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It's warming up - DSLR Question

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#1 mpaul73

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Posted 29 May 2020 - 10:30 PM

I started the hobby back Oct last year. I am shooting with a Canon 6D and so far it is going pretty well. Definitely happy with my results. The question is - now it's 70 degrees at night, am I going to start to experience a major set back NOT having a cooled camera? As much as I would love one it looks like it's a $1000 investment. To combat the noise from the heat, am I looking at doing shorter exposures? Lower ISO? Anyone with experience here please let me know. Thanks.



#2 kisstek

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Posted 29 May 2020 - 11:28 PM

I started two years ago using my Canon SL1. At first (June), I was having good luck and making some progress. By July, the need for longer exposures to bring out the Crescent Nebula and the air temperature exceeding 110 degrees was causing the subs to be all noise. Basically useless. So it was either put everything up until the Fall or get a cooled camera.

 

I considered a cooled OSC as that would have been the less expensive (almost said "cheaper" but it's not cheap!) than a cooled mono with filters. But I knew I was going to want to try narrow band imaging at some point and I'd regret being limited by the OSC. So I bit the bullet and splurged on the ZWO ASI1600mm Pro with the EFW including the 7 filters (L R G B Ha S2 O3). That's one of the purchases I have no regrets making.


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#3 Stelios

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Posted 30 May 2020 - 03:11 AM

Moving to DSLR forum for a better fit. 

 

Cooled cameras are definitely worth the money, and DSLR's definitely suffer in hot temps. Past that, I'll leave it to the forum experts for better advice as to best deal with noise.



#4 jgraham

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Posted 30 May 2020 - 07:30 AM

I almost hate to say it because the experts hate it every time I make this suggestion, but here goes... try using long exposure noise reduction. There, I said it. If I recall right I started using LENR 9 summers ago and never looked back. It takes a bit of getting used to, but I don't even think about it anymore, I just start my subs and go to bed. Across the summer I will see sensor temperatures over 40C with no problems. Heck, I'll even see sensor temperatures of 10C with my cooled cameras.

There I said it. Consider giving it a try, there's nothing to lose and maybe a summer of imaging to gain. If it turns out not to work for you then you can move on wiser for having tried. I just hope that this suggestion doesn't set of yet another LENR firestorm.

Enjoy! I hope that you find a solution that works for you!

Edited by jgraham, 30 May 2020 - 07:32 AM.

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#5 mmalik

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Posted 30 May 2020 - 08:48 AM

Cooling option of Canon here.... Regards



#6 Kevin_A

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Posted 30 May 2020 - 08:58 AM

When its cool outside I don't use LENR but when its very hot outside I tend to use LENR. If I know i will have good skies all night long I use LENR, if i anticipate just a few hours of clear skies I don't use LENR and just take darks after or during the cloudy moments. I base my judgement on overall outside temps and how much clear sky time i will have..... 


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#7 sgtusmc

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Posted 30 May 2020 - 09:27 AM

When its cool outside I don't use LENR but when its very hot outside I tend to use LENR. If I know i will have good skies all night long I use LENR, if i anticipate just a few hours of clear skies I don't use LENR and just take darks after or during the cloudy moments. I base my judgement on overall outside temps and how much clear sky time i will have..... 

Is there a benefit to using LENR over just shooting and using dark frames afterwards? 



#8 Kevin_A

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Posted 30 May 2020 - 11:49 AM

Is there a benefit to using LENR over just shooting and using dark frames afterwards? 

 

The LENR will be more temperature accurate to the time you do your sub and elliminates your hot pixels that are acting up at that moment, but LENR does waste valuable imaging time. I also tend to use it more with my faster glass/shorter exposure times (30-120 seconds) as there is nothing worse than doing a 240s sub, having a plane fly thru it then doing a 240s LENR subtraction.... as that equals 8 minutes of lost time on a throw-away sub. Generally i tend to only use it in the hot summer months when the sensor is at its worst. If its 10-15 degrees celcius outside i usually do just random darks and get as much integration time as i can..... clear skies are rare so its really up to you to decide based on your skies and temps and equipment. Cheers.


Edited by Kevin_A, 30 May 2020 - 11:51 AM.

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#9 fmeschia

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Posted 30 May 2020 - 12:05 PM

In any case, either LENR or calibration with temperature-matched dark frames will help reduce any fixed pattern in the dark signal, but can't do anything to reduce the random pixel-to-pixel fluctuations in dark signal that higher temperatures make more evident. The only cures for that are either cooling, or using a less noisy sensor, or increasing the integration time to make up for the lower signal-to-noise ratio.


Edited by fmeschia, 30 May 2020 - 12:08 PM.


#10 Michael Covington

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Posted 30 May 2020 - 12:07 PM

I started the hobby back Oct last year. I am shooting with a Canon 6D and so far it is going pretty well. Definitely happy with my results. The question is - now it's 70 degrees at night, am I going to start to experience a major set back NOT having a cooled camera? As much as I would love one it looks like it's a $1000 investment. To combat the noise from the heat, am I looking at doing shorter exposures? Lower ISO? Anyone with experience here please let me know. Thanks.

Just keep going, using your usual techniques, especially dark frames.  Although the heat makes some difference, I have gotten good pictures year-round.


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#11 sharkmelley

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Posted 31 May 2020 - 01:51 AM

I recommend using dark scaling/optimisation in your processing workflow.  It means you don't need to sacrifice the imaging time that LENR does.

 

Mark


Edited by sharkmelley, 31 May 2020 - 01:52 AM.

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#12 Readerp

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Posted 31 May 2020 - 08:16 AM

I recommend using dark scaling/optimisation in your processing workflow.  It means you don't need to sacrifice the imaging time that LENR does.

 

Mark

Ok, I'm a dummy. Is that like dark subtraction like I do in DSS?

 

One issue I have is that temp drops through out the night. Could start at 60F and end at 40F.

 

Admittedly, I only take darks at the end.....



#13 Michael Covington

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Posted 31 May 2020 - 10:41 AM

Dark optimization in PixInsight is a way of adapting dark frames to match temperatures and exposure times other than what they were taken at.  Temperature is the main concern in our case.



#14 sharkmelley

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Posted 31 May 2020 - 12:30 PM

Is that like dark subtraction like I do in DSS?

 

 

I don't use DSS but Dark Optimization is an option on the Dark tab of the Stacking Parameters dialog.

 

It is briefly mentioned in the technical reference:

 http://deepskystacke...h/technical.htm in the section Entropy-based Dark Frame Subtraction

 

Mark



#15 t-ara-fan

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Posted 31 May 2020 - 01:28 PM

as there is nothing worse than doing a 240s sub, having a plane fly thru it then doing a 240s LENR subtraction.... as that equals 8 minutes of lost time on a throw-away sub. 

If you are throwing away a sub because an airplane flew through it you are doing something wrong. 

 

The appropriate pixel rejection when stacking i.e. sigma clipping will take out the airplane and leave everything else.  You do need a dozen+ subs for this to work.

 

You might as well learn how to do this now, in preparation for when 50,000 satellites fly by every night.
 


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#16 t-ara-fan

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Posted 31 May 2020 - 01:37 PM

 . The question is - now it's 70 degrees at night, am I going to start to experience a major set back NOT having a cooled camera?

The dark current doubles every 6°C or so, and the dark noise doubles every twice that i.e. 12°C.    Yes, you will have more noise in the summer.  I have run my 6D at -20°C ambient temp, the upside of free cooling cool.gif was some compensation for it being a bit chilly.  In the summer it is definitely noisier.

 

More subs help the SNR, of course.  Make sure that live view is off, that really heats up the camera. Changing ISO won't change the underlying physics of the noise. Shorter subs won't change your SNR.

 

A cooled camera is an expensive step and an added complication for setup. I eventually got an ASI071MC Pro, it has <1/10 the noise of my 6D.   To reduce noise to 1/10 by stacking you need 100 subs.  So one shot with that cooled camera has less noise than a stack of 100 from my 6D.  Food for thought.
 



#17 Noobulosity

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Posted 31 May 2020 - 03:18 PM

I use my Canon 7DII, and also plan to use a 7D (1st gen) and 5DIII.  I have zero qualms about shooting during warm nights.  You'll get more noise due to the higher temperatures, but if you take enough exposures to help stacking even out the noise it should help quite a bit.  The noise will increase, yes, but I wouldn't call it a major setback.  But that all depends on your expectations of image quality.

 

Unless you want to invest in a cooled, dedicated astro camera, I would just roll with the DSLR if you already have it, and just see if it's enough of a problem for you to invest in the cooled camera or not.  Don't change your exposures based on the temperature, just shoot with the same ISO and exposure time as you normally would to capture your targets.


Edited by Noobulosity, 31 May 2020 - 03:20 PM.

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#18 Kevin_A

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Posted 31 May 2020 - 04:57 PM

If you are throwing away a sub because an airplane flew through it you are doing something wrong. 

 

The appropriate pixel rejection when stacking i.e. sigma clipping will take out the airplane and leave everything else.  You do need a dozen+ subs for this to work.

 

You might as well learn how to do this now, in preparation for when 50,000 satellites fly by every night.
 

Depending on how low a plane is.... i live close to an airport.... so in my case it is a total loss. I have no issues with satelites and high planes but low n slow planes are just too much to add that pic to my stack. So cheers and clear skies.


Edited by Kevin_A, 31 May 2020 - 05:40 PM.

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#19 sharkmelley

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Posted 01 June 2020 - 01:29 AM

I eventually got an ASI071MC Pro, it has <1/10 the noise of my 6D.   To reduce noise to 1/10 by stacking you need 100 subs.  So one shot with that cooled camera has less noise than a stack of 100 from my 6D.  Food for thought.

 

On the other hand, when imaging deep sky objects, the photon shot noise from the background sky (e.g. light pollution) typically dominates all other sources of noise.  This means that under most circumstances there will be only minor differences in stacked image noise from the ASI071MC Pro and the Canon 6D.

 

Mark


Edited by sharkmelley, 01 June 2020 - 03:37 AM.

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#20 Readerp

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Posted 01 June 2020 - 08:46 AM

I don't use DSS but Dark Optimization is an option on the Dark tab of the Stacking Parameters dialog.

 

It is briefly mentioned in the technical reference:

 http://deepskystacke...h/technical.htm in the section Entropy-based Dark Frame Subtraction

 

Mark

Thanks Mark!

 

Always something new to learn.

 

Cheers,

Pete



#21 Ettu

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Posted 01 June 2020 - 11:11 AM

Here's a cheap help.

A  3" 12vdc pc fan recycled from an old pc. It makes a difference, is easy to make, and the price is right. 

 

DSLR Fan Cooling.JPG


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#22 Domtbol

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Posted 01 June 2020 - 12:29 PM

 

Here's a cheap help.

A  3" 12vdc pc fan recycled from an old pc. It makes a difference, is easy to make, and the price is right.

Have you tested this , I cant see how this could cool the camera from the outside using ambient air.  To cool the camera you would need to blow air of a much lower temterature to have any effect , and also its the inside of the camera that needs cooling so you would need an even greater difference in temperature to effect the sensor.

There are numerous You Tube videos about doing this but it is a lot of work and the results are not always great, I have made one a couple of years age but I dont use it any more, I could reduce the temperature outside the camera by about 10C to 12 C. (about 20 F I think)



#23 Ettu

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Posted 01 June 2020 - 02:13 PM

Have you tested this , I cant see how this could cool the camera from the outside using ambient air.  To cool the camera you would need to blow air of a much lower temterature to have any effect , and also its the inside of the camera that needs cooling so you would need an even greater difference in temperature to effect the sensor.

Absolutely,...

The effect is not much, a few degrees C, but that difference is worth while when the ambient gets up to and above 15 deg C (~ 60 F). It helps particularly during multi sequence imaging, especially when you lengthen the pause between images to - say - 60sec, instead of just as soon as a dither is done. No, of course, this is not active, Peltier assisted cooling, this is just a cheap and easy help It simply increases the natural convective cooling rate - which of course, helps.

I find it worth enabling any time the exposure time is greater than ~200 sec, and/or the ambient is much above freezing,

 

The effectiveness no doubt varies by camera;  metal/plastic body, Battery/battery replacer, internal layout/density of  components, camera size/surface area. and so on.

For example it is absolutely worth it for my 10 yr old Canon 5DM2. But to my surprise, has almost no beneficial effect on my brand new Canon Ra, which is why - with that camera - I'm willing to pay Mike Malik's price for his active, cold finger cooling, - on that camera.

 

Couple of side notes, it helps cool the OTA a bit more quickly after sun down, (not a lot), but more than not.

Since the picture I posted, I've made a longer stand away bracket, and squared up the fan, which helped a little.

Fwiw, years ago, when I first read of this idea/observation, from a respected imager and author (And occasional contributor here - whose name escapes me at this moment). He later said he'd switched to just a box fan blowing on his whole rig, and found it nearly as effective with the camera. - plus helped the evening cool down much better - and against mosquitoes too. I tried that too, but found - at least in my case - that it introduced too much vibration on the assembly, so I went back to my little 3" pc fan.



#24 t-ara-fan

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Posted 02 June 2020 - 05:04 PM

Here's a cheap help.

A  3" 12vdc pc fan recycled from an old pc. It makes a difference, is easy to make, and the price is right. 

 

 

I did some tests with a fan blowing on my 6D at room temperature. Normally the 6D says there is a ten deg C temperature rise. With the fan, that rise dropped 5°C. 

 

I didn't take pics with the fan, just logged the temps.  I had my fan on a tripod near the camera, not bolted to the camera.
 


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#25 t-ara-fan

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Posted 02 June 2020 - 05:08 PM

I use my Canon 7DII,

The Canon 7D Mark II has very low dark current.   From an informative page at ClarkVision.

dark-current-compared_2-6c-v1.2.gif


Edited by t-ara-fan, 02 June 2020 - 05:09 PM.

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