If it's helpful, a laptop/TFT screen, with a white background, illuminated so that 1/10 sec @ iso800 puts the camera histogram around 75% is OK for flats - if you don't have a light box. The other benefit is that there is no appreciable dark noise to warrant taking dark flats. Manual focus on infinity of course.
Try equalizing the frames in PS or GIMP, which accentuates detail and may provide a better view. I'm not sure, but you may have focused on the wall. Else you need to remove the gradient. I suspect it's OK, because you have been careful with the replacement.
Cheers for the info Rowland , yer focused on the wall for that shot above, lol can see the texture, the raws are with a shirt though. Will try the notebook screen method thanks man, trying to get the screen clean is harder then the dam camera hahah. Will wack up a light box this week though as i wanna give it a bash before the cooling mod starts If you have any links to enclosures send them my way, jaycar and altronics don't really have anything light weight and strong. Really casing a ally case that has a seal though is not overboard on strength. It needs to also fit the camera chassis with a inch of space at the rear extra.
Heres what everyone's wanted to see, what really makes modding a dslr worth while. These are 10 secs at eta carinae both 1600 and 3200 ISO non modded vs stock 1100D. These are raws converted to psd then re-sized to 1366x911 and saved in level 8 of jpeg compression. No flats No darks
Small update:
Still playing around with the cooling ideas guys, so far the winner is TEC cold finger with water cooling. The main choice is do i drop the LCD and mount that way, do i go the normal route of side housing or do i go for a complete rehouse. I'am in the middle of shopping around for the TEC and sourcing some cheap water cooling gear from ocau atm. I have also being looking at potting which is filling the internals with a highly thermal conductive silicon which shields from condensation like this http://www.insulcast.com/technical/S...Anchor-LOW-363 . Though there's problems with moving parts and them getting filled as well lol, though i don'[t want to use thermal grease or other grease's which may get into the sensor.
Jay. Sounds like fun. The limitation will be condensation on the face of the low pass filter at and below dew point temperature. I have designed a circuit to warm the filter glass, but it is difficult to fit because of space restraints.
I used BluTak pressed into the components of the sensor electronics PCB to exclude condensation, and, of course the sensor to cold finger assembly is sealed with silicon. Providing the cooling is operated just above dew point, condensation won't be a problem.
If on the other hand, you want to go below dewpoint, sealing components is important. Having said that, I have had the sensor temp to -13C iced up for extended periods with no harm to the camera. At other times below dew point and high humidity with water flowing off the cold finger with no adverse effects. A cold box might be different because the cold is not localised.
Cheers Rowland, yer was thinking the same with the LP filter. I thought of maybe using a heater close to it like a element inside the camera but going in on the lens interface side. One extreme option would be to make a demister element on the LP filter it self lol but i think thats a bit out of my skill. I might google it up and could try an experiment with a demister repair kit though the shutter may get in the way :/
I have a spare sensor assembly and given the time will investigate further. The sensor frame chassis fit is very tight, with the shutter right in the way. Alternatively, directing filtered warm air from the lens side of the shutter on to the filter glass, might do the job.
Cheers Rowland here another idea i could try, I was thinking maybe use a heating element on the ground strap. If i heated the ground strap would it be enough to keep the condensation off the LP? Heres 2 pics of the 1100D, it doesn't have the sonic lens cleaner, which lol it not very useful anyhow, though you can see what i mean
Prevent condensation: All contact surfaces between heatsink and body housing, body mount and clear filter, all the screws are applied silicon O-ring for perfect seal. In the inner space we installed morecular sieve desiccant to minimize the absolute water vapor of airtight chamber.
The clear filter is wormed by the heat from heatsink and maintained the temperature over dew point.
Enhanced noise immunity: The housing material of EOS 1100D, 600D are plastic and this is easy to be affected by electric noise comming from outside.The sealed metal housing of CDS-1100D,CDS-600D protecting the inner electric circuit and added the ground connection from main board, power board, storage board to base housing made more stronger anti-noise system. This aluminum alloy housing of CDS-1100D, CDS-600D is more durable and resistant to shock than Astro50D, Astro60D.
lol they give all there trade secrets away at http://www.centralds.net I think ill have to find a clear filter now and do a rehouse
Just some copper sheet i sourced for the cold finger, slowly getting there. Its more now getting the time to pull down the camera now as its the only astro modded one i have It's .025" or .635mm thick
That's a narrow gap. The 1000D is just over 1.2 mm. Looking forward to the result.
The .635mm is the metal gauge man, i think the gaps about 1mm on the 1100D. Its going to be a tight squeeze for sure though, thinking about epoxy to bed against the pcb and copper with some good quality pc grade tim between the cmos and copper cold finger. May even just use epoxy as a protective coating on the pcb exposed side, will have to have a play once i get the camera stripped down again . I bet we have clear skys as soon as i start haha always the way :/
Since starting the 20D i have also decided to return to TEC cool the 1100D and rehouse. I just ordered up one of these sweet baby's for rehouse http://www.ebay.co.uk/itm/HAMMOND-15...item2ec3a8d196 Hopefully this rocks up soon and i can get this done by xmas I will only strip flash and LCD though along with plastic housing and rehouse inside. Once again its going to be a mc clear T-thread job. The case will act as a heatsink which will stop frosting and dewing of the mc clear and allow sub zero temps off the sensor, i may even fill it with argon since its water and hopefully air tight.
Measures: 40 x 40 mm with lead wires.
Temperature Differential (DT) (Th=27 degrees C) : >=68 degrees C
Optimum Input Voltage (Vmax) (Th=27 degrees C): 15V
Optimum Input Current (Imax) (Th=27 degrees C): 6A
Maximum Cooling Power (Qmax): 51.4W
Just waiting on the encloser to rock-up and then i can get this baby on the go. I need to gather up some case usb and power fitting for the tec and camera, from my collection of junk lol. I also need to investigate EMF shielding to bring the noise down even more and its placement, obviously the usb, tec and power will be shielded but what else can i shield. I may cascade the TEC later on for more extream sub zero temps though i don't think it will benefit a cmos sensor. I also need to make up the plates for the tec to optimize transfer of temperature difference.
If this helps. I found that bonding the camera chassis to GND reduced noise significantly, while the TEC was not operating. There was noise in the line plugged into the mains, through the 12V PSU. Noise was also a problem when the MOSFET was switching on and off maintaining temperature during normal operation. Not what I wanted.
The crude solution - I placed a 22uf capacitor across the Gate and Source of the MOSFET, effectively removing voltage spikes caused by the switching. The only effect on the system was to slow down the rate of cooling marginally. Still as quick as an SBIG from what I have seen.
Every now and then a line would appear across an image, not optimal, but stacking software rejected these pixels as outliers - so no problem.
Hope that's useful - depends on your system I guess.
Cheers for that info Rowland, its being years since i was into doing a lot of electronics. I plan to use a computer 400watt PSU and just run it at 12volt without any PWM control, there shouldn't be any spikes i'am guessing?
After a quick test last night though i don't think the encloser is able to move the heat off the TEC and may need to go for the 32watt model TEC. Did you find out what sort of heat load the cmos sensor seem to put out in your experiences and what tec was best off?
Hi Jay. I found the Tellurex FAQ's valuable. Long read but great info.
Keep in mind that I am self taught and tend to over-engineer - just in case.
This is my take on things TEC.
TEC devices are not very efficient. The heat sink must remove energy from the object being cooled and dissipate the energy required to drive the TEC. For example, if you need to move 20 watts to cool a component you need a heat sink/fan capable of handling ~40 watts - in rough figures - otherwise the TEC becomes a heater and reduces the effectiveness of cooling.
The other issue is the mass that the TEC is expected to cool overall. Is the structure in which the TEC is operating sucking the life out of it. Isolating the TEC from sources that don't need cooling, such as the box, adds to overall efficiency. I don't think the CMOS is the issue.The TEC is cooling a whole lot of additional mass as well.
Looking at cooling boxes, I would keep them as tight as possible, insulate the inside. Not have the TEC in contact at all and make a cooling path from the cold side of the TEC directly to the camera chassis, to localize cooling as much as possible. But that's my take on things.
If you can get 0C, dark noise is reduced substantially.
Just grabbed a 33watt model and will do some experiments with it, might have to go the water cooling route The 33watt tec is running great just sitting on the p4 cooler with some tim and no pressure. Its icing up nicely and running around 30 at the heatsink i guess. I ran this for 10mins straight and it seems i should be able to pull this off with the p4 cooler and encloser. This will be great as the encloser will have the mc clear t-thread thermally connected to it and should sit above ambient easy which will mean frost free
Going to use a cold finger Rowland, kindia doing a quick half arsed rip of the centrals 1100d tec cooled camera http://www.centralds.net/cam/?p=1687 . Lol would just try and go phase change cooling if it was a box only style, if i didn't it would have to be some massive TEC's and series and parallel lol. I think the cooler boxes aren't bad but unless you have got airflow to the cmos sensor then there wasted alot. Really hoping to get sub z's with just this TEC and some cleaver installation of the cold finger to prevent cooling loss while on its way from the tec to the cmos sensor
If you have any links to enclosures send them my way, jaycar and altronics don't really have anything light weight and strong. Really casing a ally case that has a seal though is not overboard on strength. It needs to also fit the camera chassis with a inch of space at the rear extra.
It's .025" or .635mm thick
