Cool modding a 5DMKII

[nebulosity. (Jo)]

Great job Rowland hope you get some awesome results.

Jo

[rcheshire (Rowland)]

Thanks Jo. I did overtime on this one, but it was worth the trouble. Nice to look down the barrel and see a fogless sensor, with the cold finger at -3C. It works in camera to roughly the same specs as the test rig, with -22C diff. Hardly budged taking a 3min dark. The 8amp TEC is a beast - tempted to try it... hmmm... No! Leave it be... Next is to translate that all to the 5d mkii.

EDIT: -7C cold finger and no condensation on sensor face. Consistent 19.5C differential. No change over 3 min exposure.

[2stroke (Jay)]

Great work man my 1100d died after the dam brother inlaw moved it from the desk i had it on uncased, so my project is at a stop till i get a 4th 1100d haha Your inspiration has cost my pockets dearly lol.

[rcheshire (Rowland)]

Last post was lost.

You probably have enough parts to build a working camera, Jay. Keep it simple. The sticking point for me was sensor defogging, but it looks like I have that under control now.

Really, the benefits of deep cooling for a 1000D or 1100D are limited, because Canon has managed to keep the dark noise low, to a point, after which it is exponential. If you can get your sensor down somewhere between 5 - 10C, any lower has marginal benefit.

The 5D MKII on the other hand benefits enormously from cooling, because the sensor temperature escalates to ridiculous levels with long exposures. Measured externally, bottom left hand side of the sesnor frame, even with cooling the sensor is 5C warmer when exposing, than the camera on temperature, which is 3C warmer than camera off. It's a beast. But cooling to -5C - 0 is adequate.

Have fun. Maybe we should have a workshop to reclaim some of the collateral.

[rcheshire (Rowland)]

I took advantage of the cold rainy night, here in Geelong, to further test the newly installed sensor defogger, fitted to my test camera, in addition to installing an Astronomik EOS UV-IR Clip-in filter, which reduces the volume of air in front of the sensor. Using a spare sensor, I did a full spectrum mod with the intention of fitting a clip-in.

I have migrated the cooling and sensor defogger to a 1000D test bed.

Cold finger temperature -10.94C, with sensor defogger set at 4V, slight condensation appeared in the bottom right corner of the sensor, but not enough to infringe upon the active portion. A slight increase in voltage will fix that. Normally running the defogger at 4.7 - 4.8V.

Very happy with this result. It is unlikely that these sorts of temperatures will be a regular thing and the test camera is working just fine. Then again for summer cooling I'm tempted to work on a more efficient setup, with a bit more aesthetic appeal.

I'm not sure if anyone is getting anything out of this? But my research indicates that one of the most ideal candidates for this set up is a 450D. 14 bit, pixel size 5.2um, same as 1100D, characteristically low noise and construction almost identical to the 1000D, which makes it a breeze to convert and cool. And a biggy - very cheap second hand.

I'm not taken with the 5D MKII as a candidate for coolling. Like many of the latest Canon offerings the sensor heats to astronomical proportions by comparison to earlier models that I have looked at. It is not very robust either. I find it too delicate/ fragile and ready to malfunction. But I do like the image scale with a 200mm lens.

In short, unless you are prepared to live with a bit of pain, mod something else. A cold finger, electric sensor defogger and a couple of good quality adjustable DC DC converters is all thats needed.

[gregbradley]

I wonder if you could make a little housing for the sensor and put in a desiccant plug which are available for SBIG cameras. That's what they use to allow cooling without dew and condensation.

Adding some argon would help too.

Greg.

[rcheshire (Rowland)]

Hi Greg.

That is probably achievable by fitting a glass cover in place of the AA piezo filter and some way of purging the cavity. That would be a straight forward solution at a squeeze. Design philosophy is minimal intervention. I'm not convinced of the reliability. I notice on some sbig cameras a small heating element.

[alistairsam]

Hi Rowland,

I came across this EOS adaptor that accepts 2inch Filters.
I think this could be used to act as a humidity seal by adding silicone around the clear glass filter so sensor wouldn't be as exposed.
this doesn't add any backfocus either.
http://www.baader-planetarium.de/sek...body-gross.jpg

they also have a similar one with a UV/IR glass.


http://www.baader-planetarium.de/sek...asst-gross.jpg
http://www.baader-planetarium.de/sektion/s17/s17-en.htm

https://www.teleskop-express.de/shop...he-sensor.html

Alistair

[2stroke (Jay)]

Originally Posted by rcheshire

Last post was lost.

You probably have enough parts to build a working camera, Jay. Keep it simple. The sticking point for me was sensor defogging, but it looks like I have that under control now.

Really, the benefits of deep cooling for a 1000D or 1100D are limited, because Canon has managed to keep the dark noise low, to a point, after which it is exponential. If you can get your sensor down somewhere between 5 - 10C, any lower has marginal benefit.

The 5D MKII on the other hand benefits enormously from cooling, because the sensor temperature escalates to ridiculous levels with long exposures. Measured externally, bottom left hand side of the sesnor frame, even with cooling the sensor is 5C warmer when exposing, than the camera on temperature, which is 3C warmer than camera off. It's a beast. But cooling to -5C - 0 is adequate.

Have fun. Maybe we should have a workshop to reclaim some of the collateral.

Myself and wife grabbed a starshoot pro v2 color aka qhy8l the other day man, lol 3rd 1100d so i've given up as its adding up to much now for experimental fun. Might see what she wants to do and may just pass onto you to tinker with instead of the bin lol, the 3rd 1100D has the noise issue which a far share of CN user have had and will just use now for a time-lapse/ lighting cam. The first cam is stripped down into pieces after i thought it was dead (Always check the battery door switch ROFL), second cam wont open shutter or something bro in law plonked it in a box with no casing when i was working on re-house AHHHHH!!! So now i'am just moving onto the ccd path so i can get back to what i enjoy without being stuck with an un-modded cam.

Have to start now on getting my second st80 collimated and maybe a rehouse of the dsi pro to shave some weight off the guide system and fix the dam flexture issues we are having. Next real project will be building a portable pc with some juiced up usb 3 ports as running 2 notebooks is getting a bit sad and i really need 2 screens. I also need the full bandwidth of usb 2 on the dsi and imager along with amps.

[rcheshire (Rowland)]

Thanks Alistair and Jay. I've moved the experimental work to a 1000D, because they are a no brainer and easy to play with and added an Astronomik uv/ir clip-in to correct the full spectrum mod, which seems to have improved the performance of the electric defogger. I want to follow this through and test it over several nights of high humidity. Though it seems to manage a cold finger temp of -5 -7C OK. Drier air -10C.

I am accumulating second hand cameras for parts at an uncomfortable rate. 1100D sounds interesting, but I have a 40D to do first.

I am not pursuing the 5d mkii until I have more data. These cameras are perhaps the least robust, in my experience.

I am also testing an improved pwm system that seems to be quieter than other designs I've tried.

I do this stuff out of curiosity. It's fun and interesting. As I get older, the late nights imaging are not compatible with my line of work. I can't afford the fatigue levels. So this keeps my interest between star parties.