ZWO ASI2600MM-Pro vs Cooled and Modded DSLR image quality

[MarsG76]

23 hours ago, The Admiral said:

Perhaps I'm being a bit dense here, but won't the output levels from either camera be influenced by their respective gains or ISO setting. How do you take that into consideration?

The CR2 raw can surely still be linear data, even if there has been a lot of gain applied from using a high ISO?

Ian

That is true, and I am comparing ISO1600 of the Canon 40D with ISO settings capability between 100 to 3200.... and the QHY raw at gain 56 on a scale that 1-100... both at half way in their gain settings... 

I'm aware of the different technologies applied.. a 14 year old camera vs the latest sensor with HGC capability and the more I play with it, the more I see the benefits.

But out of the camera the 40D shows nebulosity and structure where as the QHY raw seems to be more crushed and shows not much more than a few stars... raw without gain applied?

 

[MarsG76]

 Hello all...

O K... I had my first real comparison between the cameras and I was wrong... boy was I WRONG... after calibrating and stacking the subs, the QHY runs rings around the 40D...

I managed to get 10 x 900 second HAlpha subs at HGC gain 62, juggling between clouds, generated some flats, bias and darks and below is the (very quickly processed) result.

 

Below is a comparison of my HAlpha image taken with the 40D in February full res, next to a crop (and scaled down to 60%) of the image taken with the QHYCCD. Scaled down for comparison reasons because of the smaller pixels & higher res of the QHY generating a larger image.

Total exposure time for the 40D was 3 hours and 50 minutes and the QHY was 2 hours 30 minutes.

 

All I can say now is that suddenly I'm a believer.

Hopefully I'll have a clear sky tomorrow and capture SII and OIII to add to this image.

CS

MG

 

 

[rsarwar]

and that is solely due to DR, bit dept and increased relosution due to smaller pixel and lack of RGGB matix    

 

glad you finally came to the obvious conclusion that "brightness" means nothing but it is all about SNR. no apologies needed

Edited May 17, 2021 by rsarwar

[MarsG76]

On 18/05/2021 at 08:15, rsarwar said:

and that is solely due to DR, bit dept and increased relosution due to smaller pixel and lack of RGGB matix    

 

glad you finally came to the obvious conclusion that "brightness" means nothing but it is all about SNR. no apologies needed

You again... thanks for making me laugh... what are you talking about? Go else where, no answers needed.

Edited May 19, 2021 by MarsG76

[MarsG76]

Hi All,

I've competed the comparison image that I set out to do initially with the start of this post. Both images were taken using the same telescope and mount, and only 3 months apart, with almost the same exposure time spent for both images, so It's a close comparison.

Below are the full resolution image from the QHY camera...

 

...and the full resolution modded and Cooled Canon 40D image.

 

The scale of the two images are different due to the pixel size differences between the cameras so below is a crop and rescale of images taken with both cameras side by side...

 

The QHY image is definitely more detailed, but I'll leave it up to you to decide if it's worth the upgrade?

Pity that I can't change the title from "ZWO ASI2600MM-Pro vs Cooled and Modded DSLR image quality" to "QHY268M vs Cooled and Modded DSLR image quality" since I changed my order to the QHY camera from the ZWO due to ZWO not being able to deliver cameras before mid-July at the earliest... ABSOLUTELY no regrets!

 

CS,

MG 

[SteveNickolls]

Thanks  MarsG76 for all the effort you have put into this comparison I am very grateful for your time you have put into it.

Both images are very good and as you say its up to each one of us to decide if the upgrade is worthwhile. Whatever astro-camera I do go for it will be some time in the future as pennies have to be slowly saved up. Your work though has helped me on the trail.

May I wish you every enjoyment with your gear, oh and dark skies to image under.

Cheers,

Steve

[MarsG76]

On 24/05/2021 at 07:02, SteveNickolls said:

Thanks  MarsG76 for all the effort you have put into this comparison I am very grateful for your time you have put into it.

Both images are very good and as you say its up to each one of us to decide if the upgrade is worthwhile. Whatever astro-camera I do go for it will be some time in the future as pennies have to be slowly saved up. Your work though has helped me on the trail.

May I wish you every enjoyment with your gear, oh and dark skies to image under.

Cheers,

Steve

Hi Steve,

You're welcome... I hope that this helps astroimagers with the decision of whether it's worth (for them) going to a dedicated astrocamera with a real world use comparison that simplifies the choice without mudding the facts with numbers and test bench specs. 

I couldn't find anything online that compared (real world or other use) any dedicated astrocams to DSLRs that were cooled as well as modded so this might be useful, and upgrading from stock to modded to cooled and modded than to the QHY allows me to share some of my experiences and real results over the years.

Bottom line I find is that a dedicated camera, such as my QHY268M, is an obvious improvement in resolution and overall image quality but the DSLR produced great images too so the upgrade might not be worth it for everyone, and modding and cooling a DSLR is a lot cheaper... especially if done yourself. I'll add to this that I dare say that the ZWO ASI2600MM, and the color camera versions, will delivrer the same kind of improvement.

So far I love my new camera and definitely do not regret upgrading... but at the same time I'm glad that I waited until now to get a astrocam since this camera has features that I was waiting for (e.g. APS-C mono sensor and dew heating) and problems (e.g. amp glow and coolant leakage) sorted out... anything before this generation of cameras would (to me) be a compromise.

Clear Skies,

MG 

 

[MarsG76]

This is a unscaled 1:1 pixel comparison between the same nebula imaged with the QHY268M and my Modded and Cooled Canon 40D. Unlike the last side to side comparison where I scaled down the QHY image, this image is a crop of the actual resolution and detail capture by both cameras.

Images were exposed for a similar duration, through same filters, through the same telescope and at the same focal length.

 

The result of the comparison and the detail increase really should be no surprise when thinking about the technical aspects of the two sensors. Using the H-Alpha or SII filters with the Canon 40D used only 2.5 megapixels and through the OIII filter used only 5 megapixels of the sensor. The QHY268M is a mono camera and utilises all 26 megapixels of it’s sensor through every filter. The smaller physical pixels of the QHY sensor is the reason for the larger image scale at 1:1 pixel crop.

 

 

Edited May 24, 2021 by MarsG76

[SteveNickolls]

16 hours ago, MarsG76 said:

I hope that this helps astroimagers with the decision of whether it's worth (for them) going to a dedicated astrocamera with a real world use comparison that simplifies the choice without mudding the facts with numbers and test bench specs. 

I couldn't find anything online that compared (real world or other use) any dedicated astrocams to DSLRs that were cooled as well as modded so this might be useful, and upgrading from stock to modded to cooled and modded than to the QHY allows me to share some of my experiences and real results over the years.

Thanks again for creating this thread, I certainly endorse your reason for carrying out the experiment to show real world results particularly given the paucity of other similar work. I've shared your reluctance into not moving from a DSLR to purchasing a new astro-camera given the compromises,you clearly saw existed in the offerings laid out previously.

This thread certainly shows the value of cooling a DSLR too, the Canon 40D image would be quite sufficient an improvement from my perspective-can I ask did you modify your Canon 40D for cooling yourself?

Enjoy your imaging with the new camera. 👍

Cheers,
Steve

[MarsG76]

6 hours ago, SteveNickolls said:

Thanks again for creating this thread, I certainly endorse your reason for carrying out the experiment to show real world results particularly given the paucity of other similar work. I've shared your reluctance into not moving from a DSLR to purchasing a new astro-camera given the compromises,you clearly saw existed in the offerings laid out previously.

This thread certainly shows the value of cooling a DSLR too, the Canon 40D image would be quite sufficient an improvement from my perspective-can I ask did you modify your Canon 40D for cooling yourself?

Enjoy your imaging with the new camera. 👍

Cheers,
Steve

Hello Steve,

Thinking long and hard about such an upgrade is a normal thing since it's not cheap and can also create doubt and second thoughts of the expense if you're convinced of spending all that money for no, or very little improvement in images... but as you can see, there is improvement over even a very modded DSLR altered for the job.

I modded and cooled the 40D myself... if you're interested, I wrote of my experience in this thread: 

.

[SteveNickolls]

9 hours ago, MarsG76 said:

I modded and cooled the 40D myself... if you're interested, I wrote of my experience in this thread: 

Thanks MarsG76, I'll have a good read of your thread. 😃 I am aware of the cooled camera mod that Martin Pyott made available on You Tube. My Canon 700d was astro-modified when I purchased it years ago new and has done sterling work creating wide field nebulae shots in conjunction with an Astronomik 12nm Ha filter so you can understand my wishes not to buy an astro-camera with a smaller sensor unless that is the only affordable route to a cooled solution. Despite having a Bayer array the Canon 700D has collected some decent compositions in the past that way

Cheers,
Steve

[MarsG76]

On 26/05/2021 at 17:11, SteveNickolls said:

Thanks MarsG76, I'll have a good read of your thread. 😃 I am aware of the cooled camera mod that Martin Pyott made available on You Tube. My Canon 700d was astro-modified when I purchased it years ago new and has done sterling work creating wide field nebulae shots in conjunction with an Astronomik 12nm Ha filter so you can understand my wishes not to buy an astro-camera with a smaller sensor unless that is the only affordable route to a cooled solution. Despite having a Bayer array the Canon 700D has collected some decent compositions in the past that way

Cheers,
Steve

I completely understand.. it's a expensive jump and if you're happy with the DSLR... which I know can deliver awesome images.... than there is no hurry to upgrade.... getting a smaller sensor is really a step back IMHO.

[MarsG76]

On 26/05/2021 at 17:11, SteveNickolls said:

Thanks MarsG76, I'll have a good read of your thread. 😃 I am aware of the cooled camera mod that Martin Pyott made available on You Tube. My Canon 700d was astro-modified when I purchased it years ago new and has done sterling work creating wide field nebulae shots in conjunction with an Astronomik 12nm Ha filter so you can understand my wishes not to buy an astro-camera with a smaller sensor unless that is the only affordable route to a cooled solution. Despite having a Bayer array the Canon 700D has collected some decent compositions in the past that way

Cheers,
Steve

I had a look at your pictures and they're great... with a upgrade to a cooled mono camera you'd basically increase resolution and capture the same amount of data in around 1/3rd of the time.... might have less noise too... but overall you wouldn't find a quantum leap in improvement as you're still limited by your sky.... ultimately It's a decision where you want spend the money not need to to enter the next level of astrophotography....  

My justification was to get it was for (hopefully near) future "F2  Fastar" imaging on my C8 that I wouldn't be able to do successfully with the DSLR (covering the whole objective)...

[SteveNickolls]

Why thanks MarsG76 for the kind comments over the images I've managed to take with my dslr. Your comment "Its a decision where you want to spend the money not need to..." is a great way to put it into perspective and really resonates with me. Indeed the limitation imposed by local light pollution has always been foremost in my mind. As you rightly mention after a dslr I dont really want to move to a smaller sensor as I'd particularly wanted to do mosaics.

Yes imaging at f/2 is a great way to pursue this hobby and I wish you well in this.

Cheers,

Steve