alistairsam

I came across a forum where someone swapped the sensor of an olympus e-300 with a mono because it uses the kodak kaf8300 colour sensor which is pin compatible with the mono. the mono sensors can be purchased for $200 odd, so might be an option for some. 

just thought I'd share this info. 

e-300 looks like an old model though. 

the 450D is proving tough to remove the cfa. anyone used the glass polish on a sensor successfully? does it actually dig into the sensor layer? 

Cheers

Alistair

oh and one more question, have you done any comparisons of LRGB vs RGB, that is adding L from the mono dslr, vs RGB from an IR modded DSLR. does the mono provide detail to the DSO? 

Thanks

Thanks Luis, 

you've got some amazing images with it. 

I must admit, I wasn't very impressed with the 450D before debayering compared to the 350D. strange, I thought the 350D was definitely sharper and had more contrast. one big difference is the bigger pixel in the 350D which is what I like about it and of course its a piece of cake to debayer, well relatively speaking. 

with the 450, do you manage to get your cover glass intact, after debayering, do you stick it back on or leave it naked, do you have a flat taken with a 450D, how many have you done so far and finally how easy is it to cut a cold finger?

I was thinking, why do we need the mirror box assembly at all with the dslr's? we could possibly extend the ribbons and keep it outside the body just for the electronics to work or make a shutter emulator. that way, you can house the whole sensor and pcb in a sealed box with a T2 thread. something i'll be testing later. 

Cheers

Alistair

hi, I'm 3/4th way through the 450D sensor. attached is a pic taken with it. background is blue. 

I'm sticking to my paintbrush tool method, although its plastic, so no polish although I'm curious on how it'll work cause the cfa layer is definitely more stubborn than the 350d, but similar to the 1000D. doesn't come off that easily, so I will persevere under a microscope. I've comfortable watching the microsocope feed live on my laptop and controlling the tool. that way I can control how far I go. 

after busting two 600D sensors due to the blue area, I'm heeding to all the warning about the sides. 

interestingly enough, you don't need to go all the way. there is about a millimetre or so between the edge of the frame in this pic when compared to the sensor. 

I'm using the frame with the glass removed to protect the golden wires, thanks for the idea Gina. 

will post progress as I go. 

Cheers

Alistair

Hi All

Been a while since I posted.

I've started debayering a 450d with just a plastic tool and m halfway done. I don't bother with the epoxy, just use the frame without the glass.

Tested. The sensor, working fine.will continue tmrw.

I believe Luis here has done a few 450d's with good results,

Cheers

Alistair

We should be able to measure actual losses due to removal of the microlens if someone can take a test image indoors, remove just the microlens layer but not the cfa which is easy enough and take an image of the same object. Then compare red and blue values.

Light conditions would need to be identical though.

This test would remove the cfa from the equation.

I'm not sure the conclusion is too clear. The mono sensor appears to be more sensitive to red, but this is only because it's also receiving green and blue light. If you exposed the sensors to just red light, you would find the microlenses are still more sensitive.

Thats a nice write up.

Here they talk about their experience with different methods and finally settling on the infamous wooden tool technique which is my personal preference.http://www.centralds.net/cam/?p=6435

I think we're focusing a bit too much on the loss of microlenses.

The logic is simple, the major benefit with a mono compared to an osc is the detail provided by the luminance framd where the whole mono sensor area is used to capture all the light that falls on the surface.

Rgb data captured with full size rgb filters don't contribute to detail which is why its usually binned 2x2 and even blurred in some cases.

So the details in a galaxy for example would be more defined in a mono dslr with just a lum filter or an LP filter.

Combine that with rgb from a filter modded dslr and you're achieving results close to higher qe ccd's at a fraction of the cost which is the essence of this mod.

Qe is very important and dslr's are usually between 25 and 35%.

So longer exposures with cooled mono dslr's will easily achieve a respectable snr even without microlenses.

The 8300 ccd has a rather low qe of around 50% compared to the sony ccd's that are close to 70%. Yet there are some remarkable results with the 8300 sensor with optimal exposure and processing.

Just my 2c..

Alistair

40% increase in sensitivity is about half a stop - not a lot Though "every little helps" I guess. I'm not losing any sleep over losing a 40% sensitivity increase

Hi

The increase with microlenses is actually 15% at 550nm and 10% at 650nm in the graph.

Alistair

thought I'd share this cooling mod/body for a mono 350d built by an incredibly talented teen. Jo, hope you don't mind..

this approach to a sealed body is a lot easier than one with the tec on the outside. 

http://www.iceinspace.com.au/forum/showpost.php?p=1025258&postcount=32

http://www.iceinspace.com.au/forum/showpost.php?p=1025256&postcount=31

Alistair

hi,

Been a while since I posted..

One of the members in IIS did a comparison with a colour and mono qhy5 and this might provide some indication although its not the same as a dslr. 

http://www.iceinspace.com.au/forum/showpost.php?p=1075166&postcount=1

and here are some replies to relevant questions on that finding

http://www.iceinspace.com.au/forum/showpost.php?p=1075315&postcount=8

Conclusion was that you'd need 1.5x more exposure with a colour sensor to get the same snr as a mono. 

Loss of signal with the loss of microlenses don't appear that noticeable with "L" channel images I've tested on my mono 350D with exposures of over 4 minutes. 

Below is a comparison I did sometime back with Lui's mono 350d Ha image vs a qhy9 mono image. the 350d was not cooled so the difference in noise is obvious but I think the details are very close and getting this result from spending less than $200 on a camera is worth it. 

https://www.dropbox.com/s/rvij6c77e9umenf/Eagle-QHY9vsmono350d.jpg

Also just noticed that Luis has taken some fantastic images with his mono 450d and 350d and LRGB as well

http://www.flickr.com/photos/37419943@N08/14009936175/in/photostream/

I have been meaning to do an LRGB with my 350D to compare with a colour 350D. 

The major benefit with a mono dslr apart from narrowband would be for the luminance channel.

using all the pixels for details in the image for the L channel would add to the detail in an LRGB image as this won't be the same as a synthetic L by combining the RGB from a colour dslr. 

My 600d mod was a failure but i'm still on the lookout for a sensor. 

as for the 1100d, the price of a new one has dropped so much, so worth the risk. 

Cheers

Alistair

I won't be changing cameras - the idea is to use three cameras with three lenses all at the same time. I had started making up a camera with combined filter wheel but have decided not to waste photons by catching all three lots at the same time. A filter wheel only lets one colour through at a time. Same as OSC cameras only collect one colour photons on each pixel.

hi

not sure where you got to with this but if its lrgb then you could use just two.

one a mono for the details and the other a filter modded colour dslr for rgb. rgb doesn't

Alistair

I have a couple of 450D sensors I would like to debayer, one is half done but can't remember now if I started the other one. The idea is to have 3 matching cameras for NB widefield imaging. I was hoping to do 1100Ds as these are slightly better but the cover glass has proved virtuall impossible to remove and needs heat which can damage the sensor, so I gave up on those. The 450D glass comes off quite easily and the CFA comes off alright with very fine abrasive.

hi Gina

instead of three cameras and changing cameras, why not use a filter wheel?

so much easier and you only need one camera, no issues with the frame getting rotated when you change.

I have the sx usb wheel and 36mm unmounted filters and they're great.

cheers.

Alistair

looking good Gina

is this the 1000d

Alistair

i mustve gone over the blue area, picture is completely black,

oh well, back to square one

Hi Gina

I'd suggest pursuing a 450D if the 1100D fails. As Luis has shown, that shows the most promise being 14 bit and reasonably high res. 

I've finally removed the glass of my 600D sensor. hooray. 

I just used heat, 320C and about 15secs in one spot till I saw fringing, that then rapidly spreads and I follow the fringing.

but before I even applied heat, i used a knife and scored the sides of the glass all around and I applied the heat at an angle toward the centre of the sensor. that kept the electronics underneath only warm as most of the hot air was deflected off the glass. 

once I finished the heat I used a damp tissue to cool it off. 

I then used the knife and again scored it sideways with an attempt to lift the glass. that worked and it slowly lifted and I got the glass off intact in one piece!!

so time to test the sensor to make sure it wasn't cooked, turn it on, and its dead. nothing on the screen even when you turn on. that sounded more like a connector issue so removed everything, put everything back and it now worked, was able to take test images. 

now for the debayering. i'm keeping the filter frame as Gina has done to protect the wires, but I'm not too sure I'll be able to get to the edges. we'll see. 

i'll post results soon. 

I'll be using my wooden tool under a microscope as I did the 350D and 1000D.

excited to say the least...

Cheers

Alistair

how about placing a peltier on top of the glass to freeze the bond?

bad idea? cant see any potential damage...

Gina, I think we were all doing very well until it has been decided to use heat and epoxy during the process. Unfortunately we all went backwards when that happened. I think best thing we can do is to find ways of breaking the glass covering the sensor without damaging it or else, go for the 1000D or 450D where the glass can indeed be removed in one piece.

I wonder if we can minimize damage to the electronics by desoldering the sensor from the pcb before applying the heat.

that way its only the silicon we're heating

not sure if the damage due to heat is to the sensor or the electronics.

given that the general wisdom is not to keep the soldering tip too long on any component, it'd be prudent to remove that risk

Alistair

I wonder what the success rate for jtw is with the 1100 and 600 given that he uses the butane torch

another product to consider if anyone's contemplating filter wheels with a coma corrector. this gives a T2 thread with about 1mm increase as opposed to the 10mm of the normal T2 rings.

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p2463_Adapter--T2-Innengewinde-auf-EOS-Bajonett---0mm-Baulaenge.html

Are you planning on cleaning the surface any more Gina? with the area in the middle, could that be the abrasive taking away a bit more than the surroundings?

not going right to the edges?

Alistair

other option is to straighten the pins a bit so the chip gets lifted. mmm needs another thread, but its a thought...

I managed to get the fringing when heated on my practice 600d sensor and as Gina mentioned, the glass was still stubbornly stuck. but with some pressure, it popped off in pieces.

after applying the heat, I checked the electronics on the underside and they were all pretty hot. so not too sure if it'll survive, but its all or bust. so going with the live one tonight.

i also tried dabbing a damp tissue on the glass after heating to squelch it like we do metal, rather than letting it cool on its own. didn't make much difference but atleast I'm removing the heat quicker.

As for the gap below the sensor and electronics, jtw mentioned the 600d has only 0.6mm so is more difficult to insert a cold finger.

but what if we desolder the chip from the pcb and add metal spacers? that would lift the sensor and give more than 2mm for a cold finger.

of course it'll need precision soldering of the pins but I think it can be done.

Alistair

hi

I got the fringing on the glass but it needed a lot more heat.

320c, medium speed and atleast 20 secs on a spot.

im a bit wary of increasing the heat too much. not sure if that can desolder the gold wires on the inside

hi, when I use a white screen on my laptop as the cwb for my debayered 350d, the jpgs are in greyscale, so should be the same.

but any idea why the outer area is devoid of colour? wouldn't it be normal colours, sans IR filter?

did the glass turn white when heating?

i'm trying hot air at 300c at one spot from 3 to 10 secs, no white or discoloration.

i'm working on a dead sensor before I try the live one.

can't remember what flolic and jtw said about the heat method.

or do you heat 3 secs per spot, go around completely, then try with a knife?

Alistair