russellhq

A rectangular piece of plastic wrapped in cling film might work?

I'm not sure what you expected the results to show? I think they are in agreement with your observations.

A 2A TEC seems to work. So TEC + fan + camera + controller would be about 3A.

I would hazard a guess that as you are gathering 50% more red light and 50% more blue light and have no loss of green light, then since you're imaging sun light your image will be brighter with the debayered sensor.

You are probably experiencing differences in brightness because you are not imaging the same scene with the same settings and sensor. My previous post demonstrated the sensitivity loss on the 1100D to be around 50% on a pixel by pixel basis. In this case, I used a camera with a sensor that had half of the CFA removed, this guaranteed that the same settings and light conditions were seen by the debayered and original pixels. I also used narrowband filters to ensure a straight comparison could be made between the pixels with CFA and those without. The RAW images files are linked to at the bottom of the post if you wish to inspect them. http://stargazerslounge.com/topic/166334-debayering-a-dslrs-bayer-matrix/page-81#entry2308747

Thanks Gina, just the info I was after. I've been prototyping with 1.2mm copper (which is a pain to bend!) and that's a tight squeeze with the dead sensor. I've ordered some 0.55mm copper and 0.5mm plastic which should sort me out. I think I'll use double sided tape to secure the plastic in place before sliding in the cold finger. I probably put electrical tape on the back of the CF for a bit of extra protection as well.

SMDs! Better not file them away then

Gina, this might be a bit cheeky to ask, but seeing as you have a number of 1100D sensors in various states of operation, is there any chance you could take one of the dead ones and remove the sensor package from the PCB and post a photograph of the underside of the PCB. It would be interesting to see what's on the other side of the PCB that needs isolating from the cold finger. At the moment all I can see is the row of pins from one if the ICs, but it would be useful to know if there is any more critical circuitry under there! Good luck with the potting epoxy!

That does look quite precarious! Any more use of the torch might fry those gold wires if you wave it over the wrong part of the sensor Also, not sure why your glass keeps cracking. I can only guess it's due to the heat being applied too quickly. What setting did you have the torch on? I had mine set very, very low to the point where it was almost getting a yellow flame.

Can you post a picture of the sensor? Might stimulate some ideas?

Sounds like it's going better this morning. Good luck getting the last piece off.

Yip! I was hoping it would melt around 120-130C. Not a chance as it turned out

I used a dead sensor for this experiment. Here's a couple pictures of the front and back, if this had been a working sensor I'm not sure if it would still have been working after the cooking: Russell

Bad luck Gina, maybe it had something to do with the thermal gradient as you say. I did both my sensors like the one I did in the video. Both worked OK and the glass came off in one piece on both. Also, I did a little experiment today to see if I could re-set the epoxy that was left on the sensor package back to the cover glass using heat. I put it in the oven and took it up in temperature slowly from ambient to 250C. Epoxy didn't melt and all that happened was the board started decomposing. That's that idea ruled out now!

Slow and steady wins the race Here's my video again for some encouragement.

I just downloaded the free trial and once it expired, it was still useful to some degree. I'm not familiar with ccdinspector, so couldn't say.

Sounds good Gina. I used a program called RawDigger to measure the brightness of the pixels. http://www.rawdigger.com/ Do you think you could also have an area that has the antireflective coating removed as well? So you would have: 1. Original 2. Microlenses removed 3. Microlenses and CFA removed 3. Microlenses, CFA and antireflective layer removed Or maybe that's too much of a stretch?

I think we also need to acknowledge that the increase in resolution comes at a cost of reducing sensitivity by 50%.

Because there are 2 things going on when we debayer we should look at them individually. Firstly, reduction in QE by removing the microlenses. This, as stated, was measured to be 50%. Next, is the increase in resolution, for Ha and SII, from 1 in 4 pixels to 4 in 4. Now we are gathering light at 4 times the number of photosites but it's spread over 4 times the area. Therefore, if we take the resolution gain, we have to accept the reduction in sensitivity and increased exposure durations. But, if we combine the signal from the 4 pixels into one, we're back at the previous resolution but with twice the signal (remembering removing microlenses costs us 50%). I'm not sure how the QE charts are prepared, but looking at them I assume it's based per pixel and not the sensor as a whole, otherwise why is the green QE the same as the red and blue but it has double the number of photosites so should gather more light! If my assumption is the case, then you wouldn't see a 400% (not sure why you said 75%?) gain for mono in the red band. So, imaging in Ha with my debayered sensor should be twice as fast (remembering removing microlenses costs us 50%). But as you say, the proof will be in the pudding (But i'm not sure how you world quantitatively evaluate those results?)

I believe the losses were worked out to be 50%, based on the tests I did here: http://stargazerslounge.com/topic/166334-debayering-a-dslrs-bayer-matrix/page-81#entry2308747

My results don't agree with your conclusion. Removing the microlenses halved the sensitivity of the photosite, but debayering quadrupled the number of photosites sensitive to Ha and SII. The net effect is double the sensitivity of the sensor which would halve your imaging time.

The trouble I see with that approach is you have no control over the scene which will be constantly changing. And that will have a significant effect on your image which could give misleading results. I have debayered only half my sensor, so when I get the time to do some real world tests, I'll be able to do a direct comparison that will be able to negate the effects of the changing scene.

I think the charts are for only 1 green pixel, otherwise I would expect the QE of the green to be much higher than the R or B, but instead, the peak is roughly the same. You should be able to do before and after comparisons with the narrowband light. Since you know that 100% of the incoming light is passing through the OSC filter, therefore you can make a direct comparison with the debayered sensor and evaluate the impact of debayering on a pixel by pixel case. But as you say, if you're happy with the results then that's really what matters.

Sort of. If you look at QE charts of OSC sensors, you'll see the R, G & B pixels overlap each other. Thus, the G and B pixels are still capturing some of the Red SII light. It's not like mono sensors with RGB filters where you get a sharp cut off between the colour bands.

Indeed Here are the results from my tests using Ha, OIII and SII filters. You can see that from my sensor, removing the microlenses roughly halved the sensitivity of the photosites. But you can also see that, since all photosites on the debayered side are sensitive to the filtered light, the sensitivity of the sensor improves by 75-110% for SII & Ha (ignoring signal recorded in the B & G regions). But the results from the OIII are a bit more interesting. This showed no improvement in the sensitivity of the sensor after debayering (ignoring signal recorded in the B & R regions). Also, if you could use the signal from the B pixels, the debayering process actually makes the sensor only 75% as sensitive as the original with microlenses. Here's the table of results: Here are the RAW files if anyone is interested https://www.dropbox.com/s/l0ctwa7ve17zqky/IMG_5508_Ha_7nm.CR2 https://www.dropbox.com/s/pdv66522z911rxc/IMG_5523_SII_8nm.CR2 https://www.dropbox.com/s/vgj7t4uz57w98oq/IMG_5510_OIII_8.5nm.CR2