Mono DSLR Mod - removing the Bayer CFA

[alistairsam]

Hi

I've been thinking of this for a while after reading similar attempts at the SGL, so I bought a 350D off ebay and a USB microscope and successfully removed the CFA.
The Camera still works and opening the CR2 file in Maxim displays a monochrome image as expected.

the whole rationale behind it was to get a decent sized mono sensor without the thousands. I know it still won't compare to a 16 bit astro ccd camera, but it should fit in between and should make narrowband more affordable.

this was more of an experiment so I can then move on to a newer model with a larger sensor and convert it to mono, replace the IR filter and cool it with a cold finger.

any suggestions on which medium level DSLR sensor has reasonably high QE?
I have a 10inch F4, so smaller pixels would suit.
the 1100D and 20D have their glass screens glued on and are almost impossible to remove to get to the sensor so they're out of the question.

I just followed the 350d filter mod guide to open up the camera and get to the sensor.
after that, I removed the IR filter.
the sensor is behind another piece of glass. It was next to impossible to lift this without breaking it, so I stuck some tape and took it apart in pieces.
that exposed the sensor surface. no damage done to the sensor itself.

For a tool, I used the top end of a wooden paint brush, sharpened. this was to prevent permanent scratches to the photosite layer although its actually quite hard.
gentle scraping removes the microlens layer which is almost like a sticky coating and easily comes off.
the CFA is a bit harder but once you get an opening, the rest just comes off. its quite brittle.
I used the microscope with 500x to make sure I didn't touch the wires at the two sides as that could render it dead.

I managed to scrape off the cfa in about half an hour. so assembled and ready to test, I find out that the battery is flat and the battery charger was'nt included.

I was getting a bit impatient, so I snuck two wires into my 1000D's battery and connected it in parallel to the 350D battery and it was charged half in about 15 minutes.
enough to test.

here are a few test shots. i used a 18-55mm lens with manual focus so the focus may be a bit off but I was pretty happy with the results.

the 350D doesn't work too well with backyardEos, so I'll have to get the timer for longer exposures.

close ups show that there are still bits of the CFA left. I need to do go over it with the microscope a give it a proper clean.

I'm aware that there will be a drop in sensitivity with the microlenses gone, but it should more than make up for it with the 4x increase as now all 4 pixels are used for luminance.

With the IR filter removed, it should also suit narrowband.

Here are some videos of the "scraping".

http://www.youtube.com/watch?feature=player_embedded&v=aJ65Ve4bdOg

higher mag, you can see the bayer matrix here.
http://www.youtube.com/watch?feature=player_embedded&v=E9kxsYutm5U

now to do some real tests without the IR filter and the 10inch F4.
Will post results once I get some clear skies, and also when I move on to the next camera.
I might get a 1000D off ebay for its 6micron odd pixels and size and give that a go as well.
comments welcome.



Cheers
Alistair

[Merlin66]

Interesting!
The guys in the UK (and JTW in Netherlands) seem to have had success...
Definately not a job for the faint hearted!
Look forward to seeing your results.

[bojan]

That's awesome.. :eyepop::thumbsup:
I always thought the Bayer matrix is part of the sensor, therefore not possible to remove it without damaging the chip itself.. Because each sensor (photodiode) must have it's own individual filter, which is deposited directly on the the silicon at appropriate place(s).

Actually, all my CCD chips I accumulated over time are like that.

I shall certainly consider your approach... and I am very tempted to pay you a visit when you have some free time (we are living close) to directly see and discuss the process.

[Merlin66]

Bojan,
Think of the CFA as a "coloured screen print" onto the surface of a mono chip.
Obviously both the colour correction and IR filters will be removed from the camera body - ending up with a FULL full spectral modded mono CCD.

[bojan]

Yes, I know bayer matrix filter is "printed" on the chip..
In the past I was engraving various markings on the transistor chips using microscope, sharp needle and free hand.. I was always intrigued by how actually soft the metal deposits are and how easy it is to damage them.. and also how easy it is to control the hand movements if they are controlled by visual feedback (by watching what's going on under the microscope).

That is why I appreciate Alistair's effort and success so much.
Very brave! And successful.

Now, maybe there is a way to remove the matrix by some chemical process? Not likely..

[rcheshire]

Good one Alistair. I look forward to seeing the results.

[alistairsam]

Thanks Ken, Bojan, Rowland,

the guys in SGL have gone through several chemicals and some of the partially successful methods were
using a buffing tool with a dremel - worked for a 1000D
some sort of a paint remover
toothpaste!!

but after thinking about it and the fact that the photosites are composed of multiple layers sandwiched and are quite hard, i thought the wooden tool was the safest because it doesn't cause any scratches on the layer beneath the CFA and also because the CFA layer is brittle.

one of the members there, Gina, did every imaginable thing possible to remove the glass off a 1100D sensor and finally gave up. these sensors are actually a lot tougher than people think.

and as Ken mentioned, removing the IR filter and removing the CFA gives you a full spectrum camera, only limited by the slight loss in sensitivity due to the microlenses being removed which is unavoidable, and the fact that the QE of these sensors are lower than astro CCD's.

but still, making use of all 4 pixels opens opportunities for so many applications, narrowband, Ha, luminance, all at a fraction of the cost of a similar sized CCD.

I can now do narrowband imaging from my light polluted backyard. once I cool it of course which is another challenge on its own.

I figured, if I'm going to spend 2.5K toward a CCD, I might as well spend a few hundred trying it with DSLR's and worst case, each 350D sensor is $60 on ebay. so its very cost effective and is not really that hard if you're good with small things.

it certainly requires a steady hand and I'm used to soldering SMD's by hand, so I had no issues controlling or restricting my movement.

Bojan, it takes a bit of practise to control the hand movement based on the microscope visual feed, but its quite easy.
as I mentioned, the two edges with the contact wires are the most risky cause one contact on those wires and its very likely the sensor would be dead.

I'm thinking of moving on to a 400D or a 1000D which I know is noisier but is quite cheap and the glass does come off.

Bojan, you're welcome to come over. but be prepared to spend atleast a few hours. I have heaps of questions for you as well. pls drop me a PM.

Cheers
Alistair

[alistairsam]

I've come up with this SS to determine which one is going to be the next scapegoat so I can invest some time and money and remove the cfa, replace the IR filter, and cool it.
I just need one which I can control via BEOS and has 14 bits and between 5 and 7 microns for imaging galaxies.

this SS might be useful to someone.
The text file is tab delimited so you can import it in to excel.
Wish I could get the QE and dynamic range values as well.

I also found this site very informative in comparing various sensors.
Interesting to see that the read noise of most dslr's are lower than the kaf-8300 if i'm interpreting this correctly.

I've been very tempted to do the same with a QHY8 which uses a nikon D40 sensor.
only issue is that the sensor is pretty much glued on to the PCB so if I do damage it, i won't be able to replace it.
if it were replaceable, it would be really cool.

http://www.clarkvision.com/articles/digital.sensor.performance.summary/


Cheers
Alistair

[alistairsam]

hi

if I replaced the factory IR filter, will I need a UV IR filter to prevent bloated stars or will the bandpass characteristic of a Lum filter or a LP filter suffice to cut UV/IR?

any suggestions on where I can get a piece of glass cut to size to replace the IR filter?

As this is just a test, I cant really get the baader acf filter

thanks
Alistair

[Merlin66]

I have and use a FULL full spectrum modded 1000D (both filters removed - not replaced)
To maintain focus with std lenses I've added a clip-in Astronomik CL filter.
Different filters have different UV cut-off.
For astro work, you can add the UV-IR cut anywhere in the optical path.

[alistairsam]

Thanks Ken,

I can't get away with not having a filter as I've removed the glass covering the sensor.
if I leave it open, moisture could cause a short, so I'll need a layer of glass.
I'll see if I can get a piece of clear glass cut and use a UV/IR filter at the end of the nosepiece.

Can I use an LP filter as the L filter?

Transmission curve for the LPS-P2 filter
http://www.sciencecenter.net/hutech/idas/filtdata.htm

It looks like it covers the lower and upper ends of a normal L filter, but the added bonus is that it cuts off or reduces the Light pollution wavelengths as well.

Curve for astronomik LRGB filters
http://www.astro.uni-bonn.de/~mischa/ps/transmission_astronomik_lrgb.png


Will there be a discernible difference between a 12bit and 14bit dslr for DSO's?

I'm hoping to try it tonight if I can get the glass cut.


Cheers
Alistair

[gregbradley]

I was thinking of doing something like this at some point. I did read some posts where one guy was offering it as a service and I think it was Nikon D90's he was doing.

As you point out some may be harder than others.

I have modified a few 20Ds. The UV/IR cut filter is glued in at its edged with black silicone. I did not take it any further but I take it you are referring to the glass cover slip over the sensor?

Good work.

As far as which sensor I would think a Sony Nex 6 or a Nikon D7100 or Fuji XE1.

The current lowest noise APS camera is a Fuji XE1 (about $715 on ebay body only, Nex 6 is similar). Sony Nex 6 is not too bad either. Nikon D7100 is 24mp, no AA filter and is also low noise. Sony Nex 5r is cheaper and same sensor. I think the Nex 3N may also be the same 16.3mp Sony Exmor sensor (not 100% sure) so that may be the cheapest.

Canon EOS APSc not sure Canon advanced past the 350D/20D/40D/1100D models. The others seem a noisy. 6D 1Dx and 5D3 are clean at high ISO. 5D2 is in between. A 5D2 may be fairly cheap now or a 5D with its largish pixels.

I would not worry about DSLR pixel size - they are all smallish compared to CCDs.

Greg.

[Merlin66]

As Greg has already asked...is the glass you removed the internal (bluish) filter? or another layer of glass.
If it's just the original filter then I wouldn't worry about moisture etc.
This filter element is the one usually removed in the DSLR -increased Ha response mod.
I've been living without any filters for the past four years with no issue.
Re filters
The Hutec LPS would work as the Uv-IR cut, as well as light pollution rejection. You colour balance will obviously shift due to the filter.
Can't really comment re DSO - I only do spectroscopy.

[alistairsam]

Hi,
I was referring to the glass directly over the sensor as in the pictures attached.
the first shows the glass lifted at the top right corner, it turns grey as you lift it, if you lift too much, then it just cracks.
the second pic shows the glass removed. you need to remove this to get to the sensor surface.
so basically the wires and the sensor are exposed.
I was thinking of just sticking a clear glass over the sensor and removing the IR filter.
in the 1000D's and similar, there are actually two glass layers, the top most one is the one that's normally removed or replaced for the mod.
I believe the bottom one is the AA glass and has the piezo for dust cleaning.

I'll most probably mod a 1000D or a 400D next. the 450D seems attractive as its 14bit. but a bit more pricey for second hand.

As for the filter, I was hoping to use the IDAS-LPS-P2 filter as the "L" filter for LRGB as this from what I can see, covers the normal "L" wavelengths and cuts off LP wavelengths.

Greg, in terms of QE, I know the dslr's are only between 25 to 30%. would you know of any mid-range dslr's that have relatively high QE?
I don't think I'll try the Fuji or the Sony just yet.

yes, Guy, author of BEOS has also done mono conversions for Nikons. I prefer Canon's just for the software support although if I can debayer a D40, I might take on a QHY8!!
two second hand QHY8's (in case I break one), are still cheaper than a comparable mono.

Cheers
Alistair

[Merlin66]

Alistair,
On the 350D there's only one filter element, about 2.8mm thick, which I assume just sits in front of the "protection" glass you show.
The filters on the 1000D etc are much thinner, each is 1.0mm thick.
Edmund Optics sell thin plates of coated glass.....

[pmrid]

At the risk of asking a silly question, can you achieve a similar result by setting the camera to shoot in B&W mode?
Peter

[alistairsam]

Hi Ken,

That's right. the 350D has the glass on the sensor or just above it and the IR glass on the plastic frame above the sensor glass which is normally what is removed for a mod.
for the 1000d, it'll be the topmost glass that's replaced for an IR mod, but I'll be removing all three for the B&W mod.

Alistair

[alistairsam]

Hi Peter,

there are lengthy explanations for this, but the simplistic answer from my understanding is that it won't provide the same sensitivity.

below is just my understanding, I'm no expert though.
B&W or mono images from a colour camera use interpolated values for luminosity. that is bright and dark areas.
this doesn't change the fact that red light will get through only one of the 4 pixels due to the colour filter array above the sensor, similarly blue will enter only the pixel with the blue filter.
by removing the CFA, all wavelengths reach the four pixels and hence provides higher sensitivity and resolution.
That's the reason mono CCD's with LRGB images have more detail in them.
as you may know, with mono imaging, its the "L" channel that carries all the details.

This CFA mod appealed to me because I could use a relatively large sized chip for mono imaging at a fraction of the cost, compromise is the lower QE, noise, and lower dynamic range compared to astro CCD's.
it also allows you to do narrowband imaging using the full resolution of the chip. I've done Ha imaging with an OSC, and I can only use the red channel. so a 11M image becomes a 3M image as its only 1/4th the data.
with the 350d now being mono, I can use all pixels for Ha or other NB.


Edit: the company maxmax which also does BW conversions have a very good write-up here with example images clearly showing the difference.
http://www.maxmax.com/b&w_conversion.htm
They do sell B&W dslr's but for that price, you could get a mono ccd.

i'll post my own results a little later on.


Cheers
Alistair

[gregbradley]

Greg, in terms of QE, I know the dslr's are only between 25 to 30%. would you know of any mid-range dslr's that have relatively high QE?
I don't think I'll try the Fuji or the Sony just yet.

yes, Guy, author of BEOS has also done mono conversions for Nikons. I prefer Canon's just for the software support although if I can debayer a D40, I might take on a QHY8!!
two second hand QHY8's (in case I break one), are still cheaper than a comparable mono.

Cheers
Alistair[/QUOTE]

I did have a link at one stage to a listing of various DSLRs and their QE and read noise.

Nikon D5200 was highest with a Toshiba APSc sensor and around 60% QE. Nikon D800E was next at 59%.

Pentax K5 might be one to look at. Its the same Sony 16.3mp Exmor APSc sensor in the Fuji XE1 and Nex series. Its also in the Nikon D7000 which may be cheaper now there is a D7100.

Of the Canons a 5D may be good. It has over 30% QE as I recall and largish pixels (still small by CCD stds). They are also sometimes quite cheap.

A 5D2 is around 26% or so and 5D3 was 39%. I will see if I can find that listing and post the link.

I like your work. I think this could be a productive use of a DSLR and turn them into a nice imaging machine potentially.

59% QE with a Bayer CFA and UV/IR block in D800E. Wow, imagine a naked mono sensor what QE it must run at - it must be up over 80%.

Greg.

[rcheshire]

Alistair. If you still need a filter I have one in a spare 1000D sensor, if it will fit. I can send by post when I get back from Brisbane next week?

In the 1000D, the top glass is the AA filter/Piezo, while the glass in the plastic frame closer to the sensor is the IR-Cut filter - replace with Baader or Astrodon and leave the AA out altogether as it softens focus.

Something I've been meaning to develop for a while is a sensor face heater for a DSLR - it needs to be very small, but having cooled two DSLR's by various means, sensor face heating is essential. Small sticky strip with Nichrome filament.

[alistairsam]

that will be great Rowland.
I'm buying a 1000d and am hoping to get it modded by this weekend.

a spare filter would be perfect.

I'm also buying a few spare Sony sensors used in the QHY8 and QHY8L.
I will mod these and try and swap it on my QHY8L if i'm confident enough.
we'll see how that goes.

I've been thinking of heating the sensor as well when using a cold finger.

Cheers
Alistair

[Merlin66]

Rowland,
Could you explain further your comment:
......leave the AA out altogether as it softens focus

The AA filter element is basically a UV -IR blocking filter....I have the spectroscope transmission curves available...this should not affect focus..

[rcheshire]

RHi Ken. Several enthusiasts have been removing AA filters, by which I mean the outer glass of the sensor assembly. Apparently, one effect of the AA filter is to reduce Moire an artifact of the standard Bayer matrix and in so doing produces a slightly softer image than possible without the filter in place. This is documented on various photographic sites. The properties of UV-IR are not in dispute, it's the by-product of Moire reduction that affects image sharpness - so sharpness, not focus, is what I mean.

I was skeptical too, but a bit of research turned up a few articles on the subject.

Alistair, I also have a couple of custom made cold fingers for a 1000D - ? One needs a bit of work the other is a bit short.

[Merlin66]

Rowland/Alistair,
Whoooo
You've opened one hellava box with that AA filter comment!!!

I did the usual on-line search and I'm amazed that the issue of Moire fringes/ anti-aliasing hasn't come up before in the amateur astronomical community!
Sure, we all talk about the loss of resoution due to the Bayer matrix, but few (if any) take note that the inbuilt "AntiAlias" filter element actually blurs the image - on purpose, to prevent (or reduce) the Moire effects...

What does this mean to our "highly detailed DSLR images" or in my case the definition of fine absorption lines in DSLR spectral images.....
Hmmmmm
Need to spend a but more time and research on this one.
Thanks for raising it to the consciousness level.

[alistairsam]

Hi Ken,

I did read about the AA filter and moire a bit but didn't pay much attention until Rowland pointed it out.
So in short, its better to take it out and replace it with a normal UV/IR filter?
in the pre-press industry, we normally do use a blur filter to remove moire from scans of printed material. kind of the same thing I think.

yes I'll PM you about the cold fingers. i've got a few ideas on preventing frosting but i'll finish the b&W and IR filter mod and now the AA filter mod first and do some narrowband now that the moon is out for the next 2 weeks or so. will then move on to the cooling.

I finally managed to install the 350d drivers in windows xp and i'm figuring out how to take exposures longer than 30secs. if that works, i'll give it a crack on the first clear night out here.
i'll see if I can get a few 5 min exposures with an LP filter with the mono 350D and a few RGB exposures with the QHY8L and overlay the two.

I'm wondering if there is any interest out there for photographers to use a B&W DSLR.

Cheers
Alistair

[Merlin66]

It certainly appears that removing the AA filter (doesn't have to be replaced - in normal mods) or replacing with a UV-IR cut for non spectroscopic work would be a way to go.
I need to find some astronomical/ spectroscopic examples of Moire fringing/ antAlias effects before I start to panic.

[rcheshire]

Ken. An example is the image sharpness of my FujiFilm X-Pro1. The colour matrix is non-standard and designed to avoid Moire. Consequently, the AA filter is very weak, if not non existent, hence, image sharpness. Having said that Moire is noticeable from time-to-time. Almost inescapable.

One Mark IIID owner removed the AA filter shortly after purchasing the camera, with noticeably better image sharpness - but, Moire is problematic because of the standard Bayer matrix minus AA.

I was very disappointed with my first mod, because the image was too soft. The second is much better without the AA filter.

As an aside. Removing the AA/Piezo assembly provides a niche for a small nichrome dew heater on the plastic filter frame. A very thin heater element will fit nicely into the depression that houses the Piezo unit. DSLR cold finger cooling needs a solution to sensor fogging. With that, it will be very successful.

[Logieberra]

Great thread. I've got a little Nikon D40 lying around. From this related US thread, the Nikons appear easier to modify.

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5606114/page/0/view/collapsed/sb/5/o/all/fpart/all/vc/1

Anyone in Oz got the skills?

[alistairsam]

Hi Logan,

if I'm able to acquire spare sensors, I could mod the sensor and just swap the sensor from cameras. should be simple enough and least risk.
something like this
http://www.ebay.com.au/itm/GENUINE-NIKON-D40-CCD-SENSOR-REPAIR-PARTS-/281058339593?pt=Digital_Camera_Acce ssories&hash=item417061eb09&_uhb=1

I've got the B&W modded 350D drivers working in XP now, I need to make that serial cable for bulb exposures, and hopefully we have clear skies on monday and tuesday, i'll try out some Ha and luminosity frames and post results here.

by next week I should have a full spectrum modded true mono 1000D, I'll remove both the AA and IR filters. anyone know where I can get clear glass cut to dimension in melb?

Can't wait cause its so much easier to use via USB than the older ones like the 350D.

I will then have to pick Rowlands brain on cooling it.


Cheers

[Merlin66]

Alistair,
You may widh to consider as an "interim" just using a microscope slide glass...these are nominally 1.0mm thick and come 25 x 75mm -easy to cut. If you want to come over to Maribyrnong you can pick up a couple...
(I use them as a beamsplitter plate in the spectroscope)

[Rac]

I'm the nutter that started that thread on SGL and buffed down the 1000d sensor to see what would happen :lol:

It took a Kiwi to kick it off haha

[alistairsam]

hey Ray

Edit: sorry just checked and noticed it wasn't Gina, got a bit confused. but that thread was very inspiring, thanks. what made you think of it?
for me, it struck me at church, I clearly wasn't paying attention, but I was so excited I had to come out and google it and found your thread.

did you try any astro imaging with the 1000D at all?

I tried 30s darks with the 350D and its quite noisy. so for decent narrowband work, these will need to be cooled unless the subs can be less than 5 mins. not sure how much signal will be present.

cheers
Alistair

[Rac]

I don't know when I thought of it but it would have been to save money somehow, I think of lots of things but most of them don't work lol.

I only did some test shots. There was an increase in sensitivity but it wasn't huge. That wouldn't matter though as it would be a huge gain for narrow band work.
Yes cooling is very important with a dslr.

[rcheshire]

If we can come up with a practical sensor face heating solution the rest is easy.

[Logieberra]

Alistair, thanks for the kind offer. I'm new to this mod and still considering he pros n cons. Cheers.

[rcheshire]

This is what I have in mind for sensor dew protection.

[alistairsam]

Hi Rowland
I presume you meant to attach something?
What if we use an in body filter like this one to create an air tight chamber in front of the sensor similar to ccd's.
http://www.sciencecenter.net/hutech/filters/ffilter.htm
But if heating the glass face is the only option we could use smd resistors on the glass face to heat as they would provide higher resistance than nichrome wire for the space that's available.
Or if we replace the aa filter with clear glass and create an air tight space in front

[rcheshire]

I did intend attaching something - now attached.

It is easy enough to ensure that the air between the sensor and glass is dry by leaving the assembly in a sealable plastic bag with dessicant for a while and then sealing with silicon. That worked perfectly for my 1000D cooling mod. The problem is keeping the outside face free of condensation.

I'm looking at a heat source that will fit into the very tight space between the shutter and sensor face. Nichrome is thin enough. SBIG do the same with their ST-8300, installing a small strip heater adjacent to the outside glass.

This should provide a localised warm region around the face of the filter - that's the theory? Open to suggestions.

[alistairsam]

hi rowland,

can't you keep the outside face free of condensation by adding an LP filter at the end of the T adaptor or nosepiece?

when I had the same issue with my QHY8 nosepiece, adding a coma corrector with a spacer in a dry bag kept condensation away and I didn't need a heater strap on the spacer as is normally done.

other option for a dslr would be an eos clip filter.

[rcheshire]

I think that works for sealed set ups, such as cooler boxes. Cameras are leaky, otherwise. I do not intend sealing the camera, so a different approach is needed.

[naskies]

Wow, now that's what I call modding! :lol: Well done and thanks for sharing.

[Poita]

Yes, it is one of the reasons I've been using fuji cameras, the later ones have no AA filter and the difference is noticeably sharper images than my Nikon which has the same size sensor, same MP and same lens. It is one of the reasons I have not been a fan of DSLRs for astronomical use, the AA filter is great for stopping moire on patterned shirts in portraits, but not what you want for a 'scientific' instrument.

[Poita]

I'm amazed that Sony doesn't do a mono sensor, there would be demand for a B&W DSLR I would think.

[alistairsam]

anyone know if the bayer CFA on cmos sensors would be similar to CCD's on the nikon's?
with Sony's, is there software to use them for long exposure?
Greg mentioned a few that have low noise and high QE. might be worth trying it as well.

I debayered a 1000d spare sensor last night. was harder than the 350d, looks like the layer is a bit thinner.
just waiting for the 1000D body to arrive and I can then test with my scope.
I've removed the front glass on the 350D as well, so its now full spectrum. I will add a clear glass on the sensor face as well.

I might convert a few cameras to B&W, add the Baader UV/IR and put them up if anyone's interested. The normal lenses will work.

waiting for clouds to clear... so can only test indoors.
these are jpg's straight off the 350d with a custom white balance.
I did a comparison with a 300mm lens on a lamp post with an unmodded 1000d and the b&w 350D and noticed the difference in the small coils. not sure if the comparison is realistic, but what else do you do when its cloudy

Alistair

[wasyoungonce]

I am watching all this with avid interest.

Some of the results from a debayed DSLRs look very very promising and for a camera that is one it's end of life useful then this looks like a good proposition.

Except... the damn glass over the canon sensor! I hear Nikon's are much easier to debayer (glass removed easily) and are even gaining support for DSLR computer control, like with sequence generator pro (http://www.mainsequencesoftware.com/)!

I put a mono sensor in my SPC900NC and the changes were astounding so ramp this up to a DLSR...I am drooling at the prospect...then I remember the damn canon front glass over the sensor!:shrug:

[alistairsam]

Hi Brendan,

which glass were you referring to? the one that's stuck to the sensor itself?
It actually pops off with gentle pressure all around. you'll see it becoming milky white as you're lifting it, but the key is not to lift it too much else it'll crack.
i managed to remove the glass intact from the 1000d sensor this way.
the 350D is similar although I didn't have the patience so just broke it off.
the 1100D is the one that's reportedly extremely well stuck on. the SGL user Gina tried every method possible to get it off but failed.

one clue on which ones are possible could be from the maxmax website and the models they convert. you'd notice they dont have the 1100D there.
these are the ones they do, and I don't see any reason why we can't mod these ourselves.

Canon 60D, 10D, 20D, 30D, 40D, 50D, 60D, 70D, 300D (Rebel), 350D (XT), 400D(Xti), 450D (XSi), 500D (T1i), 550D (T2i), 600D (T3i), 1000D (XS), 650D (T4i), 5D, 7D, 1DS MKI.MKII, MK III, MKIV and 5D MKII, MK III

Nikon D1X, D2X, D2H, D100, D40, D40X, D50, D60, D70, D80, D90, D200, D300, D300s. D600, D700, D800, D3, D3x, D3000, D5000
Fuji S3 Pro, Fuji S5 Pro.
Leaf: 75S ($1,500 conversion)
Olympus E410, E420, E510, E520, E620

one point to note is that this process removes the microlenses. so to see that the results are better even without the microlenses shows that its got good promise.
I'm just waiting for a break in the clouds and will try some "L" subs and a few Ha subs.
my next venture will be on a more sensitive one and then cool it.

most important bit is not to go anywhere near those darn golden wires in the sides. they're so thin you can hardly see them and they come off at the slightest contact. that would render the sensor useless.

Cheers
Alistair

[wasyoungonce]

Yep that be the one. I read that the USA guys were not doing this mod due to this glass being a "pain". I believe they use a ceramic glue to set the glass cover. Which cannot be undone with chemicals.

I'm not worried about the microlenses nor scraping the sensor just getting the glass off and of course not damming the peripheral contact fingers.

You gents have given me inspiration I may indeed attempt this as my 450D is a little long in the tooth and am looking for "yet another project"!;).

[Poita]

I'd be interested in a converted camera just for B&W traditional photography use.

Apparently the Nikons are easier to remove the layer, (the Canon 10D for example is apparently nearly impossible) and with BackyardNik being released this year, it could make a great astro combo.

[alistairsam]

Hi Peter,

From what I've tried the canon 350D and 1000D are easy.
others have modded the 450D. I think the 20D is hard as well.
with the 1100D and some other models that have the glass very strongly glued on, best bet would be to stick some tape and break it.
you just need to make sure nothing drops on the edges with the thin wires.
since we have software for the canons, i'm staying with modding canons.
I've done a 350d and a 1000D, and will then look at something more sensitive with less noise.
all depends on how the 1000d performs.

Cheers
Alistair

[Poita]

I'd be really interested to see some flats from these.

How do you stop the camera from debayering the image in its firmware? Are the raw files not de-mosaiced?

[alistairsam]

Hi Peter,

I'll post some flats later, it won't be pretty cause I need 500x to see the cfa bits left and I do still have some specks left. but its not too bad either.
as for debayering, the trick is not to debayer. nothing to be done in the camera.
so just treat the files as mono.

in DSS, i believe there is an option not to debayer when opening raw files, in maxim, you can open them as is and stack and process, just don't debayer.
even jpg's straight off the camera can be used, just don't debayer.

edit: i'm not sure how to open them in DSS without demosaicing. I'll test and see.
at this stage, i've only tested in maxim and DPP.

here are some raw files from the camera you could try
https://www.dropbox.com/s/buy9v0k7w8etczw/IMG_1230.CR2
https://www.dropbox.com/s/ei4y83i3nx29od5/IMG_1224.CR2

I just bought a 600D. looking forward to debayering that. however, the small pixels and loss of microlenses may not make it that sensitive, but will test and see.
if only these clouds would clear.

Cheers
Alistair

[alistairsam]

saved it as TIF from DPP and maxim and they open without the bayer in DSS for stacking. Else just stack in Maxim.

[OzEclipse]

Someone mentioned a Pentax K5 as a candidate for mono-mods. There is a Pentax model called the K5-IIs. The "s" I think is meant to stand for sharp because it has no anti-aliasing filter. I don't know anything about the bonding between the bayer and the detector surface.

Really interesting thread.

Joe

[Poita]

I opened it in photoshop and they seemed to come in okay, can see the areas where there are still blobs of bayer layer, but they opened up ok. Really shallow depth of field makes it hard to judge the performance. I might have to have a go at this. The D90 sensor is relatively cheap:D
http://www.ebay.com.au/itm/Nikon-D90-CCD-Part-New-Sensors-Unit-SLR-Camera-Replacement-/370721390763?pt=Digital_Camera_Acce ssories&hash=item5650b780ab
Looking forward to the flats.

[alistairsam]

Last night was relatively clear, so had a play with the mono 350D. first light actually.

Here are links to some unprocessed subs from the camera.
https://www.dropbox.com/sh/zq4yhkjf01i72f6/DCKL0AR99R - files are still uploading.
Low resolution jpg's attached.
60s x 1 sub - iso800
180s x 1 sub - iso400

I'm pretty happy with the outcome given that this was taken through thin clouds, awful seeing, urban skies.

subs are unguided as I couldn't get the oag working with the dslr spacing.
will try again tonight.

I haven't tried stacking or processing these yet. will try later on.
from my perspective, the results show very good potential, so I'll be pursuing with a 600D.

will post more as I acquire them


Cheers
Alistair

[rcheshire]

They look very promising.

[alistairsam]

some more results

another amateur in Portugal also managed to convert his 350D to mono by removing the CFA layer using my method.

he's had better weather than us, so here is a comparison of a mono 350D Ha image with a QHY9 Mono image taken by marc from IIS.(with permission)

the 350D is uncooled, 12bits, 12nm ha filter, 5x5min Sub, 8inch F4

QHY9 mono is 16bit, cooled, 7nm Ha filter, 15x5min subs, 90mm APO

Obviously the qhy9 image is a lot smoother but I was surprised to see that there is no significant loss of detail in the dslr image and it compares very well with the qhy9 given that the cost of the 350D was $150, and the qhy9 is $2300 or so.
This makes narrowband very affordable in my opinion.
I had to scale up the 350D image as the imaging scales are quite different with the F4 and the F7.

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


Cheers
Alistair

[Meru]

Hi Alistair,

Seems like you stirred quite the interest! It's a very novel idea and also very cool. The comparison shows just how similar they two are, but this is of course bearing in mind a 90mm refractor vs a 203mm f/4 newt - I suspect the newt might always win ;) This sort of set up seems very well suited to fast newts, since the DSLRs obviously dont have peltier cooling for long subs.

I had no idea the D3200 had 60% QE, if the bayer matrix is easy to remove it might be worthwhile pursuing that path rather than the canons? I'd be very tempted to. Question then becomes how to use NB filters; you would have to get a M42 extension tube from the T-ring (Atleast 40mm to push the FW away from the DSLR where the prism sits), and if you are using a OAG that equates to almost 90mm backfocus! The steep f/4 light cone may result in a smaller-than-the-sensor image on the guidecam since the pick-off mirror is almost the same size as the guidecam sensor (I'm not sure if this is going to happen but food for thought).

I wish you many clear nights, can't wait to see the outcome of this project!

[alistairsam]

Hi Meru

Objective was not to compare an Apo and a newt but to see just how the low qe chip stacks up to a 16 bit ccd cause there are several factors against the mono dslr like qe, dynamic range, read noise, smaller pixel being a CMOS as opposed to a larger well in a ccd, loss of microlenses etc.
The subtle details have always been so enticing with a ccd compared to a dslr. So it was interesting to see how the 4 pixels reading lum contribute to details and gradations.

This hobby being so expensive, it's worth looking at how to get decent results without breaking the bank and its just plain exciting to do something radical and see it pay off.
Also with our weather and the light pollution, narrow band is mostly what you can do from your backyard and this puts it well within reach.

As for the oag, it's such a pita. I just couldn't get it focused. Have to try again.
I was planning on ditching the mpcc and getting the RCC that gives 90mm back focus.
It would cut the light cone of an f4 but should be fine as the aps-c size is small enough for vignetting not to be too bad.
Then a filter wheel and an oag can be used.

Cooling is my next step, and isn't too much of a hassle other than condensation control.
Jtw astronomy sell cooler kits for 199euro that has been known to be fitted by a school kid. I'm planning on a sealed housing like central ds. Rowland's work here is very informative as Well.

Cheers

[Meru]

Yup I definitely agree, a little bit of ingenuity and hard work will go a long way in this hobby. I also know the objective was not to compare, but I was bascially saying it's not entirely apples to apples as the f/4 obviously collects lots more light! I would really like to see how the DSLR fairs on your 10" f/4, that would be very easy to compare to other 10" f/4 images with a CCD.

As for the OAG, I'm surprised you couldnt? Did you not have enough in or back focus? I'd imagine its back focus, if you like you are more than welcome to use my extension tube on my TS9OAG and see if that helps :) You shouldnt have any issues with focus on the guidecam once you can move it back far enough, but yes I think the MPCC doesnt have enough backfocus for your set up, especially a DSLR + FW.

[nebulosity.]

G'day

Been reading about this on here and SGL and have decided to give it a go.

just got a 350D of ebay, should get it next week :)

Great work you've done guys, keep it up :thumbsup:


Alistar, be interested in your cooling, if my mono mod works I'll probably do a full cooling and rehouse.

Cheers
Jo

[rcheshire]

FYI - experimental sensor condensation control is not very effective as shown in the 5DMKII cooling thread. I'm exploring another method. The heating requirements are adequate, but plastic is not a good conductor. Dew heater needs to be relocated or adhesive aluminium sheet overlaid and in contact with the edges of the filter glass.

5mm on one side of the filter glass is free of condensation. Dew heater competing with cooling, reducing the differential by 4 - 5C - to be expected.

Bah - strip it down and start again.

[alistairsam]

hi Jo

at the moment the cooling mod is all in my head, been thinking of a few different approaches.
main thing is which camera to stick with
I love the resolution of the 600d and am going to give it another shot . but cooling it would be tricky.
I'm thinking of using pipes to deliver coolant to the cold finger and also whats involved in running the camera bare bones.
will post results once I get to it.
good luck with the mod.
cheers
Alistair

[bojan]

Hi Alistair,
today I bite the bullet and bought faulty Canon 400D on ebay... I intend to de-bayer it (after repair) and also add cooling.

You mentioned earlier in the thread you intended to do 400D.. did you manage and how did it go?

[alistairsam]

hi Bojan,

I did debayer a 450d, it was a bit harder than the 350d and took a lot of effort to get the layer off.
work, life, etc changed my priorities so I didn't get to use it. I am however cooling the 450d with a slightly different method. no cold finger.or box.

good luck with the 400d.

Cheers
Alistair

[glend]

Deleted this post, it was meant for my mono cold finger build thread.

[nebulosity.]

Great job Glen! Looks like the debayering went well.

Cheers
Jo

[glend]

Sorry i just realised i posted my image in the wrong mono dslr thread, ha ha. It was suppose to go into my mono dslr build thread. Oh well.