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Seeking advice for Magic Lantern video options EOS 550D/600D/800D (T2i/T3i/T7i)

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#1 the Elf

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Posted 16 May 2021 - 06:20 AM

Dears,

 

I'm trying to get into DSLR high resolution, lunar and solar spots for the time being, planets as soon as they are higher in the sky here in the north. I do _NOT_ want to get into imaging using a laptop, neither with the DSLR nor with a dedicated camera. My way is without computer and I'd like to optimize my images within that setup.

I have 4 different DSLRs available

- EOS 550D - T2i unmodded

- EOS 600D - T3i unmodded

- EOS 600D - T3i full spectrum mono (Bayer pattern removed)

- EOS 800D - T7i unmodded

 

What is the best way to capture high res? I learned the 550D offers a 1:1 crop mode and tested this out. I also learned magic lantern comes with a raw capture and with quality settings. I already tried raw mode with the 550D and my conclusion is it _cannot_ work because the card interface is too slow. It seems to be limited to the buffer only, some 15 seconds.

Now my question is it there is any benefit using quality settings in ML in the non raw modes and is this best with the 550D or does the huge increase in processing power and faster card writing suggest to go for a downsampled video mode on the 800D?

Is there any benefit using the mono for luminance? If the camera performs an internal debayer in video mode it will very likely ruin the extra resolution.

 

If this is better placed in the DSLR form the mods may move it there. I was not quite sure where to put it.

 

Thank you very much and clear skies!

the Elf



#2 Tulloch

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Posted 16 May 2021 - 08:04 AM

Hi Elf, I know you are quite knowledgeable in the field, and so assume you are familiar with the work of Jerry Lodriguss as posted on his website here.

https://www.astropix...resolution.html

 

The problem for you (as has been discussed here a number of times) is that recording the LiveView stream at 5x zoom directly to a computer is the best way to capture a video stream for high resolution planetary imaging. The next best way is using the 640x480 Movie Crop mode that is only available with a few cameras (including the 500D), however others (namely Grant aka RedLion) have found that the compression used in this mode reduces image quality.

https://www.cloudyni...eos/?p=10712654

 

I've not used Magic Lantern before, but others in this forum have to good effect.

https://www.cloudyni...pe-d170mm-f259/

 

In my experience connecting the DSLR to a computer produces a image that is very similar to that obtained using a dedicated planetary camera, the ASI224MC.

https://www.cloudyni...6-sct-test-two/

https://www.cloudyni...-sct-test-four/

 

So in summary, I would say that if you definitely do not want to use a computer, then the Movie Crop mode is the next best option, based upon what I've read here over the past few years.

 

Hope this helps,

 

Andrew 


Edited by Tulloch, 16 May 2021 - 08:18 AM.


#3 Tulloch

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Posted 16 May 2021 - 08:14 AM

P.S. For full disc lunar, I just use my DSLR in full frame mode, bang off around 20-30 images and stack the best 75% or so which seems to do an acceptable job.

https://www.cloudyni...r-and-c925-sct/


Edited by Tulloch, 16 May 2021 - 08:14 AM.


#4 rblackadar

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Posted 16 May 2021 - 09:44 AM

Agree with both replies so far. I would only add that for full disc shots of the moon, if 30 is good, 200 or more is even better. I've done video closeups of the moon as well, but in general they don't beat the full-disc, full resolution results (at least on my camera).

 

For planets, the T2i movie crop results are quite decent and would definitely be the way to go if not for the unfortunate compression. How much you lose in that depends, I think, on the target -- I got some really nice pics of Mars in movie crop last fall but was somewhat disappointed with my Jupiter and Saturn pics, albeit the seeing was better for Mars last year so I want to redo the comparison on the big planets when I get some time for that. I do see why you'd prefer not to attach a laptop -- it's inconvenient, and the frame rate for live view capture is quite slow, about 20fps for me in the best of conditions, compared to 60fps in movie crop. If your seeing is like mine you will need many thousands of frames, and that's a problem in live view, especially for fast-rotating Jupiter. By the way, when I capture in live view I do it via Backyard EOS, which is excellent for both for this and for DSO photography.

 

I did install Magic Lantern on the T2i but haven't really exploited it; perhaps others would give better advice about that. The two features I did use, for video, were the ability to set white balance and to keep a logfile of the capture, both features missing from the stock camera firmware as far as I could tell. (White balance is adjustable in post processing, of course, but the default AWB is annoying as it can change unpredictably over the course of a session.)

 

One caveat is that I'm not certain that Magic Lantern is entirely safe for the camera. At present my T2i sometimes goes unresponsive to all buttons except the shutter; this happens less often (or not at all?) if I boot it with a non-ML card. I don't know yet where to put the blame...



#5 the Elf

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Posted 16 May 2021 - 09:56 AM

Thank you! Yep, for full lunar disc I learned that PIPP converts the CR2 to tiff and AS!3 can read in a bunch of tiffs and do the same job as with a video. I attempted to try this from old data but I found I only kept the best raw frame that I converted into this image:

https://www.elf-of-l...j_Moon2019.html

There are some spots with great detail as well as some blurry spots in this image. Taking 200 shots is not big deal, using mirror lock and 2sec self timer it is done in 10 minutes. My mount can track lunar speed, not a problem at all.

For planets the corp mode is probably fine. Only the best of the best come up with a resolution that can be blown up to a fullHD image. When it comes to lunar details or sun spots I'd like to have a reasonably sized image. Not sure if 200 full res shots or a full HD video is better or if AS3! can mosaik a large image when I move over a given area in several rows using the crop mode. Plenty of experiments to do.

Thanks for the links, I'll dig thru them.

As ML seems a bit risky I removed it from the camera. Time will tell if I put it back on when my images turn out to be grotty. I also have to find out if my 4'' refractor or ma 8'' RC works better. In case of solar I have to make a baader foil for the RC8. I started out with a 4'' for the refractor and it works well. Got to go downstairs to the 3D print shop and check if the lady can print 8'' (just kidding, my GF is living downstairs and she has got a filament and a resin printer).



#6 Tulloch

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Posted 16 May 2021 - 04:40 PM

Full HD video is not your friend, the lossy compression used to produce a reasonable sized video is not good for high resolution planetary/lunar images.

 

If you can get ML to record in-camera the LiveView stream at 5x zoom in an uncompressed format, then that probably is the best option without using a computer. When recording to a computer (using BackyardEOS or equivalent), the compression used on the frames is negligible (the jpg quality is 99%), I'm not sure what it is for MOV format videos.

https://kuvacode.com...ve-view-quality

 

The 8" reflector will outperform the 4" in terms of resolution on the planets every time.

 

If you are new to planetary imaging, then these tutorial videos will help (at least, they helped me). Best performance is obtained when using a f/num that is around 5x the pixel size of the camera (for these cameras that is about f/20), so use a barlow to get to this focal ratio. You can capture 3 minute videos for Jupiter and 5 mins on Saturn without worrying about planetary rotational blur.

http://planetaryimagingtutorials.com/


Edited by Tulloch, 16 May 2021 - 04:50 PM.


#7 the Elf

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Posted 17 May 2021 - 03:55 AM

Thank you for the links. I have seen the videos by wwgeb on YT, I did not know there is a website as well. Yes, the videos are indeed helpful.  I think I understand the general approach. I'm currently trying to figure out how to use the actual cameras that I have in the best way. This is my first attempt taken with my mono T3i at 3x zoom:

 

2021-May-09_improved.jpg

 

It is not processed, only pushed the black point up and applied lots of unsharp mask to see what is in there. Scope is the 4'' f/7 with Baader ND5 sun foil.

 

The 550D arrived next day but since then I have not seen the sun, the moon or anything else but dark clouds. As soon as the weather improves I would like to test different settings and different cameras on the same target, either a sun spot or a lunar crater and figure out which one gives me the best result.


Edited by the Elf, 17 May 2021 - 03:57 AM.



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