First, let’s compare Dark Frames. For this test I was basically logging temperatures and for this reason I only shot 120 s Dark Frames (to record the sensor/Exif temperature every other minute). I set my Gary Honis modded T1i to ISO1600. Although it is only 120-second shots, we can clearly see a reduction in thermal noise.
Now in terms of temperature:
While continuously shooting 300 s Dark Frames my uncooled T1i will reach a steady temperature of 41 C with an ambient of 26 C or a 15 C Delta above ambient. To make sure I reached a steady state temperature, I shot 40x 300 s Dark Frames or about 3 and a half hours…
The next day, with the Cp50X-EOS set a -5 C (on the cold plate), the load on the Peltier device is about 32 W. At this cooling level, and after one hour of the same 300 s Dark Frames, the temperature was only 32 C with an ambient of 26 C or a rise above ambient of only 6 C.
I repeated this test again the following day with a temperature now set to -15 C (on the cold plate). The Peltier is now delivering about 45 W of cooling. The ambient temperature was still 26 C and the Exif recorded a sensor temperature of 29 C, or a delta of only 3 C above ambient.
Again, this is only preliminary results as I am currently working on a complete round-up of my cooling solutions, which include a test against the Box cooler CP80-EOS and revamped CP80X-EOS upgraded with a PWM temperature controller.
Noise level and other thoughts:
Standard Deviation @ 41 C (uncooled): ~ 15.5
Standard Deviation @ 32 C (CP50X-EOS @ -5 C): ~ 8.5
Standard Deviation @ 29 C (CP50X-EOS @ -15 C): ~ 7.2
The CP50X-EOS is a very simple cooler design for DSLR. It is in my eyes a very efficient way to maintain a sensor temperature at or about the ambient temperature. In most situations, it is all it takes to cut the noise level in half! In fact, when bringing the Standard Deviation from 15 to 7, not only it cuts it in half but it doesn’t leave much noise. It begs the question “do we really want to bother with condensation/insulation, heavier and more complicated designs when there is so little room for substantial improvement”. Some of us will still find box coolers a better overall solution, but for some others the CP50X-EOS might be a new simple way to cool down our DSLR’s.
For the purpose learning more about DSLR Cooling I am currently comparing all of these solutions. I am moving the new PWM Temperature Controller to the CP80-EOS and using a better hot side heat sink and fan combination to see how low it can drive my T1i down to. I am thinking that the added cooling capacity on the box cooler might combine well with the PWM Temperature Controller to adjust the temperature and reduce the overall power consumption.