DSLR cooling box v cold finger

[traveller]

Hi all, I have seen many people cooling their DSLRs in recent and not so recent posts. There seems to be two schools: put the camera into a cooling box and cool the entire camera or cool the sensor via a cold finger externally. The way I see it, there are advantages and disadvantages with each approach:
1. Cooling box: straight forward, relatively easy to do, camera dont need to be opend up. But downside with a heavier box and lack of access to camera control buttons.
2. Cold finger: better cooling, lighter, can acces buttons, but need some steady hands and open up the camera.
I am in the process of removing and replacing the sensor filter off a Canon 40D, so will be opening up the camera anyway. So I would like to hear from those of you who did cooling mods on their DSLRs of their pros and cons and any other words of wisdom.
Thanks :help::question::thanx:
Bo

[niko]

Bo,

I'm gunna have a crack at building the box as detailed here

http://ghonis2.ho8.com/rebelmod450d16d.html

seems it doesn't add too much weight

I'll let you know how I get on

cheers

niko

[traveller]

Thanks Niko,
Yes I saw that mod, but my main concern is lack of access to the buttons and live view. Although they can be overcome with a remote cable and tethering to a computer respectively.
I am impressed by Mill's attempts here (http://www.iceinspace.com.au/forum/showthread.php?t=50451)and here (http://www.iceinspace.com.au/forum/showthread.php?t=50788). But I am soooo not in his league when it comes to "hands on" mods :lol:. I did PM Mill and he suggested I go with the cooling box way.
I also had a message from Rally saying that I will need to consider amp glow and the importance of darks, so they are all factors I need to take into account.
Bo

[niko]

I've already had my heart in my mouth over the opening up of a camera so not going there.

When I use my DSLR currently it is tethered to a PC anyway so not too worried about lack of access to buttons.

Anyway, it rains all year round these days so it's access to anything at all I struggle with!!

[Phil Hart]

hi Bo

what is your motivation for doing the cooling mod yourself.. is it driven more by cost or just a general desire and enjoyment of doing it yourself?

the cold finger mod i think is pretty advanced to try yourself.. but if you're seriously contemplating it then you must know a lot more about it than i do. the coolbox approach seems like an interesting low cost way of achieving cooler sensor but from my point of view the CentralDS cooled cameras are not bad value.. at least for the cropped sensor cameras.

Phil

[traveller]

Thanks Phil, my main motivation is having a go, saving money is secondary. The body only costed me $300, so it can be nice paperweight if it fails :lol:.
BTW, the quote for a 40D supplied mod from Central DS is US$340 plus another US$46 for postage and insurance.
The critical things are thinness of the copper plate, complete insulation of the cold finger to ensure no condensation build up and lots of nerves :lol:.
Bo

[g__day]

I'd like it if some local entrepeneur offered to build cold boxes for a reasonable price (i.e cost of materials + $100 - $200). I myself don't want to go bending sheet metal etc, but it would be very nice having a usually sealed significantly cooled DSLR that's already been modded for IR sensitivity...

[White Rabbit]

I agree there is a market for these out there, although I think $200 is a little unrealistic. I'd be prepared to pay well for one of these, if the quality was of a high enough standard. The mod doesn't look that hard to do, but I'm sure someone else could do it better than me.:thumbsup:

[2stroke]

I'am still modding my 1100D cold finger style, though the problem is dew. I have all my gear to do it though are waiting on others doing it to see there results and counter measures against dew. So far the best solution i've being working with is ripping off a commercial camera modder and opting for a mc clear in between the sensor and lens plate. Using a hot finger back to this area or the encloser to warm and keep above dew point. If i can get this planned out right and air tight i should be able to get sub zero temps on the sensor without dew problems. At the moment though i'am still planing and searching for a suitable encloser thats light weight and offers a gasket to maintain an air tight environment.

[g__day]

So if someone was doing say ten of these at a time - how many hours would each unit take to produce? I basically thought about 4 hours effort * $50 an hour; else you are into diminishing returns - were the labour cost far outweighs materials consumed.

But I am slightly intrigued now - and may have a go at this myself, the results certainly look impressive. If high school kids can send a camera into near space and photograph the curvature of the Earth for under $100 and get all their gear back - well a functional unit should be well within my capabilities, it just won't look art deco!

So reading what one needs:

1. Peltier ($20 each from Jaycar for a 68 Watt unit), power supply ($25- $70), circuitry ($20), heat sink and two fans ($40)
2. 30cm square thin metal sheet to spread thermocouples' cooling effects (Aluminium would be fine) 12" * 12" ($12) 24" * 24" ($50)
3. Foam Insulation ($2)
4. Plastic shielding box ($5)

Tools and wiring, cable ties etc.

So for $140 - $200 in parts one could readily build a unit that should work and see how it helped their astrophotography...

Caution in all this thinking TEC's (Peltiers) love lots of tightly controlled current and nailed (regulated) voltages, the cooled side will condense any water in the air - so sealant and keeping air around things dry is critical, and the hot side needs efficent heat transfer (big radiator and high flow fans) to be most effective.

[avandonk]

I have two cooler boxen. One air cooled and one liquid cooled by the Franken fridge. These are now no longer needed and I am open to offers local pickup preferred.

The Peltier(s) MUST be driven by clean PWM power for temperature regulation. A thermostat will kill the Peltier. Voltage variation is OK but then the temperature will vary with ambient.




Bert

[g__day]

Terminology Bert?

Clean PWM power means what exactly? I googled it and it says pulse width modulation - which sounds complex! http://www.tetech.com/FAQ-Technical-Information.html#19

Would it just be better to have a simple on / off switch to the peltier and attach it to regulated, always on direct current so it trys to cool its target as much as it can (rather than have a cut off thermo switch)?


A Thermostat will kill the Peltier - means don't have a current limiter based on some temperature sensing device?

Could you please explain in laymens terms what exactly you mean to tell us non electricans!

Also could you post a few picks of your coolers and what they are able to achieve - would be very instructive!

[White Rabbit]

I'd be interested, if you can be bothered posting. Can you post some specifics?

[avandonk]

I used one of these to control the temperature of the Peltier cold side

http://www.tetech.com/Temperature-Controllers/TC-48-20.html

This site is also useful for info on Peltiers and how to use them.

http://www.tetech.com/FAQ-Technical-Information.html

It is pulse width modulated so the Peltier will behave as if it is being driven by a smoothly varying DC voltage. It is also a PID ie proportional integral differential controller which applies power intelligently so there is no sawtoothing that you get with a thermostat. Switching a Peltier off and on repeatedly with a thermostat will put stress on the diodes by differential expansion and contraction. A bit like breaking a steel wire by repeated bending.


You can use a set voltage DC supply but then the temperature will change with ambient making it hard to match darks.

I am using the TC-48-20 controller to keep the RH200 scope heated with five dew straps to 17C +- 0.1C so focus stays constant with ambient temperature changes and there is also no chance of condensation on the optics.

If you need more info just ask.

Bert

[g__day]

Query - are you better off having a rectangular box with fan forced cooled air moving across the camera body, or else mould a metal case that snuggly fits the camera body?

I initially wondered what if you simply wrapped a DSLR tighly in aluminium foil - until there was no air gaps - then it snuggly fit the box pictured - would it cool, faster, more uniformly, better?

Then I thought that if you could do it with aluminium foil to remove all the air spaces - you could do it (with a bit of work) with tin solder if you first made a mould of the Camera in halves (i.e. wrap Camera in plastic, Plaster of Paris it into two halves (top / bottom or front / back - any way you wish it sectioned) - create a reverse mould). Then fill this mould with solder until it meets the dimension of you box, or else simply connect the cool side of the peltier to this solder mould and insulate it with foam, silicon - whatever you like.

If there was no air gap between the camera body and its metal cooling chamber:

1. I expect it to cool quicker and more evenly across the camera body

2. You could mount the peltier pretty much anywhere you wanted - say right behind the hottest part of the camera - power circuitry and CCD

3. Removing all the air should remove a source of condenstaion and corrision

Alternately if you only have to cool a part of the camera - say the rear and where the power comes in on the left - create a metal solder cradle for that section that you wish to cool and match it to a soft silicon section for the front of teh camera - that is if the front of the camera's temperature doesn't affect the camera's performance?

What do folk think - would removing all air and placing the camera case (or parts of it you want) directly on thermoelectrically cooled metal might help performance?

Also would soft silicon (like oven mitts) be a better insulator than foam, or even use both in layers?

Cheers, Matt

PS

Searching cloudy nights - I see someone else has tried a different variation of this - throw away the box os all the camera functions can be accessed all the time, using conducting thermal pad (an impegrated silicon that conducts heat) and attach this to a peltier with barely anny insulation around the entire camera...

http://www.cloudynights.com/ubbthreads/showflat.php?Cat=&Board=DSLR&Number=5301908&Forum=f85&Words=cooling&Searchpage=0&Limit=25&Main=5301908&Search=true&where=bodysub&Name=&daterange=1&newerval=1&newertype=w&olderval=&oldertype=&bodyprev=#Post5301908

PPS

$400 - http://www.telescope.com/Astrophotography/Astrophotography-Accessories/Orion-DSLR-Camera-Cooler/pc/-1/c/4/sc/61/p/101916.uts#

PPPS

$240 - https://www.teleskop-express.de/shop/product_info.php/language/en/products_id/4824

specs here http://www.geoptik.com/en/scheda-prodotto/polar-photo-box/189/30b330/635/30b330.html

[jjjnettie]

I have this arriving in 3 weeks. :)
http://www.centralds.net/cam/?product=cds-1100d-uvir

It was a hard decision to make, I spent a long time researching my options. I know I should be advancing towards a CCD, but I think this camera will give the QHY9C, which I was going to buy, a run for it's money.

[traveller]

That would have been a hard decision jjj. So what swayed you instead of a ccd?
Matt, I guess less air means better conduction. You can also rip some of the rubber grip off if you are keen.
My filter is in the post so will update later.
Bo

[jjjnettie]

What swayed me?
I'm familiar with the capture and processing of DSLR images. So laziness is one reason.
And as I was interested in getting a OSC anyway, I honestly think that the results from this camera will be comparable.

:) I hope I haven't made a big expensive mistake. LOL Guess I'll find out soon enough.

[2stroke]

Drool...... Can't wait to see your results :) These guys have made pure magic with the 1100D, its just mind blowing seeing the dark frames :) I'am trying to do a botch up copy of there work but it's near impossible. Going through the design which there open to share they have covered every aspect from shielding to dew control, its just pure genius at work with those guys. Will be waiting with extream intrest jj of your first shots :thumbsup:

[g__day]

Impressive results on the dark frames! Now if we could just solve sky glow and blooming!

[White Rabbit]

this one looks like the bomb.
http://www.telescope.com/Astrophotography/Astrophotography-Accessories/Orion-DSLR-Camera-Cooler/pc/-1/c/4/sc/61/p/101916.uts#'

But alas it does not fit the 5D MkII.

[g__day]

Actually it looks like a complete toy compared to this:

http://cooledpix.com/category/dslr-cooling/

This guy is doing it right and its very clear to see how it evolved far beyond the cool box to a fitted solution that is well connected, temperature controlled (to avoid condensation) and still allows easy access to the camera settings!

PS

Wish I could buy one!

[jjjnettie]

I'm keen to see how they stack up against a camera such as the qhy9C.
Time to start the search for some pictures to use as a comparison.

[g__day]

I guess it would come down to the full well depth, Q/E of the chip and and its electronics. Once you have it cooled sufficently I imagine you have a significant gain.

Dying to see how your new camera will perform too!