ZWO 2600MM vs QHY 268M: A Side by Side Review

Testing the ZWO ASI2600MM and QHY 268M in a side by side comparison. Pushing each camera to see how well they both perform under 6 tests & image comparisons.
Timestamps:
0:00 Intro
0:47 Sony IMX571 Sensor
1:33 Cooling
3:43 Dew Control
5:04 Backfocus
7:10 Imaging Rates
11:15 Tilt
12:53 Practicality
16:06 Image Comparisons
20:01 Final Verdict
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[@testboga5991]

Regarding dark current, one should keep in mind that virtually no location has dark enough skies for the small dark current of new CMOS cameras at even moderate cooling.

[@PlandemicSeries-com]

I agree with everything, but you missed out on a couple of very bit issues... the "oil" leak problem that the ZWO experienced and the QHY did not... and the fan vibration that causes ZWO to have elongated stars at high focal lengths because it is connected directly to the chassis and the QHY has dampening.

[@AZ4Runner]

very good and analytical comparision. Thank you!

[@tobi.starfile]

This is a very informative video, thank you! 🙏🏻 I am using the Omegon veTEC 571 M, which is also using the IMX571 sensor.

[@AstroWithRoRo]

I haven't had a chance to use the Omegon, Risingcam, or Player One cameras, but hope to do so soon!

[@GregMcCall]

You could also compare the company's behaviour. ZWO took public domain software (ie. ASIAIR software base), modified it but did not put that source back into the community. Breaking this licensing rule is effectively stealing software in my books. ZWO has also had quality issues. Vibrations from fans causing distorted starts in certain setups, thermal paste leaking onto the front of sensors and sensor tilt particularly showing up in the larger sensors. They all add up in my mind as a company that should not rank high.

[@AstroWithRoRo]

Hey Greg! I understand your sentiment about the open source community and talk quite a bit about how I feel on this matter in my ASIAIR Mini review video. I have spoken with ZWO about this and have asked them to consider opening up the platform to 3rd party products. Thankfully I did not experience any leaking, fan vibration issues, etc. on my unit so hope that they have managed to resolve these issues from a manufacturing side.

[@LM-ek2hb]

Very nice (and IMHO accurate) comparison! I have a 268 and have used a 2600 as a loaner for a few months. I agree with your assessment. However, I believe fan vibration would go to the 268. My tracking logs definitely shows a noisier fan (at f/10) with the ZWO than with the QHY. Great video!

[@AstroWithRoRo]

Very interesting thought with the fan vibration. I haven't noticed any kind of extra noise/vibration of guiding issues with my 2600MM. In fact my 268M is louder than the 2600MM is, but I will check this out and report back with a video update if I find anything.

[@bezain7663]

Great Review Roro We are looking forward the side by side comparison with a rising am, TS, or touptek, as there is a significant price difference for the same sensor!

[@jimwaters304]

Yes, the price difference is large but I have been told the ASCOM drivers are iffy and get little support. Customer support is also problematic.

[@RobertKarlBerta]

I have a ASI 071 color Pro cooled that is used with either s small refractor or 8" Celestron SCT HD with matched .7 focal reducer. The mount is the ZWO AM5 which has proven to be an excellent mount. I use their guide camera and ASI AIR Plus for an all ZWO setup (except the scopes). This was a design for very light weight and fast setup for remote observing. Normally I image from my home observatory with a AP 1100 GTO4 mount, 6" APO refractor of 11" SCT with Hyperstar. The ZWO setup is fabulous for rapid setup, image capture and stacking. I get very good results but obviously the other setup is far more versatile and capable of amazing images....but a lot of work if I want to use it in the field...especially on only one day. I heard of the lube on the chip but I know of a LOT of owners in my clubs that have had no issues with it like me. In addition I checked the camera for vibration and had no issues. I used Vibrometer to test and also tested some of my other cameras. One of my cameras is an older SBIG STL 6300 mono with full set of RGBL and NB filters...Ha, SII and OIII. I tested that SBIG and the ASI and the meter showed them to be far below the level even an animal could sense. I followed up with actual imaging tests at high magnification/long focal lengths and didn't see any issue. While doing the testing I checked the size and model of both the ASI camera and the SBIG fans....the fans were the same brand and model! since the SBIG has been in heavy use since around 2006 I am not looking at any issues with the fan. One thing I recommend is using a small paint brush to dust off the fan blades and cooling fins....if you get an accumulation of dust that can cause an out of balance vibration. If you do have a bad or worn out fan it is very cheap ($20) and easy to replace them so I don't consider that to be a big issue. While I was at it....I decided to install some rubber isolation mounts on the ASI camera (several brands are available on AMAZON). The improvement between stock and the isolation mounts was for all intents identical according to the Vibrometer. I did note that it would be a good idea to check the routing of the power cables to the motors to ensure they aren't resting against the cooling grid in the camera as that might transfer vibration. I also tested some other cameras I had....the best vibration performance (nothing registering) was on the ATIK camera..considering that camera was about 3 times the price of the 071 color Pro cooled and the SBIG was around 10 times the price of the ASI 071 back in 2006 that is not counting the actual value of the dollar than to now! What we are getting today for our money is FAR more value and we should be thankful for that. I like the addition of two USB ports on the camera as well as the tiltable camera nose feature which is nice for squaring up the chip to the focal plane...although mine was dead flat already....and in the case of Solar Ha imaging it is a necessity to deal with Newton rings on some cameras. I won't give my thoughts on the software they used to create the ASI AIR's. You can find fault with that but again....allowing other cameras to work with this setup is not just plugging the camera name and model into the list of cameras that work with it. Finally I have owned many cameras and there have been several that had issues that had to be fixed on warranty or my own fiddling.

[@nikanj]

Very informative review Rowan. Both these cameras look great and which one you pick will come down to your individual priortieis. Although it's hard not to be tempted by the RisingCam IMX571 which cost significantly less than either of them. On a side note, I've noticed that my QHY294M has a 2-step power ramp up when cooling - 50% then 100%. It's not as gradual as the ZWO's but perhaps this is something QHY have taken note of and want to improve upon. It seems like it would be something that's fairly easy to implement in firmware if they chose to do so for their exiting line up.

[@AstroWithRoRo]

Absolutely! Each has it's own little features and quirks over the other, but both are great. I hope I can get a chance to be hands on with some of the other cameras brands soon too. Thanks for the extra info with the 294M and it's two step power ramping, very interesting and I will keep an eye out for if they make any changes to the 268M too.

[@janelubenskyi1177]

Hi ….I have the SkyWatcher 190MN as you do did you ever do collimation….could you do a video please on collimation of this telescope…I am using the sight tube that came with the telescope and also the Ocal Electronic Collimation.

[@deep_space_dave]

Awesome comparison Roro! I have the QHY268C but it has similar features as the mono. I also have the ASI2600MC Pro. I don't need the extra USB ports and the black color helps reduce reflections when using the QHY camera with a RASA 8 or hyperstar. One thing I did notice is that even though the QHY camera doesn't cool as well, it draws a lot more current than the ZWO's cooler. I have yet to use the QHY in the Summer so we will see how it holds up. One feature I really like on the QHY though is the 2CMS mode which give a very large full well but lower noise. This allows me longer shots on my RASA 8 @ F2 without blowing out the stars. I really like the QHY 268C and may purchase a mono version for the summer nebula months. Unfortunately the 2600MC pro is now collecting dust so may sell soon. Thanks for the video!

[@AstroWithRoRo]

Great to hear your experiences with the 268C. I recently purchased myself a hyperstar and am looking to get a OCS ASP-C sensor to match with it too. It's been a fun ride learning to shoot at f/2 and all the tricks you have to work through to get it performing, but the results are amazing!

[@deep_space_dave]

@@AstroWithRoRo Hey just some advice for using the 268M with your RASA. First of all you really only need 2 modes, High Gain 2CMS @ gain 56 and Extend Full Well Mode-2CMS at gain 0. The Extend Full Well Mode-2CMS will allow you to take much longer exposures with fast optics like the RASA. Last night I did a test shot to see if my tracking issues were fixed (and they were 🙂) and I was able to take a 10 minute sub-exposure without blowing out the stars on a RASA! Also the noise was significantly reduced (of course). After watching your video, a QHY268M is now available at AgenaAstro in the US so I buying that and selling the 268C so I can really take advantage of the full power of this camera! Clear skies mate!

[@jimwaters304]

For me TEC performance is high on my Must-Have list. Also the additional USB 2 ports. It would be interesting to know the ‘measured’ Dark Current / Noise on a Dark sub at a given temperature. I would also like to know if the sensors are Industrial or Commercial for each camera. IMO the QHY drivers are problematic and difficult to work with compared to ZWO.

[@magedsyehia]

12:03 hello, thanks for the informative video. Can you please explain how you can measure tilt out of the box for the ZWO camera? Because it seems that I’m having a camera tilt in my newly purchased 2600mc pro.

[@AstroWithRoRo]

Sorry to hear you are experiencing tilt. The best way I find to test for this is using ASTAP or NINA with your full optical train. That way it takes into account the whole end to end optics as sometimes tilt can be introduced from other elements. By correcting in this manner you ensure that the whole optical field is as flat as can be.

[@kalon9999]

Excellent summary and worth the view, despite being a tie. It is missing one (usually important to amateurs) category: Price!

[@AstroWithRoRo]

Great call out. I didn't include price as these have fluctuated a lot for us locally in AU. Currently these two cameras have only a 2% price difference with ZWO being slightly cheaper. Previously the QHY was cheaper so felt with that kind of volatility it was better to focus on the features each brings and let you all decide how that matches up against local prices. :)

[@kalon9999]

@@AstroWithRoRo couldn’t agree more, volatility is always a factor and that’s why I commend you on focusing on the actual important factors in your video.

[@gclaytony]

I suspect the long exposure time of the QHY is related to the size of the on board buffer, as is the frame rate. If there were a utility to monitor consumed ram buffer on the camera I believe this could be seen as the QHY has approximately 4 times the buffer size of the ZWO (I think I read that the scientific version of the QHY cameras have even larger ram buffers). The ram buffer is the greatest 'weakness' of the ZWO although it doesn't become obvious until you reach the full frame sensor line like the 6200 series and the new medium frame sensor cameras. This presents itself as camera 'freezes' or lock ups when the USB connection (due to connection/cable issues) cannot offload the image frames fast enough to keep the buffer clear/available for the next frame. It is a persistent topic on the ZWO 6200 user forums and one I was disappointed that ZWO did not address in the new medium frame cameras that have even larger raw frame file sizes than the 100mb+ of the 6200. On the issue of tilt, that is an issue that is always the sum of entire optical train and not just the camera. For QHY to claim no tilt adjustment is require is a bit of a misrepresentation of the issue and a definite gap in capability, IMO. The sum of all the flex points/tilt in the system presents itself at the camera sensor, so a lack of tilt adjustment capability in the QHY is minus not a plus. The tilt plate for ZWO gives the capability to correct this total systemic tilt, but there is some flexure in the tilt plate when you get to the setup with an OAG-L, EFW, and the camera since the tilt plate has to relocate to the telescope side of the OAG-L. The three point adjustment also makes for a lot of trial and error to get the best results. The ASG Photon cage is a much more robust solution for tilt/backspace adjustments. The ASG Photon Cage (4 point adjustment) in combination with the Hocus Focus plug in for NINA makes the entire tilt adjustment process about as easy and robust as is available today. QHY had notorious issues with its drivers up to the end of 2021 when they finally got a stable driver set released., the forums of Cloudy Night and QHY were full of reports from users trying to resolve/find work arounds for QHY driver problems.

[@tsanggary6422]

16:55 I'm really interest in the iOptron HAE29 and eager for the review video! Now I subscribed and wait! Is it worth buying the EC version for the realtime PEC?

[@AstroWithRoRo]

Thanks for the sub! Unfortunately I didn't get a chance to get hands on with the EC, but as a small spoiler I have been very impressed with the non EC performance (so long as you are able to keep fast guide exposures).

[@rtpman1953]

Interesting and fair test of the two cameras. For the ZWO, you mentioned using gain of zero to take full advantage of the full well value. What would you suggest for the offset? Also, looking forward to your mount review.

[@AstroWithRoRo]

I have been successfully using an offset of 25 and getting very nice results.

[@zaphus]

Great comparison. Nobody should regret their purchase of either of these cameras. I am interested in your mode choice on the QHY, I was under the impression that Mode 1 Gain 56 was the go-to mode. What is the difference with Mode 5 (or the equivalent on the ZWO)?

[@AstroWithRoRo]

QHY has released 2 new modes (4 and 5) which are improved versions of modes 0 and 1. Mode 4 (photography mode 2cms) should replace the use of mode 0 and High gain conversion mode 2cms should replace the use of mode 1. They serve the same function as the original modes but have better noise reduction and as such improved dynamic range.

[@dumpydalekobservatory]

Great assessment between the two cameras I myself use the Altair Astro 26C for imaging on a RASA 11 a 102mm refractor & even my 1200mm reflector & it performs great, it to has the IMX 571 sensor although not a fan of the colour of it 😂, sorry but I'm not a fan of ZWO products anymore especially after reading about the open source software & the ASI Air which they're making a ton of money from it & not putting anything back into the community.

[@desbarry8414]

The ZWO had well documented issues with the thermal paste bleeding onto the sensor, ZWO at first didn't acknowledge the issue which really pissed me off. Being in the UK I instead purchased the Altair Astro 26C with the exact same sensor and saved over £600. The QHY is also more expensive than the Altair with the same sensor. Their loss.

[@matthewhoag1510]

The QHY has 4 shooting modes. Does ZWO have the same?

[@AstroWithRoRo]

The ZWO has one shooting mode, but does have the dual gain ability.

[@marklindsey1995]

I think the one that doesn't leak oil on the sensor will win.

[@AstroWithRoRo]

Thankfully I did not experience any oil leaks with this unit, so hope that they have resolved that problem. Certainly it is not great for anyone who had such an issue occur though.

[@StereoSpace]

In my opinion, the ZWO came out slightly ahead on ease of use and dark current over temperature range. Otherwise, very similar cameras.

[@AstroWithRoRo]

Agreed, the 2600MM is definitely easier to use (with both the ASIStudio software and USB ports).

[@Calzune]

I wonder if zwo will release a "3600mm" (or whatever it will be called) anytime soon... I planning on buying the 2600 in a couple of months and with my luck the next gen camera will be released a couple of months later 😂

[@Loopy01]

They've actually recently released their new 2600 duo line of cameras, so i don't think we'll be getting anything new in the near future.

[@jimwaters304]

@@Loopy01 IMO the Duo camera is limited. It requires a larger image circle so the OAG sensor can work. This means a more expensive scope.

[@Loopy01]

@@jimwaters304 Oh i agree. I'm not necessarily saying that the duo line is superior to the regular 2600, just that we're probably not getting a new generation of cameras in the near future.

[@GregMcCall]

@@jimwaters304 BTW, its an On Access Guider chip. (same access as the camera). OAG have something like a prism to divert light of the axis

[@nikaxstrophotography]

I think the ZWO ONLY wins by a smidge due to the usb ports at the back allowing more versatility, that's about it.

[@jimwaters304]

What about TEC performance???

[@nikaxstrophotography]

@@jimwaters304 much of a muchness

[@MrGuilletv]

qhy win here....remember fans vibration and oil leak....

[@Hilmi12]

I disagree on your assessment on backfocus, any camera that gives you more backfocus wins hands down. You can get to 55 mm with adapters provided, then great. More back focus more better. Sometimes you want to squeeze in something like an adaptive optics unit

[@AstroWithRoRo]

Totally understand your thoughts there! I set the test to achieve that standard 55mm, but agree the QHY provides more flexibility with the 11mm extra. It does come at the cost of a smaller OAG pick off prism which some may not want to make the sacrifice on. Either way, it's great to have the two options available!