MF18 Frequently Asked Questions (FAQ)

A. Please try ① and ② based on your symptoms; if the issue persists, please request a repair.
※ Note: If you request a repair without first trying these steps (resetting, cleaning, etc.), and the issue is resolved by our performance of these tasks—regardless of the warranty status—we will charge a separate fee for verification. ① Resetting the MF18

② Hot shoe cleaningLink to hot shoe cleaning guide

Symptoms

1. Neither flash head A nor B fires1-1 Pilot light is (off / lit in red / takes a long time to turn green) → Replace batteries After checking the battery orientation, if the power does not turn on or the symptom persists after a reset, the batteries may be exhausted. Please replace all four with new alkaline or fully charged NiMH batteries. 1-2 Pilot light fires when pressed but doesn't fire with the camera shutter → Reset, clean There may be a software glitch or a poor connection with the camera. Please ensure the unit is correctly attached to the camera, then try resetting and cleaning the hot shoe. 1-3 Flash does not fire even when the pilot light is pressed → Request repair If it does not fire after a reset, the product may be faulty; please request a repair. 1-4 Flash fires intermittently when the coiled cord is moved → Request repair The coiled cord may be broken; please request a repair.
2. Sometimes only one of flash heads A or B fires even after reset
   → Request repair This may indicate a broken cord or degraded flash tube; please request a repair.
3. Flash fires but (images are dark / inconsistent brightness in similar shots / images are pure white even when settings are changed)
   → Reset, clean hot shoe → Request repair If resetting or cleaning does not improve the situation, the product may be faulty; please request a repair.
4. Popping sounds, other abnormal noises, odors, or overheating
   → Request repair Since the product is not hermetically sealed, dust inside the flash head may burn from the heat of the tube, causing a slight smell of burning paper. If you hear a "pop" or detect smoke, unusual odors, or abnormal heat, immediately remove the batteries and request a repair.

A.

Resetting the MF18 / MG8000 / Di866 series (Method 1)

(1) Turn on the power, press the Set button once to return to the main menu, and enter the purple wrench icon (SETTING) in the bottom right of the screen.

(2) Scroll down to reach the second page, where you will find a "Reset" item. Press the right directional button to select it, then press the Set button to complete the reset.

Resetting the MF18 / MG8000 (Method 2)

(1) Turn on the power and, while in shooting mode, press and hold the center "Set" button.

(2) After holding the "Set" button for a certain period (approx. 5 seconds for MG8000, approx. 10 seconds for MF18), the screen will change to a green "A" (Full Auto), indicating the reset is complete. For the MF18, the modeling light (white LED) on the ring light will turn on (or turn off if it was already on) while you are pressing the button; continue holding it. Once reset, the green "A" appears, and you can release the button, causing the modeling light to turn off.

A. During repairs, we update the unit to the latest firmware version and perform operational checks, even if not specifically requested. Please check the latest version in the firmware update history.

A. We offer a (paid) service to install magnets onto the flash head unit. This allows the attachment of the separately sold cross-polarizing filter (MF-PL). For pricing and submission details, please contact us.

A. First, please try the reset procedure. If the issue remains, we will accept the product for service. Defects within one month of purchase are generally repaired or replaced free of charge, provided they are not due to misuse such as drops, water damage, or battery leakage. Please submit a repair request and send the product along with proof of purchase (store receipt or a screenshot of the purchase history from an online store). Photographic proof of purchase is also acceptable. For more warranty details, please see About Warranty.

A. Please check if images are still dark when shooting with the pilot light lit in green. If you shoot while the light is red, the flash may not fire or may provide insufficient light. If it takes longer than 8 seconds for the light to turn green after firing, the batteries may be exhausted; please replace them with new alkaline or fully charged NiMH batteries.
If the problem persists or only one side fires, we will accept the product for inspection and repair (Repair Request).

A. This is a service where we exchange the unit for a refurbished one at the same cost as a repair, used when repairs take too long or the cause is difficult to identify. Refurbished units are products that have been restored by the manufacturer (such as initial defect returns or demo units) and are in a condition equal to or better than the one provided. Once you agree to the exchange, we will guide you through the payment process and ship the unit after payment is confirmed. Please check Repair Fees and Applicable Models for costs.

A. For courier repairs, please fill out the repair request form on the Repair Request page and send the product to us at your own expense after submitting the form. Do not include your camera or lenses. If you wish for free warranty repair, send the MF18 unit and proof of purchase, such as a store-issued receipt. The original box and other accessories are not required. For non-warranty repairs, proof of purchase is not necessary.

A. If the power turns on and test firing (pressing the pilot light) is possible, repair may be possible. However, the impact of a drop may have damaged other internal parts. If we determine that repair is not possible, you can choose to have it returned unrepaired, disposed of by us, or traded in. Please check Repair Fees and Applicable Models for costs. Apply via the Repair Request page.

A. This may be caused by damage to or degradation of the battery magazine. Please purchase a new BM-01 battery magazine. For purchase methods, please see Where to Buy (available at the Nissin Digital Direct main store).

A. The drop impact may have bent the terminals that contact the batteries. Try using tweezers or a similar tool to gently lift the four terminals that contact the negative ends of the batteries. This may restore power.
If it still does not turn on, or if it turns on but does not fire correctly, or if there is unusual noise, odor, heat, or smoke, immediately stop using it and submit a Repair Request. Repairs for drop damage can be complex; if we determine it is unrepairable, we may suggest a trade-in purchase. Please check Repair Fees and Applicable Models for costs.

A. The only difference is whether or not the unit supports the separately sold dedicated cross-polarizing filter (MF-PL). Other basic performance specifications (hardware, software, and compatibility with lenses/cameras) are identical.
MF18 / MF18 II / Cross-Polarizing Filter MF-PL

A. The MF18 (for Nikon) comes with a 62mm adapter ring as standard, allowing it to be attached directly to the lens. Please check the camera compatibility table for functional compatibility (e.g., TTL flash control) with your specific camera body.

A. If you cannot change your account information via the website, please contact us via the contact form with your old and new email addresses. We will update the contact information for your repair and your newsletter subscription address.

A. Physically, it can be attached to F-mount/Z-mount lenses with a filter diameter of 77mm or smaller. However, we do not recommend attaching it to zoom lenses where the filter thread moves forward/backward or rotates during focusing, as this puts strain on the lens motor and may lead to failure.
62mm lenses (e.g., AF-S VR Micro Nikkor 105mm f/2.8G IF-ED, NIKKOR Z MC 105mm f/2.8 VR S) can be attached using the included adapter ring. When using F-mount lenses on Z-series cameras, an FTZ II adapter is required.

A. 82mm adapter rings sold on overseas websites are not available for purchase in Japan. You could physically attach it by combining a commercially available step-down ring (82mm to 77mm) with the 77mm adapter ring included with the MF18. Note, however, that depending on the lens and aperture, vignetting (insufficient light in the corners) may occur. We do not recommend any specific step-down ring (please note that a step-up ring will not work).

A. We do not have any specifically recommended storage cases. Duralumin (aluminum) camera cases with adjustable partitions are generally easy to use. Since you must send only the MF18 unit when requesting repairs or firmware updates (camera and lenses cannot be included), we recommend keeping the original retail box to make packing easier.

A. The MF18 (for Nikon) includes a TTL flash control mode, which automatically adjusts brightness based on shooting distance and camera settings. Once set, there is no need to change settings on the ring flash even if the distance or composition changes.
However, TTL flash control cannot be used with some third-party lenses that lack electrical contacts on the mount, as aperture and distance data are not transmitted to the camera (it generally works fine with autofocus-compatible lenses).

A. If the filter diameter matches the included adapter ring, physical attachment and firing are possible. However, if you attach the flash head to a lens where the filter section moves during focusing, it can strain the lens's AF motor and lead to failure. We take no responsibility for lens failures caused by such attachments; please use at your own risk. Check your camera combination in the compatibility table.

A. The NIKKOR Z MC 50mm f/2.8 is used for intraoral photography and works without issues. Its filter size is 46mm, but you should attach the MF18's included 62mm adapter ring to the 62mm accessory frame on the outer side of the lens tip.
The NIKKOR Z MC 105mm f/2.8 VR S can also be used, but because of its longer focal length, you must keep a greater distance from the subject, making shooting posture more difficult; the lens is also large and heavy, making it difficult to hold with one hand.
Note: If your MF18 firmware is old, it might not support the Z series. In that case, please contact us.

A. There are four potential causes:

1. Camera is not compatible: We have not verified cameras not listed in the compatibility table and cannot guarantee operation. For example, the EOS Kiss X10 lacks an X-contact (center pin), so it likely won't work (the "EOS Kiss X10i" is a different model).
2. Outdated firmware: Please check the firmware update method for details on checking/updating.
3. Program glitch: Pressing and holding the Set button for over 10 seconds while powered on resets the unit and automatically switches it to A mode.
4. MF18 hardware defect: If it fires at full power even during pilot light test, or does so on other compatible camera bodies. In this case, please request a repair.

Check in the following order:

1. Reset the MF18: Press and hold the [Set] button for over 10 seconds (until the screen changes to green "A").
2. Check if the camera's "Exposure Compensation" or "Flash Compensation" is set to the plus (+) side (see your camera manual for instructions).
3. If the camera is not officially verified, whiteout from the start might be a compatibility issue rather than a defect. If you have another camera body you previously used normally, try attaching it to confirm proper function.

A. Normally, changing batteries should not affect the MY TTL settings, so the MF18's program may be glitching. First, try the reset method (pressing and holding the "Set" button for 10+ seconds while powered on). If it does not improve, please contact us with sample shooting data attached.

A. There are no dedicated lens caps or covers that can be used while the MF18 is attached. Using a commercially available drawstring pouch for protection is a practical solution, though we do not recommend any specific product.
To protect the lens, attaching a lens protection filter between the lens and the adapter ring is also effective. Since inexpensive filters can reduce image quality or be difficult to clean, we recommend protection filters labeled as "water-repellent/anti-fouling."

A. The MF18 runs on four AA batteries (alkaline or rechargeable NiMH), so no power cable is required. It does not support AC mains (100V) power. The unit does have an external power terminal, but it is for connecting a separately sold power pack (rechargeable external power), which is no longer in production.

A. When the MF18 is used with Nikon cameras, it determines flash output by combining the results of a pre-flash measured just before the shutter opens with shooting distance data obtained from the lens. The main causes for dark images are:

1. Focus is set closer than the intended subject: If focused too close, output is restricted, making the back look dark. If the AF red frame is not where you intend it to be in Auto-area AF, please switch to a different AF area mode.
2. Mirror reflectance: Glass mirrors with special coatings have near 100% reflectance and minimal effect, but stainless steel mirrors have about 60–70% reflectance, which can lead to darkening.
3. Light is not hitting correctly: Due to parallax between the lens and the flash head, at close distances, lips might cast shadows, or the mirror angle might be inappropriate. Rotate the flash head unit to adjust, or change the angle of the mirror.

If the adapter ring's rubber ring is dirty with sebum and slips, clean it with anhydrous ethanol or replace it with a standard rubber band.

A. We cannot guarantee operation for unverified combinations. You can apply via the "Request Verification" section on the compatibility table page, but verification takes time. Once completed, it will be reflected in the compatibility table, so please check back periodically. We do not provide individual notifications.

A. The external power terminal is compatible with the external power terminals used for genuine camera manufacturer strobes. Its rated input is approximately 300V DC, so it will not operate if 5V or similar is input. The compatible external power source, "Power Pack PS8," has been discontinued.
The USB terminal (USB mini-B) shown in the instruction manual is for firmware updates only. If you input 5V, the LCD will turn on and you can operate the menu, but the unit will not charge, and the flash will not fire.
The Battery Magazine BM-01 is included with the main unit but is also sold separately (for how to purchase, please see How to Purchase). If you use it frequently for business, it is convenient to have an extra BM-01 set with charged nickel-metal hydride batteries, allowing for battery replacement in a matter of seconds.

A. The Tamron SP 90mm F/2.8 Di MACRO 1:1 VC USD (Model F017), which has a 62mm filter diameter, is a lens that we also recommend, and it can be attached to the MF18 for Nikon via the included 62mm adapter ring.

A. If you keep the intraoral settings, the MF18 will fire at a high intensity, causing dark shadows. You can reduce this somewhat by opening the aperture to around F4–F5.6 or increasing the ISO sensitivity to around ISO 400–800 (this effect is limited in dark rooms).
Using a film viewer creates backlighting, which can cause flare due to diffuse reflections within the lens, potentially leading to a foggy, blurred image or distorted colors, so please take test shots while adjusting the settings. Depending on the environment, you may be able to get good results using the camera's P mode.
If your camera has a user preset function (e.g., U1, U2 on the D610), it is convenient to register the intraoral and portrait settings separately and switch between them using the mode dial. Please note that the D100 uses different external flash communication specifications than modern models, so the MF18's TTL and A (Auto) modes cannot be used.

A. In Wireless TTL mode, the row above A (+/-EV) is used to set the flash exposure compensation for the entire unit (Flash Unit A + Flash Unit B), and the B row is used to set the light ratio between Flash Unit A and Flash Unit B. Remote strobes should be set to Group C, and the compensation for them should be set using the C row on this unit. For this reason, the A row is displayed as "---" and cannot be configured. Because the genuine Nikon optical wireless system used by this unit was not originally designed for ring flash control, some of the terminology may be confusing.

A. If the images appear bright when the flash is attached to another camera, the issue likely stems from the settings on the original camera. Please try the following steps in order:

1. Initialize the external flash settings in the camera menu.
2. Set the exposure compensation to ±0.
3. If that does not resolve the issue, initialize the camera settings themselves, then reset the ISO sensitivity, aperture, and shutter speed for intraoral photography.

If there is still no improvement, set the camera dial to P mode and take a photo indoors without the MF18 attached. If the photo is still dark, try replacing the lens with one from another camera; if it remains dark, there may be a defect in the camera body, but if it is normal, the original lens may be faulty.
For lenses without electrical contacts, such as manual focus-only lenses, the MF18's A (Auto) and TTL modes cannot be used; please use M (Manual) mode or switch to a lens with contacts.
If the images are dark on other cameras as well, there may be a defect in the MF18. Because there is a possibility of a program malfunction, please first try the reset method. Since exhausted batteries can cause longer charging times or weaker flashes, if the pilot lamp takes a long time to change from red to green, please replace the batteries with new alkaline batteries or fully charged nickel-metal hydride batteries. If this does not improve the situation, or if only one side of the flash fires, please request a repair. If the unit is within one year of purchase, please attach proof of purchase (receipt, order history, etc.).

A. While stopping down the aperture increases the depth of field, closing it too much causes diffraction, which results in the entire image becoming blurred, so we do not recommend stopping down more than necessary. Additionally, as you stop down, the light output of the ring flash increases, which lengthens charging time and reduces the lifespan of the flash tube.
The recommended values listed on the web are an example of settings that allow even those unfamiliar with photography to take shots with almost no failures; you do not necessarily have to use these exact values. Please take test shots while changing the aperture and ISO sensitivity to find your preferred settings. Furthermore, with the same angle of view and aperture, the larger the sensor, the shallower the depth of field. Please note that on Nikon cameras, the aperture automatically opens as the shooting distance decreases, so the actual depth of field may be slightly shallower than the same F-number displayed on Canon cameras.

A. Flash tubes are consumable parts and degrade gradually based on the number of times they are fired. If only one side fires, it is highly likely to be a failure requiring repair.
If you cannot reduce the number of shots taken for business, you can increase the ISO sensitivity or open the aperture to reduce the required flash output, thereby extending the lifespan. Doubling the ISO sensitivity halves the required flash output, and opening the aperture by 1/1.4x (three clicks in typical settings) also halves the output. However, since increasing ISO sensitivity lowers image quality and opening the aperture narrows the area in focus, we recommend ISO 400 or lower and aperture F22 or higher for intraoral photography.

A. The filter size of this lens is 46mm, but there is a 62mm thread for accessory mounting on the outer lens barrel. Please attach the included 62mm adapter ring there (no separate purchase required).
While it is physically possible to attach the unit to the 46mm filter thread at the tip of the lens by using a step-up ring or similar, please do not do so, as this puts stress on the internal lens motor and may cause failure.

A. Because it is not a dedicated macro lens, it may be difficult to focus and take photos for intraoral purposes. If there is no diameter that fits the adapter ring included with the MF18, it is physically possible to attach it using a commercially available step-up ring (e.g., 46mm to 52mm), but we do not recommend this as it may put stress on the lens's internal motor and cause failure. We recommend that you obtain a dedicated macro lens such as the NIKKOR Z MC 50mm f/2.8.

A. Cause: Flash light normally undergoes diffuse reflection on the surface of teeth, but if moisture is present, specular reflection occurs, causing those areas to become overexposed.
Solution: Blowing off moisture before shooting can reduce reflections. Also, using a cross-polarizing filter (MF-PL) can significantly suppress reflections (exclusively for MF18 II).
When shooting with Auto ISO, due to the specifications of the MF18, the sensitivity may rise to the same level as if no flash were used, unlike with genuine flashes. At high sensitivities such as ISO 6400 or ISO 12800, the exposure will be excessive even at the MF18's minimum light output (1/64-2/3EV), so please set the ISO sensitivity manually. If images are still completely white even when set to around ISO 100–800, there may be a defect, in which case we will handle it through repair or replacement (Repair Request).
When investigating defects, we will ask for your camera's exposure mode, shutter speed, aperture, ISO sensitivity, the MF18's flash control mode (TTL/Manual) and settings (TTL exposure compensation value / manual output level), and the conditions under which the issue occurs.

A. There may be a communication error between the camera body and the lens. Wipe the eight electrical contacts arranged in a row on the inside of the lens mount on both the camera and lens sides with a small amount of anhydrous ethanol, and attach and remove the lens several times. If this does not improve, there may be a failure in the camera or lens, so please consult the camera manufacturer.
Please note that lenses without electrical contacts may not be recognized as attached, resulting in a "Lens not attached" display. In this case, the MF18's A (Auto) and TTL modes cannot be used; please use M (Manual output) mode.

A. Please check the following causes:

1. The lens does not support automatic flash control: For lenses without electrical contacts that cannot convey aperture information to the camera—such as foreign-made manual-focus-only lenses or lenses from other manufacturers included with dental imaging systems—TTL flash control will not operate normally even if the flash fires. It may also fail to operate correctly if a mount converter or extension tube is used.
2. ISO sensitivity is set to AUTO or is very high: Setting ISO to auto indoors can lead to high sensitivity, causing the flash to exceed its control range and overexpose; therefore, we recommend ISO 100–400 for close-up photography.
3. Camera wireless flash (WL) is set to "ON": Please set it to "OFF."
4. Failure of the camera or MF18 (including initial defects): If an error appears on the camera screen, poor contact due to dirt or deformation on the hot shoe may also be a cause.

If none of the above apply, the unit will need to be sent in for repair (inspection). Please check the Camera Compatibility Chart to confirm the status of your camera.