Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

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Product: Zeiss DTI 3/35

Instructions for use

ZEISS products are famous for outstanding optical performance, precision engineering and a long service life.

Please observe the following instructions for use in order to obtain the best from your thermal imaging camera and to ensure that it remains your constant companion for many years to come.


Environmental influences

  • Note: Never point the lens of the device directly at intense heat sources such as the sun or laser equipment. The objective lens and eyepiece can function as a burning glass and damage the interior components.
  • Caution: Avoid touching the metal surface (cooling fins) after exposure to sunlight or cold.
  • Caution: Protection class IP66 is only achieved when all rubber covers are firmly closed.

Ergonomics note

Caution: Take breaks after longer periods of use to avoid wrist pain.

Risk of swallowing

Caution: Do not place this device in the hands of small children. Incorrect handling can cause small parts to come loose which may be swallowed.

Safety instructions for battery

  • Handle the device with care: Rough handling can damage the internal battery.
  • Do not expose the device to fire or high temperatures.
  • Do not disassemble the device to access the battery. The battery is not meant to be replaced by the end user.
  • Only use the battery charger included in the delivery package.
  • Only charge the device at temperatures ranging between 10°C and 40°C.
  • The battery capacity decreases when operated in a cold ambient temperature. This is not a fault and occurs for technical reasons.
  • Do not store the device for long periods at temperatures below 0°C or above 35°C. This permanently reduces the capacity of the battery.
  • If the device has been damaged or the battery is defective, send the device to our after-sales service for repair.

Safety instructions for the power supply unit

  • Check the power supply unit, cable and adapter for visible damage before use.
  • Do not use any defective parts. Defective components must be replaced.
  • Do not use the power supply unit in wet or humid environments.
  • Only use the original cable provided with the battery charger.
  • Do not make any technical modifications.

For further information and safety instructions, please refer to the QuickGuide provided. This is also available on our website in the download center: www.zeiss.com/hunting/downloads

Disposal of batteries

In the European Union, this symbol indicates that the battery used in this product may not be disposed of in domestic waste and must be collected for disposal separately. When returning used batteries, please use a collection system that may exist in your country.

The materials and substances in the batteries may have a detrimental impact on health and the environment.

By depositing empty batteries at a recycling facility, you are contributing to the protection, maintenance and improvement of the quality of our environment.

Please only return discharged batteries.

The battery used does not contain mercury, cadmium or lead in quantities exceeding the limits defined in Directive 2006/66/EC.

User information on the disposal of electrical and electronic devices (private households)

The WEEE symbol on products and/or accompanying documents indicates that used electrical and electronic products must not be mixed with ordinary household waste. For proper treatment, recovery and recycling, take these products to the appropriate collection points where they will be accepted without charge. In some countries, it may also be possible to return these products to your local retailer when you purchase a corresponding new product. The proper disposal of this product serves to protect the environment and prevents possible harmful effects on human beings and their surroundings, which may arise as a result of incorrect handling of waste.

More detailed information on your nearest collection point is available from your local authority. In accordance with state legislation, penalties may be imposed for the improper disposal of this type of waste.

For business customers within the European Union

Please contact your dealer or supplier regarding the disposal of electrical and electronic devices. He will provide you with further information.

Information on disposal in other countries outside of the European Union

This symbol is only applicable in the European Union. Please contact your local authority or dealer if you wish to dispose of this product and ask for a disposal option.

Intended use

The device is intended for displaying heat signatures during nature observation, remote hunting observations and for civil use. This device is not a toy for children.

Use the system only as described in this instruction manual. The manufacturer and the dealer accept no liability for damages which arise due to non-intended or incorrect use.

Function test

  • Before use, please ensure that your thermal imaging camera has no visible damage.
  • Test to see if the thermal imaging camera displays a clear, undisturbed image.
  • Check that the settings for the thermal imaging camera are correct. See the notes in the section Observation mode.

Package check list

Product Order no. Package check list
DTI 3/35 52 70 10 Thermal imaging camera
Neoprene strap
Carrying case incl. shoulder strap
Charging adapter incl. USB cable
Optics cleaning cloth


Installing/removing the battery

The ZEISS thermal imaging camera DTI 3/35 is equipped with a battery. It cannot be removed.

Observation with and without glasses

Thanks to the flexible eyecup, the thermal imaging camera can be used with or without glasses. It offers a full field of view in both cases.


Focal length 35 mm/F1.0
Lens type Germanium
Detection range
(object size)
m (yd) 1,235 (1,350)
1.8 x 0.6 (2 x 0.7)
Subjective angle of view ° 30
Field of view at 100m
(field of view at 100 yards)
m (ft) 19 (57)
Field of view °
horizontal x vertical
11 × 8
(diagonal 13)
Optical magnification 2.5
Maximum digital zoom 4x
Zoom increments in 0.5x increments 1.0 – 4.0 x


Sensor resolution px 384 x 288
Sensor pixel pitch μm 17
Frame rate Hz 50


Display resolution px 1,280 x 960
Display type LCOS


Interfaces USB: charging +
data transfer
WLAN: data transfer
Battery Lithium-ion
Battery life up to 7 hrs.
External power supply 5V / 2A (USB)
Internal memory GB 15
live-streaming feature
WLAN frequency GHz 2.4
WLAN standard IEEE 802.11a/b/g/n
Connection with other devices ZEISS Hunting app. USB


Protection type IP66
(protected from
heavy rain)
Operating temperature range °C (°F) -10 / +40 (+14 / +104)
Length x width x height mm 193 x 60 x 65
Weight g (oz) 420 (14.8 oz)


Attaching the carrying strap

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

Power on/off

Press the on/off button (5) for a longer time to switch on the device. The LED (9) is green. The LED (9) lights up red when the charge level is low.

Press the on/off button (5) for a longer time to switch off the device again. The LED is off. When switched on, the LED (9) lights up red when the charge level is low.

Note: The on/off button (5) must be pressed until the OFF symbol appears on the display. Only then can the on/off button (5) be released and the device switches off. If the on/off button (5) is released before the OFF symbol is displayed, the device does not switch off but switches to standby mode.

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

Standby mode

Briefly press the on/off button (5) to switch the device to standby mode. The LED (9) blinks green. Briefly press the on/off button (5) again to switch the device back to observation mode. The LED (9) is permanently green.

In standby mode, the LED (9) flashes red when the charge level is low.


The device enables you to perform automatic (Auto Calibration = On) or manual calibrations (Auto Calibration = Off).

In automatic mode, the device automatically performs a calibration by closing and opening an internal shutter when necessary. A gentle click should be heard. In this mode, you also have the option of performing the calibration manually by pressing the Shutter button (6) and the Menu button (8) simultaneously.

There is a further option for performing a manual, silent calibration. Go to the device menu and set the “Auto Calibration” option to “Off”. Then return to the observation mode. Close the lens cap manually. Now press the Shutter button (6) and the Menu button (8) simultaneously. The device is now calibrated again.

Note: Always cover the lens when performing a manual calibration. Otherwise the sensor cannot calibrate correctly and the image will deteriorate, e.g. ghost images. If you forget to cover the lens during a manual calibration, repeat the calibration procedure with the lens covered.

Observation mode

Look through the viewfinder (10) to observe the scene. Turn the diopter adjustment (11) on the side to focus the screen. Turn the focus ring (1) on the lens to focus on the scene.


In observation mode, the arrow keys (7) can be used to zoom in (right arrow key) and zoom out (left arrow key) the scene. Zoom in increments of 0.5 between 1.0x and 4.0x. The zoom function is circular, i.e. if you press the right arrow key (7) again after a 4.0x zoom, you will return to 1.0x.

The currently set digital magnification is shown on the display.

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

Color modes

The scene can be displayed in four different color modes. Briefly press the menu button (8) to change the observation mode.

When changed, the selected mode is shown on the display as text for about 2 seconds.

The following color modes can be selected:

  • White Hot: Cold areas are displayed here in black and warm areas in white.
  • Black Hot: Cold areas are displayed here in white and warm areas in black.
  • Red Hot: Cold areas are displayed here in black and warm areas in white. In addition, the warmest areas are shown in yellow to red.
  • Red Hot: A varied color palette displays cold areas in black to blue and warm areas in yellow to white.

Shooting mode

You have the possibility to take photos and videos. Press and hold the Shutter button (6) to switch between the two shooting modes. The symbol at the top left of the display changes to indicate the selected mode.

Briefly press the Shutter button (6) once to capture a photo or record a video.

Briefly press the Shutter button (6) again to stop a video recording in progress.

Note: Longer video recordings are automatically split into several smaller files of 10 minutes each when saved.

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual


Press and hold the menu button (8) to show the main menu on the display. Look through the viewfinder (10). The main menu offers the following options:

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

  • Brightness: Set the brightness of the display here. There are four brightness levels to choose from. The brightness is lowest at level 1. The brightness is highest at level 4.
  • Contrast: Adjust the contrast of the scene here. There are four contrast levels to choose from. The contrast is lowest at level 1. The contrast is highest at level 4.
  • Hot Tracking: In observation mode, select “Hot Tracking” to highlight the warmest point in the scene with a small red square.
  • Auto Calibration: Set manual (Auto Calibration = Off) or automatic calibration (Auto Calibration = On) here.
  • P.I.P. (Picture in Picture): A central section of the image is enlarged by a factor of 2 and shown in a small magnification window on the display.
  • WLAN: Switch WLAN on/off. When WLAN is switched on, the device creates a hotspot that allows another device (e.g. smartphone) to make a connection.
  • System: Make all system-relevant settings here, including language, time and factory settings.

The arrow buttons (7) and the menu button (8) are used to navigate in the main menu.

Press the right arrow button (7) to scroll down. Press the left arrow button (7) to scroll up.

Briefly press the menu button (8) to select a menu item. This opens the submenu.

Make your settings using the arrow buttons (7).

Briefly press the menu button (8) to confirm your selection and return to the main menu.

Press the menu button (8) for a longer time to exit the main menu and return to observation mode.

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual


The “System” submenu has the following options:

  • Factory Reset: Select “Factory Reset” to reset the device to the factory settings.
    This also deletes all data saved on the device, including images and videos.
  • Reset Settings: Select “Reset Settings” to reset all settings to the default values for the device.
  • Language settings: Select a menu language here.
  • Date / Time: Set the date and time of the device here.

You can also view the following information:

  • WLAN SSID: The name of the WLAN hotspot is displayed here.
  • Firmware Version: The current firmware version is displayed here.
Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

Factory reset

To perform a factory reset, select “System” in the main menu. Then navigate to “Factory Reset”. Select “Yes” and confirm your selection. A second security prompt follows, which must also be confirmed with “Yes”.

Reset settings

To reset the settings, select “System” in the main menu. Then navigate to “Reset Settings”. Select “Yes” and confirm your selection.

Note: The device must be restarted for the reset of the settings to be completed successfully.

Date and time

Select “System” in the main menu to set the date and time. Then navigate to “Date / Time”. You can now set the year, month, day, hour and minute individually. The “Time Format” setting allows you to choose between 24-hour and 12-hour display. Be sure to set the current date and time, as your photos and videos will be time stamped.

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

Note: If the battery is completely discharged, the device loses the set date and time.

Reset the date and time so that your images and videos get a correct timestamp.

Firmware update

A firmware update can be carried out using the ZEISS Hunting App. Follow the instructions for this in the ZEISS Hunting App.

Note: Make sure that the device is fully charged before updating the firmware. Do not switch off the device during the update, otherwise it may be damaged.

LED status

Operating status Charge state LED color LED status
Does not charge Green Constant
Does not charge
(low charge level)
Red Flashing
Charging Red Constant
Charging (fully charged) Green Constant
Standby Does not charge Green Flashing
Does not charge
(low charge level)
Red Flashing
Charging Red Constant
Charging (fully charged) Green Constant
Off Does not charge
Charging Red Constant
Charging (fully charged) Green Constant


Note: To avoid fading in the dark, the brightness of the LED is kept low. The LED may therefore sometimes be only barely visible in daylight.


Fault Possible reasons Solution
Will not boot. Battery is empty. Charge the device.
The device is not charging. The USB cable is defective. Replace the USB cable.
External power supply is not sufficient. Check if the external power supply is fine.
The USB cable is not properly connected to the device. Unplug the USB cable and check that the connector and port are undamaged and free from dirt.
The image is unclear.
The image has streaks.
The background is not uniform.
The device must be recalibrated. Follow the instructions when performing the calibration procedure.
The image is too dark. The screen brightness is set to low. Adjust the screen brightness.
The image on the display is flat. The contrast is set too low. Adjust the contrast.
The computer does not recognize the device (internal memory). The device is not switched on. Transfer the images after turning on the power.
The USB cable is not connected properly.
The required software has not been installed. Please read the notes in the section “USB interface”.
The time infomation on the images is incorrect. The time information (time/date) in the device is not yet set. Follow the instructions to set the time information.
Image quality is poor.
The detection range is too short
Poor weather conditions may have adverse effects (e.g heavy snowfall, rain, fog, etc.)
The smartphone does not connect to my DTI 3/35. The WLAN password is incorect. Enter the correct password.
There are too many WLAN networks in the immediate vicinity of the device. There may be adverse effects. Move the device to a location with few or no direct WLAN networks.
The WLAN signal is repeatedly lost or interrupted. The ZEISS DTI 3/35 is too far away or there are too many other WLAN networks nearby. Change the location of the device so that a WLAN signal is detected directly.
There is an obstruction between the device and the receiver.


This device is equipped with a WLAN function. Go to the menu and switch on the WLAN function. When activated, WLAN is indicated by a WLAN symbol in the upper right corner of the display. You can now connect your smartphone to the device via WLAN.

Note: When first used, the preset password for the WLAN connection to the device needs to be changed to prevent unauthorized access by third parties.

The ZEISS Hunting App is required to change the password.

Default password: 12345678

To increase user comfort, the ZEISS Hunting App synchronizes your password on all logged-in devices.

To increase the security of the connection, we recommend that you change your password.

To extend battery life, we recommend that you only switch on the WLAN function in the device when the device needs to establish a data connection to the ZEISS Hunting App.

ZEISS Hunting App

Install the ZEISS Hunting App on your smartphone and open the app. Follow the steps shown there to connect to the ZEISS DTI 3/35.

The ZEISS Hunting App allows you to transfer images and videos to your smartphone, view the live image, make settings and use other functions. A more detailed description can be found in the help function of the app.

Note: To use the ZEISS Hunting App and its functions, ensure that your smartphone is connected to the ZEISS DTI 3/35 WLAN network.

Note: Every time you connect to the ZEISS Hunting App, the current date and time are automatically transferred from your smartphone to the device.

USB port

Use the USB interface (14) on the bottom to charge your device or to transfer data (photos and videos) to your PC.

The ZEISS DTI3/35 connects as an MTP device using the USB interface. The device is automatically recognized and can be used immediately on computers with Microsoft Windows 10 operating system software. For computers with Apple Mac OS operating system software, you need to install additional third-party software to access the data stored on the device, such as “AndroidTM File Transfer”. ZEISS assumes no responsibility or guarantee for third-party software.

Microsoft and Windows are either registered trademarks or trademarks of Microsoft Corp. in the United States and/or other countries.

Apple and Mac OS are registered trademarks of Apple Inc. in the USA and other countries.

Android is a trademark of Google LLC.

Tripod thread

A 1/4-inch standard thread (13) for standard tripods is located on the bottom of the device. Screw the device onto a tripod for more steady shooting.

Charging the device

Charge the device via the USB port (14) when the battery is empty. The battery charge level of the device is shown in the upper right corner of the display. When the charge level is low, the display changes to red. When the device is being charged, the LED (9) lights up red when the device is switched on and off. When the battery is fully charged, the LED (9) lights up green.

Replacing the lens cap

To replace the lens cap (2), unscrew the screws (3) using a screwdriver. Remove the retaining plate (4) and the defective lens cap (2). Fit the new lens cap (2) and retaining plate (4). Tighten the screws (3) using a screwdriver.

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

Zeiss DTI 3/35 Thermal Imaging Scope Instruction Manual

Care and maintenance of the device

Do not rub coarse particles (e.g. sand) from the lenses. Blow them off, or use a soft brush! Over time, fingerprints can corrode the lens surface. Breathing on the lens and polishing it with a clean optical cleansing cloth is the easiest method of cleaning the lens surface.

Dry storage and keeping the outer lens surfaces well ventilated, especially in the tropics, helps to prevent a possible mold film forming on the optics. Your ZEISS DTI 3/35 requires no further special care.

Care and maintenance of the battery

Follow these steps to extend the battery life:

  • Avoid storing the device at high temperatures.
  • Avoid storing the device with a fully charged battery.
  • Avoid complete discharging of the device.

Spare parts

Should you require spare parts for your device, e.g. the lens cap, please contact your specialist retailer, your local distributor or our after-sales service.

For Customer Service inquiries we are happy to take your calls from Monday to Friday from 8:00 a.m. to 4:30 p.m. (CET).

Tel.: +49 (0) 800 934 77 33
Fax: +49 (0) 64 41-4 83 69

ZEISS is a byword for reliability and a high level of quality. Therefore, quite independently of the seller‘s warranty obligations to the customer, we the manufacturer offer a two year warranty on this ZEISS product, which can be extended for a further year upon registration of the product if registration is made within four weeks of purchase.

The scope of the warranty can be seen by accessing the following link: www.zeiss.com/cop/warranty

Register your product at: www.zeiss.com/cop/register

Manufacturer‘s address
Carl Zeiss AG
Carl-Zeiss-Strasse 22
D-73447 Oberkochen
www.zeiss.com/nature and www.zeiss.com/hunting

Subject to changes in design and scope of supply due to technical improvements.

No liability for mistakes and printing errors.

Data protection notice

Personal data is processed when using the DTI 3/35.

Our information on data protection and the processing of personal data can be found in our download center: www.zeiss.com/hunting/manuals

Legal and regulatory information

Wireless transmitter module frequency range: WLAN: 2,412 – 2,462 MHz

Wireless transmitter module power: 100 mW

Carl Zeiss AG thus declares that the thermal imaging camera DTI 3/35 complies with the directives 2014/53/EU and 2011/65/EU. The full text of the EU declaration of conformity as well as additional information are available at: www.zeiss.com/dti-335/conformity

Regulatory Information USA and Canada




IC-ID: 22938-DTI335

1. This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.

2. Changes or modifications not expressly approved by the party responsible for compliance could void the user‘s authority to operate the equipment.

NOTE: The manufacturer is not responsible for any radio or TV interference caused by unauthorized modifications to this equipment. Such modifications could void the user’s authority to operate the equipment.

NOTE: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications.

However, there is no guarantee that interference will not occur in a particular installation.

If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

  • Reorient or relocate the receiving antenna.
  • Increase the separation between the equipment and receiver.
  • Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
  • Consult the dealer or an experienced radio/TV technician for help.

This equipment complies with FCC RF radiation exposure limits set forth for an uncontrolled environment.

Name of Responsible Party
Carl Zeiss SBE, LLC / Consumer Products
One North Broadway, Suite 1501
White Plains, NY, 10601, USA
Phone +1 800 858 6745

We, Carl Zeiss Inc. hereby declare that this product was tested conforming to the applicable FCC rules under the most accurate measurement standards possible, and that all the necessary steps have been taken and are in force to assure that production units of the same equipment will continue to comply with the Commissions requirements.

Regulatory Information California

The BC mark indicates that this product is in compliance with the California

Energy Comissions regulations on battery chargers.

Power supply unit manufaturer

Shenzhen Simsukian Electronic Technology Co., Ltd.
Building 1, the 5th plant, Jiayi Industrial Park
Daping Community, Guanlan Street Longhua District
Shenzhen P.R. China
Model identifier: SK22G-0500200Z


Input voltage VAC 100 – 240
Input frequency Hz 50 / 60
Output voltage VDC 5
Output current A 2
Power output W 10
Average operating efficiency % 82.98
Power consumption at zero load W 0.068


Ambient conditions
Operating temperature °C (°F) -0 / +40 (-32 / +104)
Relative humidity rH 25% – 90%
Storage temperatures °C (F) -30 / +60 (-22 / +140)
Protection type IP 20


Carl Zeiss AG
Carl-Zeiss-Strasse 22
73447 Oberkochen


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