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Removing all unwanted parts of a DSLR to make a minimal weight and volume astro camera


Gina
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I can't remember now how much it reduced the weight but I think it was quite significant.  The main purpose was to reduce the size.

I tried several commercial boxes but finally used a 3D printed plastic case which I could design to a specific size and shape.  I used Peltier TEC cooling.  I have written a thread or two (maybe more) on all this.

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Very wise :)  Buy a cheap second hand camera - sometimes non-working ones are alright in the functions you want.  eg. it might have a broken flash or mirror or something else noe wanted for imaging.  I have bought several non-working cameras from ebay that had everything wanted for imaging working fine :)

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Googling "canon camera hacks error "code 30" " comes up with a suggestion that it's a jammed shutter - they might detect that via movement or the current drawn when a shot is taken - pass. The shutter parts are often called curtains, 1st  and 2nd. Fast exposures are taken by one following the other with the gap setting the exposure. Some time ago one of these curtains went electronic. When a camera is in live view mode both are effectively electronic. On mirrorless cameras they are always electronic.

Just a note on screwdrivers. If you find that a Philips screw driver doesn't fit the screws perfectly and it can rotate or even rock a little when it's in the screw they are probably JIS. This is a modified Philips head with reduced cam out.  Not sure on cameras but with the tightness of some screws in things like microscopes they are essential. Mine came in a set of 3 from a place like this link and are branded Hozon. The rather large middle sized one with a 5mm dia shaft tends to fit all screws what ever size they are. I've yet to find a use for the smaller 4mm dia shaft or the larger 5.5mm one. They were cheap but I had to spend some time looking around for them - most showed out of stock. They are used on motorbikes, model aircraft and model helicopters.

http://www.probuild-uk.co.uk/aircraft-division/tools/screwdriver-sets/jis-screwdriver-set.html

John

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  • 6 months later...

I've started playing about with 1100Ds again so may be able to report the weight reduction attained with stripping unwanted parts off for astro imaging.  I have a renewed interest in debayering and will be trying this too (but not in this thread).  I also expect to resurrect one or two other threads relating to DSLRs for astro use.

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Hi Gina,

My first post, but watching your work for a long time .....   thank you  for sharing    :icon_salut:

I have a 1100d and want to use the old Meade 416 CCD heatsink/Peltier. Will try to minimise the camera size/weight...will see how to interface it.

The 416 has a multistage Peltier....very nice. I achived 40deg reduction from ambient 12V@ 1.2A ....without fan!

For the cold-finger....not sure how to interface it, a 1mm 'U' shape copper or a copper foil I have. What I like to do is to see if the pcb attached to the CMOS chip

'shiftable' ....I mean extend the connections and secure the board to the side then the cold side of the Peltier pressed against the back of the CMOS....like the CCD cameras.

Not sure if this is possible... yet to pull the camera apart....what you think?

(sorry, spellcheck never understand my accent :icon_redface: )

Mick

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Hi Mick and welcome to SGL - thank you for posting :)

Fitting a cold finger to an 1100D sensor is tricky.  Not only is the gap very small but there are surface mount components on the PCB behind the sensor - care is needed not to damage those.  As I recall, I used a 0.7mm strip of copper sheet in a U shape (plus some thin insulation to protect the SMDs) but I will refer to another thread for that.

As for separating the sensor from the imaging PCB, I'm not sure.  It would be very tricky and I'm not sure it would be worth it.  With my coldfingers I have achieved up to 28°C below ambient but little is gained in noise performacne by taking the sensor much below 0°C.  Slight improvement down to -5°C but then no more - no difference between -5°C and -15°C.

As I said I will be covering the subject of cooling in another thread and I already have threads on this subject in this forum.  I shall be covering the whole matter of cooling, dehumidifying and building a new enclosure to replace the unsuitable standard camera case, and suchlike shortly.

Hope that helps :)

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Just stripped down an 1100D and removed the red-cut filter.  Stripped the camera right down as far as needed to remove the mirror unit.  I shall want part of the ribbon cable from the top part but otherwise I would estimate that the unwanted parts weigh more than those required for astro use, but I'll weigh everything and then we'll see :D  The sensor is right out and ready for the cover glass removal and debayering process but I think I'll put it back together enough to test with my obsy laptop (currently indoors) and make sure it still works before the more drastic part.

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Stripped camera is working fine with Canon EOS Utility :)  PHEW - stage one completed :)

Here is an image taken by room lighting 1/5th sec @ f4 ISO 800 roughly manually focused using standard Canon lens.

post-13131-0-97333400-1448135696_thumb.j

Edited by Gina
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Improved the focus, though this screenshot of the teamviewer image hasn't come out too well.  I'll see if I've captured it on the laptop.

post-13131-0-07335000-1448137674_thumb.j

Later...  Well, I have them but they are CR2 format raw files, of course, and I'll have to look up what I use to convert them as I can't remember.

Edited by Gina
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I have now weighed the camera and parts.   Standard 1100D c/w battery as supplied weighs 494g whilst my astro stripped camera weighs 189g a saving of 305g.  In round terms, standard camera weighs about 500g and I have stripped off 300g leaving about 200g.  In other words more than half the weight is surplus to astro requirements.  You will have to add the weight of an alternative case as you can't use the camera without excluding light.  The new case could be quite light though.

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Great project idea Gina (I only found the thread yesderday).  To shed 3/5ths of the original weight and still have a working camera is an impressive feat.

Now I've found this thread I'm looking forward to seeing more :)

Edited by Chris Lock
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Thank you Dan and Chris :)  I'll either find the case parts I 3D printed before or print new ones and then I can weigh those and say what the final saving will be.  I think there's a good chance of getting it under 50g :D

One other difference is that the vibration when opening and closing the shutter is very much reduced by removing the mirror assembly.

Edited by Gina
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I might do that on my next one - there are so many tiny screws to take out to do it the way I did.  You have to take the main metal plate out and the shutter before you get to 4 or 6 screws to get the mirror mountings out.

I've just won an auction for a 450D with broken mirror on ebay for just over £45 inc postage.  That will be a good candidate for brute force on the remaining bits of mirror :D  450D sensors are easier to get the cover glass off and debayer.  Just very slightly poorer astro performance and ISO only goes up to 1600 whereas the 1100D goes up to 6400.  That is going too far and the noise goes up a lot but I used to find 3200 quite usable.

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A clear sky tonight but a bright moon.  However away from the moon looking SE and low the moonlight is much less of a problem.  I have pointed one of my astro converted camers out of the east window of the living room and taken some shots of the stars.  I have even captured the Orion Nebula though it's tiny in the frame using the standard Canon zoom lens at it's longest setting (55mm).  I roughly focused by hand.  This is very far from an astronomical setup but thought I have a try :D  Earth's rotation meant that 5s was the max exposure even at this wide angle.  I tried ISO 6400 but the noise was terrible.  Hardly surprising with no cooling and not even fully outside and allowed to cool.

The image below was taken at ISO 3200 with a 5s exposure and lens wide open at f5.6 (it says).  Saved in JPG format and minimally processed in Photoshop.  Firstly the fullscreen image resized and then the full resolution cropped.

post-13131-0-20639900-1448233358_thumb.jpost-13131-0-66876100-1448233355_thumb.j

Edited by Gina
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