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Gratical EVF Support

Welcome to the support page for the Gratical EVFs. On this page you will find EVF support including the current version of the firmware, current manuals, and FAQ's. If you have additional questions email or call 1-888-294-3456.

Registration: If you are looking to register your Gratical EVF, please do so here. 

Manual: Click here to download manual. 

Gratical HD Firmware 
*This firmware is NOT compatible with the Gratical Eye.  Click here to download Firmware Update 3.4 (for HD and X models only) to a FAT32 USB drive. 

 Gratical Eye Firmware Updates

*Only compatible with the Gratical Eye

UPDATE 8/14/18 - Click here to download Firmware Update 1.2 (for Eye models only) to a FAT32 USB drive.

Watch our video about the new interface included in update 3.00.

To update your Gratical EVF with the latest firmware, first format your USB drive to FAT32 for compatibility (learn how here). Download the firmware update above and transfer it to a USB drive. Insert your USB drive into the Gratical’s USB port, select UPDATE from the menu and select USB DRIVE. Select START UPDATE and follow the on screen instructions. The current firmware version can be confirmed in the ABOUT menu. For more information, see page 18 of the Gratical HD Manual above. If you have any questions or concerns, email us at

Attention MAC users: Some MAC users are experiencing difficulties when downloading the Gratical Firmware file. When you hit download, if it opens a text file with a bunch of characters; re-download the file by holding down the option key while clicking on the download. This should clear any problems.

Burn In Warning: OLED displays can develop “burn in” over time if a static image is displayed too long. This means the screen will retain a ghosted image of what was being displayed. Burn in can only occur from display data produced by the camera and not the Gratical’s scopes. To avoid this problem, we recommend you turn off the camera display data whenever possible or use the Gratical’s scopes instead of the camera’s scopes. The Gratical Eye has a Proximity Screen Saver to combat burn in.

If you do begin to notice burn in, you can attempt to correct it by leaving the Gratical powered on but not plugged in to a camera. Doing this with the Gratical’s blue screen displayed overnight or for a few hours can help to fix minor burn in. You can also try using screen burn fix or stuck pixel videos. There are some non-Zacuto created videos, like this one , that suggest some other ways to alleviate or eliminate burn in.

Burn in is not covered by warranty. Email for a repair estimate.

Gratical EVF FAQ's

Q: What is the difference between Full Display and 16x9?

A: The full screen display is 1280x1024, which is 4x3. To see a 16x9 image it has to cut off some of the vertical of the full screen which results in a 1280x720 (HD). The space that was cut off to show a 16x9 image is replaced by default with the threes scopes, histogram, waveform, and vectorscope. The screen can also be centered and scopes can be removed

Q: Does the Gratical HD display 4k?

A: If you're shooting in 4k you won't be able to send the raw 4k signal to the Gratical HD, but it will be able to read a scaled down signal like 1080 60p. You will be able to download custom LUTs to the Gratical so that you control exactly what you're seeing, whether you want to see the image as you are shooting or as it would look after editing.

Q: What is the size and weight of the Gratical?

A:1.5 lbs, 5.5" x 3" x 3.8" (L x W x H)

Q: How do I clean the diopters with anti-fog coating?

A: Blot or gently wipe with microfiber. If exposed to moisture or moistened, use compressed air to remove the droplets and, ideally, allow a few minutes to air dry before wiping. If any liquid cleaners are used (deionized water being the best choice), air dry or use compressed air before using microfiber.

Q: What happens when you need 4K out of your camera to a recorder and want to use the Gratical HD? Can it handle downscaling to HD of the signal?

A: The downscaling would need to occur before it reaches the Gratical and so in-camera. The highest quality signal that the Gratical can take in and display is 1080 60p. Reading a 4K signal that is not downscaled is something we are working on for the 4k and 2k signal capability.

Q: How long does the battery last?

A: About 3 hours, it depends on the features turned on and loop throughs.

Q: How do I convert my USB drive to a FAT32 compatibility?

A: Once you download the firmware the next thing you need to do is have a USB Thumb Drive formatted to FAT32.  Please note this is not the default file system used for either Mac or PC and by formatting your thumb drive in this way it will erase all data that is currently on the thumb drive. You must also use a thumb drive and NOT a USB cable from your computer.

Windows 7 Mac OS X
  • Open My Computer
  • Right Click on the thumb drive
  • Left click on Format
  • Set File System to FAT
  • Check Quick Format
  • Left click Start
  • Left click Ok for the warning that your erasing all data
  • When done left click on Ok
  • Go to Applications
  • Go to Utilities
  • Open Disk Utility
  • Select the thumb drive
  • Choose Erase
  • Select MS-DOS File System
  • Click Erase

Q: Why do I sometimes see a sudden shift in brightness of my Gratical even though I didn’t make an adjustment?

A: The brightness of an OLED will change depending on the operating temperature of the OLED. This is a trait inherent to OLED technology. In order to keep the brightness at a proper level, we make small adjustments to the brightness over the short warm up period. This adjustment should only be noticeable in the first few minutes after powering on the Gratical.