Which camera would you choose ASI294MC Pro or ASI533MC Pro?

Hi Sebastian, 

I went with the 294MC-Pro and I really like this camera. I chose it mainly because if prefer the 4:3 ratio over the square ratio.
The 294MC-Pro and 533MC are similar, the major differences being:

• The aspect ratio: 294 is 4:3 and 533 is 1:1 (square). I would recommend checking framing tools and see if your desired targets would fit in your frame unless you want to do mosaics.
• 0 amp glow on the 533MC. I would still use darks with it. Since its a cooled camera, building a dark library is a easy to do in cloudy nights. Amp glow easily calibrates out on the 294MC-Pro.

Regarding the bin unlock, I think you are talking about the 294MM pro, which has an IMX492. It is not available for the 294MC (which has a IMX294 sensor). I have no experience with binning on my end. I might be totally wrong, but I think it is more useful for mono setups where you would bin 1x1 for lum and bin 2x2 for other filters. Binning with these 2 cameras would be done at the software level and would not really fix sampling problem. If you are undersampling and if you dither your subs, you can use drizzle during the stack to address that, but that will increase noise, so you need longer integration time.

Be aware that if you plan to use a narrowband filters like a Radian Triad Ultra or an optolong l-extreme, they might not play well with the 294MC-Pro, I cannot tell about the 533 however. Here is a link about this: https://www.cloudynights.com/topic/661685-word-of-warning-asi294mc-pro-and-opt-triad-and-nb/.
I my 294MC-Pro with an l-enhance filter and it works fine. 

I hope this helps!

Cheers

I had both cameras and they are both excellent.  You cannot go wrong with either one with your scopes.  Personally, I thought the 533 gave cleaner images but you have 40% less real estate to work with compared to the 294.  The square sensor of the 533 is not a big deal and in fact looks nice for many images.  

The link Marc shared is good to know but I can tell you that both the 533MC and 294MC work just fine with the L-eNhance filter from Optolong.  So there is no reason why the L-eXtreme would not work with the 294MC but I never tried the Radian Triad Ultra. 

I tested the 294MC at bin 1 and bin 2 and bin 2 (4.63 px) and bin 2 (the new default setting after ZWO unlocked the binning) works best.

Overall for ease of use I would get the 533MC for its cleaner images and no amp glow to deal with.  If, on the other hand, you want a larger FOV and don't mine  calibrating out the amp glow (which is not a big deal)  then the 294MC is the choice.

Bruce Donzanti:
I tested the 294MC at bin 1 ....

Hi Bruce,   this is very confusing.   Everything I've heard says bin 1 is only available for the mono (MM) cam.   Can you describe your MC bin1 test?   I would love to have a 294MC with those small pixels for my RASA11 config!    That would give a larger field with smaller pixels than my 183MC!

@Doug Summers that's the output of plate solving this image visible behind.

Hi Sebastin, 

I am an amateur and Have been into this hobby for only a while. So take my comments with grain of salt.
I have had a chance to use ASI 294MC and ASI533MC for a brief period.
I like them both. 

1. 553MC looks really nice on paper. It has low noise and no amp glow. Do I need to still take darks when using dithering when there is no amp glow? I know thats true for some CCDs like in DSLRs, not sure about this CMOS sensor. - Yes you still need darks for calibration
2. 294MC had recently got an update to unlock native pixel size. Seems like now its like 2 in 1 camera? Can I use the 4.63 and 2.31 pixel sizes with hardware binning like I would have 2 different or am I missing something and this does not have advantages over software binning? - Not True. It is for 294MM with different sensor
3. Which one would be better sampled with my scopes? Seems like 553MC has a bit too small pixel for my Newton but could it be "fixed" by binning? This also applies to the second question regarding software/hardware binning. - Depends. Not sure. I had good guiding and I liked my results of Image in 0.83 image scale better than 1.67. 

Other than the above questions, you might want to consider the calibration challenges (flat frames) in 294MC. There are plenty of discussions around it, facebook ASI groups, cloudynights etc. If you have good understanding of calibration frames, you probably wouldn't struggle as much as I did. 

Due to my imaging needs I chose ASI294MM and MC for the sensor size and shape over ASI533MC.

I pushed the image I posted above to Astronometry and you are right, its FOV matches the mode with 4,63 um pixel size. 

However I have found the description on the QHY site that sounds like both sensors could have unlocked native pixel size, just not sure if this actually makes sense for the color version. This description confused me so I thought both versions are capable of unlocking.

The new QHY294 Pro is a 4/3-inch back-illuminated camera, equipped with Sony IMX294 (Color) and IMX 492 (Mono) sensor. The 294 Pro has 11.7 MP at 4.63um, 14-bits A/D. The IMX294 and IMX492 chips have 46.8 million 2.315um pixels, which Sony 2×2 bins on-chip to create the sensor’s advertised 11.7 million 4.63um pixel array. The QHY294 Pro series camera is capable of locking and unlocking the on-chip binning to provide two readout modes. The first mode reads the sensor “locked” mode to produce 11.6mp images with 4.63um pixel size and 14 bits per pixel. The second read mode unlocks the binning to produce 46.8mp images with 2.315um pixel size at 12 bits per pixel.

Considering the pixel sizes are constant for both cameras:

• 294MC is safer choice for my 8" Newtonian scope and just a bit under-sampling the 65Q APO (not a big deal I guess?).
• 533MC for 8" Newtonian could be a bit over-sampled, and sensitive to poor seeing?

I have read some posts about the flats in 294MC after your pointed that out and really looks like its quite hard to take the good ones. I got the Lancerta FlatBox so quite "smooth" light source but there is always a risk. Some of them seem like darks problems taken with the light leak.

I was considering bigger/more expensive cameras like 2600MC and 071MC but with those the pixel size difference is even bigger and I guess its better to make a mistake with something cheaper 

I do not believe you can "unlock" the 294mc.  Even if you could.. it wouldn't work with the bayer matrix that's sitting on top of the sensor since the bayer matrix is still patterned for 4.63um pixels.  The 294mm doesn't have a bayer matrix so its not a problem for it.

I have no personal experience with the 294mc but I've seen some people have had issues with NB filters like the L-Extreme... with red patterns on them.  There's a pretty long thread on CNs from a year ago that covers the issue.   You can research it and decide if its a concern or not.

The ASI533 doesn't have amp glow like the 294 or most other cameras do.. so if you take enough subs.. you can skip taking darks.  That said.. darks are easy to make.. you can build a library on a cloudy night, and the images look better with dark frames so I don't fully get this desire/need to not take dark frames.

If you have dust or vignetting then you need flat frames regardless.


I posted a review of my 533 to youtube that gives plenty examples of what kind of images you can get with the camera. 

https://www.youtube.com/watch?v=nbkMxspZdmc

In the end its a hard choice.. they are both solid cameras.  The 533 is the more forgiving of the two and would get the nod from me unless you prefer the larger FOV I don't plan to shoot much NB with it.

Calibration with darks is intended to remove repeatable dark current patterns and if there is no amp glow dihering is enough. Subtracting  darks removes the dark current noise but also ads darks random noise to the final image. Frome the MaximDL manual:

So subtracting a dark frame eliminates noise, because it gets rid of the gross pixel-to-pixel variations in dark current. Unfortunately, and perhaps counterintuitively, subtracting a dark frame also adds noise to the image. Every pixel has random read noise, plus the residual dark current noise. This noise does not subtract, but rather adds in a root-sum-square fashion. Therefore simply subtracting one dark frame increases the noise level 41%. The way to get rid of this noise is remove it by averaging multiple dark frames. Every time you quadruple the number of averaged frames, you drop the noise contribution in half.

https://cdn.diffractionlimited.com/help/maximdl/Dark_Frame_Calibration.htm

@James this makes sense that unlocking in terms of color camera due to the bayer matrix is impossible even though the native pixel size is smaller. Sorry for this confusion. 

I am a bit sceptical with 553MC due to its small pixel size but after all your post I think I going to give it a try  

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I used mine with a little sv70t and a celestron Edge HD8.  As long as your mount can track well and your seeing is at least average it should work fine with the newt.

I'm holding out for the 2600MM but I might have to cave and just get something I can actually afford at some point earlier than that
The 533 seems to be a fantastic sensor, just a bit small for what I was hoping for

Sabastian - you will be very happy with your choice.  Once it arrives just go and enjoy it!!

Bruce

Thanks guys! 

I also had checked before ordered the outcome FOV for my scopes, although its quite small sensor seems like most of the known objects fit well. Maybe a bit tight for the biggest ones like Andromeda Galaxy but I can use the Samyang 135 for those. Attaching examples with 420mm and 1000mm, maybe this could be useful for someone.