Live View noisy and unclear

[curlynerd]

I'm running BYEOS 3.1.17 and my Canon T7i/800D. First of all, I love BYEOS and it's taking wonderful shots, so no complaints at all. My question is about 2 things:

 

1) In Live View, I see quite a bit of noise moving around. I'm using my Laptop to connect with BYEOS. There's so much noise that it's difficult to see particular objects in the Live View unless I use Star-HD. This makes it challenging to focus using my bahtinov mask and is generally disconcerting. All the noise goes away when I take a photo, so it's only in Live View Frame and Focus that it's an issue. Is there some setting related to this?

2) What are the key settings to enable/disable for the T7i in BYEOS?

[admin]

Live view is noisy for sure, it's barely a few milliseconds of data and only the brightest stars will resolve.  When you get a bright star (around mag 2 or brighter) you will easily resolve amongst the noise and it should be easy to focus.  StarHD is a fancy word for common functions... I myself don't find it very useful once you have a nice bright star in the FOV.

Other than setting ISO to 800 I think most of the settings will depend on your setup and outside conditions.  It's a trial and error process.

[curlynerd]

Guylain:

 

Guylain:

Thanks for the quick response. I've got the photo settings pretty well dialed in, but thee T7i has other settings related to things like automatic Noise Reduction, etc., that I have all turned off.  It was these types of settings I was referring to, like AF settings as well that seem to have an effect on BYEOS. All those pesky menu items!!

The funny thing about Live View is that on my older 7D Live View doesn't have all of the "noise" that I see with the T7i. When I say noise I'm talking about what looks like artifacts moving around on the screen. "StarHD" does clean that up. I don't expect to see much as far as stars in Live View, except as you say that bright star used for focusing with the Bahtinov mask. Generally that's the only time I use Live view.

Love your software. Simple capture from your BYEOS below with the ES ED80, T7i with CLS filter.

 

 

 

[s3igell]

Remember that even though the 7D is an older model than the T7i, the 7D is also in a higher Product Class (Semi-Pro vs Prosumer) that often means better quality Electronics.

Or, it can also be simple Environmental Factors such as running the 7D on a Colder Evening than the T7i.  Or you spent longer in LiveView on the T7i just before the Imaging Run.  (In either case: Warmer Sensor means More Noise)

[curlynerd]

So, would you recommend the 7D over the T7i? I still have both and I respect your opinion. 

 

Chris

[astroman133]

So, you have both cameras, which do you recommend?  That question is easy to ask, but difficult to answer.

The answer depends a number of factors such as:

What type of imaging are you doing (nightscapes, deep sky, planetary, wide-field)  ?
For deep sky, what telescope are you using ?
What sky conditions do you typically encounter?

The 7D is a DIGIC IV model that was announced in 2009. The T7i is a newer DIGIC VII model that was announced in 2017. Have 3 generations and 8 years of improvements resulted in any benefits for the type of astrophotography that you do? Have any of the improvements and features since 7D even been incorporated into the T7i? Are they important for the type of astroimaging that you do?  Likely features like touchscreen LCD, built-in WiFi, more autofocus points, larger burst mode buffer of the newer model are not especially relevant for AP.

Likewise are the faster shutter, longer battery life, and better view finder of the 7D important for astrophotography?

I would also suggest that if you already have both cameras that the fact that the T7i costs half as much as the 7D is also not particularly relevant to which camera you might choose on any given night.

Do the smaller pixels in the T7i give you noticeably better images? That answer probably depends on your sky conditions and the focal length and optical quality of the telescope.

It probably comes down to factors such as do you actually see a difference in the noise levels in images from one camera or the other? Is the T7i's articulating LCD display useful for your workflow? Which camera is easier to operate, by feel, in the dark?

As I said above, it is not a question with a straightforward answer that is applicable to everyone; even if they already have both cameras.

[astroman133]

In regard to your question about noise in LiveView...

As Guylain said, each LiveView frame is very short. In order to see even bright stars the data needs to be severely stretched (brightened). This is done by increasing the ISO to its maximum value and increasing the "exposure" to up to 2 seconds. Of course all this brightening also makes the thermal noise more evident.

Things that you can do here to reduce thermal noise are to use LiveView as little as possible because when it is on the camera heats up. You can also reduce thermal noise by using an A/C power source rather than a battery since using the battery generates heat within the camera.

When comparing the two cameras for LiveView noise, be sure to compare them at the same ISO and exposure settings.

Finally, if the noise is too difficult to work around, you could use 2 second Snap images for focusing instead of LiveView.

[curlynerd]

Thanks for the answers, and here is some background:

OTA: Explore Scientific  ED80

Environment: With laptop, not using LCD, on AC power (5A Celestron) generally in the front of my property. 

HW: T7i generally (with CLS filter), bought used 7D when T7i was at Canon getting repaired, Starshoot for autoguide, StarSense for alignment after SharpCap

Shooting SW: BYEOS, SharpCap for Polar Alignment (using StarShoot), PHD2 for autoguide, Stellarium for generally choosing target and moving to it.

Post-Processing SW: DSS and Photoshop with Gradient Exterminator and Astro Tools. Sometimes experiment with Nebulosity as well. Registax for planetary, then Photoshop.

Targets: 95% deep sky, 5% planetary

 

So, I think that covers most of the questions.  I will try to make time to capture the same target with both cameras to see if there's a noticeable difference, but I'm always curious to hear more experienced people's opinions as well.

 

Thanks again,

Chris.

[astroman133]

Chris,

I intended the questions to be for you to answer and decide. That said, I would imagine that with the focal length of 480 mm, the smaller pixels of the T7i would be well-matched. So if the 7D is has lower noise then the tradeoff would be noise vs. resolution. If random/thermal noise is about the same then the higher resolution of the T7i would tip the scales toward it. At longer focal lengths or with bad seeing, the 7D might be better matched.

Good luck.

 

[curlynerd]

Rick:

 

OK, missed the rhetorical question...:) As I said, I'll try both when I have a chance. I was so happy to have the T7i back, I dropped the 7D experimentation. I do appreciate the info and it matches what I was thinking for the most part. 

 

Chris