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.

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

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