ZWO Cameras

[centroid]

What is you experience/opinion of ZWO cameras.

Coming back to astro imaging after a break of over 7 years, it is very apparent that things have moved on in terms of technology, and choice of camera.

In my imaging days, I always used Starlight Xpress cameras, MX7C, MX7, H9C, H9, and lastly an H16.  These of course were all CCD based,  and CMOS sensors were very much the budget option.

Now I see a wide variety of CMOS sensor based camera, making some impressive claims.

One that 'on paper' seems a good option for my needs, is the ZWO ASI 183 MC-Pro, with the Sony IMX183 CMOS senor.

My question is, would I be disappointed after using SX CCD based cameras, or has CMOS sensor technology really advanced.

For my photography, I use a Full Frame Canon EOS 5d Mk4, which of course has a CMOS sensor, and the SNR on that is excellent, and in a different league to the SNR of EOS 7d Mk2 with its APSC sensor.

Edited August 15, 2021 by centroid
typo

[neil phillips]

Hi Dave i only do lunar and planetary. So my observation about current cameras is based on that. But both zwo and qhy. Are very good products. I love both my cameras. (zwo 178m for lunar) The 462c chip in either brand, is really on another level for a single shot colour camera for planetary. I know this doesnt really answer your question. But i dont think you would be dissapointed generally, with either brand. I can say the 462c camera has been my favorite planetary camera i have used since starting. From my limited experiance. I dont miss CCD in the slightest. I believe there is a similar chip to the IMX 462c  made by player one in the IMX 464 chip. Which is larger. If i hadnt have got the 462c i may have been tempted by that. If you ever wanted a planetary camera. The imx 224 is not too shabby either. But the IR response of my QHY 462c camera is just something to behold. Welcome back Btw 

[newbie alert]

Hi Centroid, well in 7 years things have changed quite a bit... personally I use a ccd  and have never owned a ZWO,  but I follow the rapid changes in cmos as one day I might change

Regarding the 183, it's a good camera with its tiny pixels, but does suffer with its ampglow so careful calibration frames will be needed... 

There are camera's that are ampglow free, such as the 533, 2600 and 6200 but you have to take into account that all cmos create massive file sizes compared to your starlight xpress ccd..

A friend uses a GB on just 1 target, so hope you have plenty of oomph and storage space on your computer

But if you choose a cmos , you won't go too far wrong with a zwo or  qhy 

[wimvb]

Sony announced a few years ago that they decided to stop their production of ccds alltogether. Other manufacturers have followed. With the exception of specialised areas, ccd is being replaced by cmos. Cmos has caught up and surpassed ccd. But beware when you switch to cmos; they have their own quirks. 

Edited August 16, 2021 by wimvb

[centroid]

3 hours ago, neil phillips said:

Hi Dave i only do lunar and planetary. So my observation about current cameras is based on that. But both zwo and qhy. Are very good products. I love both my cameras. (zwo 178m for lunar) The 462c chip in either brand, is really on another level for a single shot colour camera for planetary. I know this doesnt really answer your question. But i dont think you would be dissapointed generally, with either brand. I can say the 462c camera has been my favorite planetary camera i have used since starting. From my limited experiance. I dont miss CCD in the slightest. I believe there is a similar chip to the IMX 462c  made by player one in the IMX 464 chip. Which is larger. If i hadnt have got the 462c i may have been tempted by that. If you ever wanted a planetary camera. The imx 224 is not too shabby either. But the IR response of my QHY 462c camera is just something to behold. Welcome back Btw 

Thanks for your input Neil. Any info is helpful in decision making. The choice available now is very different to what it was back in my day.

[centroid]

3 hours ago, newbie alert said:

Hi Centroid, well in 7 years things have changed quite a bit... personally I use a ccd  and have never owned a ZWO,  but I follow the rapid changes in cmos as one day I might change

Regarding the 183, it's a good camera with its tiny pixels, but does suffer with its ampglow so careful calibration frames will be needed... 

There are camera's that are ampglow free, such as the 533, 2600 and 6200 but you have to take into account that all cmos create massive file sizes compared to your starlight xpress ccd..

A friend uses a GB on just 1 target, so hope you have plenty of oomph and storage space on your computer

But if you choose a cmos , you won't go too far wrong with a zwo or  qhy 

Thanks for that input. I know that CMOS produces large files, the RAW files (Large) from my EOS 5d Mk4 can be be up to 45Mb. Interesting about the Amp glow, I wonder the Peltier cooled versions, overcome, or minimise the problem. The Large Kodak CDD in my H16 suffered from Hot Pixlels, by the Hot  Pixel in Maxim dealt with that very effectively.

[centroid]

2 hours ago, wimvb said:

Sony announced a few years ago that they decided to stop their production of ccds alltogether. Other manufacturers have followed. With the exception of specialised areas, ccd is being replaced by cmos. Cmos has caught up and surpassed ccd. But beware when you switch to cmos; they have their own quirks. 

I guess with the advances in CMOS the CCD would start to lose favour, although I believe that Starlight Xpress are still using them, albeit likely not Sony.

[MartinB]

I wrote an article for AstronomyNow! magazine on CMOS cameras if you can get hold of a copy.  CMOS chips read much faster than CCD and are therefore better for video applications.  As a consequence they became the chips of choice for smart phones.  This led to massive investment in CMOS technology.  CCD chips still have the edge when it comes to pixel to pixel consistency which is important in scientific applications but much less so for "pretty picture" imaging.  The principle advantages of CMOS cameras are cost and low read noise (allowing much shorter sub exposure times).  You have adjustable gain settings which is very useful when switching between broad band and narrow band targets.  Amp glow is easily managed using time matched darks.  Many newer chips have eliminated amp glow.  I have 3 ZWO cameras and my old QSI CCD never comes out of it's box!  

The ZWO ASI 183 MC-Pro is a superb camera and also works extremely well with camera lenses such as the brilliant Samyang 135mm.

[wimvb]

1 hour ago, centroid said:

Thanks for that input. I know that CMOS produces large files, the RAW files (Large) from my EOS 5d Mk4 can be be up to 45Mb. Interesting about the Amp glow, I wonder the Peltier cooled versions, overcome, or minimise the problem. The Large Kodak CDD in my H16 suffered from Hot Pixlels, by the Hot  Pixel in Maxim dealt with that very effectively.

Amp glow is still present with peltier cooling, but it calibrates out with darks. Otoh, you also need dedicated darks to calibrate flats. Newest cmos sensors have no or at least much less amp glow than those from "last year".

[geeklee]

I have the 183MM and this heavily stretched 180s master dark would give you a few moments of pause (at the very least):

Here's a 180s Ha frame from the 183MM and a Samyang 135:

And here's the calibrated version (just with a Master Dark)

At 1:1

It took a while to get used to compared to my other cameras but I'm confident the master darks will always calibrate this out.

The 183MC-Pro looks the same (or similar) from what I've seen.

Edited August 16, 2021 by geeklee

[newbie alert]

7 hours ago, centroid said:

Thanks for that input. I know that CMOS produces large files, the RAW files (Large) from my EOS 5d Mk4 can be be up to 45Mb. Interesting about the Amp glow, I wonder the Peltier cooled versions, overcome, or minimise the problem. The Large Kodak CDD in my H16 suffered from Hot Pixlels, by the Hot  Pixel in Maxim dealt with that very effectively.

Peltier cooled minimises dark noise, ampglow is to do with the electronics, and I'd question if the starburst is from the amplifiers due to it coming from one location, rather than every row where  the amplifiers are.. so if you look at the starburst from the 183, which as said needs careful calibration 

The Kodak 8300 does suffer with hot pixels, some said it was reduced if run at a slightly higher voltage

[centroid]

17 hours ago, newbie alert said:

Peltier cooled minimises dark noise, ampglow is to do with the electronics, and I'd question if the starburst is from the amplifiers due to it coming from one location, rather than every row where  the amplifiers are.. so if you look at the starburst from the 183, which as said needs careful calibration 

The Kodak 8300 does suffer with hot pixels, some said it was reduced if run at a slightly higher voltage

My H16 had a Kodak 'chip' and that suffered from Hot Pixels to a far greater extent than did the Sony CCD 'chip'. However, the 'Hot Pixel' filter in Maxim did an excellent job of removing them. I think that amp glow, and starburst often get confused. Amp Glow is thermal noise from the amplifier, which the Peltier cooling in my then SX CCD cameras, resolved. As I understand it the "star burst' is an unwanted side effect from the backlit CMOS 'chips'. Apparently, the later IMX 533 CMOS 'chip' reduces this to an "acceptable" level, or as some say, eliminates it, if the subs aren't too long.

[centroid]

On 16/08/2021 at 11:07, MartinB said:

I wrote an article for AstronomyNow! magazine on CMOS cameras if you can get hold of a copy.  CMOS chips read much faster than CCD and are therefore better for video applications.  As a consequence they became the chips of choice for smart phones.  This led to massive investment in CMOS technology.  CCD chips still have the edge when it comes to pixel to pixel consistency which is important in scientific applications but much less so for "pretty picture" imaging.  The principle advantages of CMOS cameras are cost and low read noise (allowing much shorter sub exposure times).  You have adjustable gain settings which is very useful when switching between broad band and narrow band targets.  Amp glow is easily managed using time matched darks.  Many newer chips have eliminated amp glow.  I have 3 ZWO cameras and my old QSI CCD never comes out of it's box!  

The ZWO ASI 183 MC-Pro is a superb camera and also works extremely well with camera lenses such as the brilliant Samyang 135mm.

I am leaning towards the IMX 533 Martin, due to its "claimed" improved starburst problem. 

[newbie alert]

31 minutes ago, centroid said:

My H16 had a Kodak 'chip' and that suffered from Hot Pixels to a far greater extent than did the Sony CCD 'chip'. However, the 'Hot Pixel' filter in Maxim did an excellent job of removing them. I think that amp glow, and starburst often get confused. Amp Glow is thermal noise from the amplifier, which the Peltier cooling in my then SX CCD cameras, resolved. As I understand it the "star burst' is an unwanted side effect from the backlit CMOS 'chips'. Apparently, the later IMX 533 CMOS 'chip' reduces this to an "acceptable" level, or as some say, eliminates it, if the subs aren't too long.

ZWO advertise their zero ampglow camera's with and without the starburst 

Which makes no sense

[vlaiv]

It's also worth noting that CMOS cameras come with very small pixels.

I think that has to do with all the megapixel craze that has caught up smartphone and compact camera market (higher megapixel count is always better, right? )

Not long ago when CCDs were main astro imaging sensor - pixel sizes were in 5µm - 9µm range. Some models even had very large pixels like 24µm.

Latest cmos sensors are at 3.75µm or below - going down to 2.4µm in astro applications - and easily down to 1.2µm in smartphones.

This can easily lead to oversampling. CMOS sensors can't bin in hardware - but they bin in software and only difference is level of read noise. With CCDs binning will result in larger effective pixel size - but read noise will remain the same. With software binning - same thing happens to effective pixel size - but read noise grows as bin factor (x2 bin - x2 increase in read noise, x3 bin - x3 increase and so on).

Good thing is that CMOS sensor have very low read noise compared to CCDs.

When I was choosing my main imaging camera - two models were came up that were interesting and within my budget - camera with Kaf8300 CCD and ASI1600. First one has 5.4µm size and about 9e of read noise (depends on camera model), while ASI1600 has 3.8µm and 1.7e of read noise.

I then realized that I can bin x2 and x3 depending on needs ASI1600 3.8µm pixels to get 7.6µm pixel size or 11.4 (both pixel sizes that are matched by other CCD cameras) with read noise of 3.4e or 5.1e - both still well below Kodak CCD offering (later being comparable to some Sony low read noise CCD sensors).

Another good thing about software binning is that you can decide on bin factor after you take the image. Night was particularly good and seeing fine - go with higher resolution, and if not - bin more to recover even more SNR.

[wimvb]

4 hours ago, vlaiv said:

I think that has to do with all the megapixel craze that has caught up smartphone and compact camera market (higher megapixel count is always better, right? )

Many of the sensors that go into astro cameras are developed for machine vision (including cars) and security/surveillance cameras. These applications can utilize smaller sensors than consumer cameras (dslr), but still need resolution, while being larger than sensors in mobile devices. Smaller sensors are cheaper because manufacturers get more of them from each silicon wafer. They are also easier to incorporate in systems. Here it isn't consumer's rave that drives the development, but economy.

Also, because cmos sensors read out individual pixels, developers can get very creative with read out modes. One of the latest developments is tetrapixel design, where each "ordinary" pixel in an RGGB configuration is actually made up of 2x2 small pixels. These tiny pixels can be read out individually and even exposed individually, giving a much larger dynamic range than ordinary pixels. The ASI294MC camera has this feature. Such a feature is highly desirable in traffic cameras and security cameras which have to deal with a very high dynamic range (for example when identifying a driver in a dark car at night with bright headlights and bad weather).

Otoh, with the ASI294 (the mono version), consumers did oddly enough want more pixels. ZWO had locked their camera to bin 2x2 with 4.63 um pixels. But consumers demanded the sensor to be unlocked to allow small 2.315 um pixels, all 47 million of them. Folly, in my opinion, because it degrades the specs.

[jacko61]

On 17/08/2021 at 12:05, newbie alert said:

ZWO advertise their zero ampglow camera's with and without the starburst 

Which makes no sense

Sorry for being a bait late to chime in but they don't.  Their ad shows what a frame from a camera with ampglow looks like then they show the 533 frame which has no ampglow. 

Graeme

[newbie alert]

50 minutes ago, jacko61 said:

Sorry for being a bait late to chime in but they don't.  Their ad shows what a frame from a camera with ampglow looks like then they show the 533 frame which has no ampglow. 

Graeme

What's the ampglow from a 183 look like??

 

[jacko61]

3 minutes ago, newbie alert said:

What's the ampglow from a 183 look like??

 

There's an example on this old  thread   

 

[newbie alert]

Yes as I've show here also.. but you've missed the point.. it's showing the starburst.. where's the amplifiers on a cmos camera???  

[Budgie1]

I think this tutorial on the ZWO website may explain it better: What is Amp Glow and how do I manage it?

It starts by saying: "Amp-glow is a generalized term and has been used in CCD era. It originally referred to “amplifier glow”, however these days it generally refers to any kind of “glow” in the image that is caused by the camera itself."

So think of Amp Glow on a CMOS sensor in the same light as calling a vacuum cleaner a "Hoover".

[newbie alert]

8 hours ago, Budgie1 said:

I think this tutorial on the ZWO website may explain it better: What is Amp Glow and how do I manage it?

It starts by saying: "Amp-glow is a generalized term and has been used in CCD era. It originally referred to “amplifier glow”, however these days it generally refers to any kind of “glow” in the image that is caused by the camera itself."

So think of Amp Glow on a CMOS sensor in the same light as calling a vacuum cleaner a "Hoover".

A hoover is a brand name for a vacuum cleaner, and it's only a vacuum cleaner for people of a certain age.. anyway nothing to do with astro or camera's

So why don't zwo or any other brand name call it what it actually is than call it what it totally isn't... why not call it a sausage glow ? 

It isn't glow from a sausage

And it isn't glow from the amplifiers 

Why not call it what it actually is, it has a name /term, so why not use that than what it totally isn't 

 

[iantaylor2uk]

I have a ZWO 071MC Pro camera and have never seen amp glow on it. I've been very pleased with the camera. I also have a ZWO 120 mini MM guide camera. If you go the ZWO camera route you can also use an ASI Air Pro which makes life much easier in many ways.

[Budgie1]

5 minutes ago, newbie alert said:

A hoover is a brand name for a vacuum cleaner, and it's only a vacuum cleaner for people of a certain age.. anyway nothing to do with astro or camera's

It's the best analogy I could come up with at 1am, and being of a certain age. 🤣

[adyj1]

13 minutes ago, newbie alert said:

So why don't zwo or any other brand name call it what it actually is than call it what it totally isn't... why not call it a sausage glow ? 

I'm as anally retentive as the next pedant, but if you're selling to the masses it is probably better to use an inaccurate term that everyone understands and helps sell your product than it is to be accurate and confuse people....