GTom

45 minutes ago, Stub Mandrel said:

Surely reflected or not, it's going to be lost light anyway as it's only photons that miss the light-wells.

You can't ARE coat the wells themselves without stopping them working.

What about a plastic/polymer type coating? (Don't ask which one, I am still seeking options here). Obviously the coating has to be a strong electrical insulator and shouldn't use heat, etc for curing.

There are clip filters for FF Canons from Astronomik. However, this case I'd raise the bet and vote for something airtight and fill the housing with argon (I have access to) in order to eliminate any kind of internal fogging.

Regarding optical elements: I'll have a Baader filter maybe ~50mm from the sensor and a flattener with concave rear glass (=enhances the reflected light) around 90mm from the sensor. Besides ghosting, I would like to capture those photons too :D.

10 hours ago, Thalestris24 said:

I think the glass can be bonded to the silicon surface but don't quote me!

That's very well possible. If I decide for a commercial conversion (Brent most likely), I'll certainly ask in general about sensor reflectance. Actually my worry is more the ghosting on the rear lens of my flattener than the actual light loss. I have a tsflat2.5, which might be a great glass but its coating looks too shiny. I've also seen complaints on the Riccardi reducer.

Edit: Ouch, You got quoted,  sry. Anyway, I am more fan of a coating like-solution, instead of bonding the glass.

30 minutes ago, Thalestris24 said:

I believe you can put AR glass in front of (on?) the sensor but don't ask me how it's done!

That doesn't help the reflection of the silicon surface. Of course with an AR window you won't get ghosts back but you still loose the light what's reflected.

Other thing I just mentioned above is reflection. The microlens+Bayer array acts as an AR coating, without that, the bare silicon reflects 20+% of the incoming light! This you can clearly see, because the modded sensors are shiny. Added, that large pixels are less affected, a rudimentary polymeric AR-coating could probably curb the losses.

To my knowledge, neither of the modders (Brent and CentralDS) coat the sensor with an AR-resign. That's one more reason to learn the process.

OTOH, as I read, CentralDS claims their work is scratch-free: is there a chemical that dissolves a 6D CFA?

I was wondering, has anyone tried to put some kind of AR-coating on the mono-modded sensor? The AR-coated cover glass is of course a good thing, but it doesn't help reflection loss. Bare silicon has a reflectance of up to 30%(!), even the simplest coating would help...

9 minutes ago, Xplode said:

I meant the 6D mono mod price from Hypercams that you wrote is $320...Where did you get that price?

I Just realized that was a mistake, I mixed up the mono and ICF-prices .

I don't understand JTW either, anyway they don't take 6d, so they are out of business for me. However at the CentralDS/Hypercam price point I want to learn how to do the removal properly, that I have a 90+% survival rate for my next camera...

BTW, you are the best person to ask regarding the 6D: how much difference do you see in narrowband images? (trying to estimate the microlens loss)

The centralDS website states the modification prices. 6D conversion costs 900$, APSc cameras cost 600$. For a comparison, JTW sells a ready cooled mono 700D for 660€.

BTW I really like the cooling concept of CentralDS, if I can get a longer sensor cable, I might do something similar.

It seems, just as my first IR-mod, I have to do this myself too (that time ~5 years ago the ICF removal was just as big bang as a mono conversion today. Everybody sent their cameras to MaxMax and Spencer's for the price of a new camera - on a conversion that takes you 1 hour with practically no risk).

Collecting the critical points where things can go south for myself, please correct me if wrong/key elements are missing:

- static electricity->how to ground the sensor? 

- Breaking the sensor glass / damage to the silicon by the fragments -> efficient heating or chemical removal of the glue. Any efficient chemicals out there, that doesn't damage the sensor? What about acetone, dichloromethane? 

- protecting the gold wires -> mask or glue?

- "not to touch" area on the sensor's borders. How much to spare from the process?

- polishing techniques: which materials to use? How much force to apply? How to avoid killing pixels/entire rows?

- how to seal the sensor properly once the job is done?

+Joker: is there an antireflex paint one could use on the bare sensor? I see shiny silicon definitely causes problems with reducers (sorry, german).

I probably won't try it myself, I am looking for a business doing it. Hypercams - if still active - would do it for ~320 $/ a bit more than the price of 1 sensor/, but for the time being I asked europeans (astroghost & jtw) first, to keep shipping costs down. Btw, new sensors go around 260-300 $, that's at stake if I start experimenting, but I won't, unless I see a fool-proof 6d debayering guide:D

Edit: running circles to find a conversion service but other than CentralDS (900$!! for the conversion = that's more than the price of 3 new sensors) no luck so far...  Apparently I have to go the hard way...

20 minutes ago, Adam J said:

Yes I agree, however...QE is a measure of the percentage of the incident photons converted into electrons and that includes the effective aperture of the pixel. So in terms of signal to noise per pixel although the Nikon cameras start out with a higher QE ~50% as opposed to Canon 40%. You have to also consider the smaller pixels in the newer cameras. I calculated it and the light collected per pixel in my 1000D at 35% QE is still more (per pixel) than the D5100 with its QE of 50%. However the D5100 has better noise so it gains quite a bit of performance from that. 

Incidentally in your link they compare the original 5D with the newer Sony sensor...not a fair comparison. The 5D had horrific QE (26%) and the 5D MK2 (31%) even in comparison to the 1000D (35%) so while the 1000D has poor QE its not so poor as the two sensors pictured in your link.

I did think about the 550D (same sensor as 600D) with QE (41%). However my logic is that if the 1000D is breaking even using super pixel, (but worse when processed for full resolution) then the 550D might do a little better than breaking even and the D5100 might do better still....but even if the D5100 is seeing a performance advantage post mono mod due to its sensor construction I would not expect it to be a huge one, i.e. it might not be sufficient performance increase to make it worth the effort and the D5100 is more expensive.

In terms of risk vs reward, independent of the camera / sensor a larger performance boost is obtained through cooling than via a mono mod in my experience.

If you get a D5100 and have a go with it, please please post some analysis here. I would be very interested.

Plans changed, I am going Full Frame. I just learned that the 6D performs the same as the D610 and sony a7 (apparently canon learn't how to properly fab sensors even with their ancient 500nm tech), thus I am decided now, I'll grab a 6D for monochrome and keep the d5100 for color. But for sure, I'll take standard shots of all kinds for a meaningful comparison.

On 11/30/2016 at 18:55, Adam J said:

Cooled mono 1000D M45.

All in all i think that the camera breaks out about even following the mod. Still it was an interesting project

Absolutely! Moreover, I linked above, that Nikons might have an advantage here, because of their smaller diodes (that might be the case for modern Canons too)

Thanks for everybody! The reason I asked was the ~20% Tele Vue deal (ends today) at two german stores, I ordered the 2x powermate then alongside a 10mm Ethos. This way even if 1.75mm is useless, I have 3.5mm (171x), 10mm (60x) and powermated 5mm (120x). Adding the powermate was way cheaper than adding even a delos...

I am looking for a really good Barlow, that doesn't compromise the performance even of the greatest EP's. Speaking of good EP, I already have a 3.5mm Delos - "Barlowing it" puts any scope on its edge anyway.

I intend to use it on my 90/600 APO and possibly a c11 in the not-so-far future.

Any recommendations, which one to take?

Right now, I am looking at the Powermate 2x. I see, it's a corrected optics, but is it also APOchromatic?

Other, quite exotic piece I found and seems interesting, is the Baader Fluorit Flatfield Converter. Latter seems interesting for planetary photography too.

Thank you for the effort! I compiled a quick 100% crop from each of your shots, trouble is, that the focusing seem to went a bit rouge:(

What I see, is that the Mono image is great, sharp and the stars should be there are there. The nebula interestingly fades in the full-resolution image "thanks" to the loss of microlenses.

Binning - here deBayering OTOH bring the missed intensity back, even adds a tiny bit to the intensity. Unfortunately the focus issues didn't allow for limiting magnitude check :(.

Based on this result I'd say the conversion doesn't really boosts the sensitivity of the 1000D - which is not surprising if we look at the Canon vs Nikon (=Sony) pixel structure.

BTW, has anyone tried to deBayer the sony A7? Being fullframe, it's quite an affordable camera. However, looking at replacement sensor prices I'd probably check if a pro could do the monochrome mod...

In the meantime ZWO is not stopping in the production of newer and newer CMOS cameras. If their newest APSc model gets a mono buddy, I wont bother/invest time&money in debayered stuff. They effectively halved the cost of entry to the "ccd-world".

I'll probably buy just a sensor... 

Anything less than 50% (1EV) is a positive figure for narrowband imaging... H-alpha is crippled 2EV, O-III is around 1.5EV using the Bayer array.

 I just checked I CAN USE filters with my d5100 AND the Rriccardi reducer (reducer needs 76mm, -Nikon flange: 46.5mm -Baader UFC: 13mm leaves 16mm for adaptors, GREAT, I can sell an unnecessary camera now ) .

I'll collect some courage (+spare sensor...) and try your mod, including the cold finger. I was hoping JTW accept sensor assemblies for conversion but they need the whole camera - which of course involves more costs (work & shipping), thus commercial
solution seems to be a no go, I am not shelling out the price of an asi1600mm-cool on a dslr-mod... Free modding my d5100 at home is a different story:)

1 hour ago, russellhq said:

Some pretty impressive work has been achieved with a standard DSLR by Scott Rosen http://www.astronomersdoitinthedark.com

I think the key to Scott's success is dark skies: they make everything better ?

Of course, if someone has a Uluru or equivalent in the backyard ...

Everybody has a different budget, approach and goals in this hobby. Anyway, lots of satisfied people are using self-modded "color" DSLR-s budgeting them at their normal photo market value. I am actually reviving my astro-hobby after several years of "absence" and need a bit of a guidance.
I have a bit of a budget on an airline-portable setup now, but want to spend it wisely. 

For me, time is very precious, those tens of hours of exposures one often see on astrobin, would take years in my case even for circumpolar objects. Boosting camera efficiency by a factor of 2, not to mention more, would bring me much closer to the result. As I understood, B&W conversion
in theory (and from the real life samples) should bring 1EV advantage - this is like taking a 130mm APO instead of my current 90/600! Going forward I was curious if there is a meaningful second step, like 2+EV advantage by using a dedicated astro camera as the ZWO ASI.

Speaking of price, one doesn't necessarily need the "top dog" asi1600mm, there are solutions at 1/2price with 8mm diameter - which might be perfectly fine for smaller objects.

1 hour ago, Adam J said:

I dont think anyone is going to argue that the ZWO ASI1600MM-Cool is not a superior sensor for astro work across the board and by quite a long way. I have personally only spent about 50 pounds doing this as I got a broken 1000D for 40 pounds fixed it and purchased some polish on top of that. I simply cant spend over 1000 pounds on an astro camera. If this mod is not going to give me better performance I will just stick my 450D into the cool box and use that without mono modding it. it actually takes a pretty decent image at -15c. 

 

I would not recommend anyone paying for a conversion as that would not be cost effective in comparison to a dedicated camera like the ASI, for the same reason I would not recommend that someone try to convert one of the more expensive DSLR's. But if you have the skill and a lack of cash then it might help is certain areas if you convert a budget DSLR. If only for lum for galaxies or reflection nebula. To be honest its also been fun doing it.

This mod really is for someone who cant afford cameras like the ASI not for someone trying to equal their performance for less cash because they are going to be disappointed.

I think I see here, that you're completely right... (mono modded D600 vs ASI1600mm-cool). A few more pics and I am convinced... I started a smalltalk around the a7s vs the ZWO, the a7s might be the last stand of consumer cameras here. However, mono-modding it is a financial Russian roulette...

12 minutes ago, Gina said:

I really can't see any treatment of a DSLR coming anywhere near the performance of the ZWO ASI1500MM-Cool.  There may have been improvements in DSLR technology but I can't see any reason for manufacturers of DSLRs to make them that much better for astro imaging, the scale of users would simply not warrant it.  And if such a camera were available it would be bound to have a similar cost to the ZWO camera.

When I was experimenting with debayered DSLRs I was comparing with CCD sensors at two or three times the cost of the ASI1800MM-Cool.  I certainly spent more than one of those ZWO cameras cost had they been available.

That is quite a difference in intensity! Were they identically exposed? (time, aperture, target)

1 hour ago, Herra Kuulapaa said:

Unfortunately I've sold the mono and converted RGB to cooled so it's not possible to conduct more tests at this point.

I must say that the demosaicing algorithm is very good to replicate almost same detail level. The true difference comes in narrow band where all the four matrix pixels will record signal same way.

Here is a small comparison of the same full spectrum target in true raw:...

 

Nice clear + apparently a bit more details than the RGB. Do you still have both cameras? Can you do a comparison with narrowband filters (H-a + O-III) and a fast, maybe f/2 lens?

I am awaiting a commercial offer for the conversion of my a6000, but I fear that the final costs (a6000 resale value, conversion, cold-finger cooling+ all shipping&taxes) will go beyond the price of an ASI1600mm - the next question would then be if the tortured a6000 is any better, which I doubt...

26 minutes ago, Herra Kuulapaa said:

Hmmm., there is something funny in your test. It might be the sensor too, because Exmors seem to behave very nice after mono conversion. They have much more narrower conductors than 1000D, which may decrease the amount of photons hitting them.

Here is some real world testing

Here is a comparison of full spectrum RGB D5100 on left vs D5100am (astromono) on right. Both files are true raw (non debayered).

click it large

Right, I thought Mediafire doesn't need a registration for uploading, but apparently it does.

Nice test Adam, very interesting: clearly more intensity when all pixels are used but less details. Latter goes in the opposite direction as Maxmax's marketing, claiming that monochrome should yield more details.

Can you share the raw files?

I don't really see  loss of intensity on the subpixel level (#2 vs #3), maybe 1/3stop, whereas the gain on the additional pixels is substantially more, my guess is around 1EV.

12 hours ago, Adam J said:

Ok I have a set of comparison images. Some baby food bottles on the side in my kitchen but it will have to do.

Each image is a 1/50th of a second exposure through my Baader 2" 7nm filter fitted to the front of a 50mm lens ISO800 F1.8 (although as discussed short forcal lengths may have an effect on the mono sensitivity).

From left to right: 1) Mono Camera Single Red Channel Only Extracted. 2) Mono Camera all four pixels extracted (2x2). 3) RGB Camera Red Channel Only Extracted (Green and Blue Removed).

I think that the clear winner in this test is the original OSC camera it simply has the best signal to noise ratio. Now I will still be doing the real world test on a Ha nebula as soon as possible as you could convince me that this may be due to the short focal lenght of the lens....but I would not bet on it.

You could also convince me that ultimately with longer exposures / integration I would get more detail out of the mono when processing it for full resolution as opposed to binning it. But from what I can see here I would expect to have to increase the integration time by about a factor of four to achieve the same signal to noise level as in the Red channel only of the RGB camera.....I have seen this done by someone with a mono camera and the results are very good but the integration times are crazy (10's of hours). This leaves me of the opinion that the camera is (baring a a big change in the real world test) not going to give me what I am looking for and I would be better off taking H-a and OIII data with the bayer intact.