NIKON RAYFACT GF 80mm F4 LENS TEST

Nikon Rayfact GF 82mm f/4 Line Scan Lens 

Rayfact is a brand name for high-precision, high-quality industrial-use lenses made in Japan by the Tochigi Nikon Corporation. Rayfact is not very well known outside of the macro photography world, but they are probably most famous for producing the Eco-Glass versions of the famous Printing Nikkor 105mm F2.8, and Printing Nikkor 95mm F2.8.

This is the 80mm 0.47x Nikon Rayfact GF version that is rated at 0.4x - 0.5x with normal mounting and when mounted in reverse, this lens can give you a seriously good 2.1x image. The factory recommends this lens for use on sensors down to 4.6 μm pixel pitch and up to a 42mm image circle so its a perfect match for full frame sensors like the one in the Nikon D850 with 4.35 μm pixels.

The information on this page is from my own personal testing on my own lens. I purchased this lens on the used market, this product was not given to me, I was not paid to write this, nor did the manufacturer or distributor loan me this lens for this review. This page is not set-up to generate money using affiliate links, this is not a fan page.

IMAGE QUALITY at 2.1x

Although this lens doesn't look like anything special, in a recent test shoot comparing high-end lenses the Rayfact GF lens performance was one of the very best, in fact, it came close to beating all the other lenses. Out of these competitors:

Schneider 85mm Macro Varon CAS Line Scan Lens
Canon MP-E 65mm 1-5x Macro Lens
Minolta Elite 5400 Scanner Lens
Rodenstock Scitex S-3 67mm Scanner Lens
Rodenstock Scitex S-3 89mm Scanner Lens
Rodenstock Magnagon 75mm f/3.5 Scanner Lens
Rodenstock Magnagon 75mm f/5.6 Scanner Lens
Rodenstock Rodagon 80mm f5.6 Scanner Lens

The Rayfact GF 80mm f/4 images were sharper and cleaner than almost every lens on the list, except for one lens, the Minolta Elite 5400. The Rayfact GF 80mm output is fantastic with excellent sharpness from corner to corner, and no chromatic aberration anywhere in the frame.

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.

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.

All three lenses do a good job here resolving plenty of sharp details but cleanest and more accurate colors are in the Rayfact crop.

Click on the above image that 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 edge going to the Rayfact.

Click on the above image that 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 Canon crop is detailed and sharp but the red fringing makes the image appear to be less sharp compared to the others. The Rayfact seems to be just a tiny bit sharper than the Macro Varon, which is a fantastic lens, one of my all time personal favorites.

All of these images were made with the identical lighting, camera settings, and processing. The Canon has an obvious issue with lateral chromatic aberrations where the two line scan lenses are completely CA free. The black areas in the Canon image really show the red fringing. The Rayfact lens presents the cleanest and truest blue tones of the three.

Click on the above image that 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.

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 hint of green LoCAs. On the right the Schneider Macro Varon does an amazing job and is 100% LoCA free.

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.

MECHANICAL QUALITY

This Rayfact lens feels really solid and well put together. This is an industrial lens so it has been designed to withstand dust, heat, shock and vibrations present in an industrial environment. The Rayfact F-mount focus helicoid adapter and is very rigid and very smooth. Both the lens and the helical adapter have lock screws.

PRICE/PERFORMANCE

The Nikon Rayfact GF lens is an excellent buy on the used market. Highly recommended if you can find one in the magnification range you are looking for.

AVAILABILITY AND COST

New Rayfact lenses are extremely expensive compared to consumer market lenses. Thanks to the fact the Rayfact brand is virtually unknown, they sell for very reasonable prices on the used market, if you can find one. Rayfact lenses do show up on the used market occasionally but be careful, the most common series found on Ebay is the Rayfact MJ series (see the lens series chart below) which I would not recommend since they are made for very old low resolution sensors. This lens is the first and only used VL Rayfact that I have seen online, and I wouldn't hesitate to buy another.

 

TECHNICAL SPECS

Nikon Rayfact GF 80mm f/4
Part Number: QVM05041MF
Type: Industrial Large format 12K Line-scan Lens
Focal length: 81.90
Magnification: 0.47x forward and 2.1.x in reverse
Aperture range: f/4 - f/8
Maximum and sharpest aperture: f/4
Vignetting: 0% at f/4
Distortion: 0.019 % at 0.47x
Relative Illumination: 90%+ at 0.47x
Illumination in % from the optical axis to the maximum image height
Optical Design: 7 elements in 5 groups, no protective cover glass
Manufacturers recommended magnification range: 0.4x - 0.5x
Working distance: More info coming soon
Lens mount: This lens has M40.5 P=0.5 threads on the barrel. Quite a few M40.5 adapters are available on Ebay.
Filter thread: M30.5 P= 0.5mm. Thankfully there are plenty of M30.5 x 0.5 adapters on Ebay to make reverse mounting easy.
Lens hood: More info coming soon

PROS AND CONS

What I really like:
Easy installation in forward and reverse thanks to available adapters
Very uniform sharpness and contrast from the center to the far corners
Clean APO color correction

What I dislike:
Very hard to find used
Extremely expensive new from Tochigi Nikon (still waiting for a quote on a new lens, but I was at least warned it was "extremely expensive")

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 BOTTOM LINE

The Nikon Rayfact GF series lens is an excellent performer full frame cameras and APS-C sensors and smaller, that is if you can find one!

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. 

There are four lenses in the GF series lineup:

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

All the lenses in the GF series have less than 0.1% distortion and almost zero vignetting. Tochigi Nikon designed the GF lenses for use with 12K line scan cameras that are used to identify flaws directly within the production process of semiconductor, FPD (flat panel display), and PCB (printed circuit board)

NIKON RAYFACT-GF-Series.jpg

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.

Optical Design Protective Glass Image Circle Sensor Resolution APO Correction Distortion Vignetting Lens Mount Filter Mount
Nikon Rayfact GF 80mm F4 7 elements, 5 groups No 43.6mm 4.6μm 5.8μm 400nm to 700nm 0.090% 0% @ f/4 F-Mount M30.5 P= 0.5mm
Nikon Rayfact VL 0.5x 10 elements, 6 groups Yes, + 2 Lenses 62mm 5μm 9.8μm 400nm to 700nm 0.010% 0% @ f/4.9 M55 P= 0.75mm M55 P= 0.75mm
Nikon Rayfact 95mm F2.8 2x 14 elements, 6 groups Yes, + 2 Lenses 32mm 5μm 2.8μm 400nm to 800nm 0.001% 0% @ f/4 M45 P= 0.75mm M43 P= 0.5mm
Nikon Rayfact 95mm Reversed 14 elements, 6 groups Yes, + 2 Lenses 64mm 5μm 5.6μm 400nm to 800nm 0.001% 0% @ f/4 M45 P= 0.75mm M43 P= 0.5mm

The GF lens is listed with a Rayfact F-mount helicoid adapter but my helicoid came with a M40.5 P=0.5 threads. Either way you can unscrewed the Rayfact adapter and use a M40.5 x 0.5 to M52 x 0.75 adapter to mount the lens to give you more options.

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