Nikon Group Companies website: https://www.nikon.com/about/corporate/profile/group/ Its hard to get an idea of how Nikon and Tochigi Nikon are related. I do know that it's conglomerate of several companies which have joined, split, and then joined again under the Nikon Group over the years. This is very common in Japan.
Tochigi Nikon develops, designs, and markets optical devices for semiconductor/FPD lithography systems and is a core company of the Nikon group of companies.
LINKS FOR MORE INFO
The GF lenses seem to have disappeared from the Tochigi Nikon site and the US distributor but the Japanese distributor still has a page up.
The official Tochigi Nikon site:
http://www.tochigi-nikon.co.jp/en/products/lens/index.htm
Nikon Rayfact GF 80mm on the Tochigi Nikons distributors site in Japan:
http://www.daitron.co.jp/products/category/index.cgi?c=zoom&pk=518&sw=1