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Old 11-03-2016, 04:08 AM
mmalik (Mike)
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Makings of a cooling module for DSLR

I have developed this cooler that mounts to almost any DSLR [...that has a tripod socket hole]; will share more details soon. I think astro imaging can greatly benefit from such a cooling device in reducing thermal noise in the images. Regards
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Old 11-03-2016, 04:16 AM
mmalik (Mike)
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Not all DSLRs have flip open LCDs, plus securely mounting to the LCD recess without intervention is almost impossible. Base provides easy non-invasive mounting and heat conduction paths for most DSLRs. Regards


Note: Following are a7S heat conduction points for the sensor and logical heat conduction paths for the base; point with red arrow specifically comes in contact with the base with a heat conducting pad installed by default.
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Old 11-03-2016, 05:07 AM
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janoskiss (Steve H)
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Looking at it naively, I'd worry about temperature gradient across the sensor with a setup like that.
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Old 11-03-2016, 05:26 AM
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ZeroID (Brent)
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Hi Mike,
How do you control & measure the effect of your cooler on the camera ?
Myself and a few others on here having gone down extensive experimental paths with cooling DSLRs and have found any external cooling systems are minimally effective at best and the only consistent solution is the cold finger behind the sensor with TEC and temp management.
I have a modified Canon 450D which gets a 20* delta on ambient as measured at the sensor ( BYE reports the CPU board temp ).
Our experiments with cold boxes and thermal transfer points certainly took internal temps down 5-10* but as soon as power was applied the temp rose faster than the system could remove and near ambient temps were the best acheived.
To be useful you need to reliably and consistently achieve deltas of 15-20* below ambient at the sensor. The general rule being that every 5* drop halves the noise at the sensor.

EDIT: Yes, I was going to mention gradient as well
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Old 11-03-2016, 09:00 AM
glend (Glen)
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Be very careful of what this guy is promoting. He has a very long thread (2000 posts) on Cloudy Nights on the ongoing development of an external cooler attached to a DSLR base (a highly inefficient and as yet entirely unproved design). Even the old style cooler boxes are probably more efficient and they are long out of production.

As most well researched DSLR modifiers know, only cold fingers directly cooling the sensor produce the results needed to null noise. The arguement that if you buy a low noise modern DSLR camera (which make cold finger placement very difficult or impossible (but no one has tried it)), then cooling only the base and relying on plastic and frame conduction to get some temperature reduction at the sensor - is frankly wishful thinking.

His designs are entirely unproven on any camera, he has no way of actually measuring sensor temperature (relying on EXIF processor data), and he has avoided any field testing and Dark vs Bias/offset file comparison, which would validate or at least indicate what if any noise reduction was being created. Be aware that he has a commercial interest in selling kits or parts, and camera mods.

It is disappointing that he has now popped up here.

I have reported this thread.

Last edited by glend; 11-03-2016 at 09:11 AM.
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Old 11-03-2016, 10:15 AM
mmalik (Mike)
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I don't think temp. gradient is an issue; I have done some testing and will be doing more. Will share some test results soon. Regards

Last edited by mmalik; 11-03-2016 at 02:22 PM.
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Old 11-03-2016, 02:16 PM
mmalik (Mike)
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Quote:
Originally Posted by ZeroID View Post
How do you control & measure the effect of your cooler on the camera?
It is an Arduino based PWM (Pulse-width Modulation) system that uses analog pot (potentiometer) and reports real-time coldplate temp. Measuring effects on the camera of course is EXIF based. Regards
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Last edited by mmalik; 11-03-2016 at 02:59 PM.
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Old 11-03-2016, 02:41 PM
mmalik (Mike)
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If there was any goal in developing such a system, it was one... bolt-on cooling of the base of any camera that has a tripod socket hole.


Not all cameras have flip open LCDs; ones with flip LCD don't have secure means of mounting a cooler. In short, cooling of the back was definitely not a consideration.


Idea was to NOT have to open the camera; cold finger of course was NOT a consideration either.


Camera bottom cooling results are 'not' going to be uniform for all cameras; cameras like Sony alpha that have conducting structures inside may benefit the most; most Canons' internal structures at the base are not so conducive, but decent results can still be obtained regardless with adequate insulating post module installation. Note: Module does have coldplate side and TEC side insulation; it is the exposed camera side coldplate insulation that I am referring to. Regards

Last edited by mmalik; 11-03-2016 at 03:00 PM.
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Old 13-03-2016, 01:43 PM
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ZeroID (Brent)
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EXIF temperature results are measured at the processor and have no relevance to sensor temperature. Long exposure times will heat the sensor and neither be measured accurately nor controlled. Also the gradient on the temp through the conduction from the base WILL have an effect, there will be a noise gradient across the sensor. Not a cooling solution at all.
The only place I have heard of this working at all is on a high end metal bodied camera and even then it was not able to be accurately managed as the temp was still measured at the processor.

EDIT: All cameras have a tripod mount hole .. even my wee Fujifilm.

EDIT Again: And showing a complex piece of electronic equipment showing the number 6 and not connected to anything visible proves absolutely nothing. How does the user control and measure the unit and camera at the scope ? I don't think I'd want to be powering that piece of gear out in the field.
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Old 14-03-2016, 01:15 AM
mmalik (Mike)
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I have a different philosophical perspective... there is something that always gets missed in such technical discussions is that a cooling device in itself that is designed and operates optimally comes first and foremost.


Cooling modules abound, big bulky heavy ones, cold finger ones, boxy ones, etc. This was an effort to design a compact yet efficient cooler that could be effortlessly mounted to the base of any camera. Lot of thought went into the type of power connectivity; RJ45 was selected for easy connection/disconnection after module gets mounted to a camera (so one doesn't have to contend with cables while installing).


Point being, cooling device in itself comes first. Once you have such a device [...which we do now], then comes the camera, dark frames, EXIF temps., etc. [which I did test, will share results soon, and will do more of...]


Idea here wasn't to develop the biggest/bad-est cooler that could freeze the heck out of a DSLR, rather develop a smaller efficient cooler for moderate cooling of a DSLR.


Lastly, when it comes to DSLRs, there are variables in terms of camera design. Some camera designs will conduct heat better than the others. Does that negate the efficiencies achieved in cooling design itself... no. Regards



Note: Efficiencies achieved are numerous... TEC type/design [TEC is USA made], power used (volt/amps), [relatively lower powered design to produce less heat and more cooling], how TEC gets driven (linear vs. pulse modulated), fan used to dampen vibrations, fan power/cfm, heatsink used for heat dissipation, coldplate size/type, coldplate insulation materials/specs, power connectivity (type/ease of use), AC vs. Powertank flexibility, etc. I'll elaborate on in coming posts.

Last edited by mmalik; 14-03-2016 at 04:25 AM.
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Old 14-03-2016, 05:26 AM
mmalik (Mike)
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I have done extensive testing of the TEC both with linear power and pulse modulated (PWM) power; I can conclusively say that PWM drives and produces cooling to the max. Oscilloscope traces of UNO PWM. Regards
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Old 14-03-2016, 07:01 AM
glend (Glen)
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At the risk of giving this thread more oxygen; PWMs have been used to control TECs for years now, and do a good job when coupled with the right camera, simple control circuits and cold finger design. I would suggest that those interested in workable DSLR cooling read rcheshire's excellent thread on this subject in the DIY forum here. Rowland conducted sufficient field testing and Dark to Bias sub comparisons to validate his design , which was also peer reviewed by other builders, myself included.

Effective DSLR cooling is all about cooling placement, and there is no substitute for direct sensor cooling, although there have been many attempts by well respected DSLR modder's like Gary Honis, and others. I would remind readers of the hype surrounding the various 'cooler box' designs of some years ago, which were even sold as commercial products such as the Orion version; these are all gone now as users soon found that external cooling was not giving them the performance expected and fell far short of successful cold finger designs.

It would be useful if mmalik were to spell out exactly what his objectives are for this thread - which seems to be an offshoot of his Cloudy Nights thread. Is he promoting a commercial interest in the supply of componentry and kits?

Last edited by glend; 14-03-2016 at 07:51 AM.
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Old 14-03-2016, 01:23 PM
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Still no results to see for it. Yet to see a working system and quantified photograhic results from it.
He is selling a beer fridge .... probably expensive.
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Old 14-03-2016, 02:34 PM
mmalik (Mike)
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Following test results are from early on testing on a Sony a7S during the development process; more to be presented in due time. Regards

  • Baseline 3min dark taken at 76F ambient with cooling module OFF; baseline dark RAW available here...
  • 3min dark taken after 30min of cooling module start; dark RAW available here...

Note: Small (identical) sections of corresponding in-camera JPGs shown, zoomed-in at 150%
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Old 14-03-2016, 03:25 PM
mmalik (Mike)
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Following test results are from early on testing on a Canon 7DII during the development process; more to be presented in due time. Regards


TEST METHOD:
  • A lamp was used to gradually warm up the camera (for ~2hours)
  • A baseline reading was taken at this time with cooling module off
  • Cooling module was started and a test reading was taken (after ~2 hours)
  • Heat source was present throughout the test
  • 3 meter RJ45/Ethernet cable was used for cooling module/power/PWM interconnectivity
  • Baseline RAW...
  • Test RAW...
Note: Small (identical) sections of corresponding in-camera JPGs shown, zoomed-in at 400%
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Last edited by mmalik; 14-03-2016 at 04:29 PM.
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Old 15-03-2016, 04:14 PM
mmalik (Mike)
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While no one is arguing the end result of reduced noise in the images, I am at the last stretch of enhancing the inherent performance characteristics of the cooling module itself. I'll chronicle all that went into the development of the module in due time but let me jump to one of the last characteristics of the module being upgraded, and that's coldplate insulation.


Here is a test user leaving the module running indoors at room temperature with 1/16" insulation which proved to be insufficient. Upgrading insulation considerations in coming posts. Regards


Note: Images courtesy of Steve
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Old 15-03-2016, 04:22 PM
mmalik (Mike)
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One enhancement that's being made is an upgrade of coldplate (closed cell) neoprene insulation from 1/16" to 1/8", here is why...
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Last edited by mmalik; 16-03-2016 at 12:54 AM.
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Old 15-03-2016, 04:26 PM
mmalik (Mike)
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A comparative analysis...
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Old 16-03-2016, 05:10 AM
mmalik (Mike)
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You may think a lot is being made of (coldplate) insulation but if you knew all that went into development of the rest of the module it is worth the extra effort.


So here are my thoughts...


1. I think 1/8" now with some experimental experience and improved application (corner coverage) will do a great job on the TEC side


2. On the coldplate perimeter, I feel 1/8" will also do the job and will look nice as well; there is a possibility of considering 3/16" for the perimeter


3. The camera side of the coldplate is something users will need to improvise given the foot print of the their camera; on areas extending beyond the camera, of course folks can go as thick as they wish. This is where 1/4" can be a possibility but in limited application. For most part I think 1/8" here will do the job as well. Regards


Note: Neoprene used is closed-cell and is of really good quality with strong native adhesive that bonds very strongly to the coldplate, and was imported form EU

Last edited by mmalik; 16-03-2016 at 05:41 AM.
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Old 16-03-2016, 05:14 AM
mmalik (Mike)
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3/16" is an odd one; not may made in that thickness specifically. I tested the strength of the native adhesive for bonding 1/8" & 1/16" together, and it looks good and very strong. So yes, 3/16" can be an option for the (coldplate) perimeter and where needed. Regards
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