Canon 350d Internal Temperature Evolution
The Watercooled - Peltier - Cool Box
by Andy Strappazzon
This is my attempt to study the Temperature Behavior inside a canon 350D Reflex (DSLR). The noise generate by the CMOS is directly linked with Temperature, and it's use to say that every time you increse the temperature by 6°C the noise signal is doubled. Let's see how the temperature behave inside a 350D.
A First Series of measurement have been made in an open Room.
The The Second Series have been made in a home made CoolBox.
The Purpose of the study is double: First, with the use of the internal Temperature Sensor, is to avoid taking "Darks" on the field and loosing more than one hour. The goal would be to generate a Dark Database based on the temperature. Second, see the impact of the use of the Cool Box or More advanced technique to cool down the sensor. Indeed these technique are quite complex to put in place and need a lot of energy. Results might vary, of course, according to machine. A Canon has a different system to Leica, I phone 4, Nikon and other photographic equipment. Perhaps the same experiment could apply to all the different machines.Very difficult to put in place on field.
Canon 350 D - Temperature Evolution in a Cool Box
Cool Box Setup Description:
The Cool Box is an insulatd Iron Box, cooled down with a Water Cooled - Peltier Device. A Radiator and a fan circulate the air inside the Box. By expereince, without any device working inside the box, the temperature inside the Box is 8°C less than the External Temperatre.
The WaterTower is the Closed Water Circuit that circulate the water from the Waterblock attached to the Peltier and a 360cm * 12cm Radiator using 6 fans (12cm*12cm). A 250Watt computer allimentation generate the electricity to the Peltier Module (4cm * 4cm) and to the water pump.
Finally, the temperatures are tracked by 2 monitors: One for the internal Temperature (Sensor Taped on the CMOS) and another for the external Temperature. On the left, you have the control box of the 350D Canon (DSLR).
1Comments about the graphs:
1) In Pink (Off- On), you have the effect of switching on the Canon 350D. You gain 6°C !
2) In Yellow (test 1), Blue (Test 2) and Light Blue ( Test 3), you can monitor the temperature of the 350d in open air room but starting from different temperature room (12°C, 15°C and 18°C).
3) In Brown (Cool Box 2), you have the evolution of the temperature but in the Cool Box (Starting at 10°C). Winter time..
4) Finally you have the Data of Cool Box (dark pink) that show the evolution of the temperature when you initiate the Cool Box and the Canon 350D procedure in the same time (3min lights + 2sec intervals). Where you can see the delayed impact of the Cool Box on the internal temperature in the operating mode.
The First graph, is the measured temperature, the second one have been corrected by the room temperature evolution and set at 0 as the inital point for comparaison.
The initial behavior is always the same for the first 10-15minutes. The temperatue quickly increase of about 5°C. After 20minutes, 6°C , you have already doubled the noise background! The upper limit is around a 10°C temperature increase (after around 80minutes). The upper limit seems to be impacted by the initial temperature but the effect is limited and the ambiant temperatre evolution have also a impact.
10°C ==> 18°C (Delta of 8°C)
12°C ==> +/- 21°C (Delta of 9°C)
15°C ==> 25°C (Delta of 10°C)
18°C ==> 29°C (Delta of 11°C)
Any way, we can say that after 20minutes you have double the noise background and that after 60 -80 minutes you have reach a constant temperature that will be impacted only by the ambiant temperature. Note that any ambiant temperature variations have an impact on the Cmos Captor around 5 to 10 minutes later.
The Cool box utilisation reduce the temperature of about 10°C when used in parallel of the 350d!
Copyright © 2009, Andy Strappazzon. All rights reserved.