Canon 450D DSLR Modification

Noise associated with warm sensor temperatures during long-exposure shots usually has an effect of turning a supposedly black region into noisy and grainy one. In a typical DSLR, the imaging sensor heats up during exposure, causing its temperature to reach up to 10 deg C above ambient (with sensor temperatures reaching up to 35 to 40 deg C), further increasing the thermal noise. By cooling down the imaging sensor, it is possible to eliminate or somehow minimize this thermal noise.

Important: This project is a work-in-progress. Learn about the most recent modification attempts here. Links to other related prototypes are listed at the end of this article.

In this project, I will describe how I modified my Canon 450D DSLR to become a dedicated astronomical camera, with all functions intact including the auto-focus capabilities, and thus, may still be used for non-astronomical purposes.

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Filter modified (Baader BCF) and Peltier-cooled Canon 450D

Part of the modification is the replacement of the camera’s stock (built-in) filter with a Baader BCF. The filter allows  greater sensitivity to H-alpha wavelengths emitted by most deep-sky objects, while at the same time eliminate unwanted UV and other IR wavelengths. This filter is necessary for any system that uses lenses in the optical train.

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Stock filter (left) replaced with a Baader BCF (right) to improve the camera’s sensitivity to H-alpha wavelengths

In my first prototype of a cooled DSLR camera, I used a Peltier module to directly cool down a Canon 450D’s imaging sensor, through cold plate (or cold finger) approach. Through this method, I was able to lower the temperature to up to 21 deg C below ambient, even when the camera is operating. To avoid issues related to condensation, the camera was equipped with nichrome wires to maintain the front of the sensor a few degrees above ambient (same principle in a dew heater).

To effectively dissipate heat buildup on the hot side of the Peltier module, I used an aluminum heat sink with a fan. I specifically used a magnetically-levitated fan (Sunon) mounted on rubber pads for this purpose to minimize vibration.

Below are some photos of the project during construction and detailed descriptions of some of the key steps in the modification.

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The camera’s imaging sensor, a CMOS (left)
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Disassembling the CMOS’s cell/holder
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Carefully removing the stock filter with a sharp blade
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Installing the Nichrome heater and a thermometer’s sensor
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Shown here is a 1.8 mm gap between the imaging sensor and its circuit board, where the cold plate will be placed
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Reassembling the imaging cell. The 4 wires visible on the left are for the Nichrome heater and the thermometer’s sensor.
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Cold plate fashioned from a solid copper plate
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A metal grinder was very useful in achieving the plate’s correct thickness, which is a little thinner than the 1.8 mm gap
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Precise measurement using a caliper is necessary to avoid any strain on the sensor and its circuit board
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The cold plate (left) with the thermometer sensor attached. Electrical tape on the back side of the cold plate provides electrical insulation.
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Thermal paste promotes effective heat transfer between surfaces. Thermal paste is applied between (1) the  sensor and the cold plate, (2) the cold plate and the cold side of the Peltier module, and (3) the heat sink and the hot side of the Peltier module. Note that you only need to apply a thin layer of thermal paste (just to fill the gaps and imperfections on the contact surfaces, as applying too much thermal paste will do more harm than good). Also, you must apply ample pressure (using clamps) between contact surfaces in order to squeeze out excess thermal paste and promote heat transfer through conduction, with plates in direct contact with each other and all remaining gaps filled with thermal paste instead of air.
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The L-shaped cold plate rests on the backside of the CMOS sensor and is secured in place by 2 screws mounted directly onto the side of the camera.
eteny_450D (13)
Thermal insulation is achieved by using mounting tapes and aluminum tapes. Effective thermal insulation is necessary to achieve lower system temperatures.
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Side view of the camera showing the cold plate attached firmly on its sides using 2 screws
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Another view of the camera showing the cold plate. Notice that the camera operates perfectly after the modification.
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Connectors are soldered on to the wires leading to the 2 thermometer sensors and the nichrome heating element
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Shown here is a 40 mm by 40 mm Peltier module used in the modification
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An aluminum heat sink is used to dissipate heat from the Peltier module’s hot side. A DB25 female connector is used to connect the camera to an external controller box.
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An image showing how the components are connected to the DB25F connector
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Thermal paste applied onto both sides of the Peltier module. Note that you only need to apply a thin layer of thermal paste (just to fill the gaps and imperfections on the contact surfaces, as applying too much thermal paste will do more harm than good). Also, you must apply ample pressure (using clamps) between contact surfaces in order to squeeze out excess thermal paste and promote heat transfer through conduction, with plates in direct contact with each other and all remaining gaps filled with thermal paste instead of air.
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Aluminum (anodized) heat sink and its enclosure/case
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60 mm magnetically-levitated fan (Sunon) used to minimize vibration
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Initial test showing a recorded sub-zero temperature and the formation of ice on the cold plate
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A fully-assembled filter-modified (Baader BCF) Peltier-cooled camera
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Modified Canon 450D DSLR. The camera may still be used with any Canon DSLR lens.
modified_Canon450D_outdoor
All functions of the camera remain intact including auto-focus, and thus, may still be used for non-astronomical purposes.
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A sample outdoor shot (custom white balance)
cooled vs uncooled
The screenshot shows dark frames (images taken in complete darkness, with the lens cover/cap on) taken with and without cooling (left and right, respectively) at 16 minutes exposure, ISO 1600 (ambient 30 deg C, sensor temperature: -4 deg C). More test shots will be posted soon.

This is still a work-in-progress. Results of field-tests conducted recently and actual shots taken with the camera will be discussed in my future posts. Clear skies!

To view other my other DSLR modification projects, follow the links below:
August 2014 Modified Canon 450D DSLR for Astro-imaging (improved sealed chamber prototype)
March 2014 Modified Canon 450D DSLR for Astro-imaging (sealed chamber prototype)
February 2014 Modified Canon 1000D DSLR (Baader BCF filter replacement)
December 2013 Modified Canon 450D DSLR for Astro-imaging (custom-fabricated lens mount)
November 2013 Modified Canon 450D DSLR for  Astro-imaging (sealed chamber prototype)
February 2013 Modified Canon 450D DSLR for Astro-imaging

For DIY astronomy projects useful for astrophotography, click here.
For tutorials on how to get started with astrophotography, click here.
To visit my astrophoto gallery, click here.
To subscribe to this site, click here.

© Anthony Urbano (Manila, Philippines)

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9 thoughts on “Canon 450D DSLR Modification

  1. Wicked, surprised Canon (or other) havent scooped you up yet! Definitely a badass modification. What resources did you utilize to embark on this endavor (ie 450D circuit/wiring digrams, similar DIY modders, etc)? What are you using for power the source(s)? Any detials on your external controler box, using RaspPI or Arduino?

    • Thanks Michael! For this project, I used a Canon 450D, the Baader BCF replacement filter, a Peltier module, some nichrome heating wires, 2 digital thermometers, a maglev fan, and a 12V 12A power supply. The controller box is just a simple switch board that allows me to control (turn on, off, or set to low, med, and high) the following components independently: 1. cooling (Peltier) and 2. heating (nichrome). The box will also house the LCD readout of 2 thermometers. Perhaps in the future I could include a micro-controller (perhaps using Arduino, or even with a simple 555 IC hooked to a transistor) to provide a means to regulate the temperature. For now such a feature is not yet necessary since I always operate at maximum cooling for the Peltier module (the cooler, the better) and a pre-defined heating level for the nichrome. I will include links to several references and similar mods as soon as I find time to continue writing this article :)

  2. Hi Eteny,
    This is an awesome mod, it looks very neat, compared to other DIY that I’ve seen :-)

    I have a few questions if you don’t mind …

    1. Do you have a wiring diagram for the setup, I could see you used DB-25, do you have DB-25 USB wiring as well? Do you source the power from your laptop USB port or external battery ?
    2. Does the heating wire help with the condensation?
    3. How many watts is the Peltier, the lowest one I saw was 60w, is it sufficient ?
    4. Your enclosure case looks really neat, anywhere I can source the same case?

    Many thanks in advance.

    Best regards,
    astroboyz

    • Thank you for your kind words Astroboyz :)

      The decision to use a DB25 connector was only arbitrary :) It was chosen only in the interest of having access to an ample number of connection points. The camera still connects to a computer via the USB port.

      The heating wire helps avoid condensation but only up to a certain extent. You may need to experiment with your setup to find out how low you can go without condensation problem. To fully-eliminate the condensation issue, you need to put the whole thing inside a sealed chamber (you may refer to the other versions of the my camera modification).

      I am not sure of the exact wattage of my Peltier module (it has no label), but I power it using a 12V 12A power supply with no problems (12V at 12A is equivalent to 144W!) :) Note that modules with higher wattage needs better and larger heat sinks. The enclosure used was taken from an old dehumidifier, I am not sure if this particular casing can also be found elsewhere. Good luck!

      Eteny

  3. Hey there do you offer service to modify cameras? Awesome site my friend! love it!
    Cheers from Canada!
    Clerar skies!
    Martin

    • Hi Martin! I am afraid I can only extend the camera modification service (free of charge) to enthusiasts in my locality (Philippines). The difficulty, transit time, as well as the costs of sending the camera from abroad and back hinders me from accepting such requests. Feel free to get in touch with the DSLR Modifications Yahoo Group. I am a member of that discussion group and I believe fellow camera modifications enthusiasts would be able to help you locate a camera modification service near your locality that you can avail of. You can even find useful info there that will help you gain confidence to do the modification yourself! There are lots of good folks there who are more than willing to help :)

  4. Eteny,

    Can you specify the thermometer sensor in the picture and also the display you use?
    Maybe a search in Google?
    This is a very nice site. I like your projects very much.

    Stijn

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