Sony NEX-7 / Registax - Video vs Stills for Lunar Photography

Started Nov 1, 2012 | Discussions
Railton
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Sony NEX-7 / Registax - Video vs Stills for Lunar Photography
Nov 1, 2012

I thought it might be useful to share a comparison I've done between the use of video and stills in Registax.  The video and stills were taken within about 10 minutes of each other so should be a good test.

Still processing is as descibed on my other thread ""Full Moon - Stacked"

Photoshop Elements 10: Each photo was cropped to 3200x3200 with the moon in the centre (Registax doesn't like the moon moving around the frame too much) and had Auto-Levels run to bring up the brightness.

Registax:

  • Load the 56 images
  • Use "Set Alignpoints" to let Registax choose the points
  • Align, limit (53 frames were chosen automatically) and stack
  • Set Wavelet parameters to: 9.7, 4.8, 2.4, 1.1, 1.1, 1.0
  • Set Gamma to 0.7

Video processing was as follows:

Video was taking in MP4 format and converted to AVI using "Prism Video Converter".  This was loaded into VirtualDub where I trimmed the video to 300 frames and saved.  I actually had about 540 useable frames but the output file from VirtualDub needed to be less than 2GB otherwise Registax wouldn't load it.

Registax:

  • Load the AVI images
  • Use "Set Alignpoints" to let Registax choose the points
  • Align, limit (285 frames were chosen automatically) and stack
  • Set Wavelet parameters to: 2.4, 2.4, 1.8, 1.1, 1.1, 1.0
  • Set Gamma to 0.8

Results:

Stills

Video

My conclusion:

Although it is easier to capture many frames using video alot of detail is lost through video compression so its it better to do a fewer number of stills (not surprising really as the stills are 24mp and the video 2mp).  With 10fps on the NEX it's pretty easy to take a lot of stills.  I'm looking forward to the next clear night to try again.

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razor2277
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Re: Sony NEX-7 / Registax - Video vs Stills for Lunar Photography
In reply to Railton, Nov 1, 2012

Looking good! I had the same experience with my NEX-5 trying to stack videos. The compression KILLS the quality. Definitely give this another try when it is quarter moon to get all the nice crater detail. Shooting the full moon is difficult to get much detail because of the lack of shadows.

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RustierOne
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Re: Sony NEX-7 / Registax - Video vs Stills for Lunar Photography
In reply to Railton, Nov 1, 2012
Railton Wrote:

My conclusion:

Although it is easier to capture many frames using video a lot of detail is lost through video compression so its it better to do a fewer number of stills (not surprising really as the stills are 24mp and the video 2mp). With 10fps on the NEX it's pretty easy to take a lot of stills. I'm looking forward to the next clear night to try again.

Thanks so much for working out the technique of converting NEX video to AVI for Registax. I have often wanted to do that, but couldn't find a video converter that made an AVI that Registax liked. What you've done is really exciting!

I also have been very curious if the AVCHD format would be less compressed than the MP4. I somewhere read that it was a higher quality than MP4. A good experiment would be to try that conversion to feed to Registax.

There are some real benefits of a video stream being fed into Registax - principally just the far greater number of individual frames from which Registax can choose the moments of good seeing. Sometimes its just a small part of the entire frame that's particularly sharp. From what I remember about Registax, it's capable of piecing together the sharp portions of different frames to form the final stack. And of course the larger the stack, the larger the signal/noise ratio will be.

When I've used my Imaging Source video camera on the Moon at 60 fps, some of the AVI fed into Registax has had over 17,000 frames to choose from. But that camera is only 640 X 480. So to form a decent size image requires stitching together a bunch of frames. With the still camera video, even if only 2 megapixel (1080 X 1920), there would be great improvement in that regard.

Another consideration in getting a large number of individual JPGs (either 16- or 24-megapixel) is the wear and tear on the shutter. I don't know what its rated life might be. But cranking off a bunch of 20,000 frame sequences might be a concern. When all is said and done though, that may well be the best way to go with planetary imaging. By the way here's a link to my simple device for keeping the shutter button depressed.

http://forums.dpreview.com/forums/post/41451627

Maybe there's another way to accomplish the same thing, but I couldn't find a way in the Sony's menu selections.

Best Regards to All,
Russ

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Railton
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Re: Sony NEX-7 / Registax - Video vs Stills for Lunar Photography
In reply to RustierOne, Nov 6, 2012

I trawled the net for information in shutter life.  There isn't anything concrete but the general concensus was that shutter life would be about 100,000 actuations.

If using the NEX then ensure you have the electronic front curtain option enabled, with this enabled there is only 1 actuation per shot rather than 2 so it effectively doubles the shutter life.

There are companies that will replace the shutter if it wears out but I don't know what price they would charge.

Railton.

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RustierOne
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Re: Sony NEX-7 / Registax - Video vs Stills for Lunar Photography
In reply to Railton, Nov 6, 2012

Railton wrote:

I trawled the net for information in shutter life. There isn't anything concrete but the general concensus was that shutter life would be about 100,000 actuations.

If using the NEX then ensure you have the electronic front curtain option enabled, with this enabled there is only 1 actuation per shot rather than 2 so it effectively doubles the shutter life.

There are companies that will replace the shutter if it wears out but I don't know what price they would charge.

Railton.

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Kit: Sony NEX-7, Sky-Watcher Skymax 90 telescope.

Thanks for the info on shutter life. What you found is in line with what I had previously seen. That's a good tip about the electronic shutter. Until I hear more about whether AVCHD video is useable, I'll try some short JPG series on Jupiter.

This time around it will be much higher in the sky (for northern hemisphere observers) than it has been at previous apparitions. With Jupiter currently at almost 22° north declination, at my latitude (43-1/2° North) Jupiter culminates at over 68° elevation. That last time I did any Jupiter imaging (with any old Olympus C5050, 5 mega-pixel in 2008), it was at 23° south declination and culminated at only 24° elevation. So this year its 44° higher than it was in 2008. Here's what I got back then:

Jupiter with Shadow of Callisto (1st moon on right), “Red Spot”, moons Ganymede (left), and Europa (far right); stack of 50 JPGs; Celestron C-8

With better seeing at higher elevation, improved sensor and processing techniques, I hope to improve on the results.

Best Regards,
Russ

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DuncanDovovan
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Re: Sony NEX-7 / Registax - Video vs Stills for Lunar Photography
In reply to RustierOne, Nov 6, 2012

Impressive result!

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munchmeister
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Re: Sony NEX-7 / Registax - Video vs Stills for Lunar Photography
In reply to Railton, Nov 29, 2012

Thanks for posting that comparo. Was the video taken with the Sony also?

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RustierOne
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Sony NEX-7 / Registax - Video vs Stills for Lunar Photography
In reply to Railton, Dec 5, 2012

Railton wrote:

I thought it might be useful to share a comparison I've done between the use of video and stills in Registax. The video and stills were taken within about 10 minutes of each other so should be a good test.

My conclusion:

Although it is easier to capture many frames using video alot of detail is lost through video compression so its it better to do a fewer number of stills (not surprising really as the stills are 24mp and the video 2mp). With 10fps on the NEX it's pretty easy to take a lot of stills. I'm looking forward to the next clear night to try again.

Kit: Sony NEX-7, Sky-Watcher Skymax 90 telescope.

Does anyone know of a comparison of the video quality of MP4 video versus AVCHD? I know the Sony NEX cameras can do video in either format. The AVCHD at 1080P would be 1080 X 1920 (at 9:16 aspect ratio), which would also be about 2 MP - but at what quality?

Some other questions:

Is there a method to convert AVCHD to AVI that's acceptable to Registax? Do other makes of cameras have some other video modes which might be more useful?

With the Moon having a wealth of fine detail in the image, the JPGs at 24 MP look much better than MP4 with 2 MP. But I believe (as you too noted) that most of the difference is due to compression. The MP4 stack has quite a bit less noise than JPG stack, but also way less detail. It just looks "plastic" smooth compared to the JPGs when both are zoomed way in.

Of course the advantage of video is the ability to capture a lot of images, some of which will be taken during better seeing. With large JPGs of 24 MP you quickly run into Registax's gigabyte limit. That's more of a consideration with the Moon because of its large angular size and wealth of observable detail, which may well benefit from lots of megapixels. And your 90mm aperture is capable of showing lots of fine detail on the full Moon disc.

But you may also benefit from experimenting with 6-megapixel JPGs on your NEX-7 (binned 2 X 2) to enable a larger JPG stack. This would allow 4 times as many images before hitting Registax's limit, which should give it more to work with and improve the noise level as well. That megapixel resolution should still resolve a large amount of detail.

Lacking an astronomical-tuned video camera (i.e. low noise, low compression, fast frame rate), maybe the best we can do is with multiple JPGs. If the seeing is good, the results can be quite good on the Moon.

Best Regards,
Russ

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Railton
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Re: Sony NEX-7 / Registax - Video vs Stills for Lunar Photography
In reply to RustierOne, Dec 7, 2012

What version of Registax are you using?  I have v6 and have not hit any memory limits but then again I've only stacked about 40 images.

Prism Video Converter will convert AVCHD files as well as MP4's.

jmac698 says the video stream exist of key frames that contain a full image followed by a number of frames that just contain the changes then followed by another key frame.  The key frames on their own should be much better quality and he says he knows a way to extract those.  Only about 1 in every 15 are key frames but you are still going to get a couple per second and saves the shutter.  I've sent him a couple of my videos so will keep you posted.  Take a look through this thread for more details: Full Moon - Stacked

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RustierOne
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Re: Sony NEX-7 / Registax - Video vs Stills for Lunar Photography
In reply to Railton, Dec 7, 2012

Railton wrote:

What version of Registax are you using? I have v6 and have not hit any memory limits but then again I've only stacked about 40 images.

Hi Railton,

I was responding to what had been written in your original post:

Railton wrote:

Video processing was as follows:

Video was taking in MP4 format and converted to AVI using "Prism Video Converter". This was loaded into VirtualDub where I trimmed the video to 300 frames and saved. I actually had about 540 useable frames but the output file from VirtualDub needed to be less than 2GB otherwise Registax wouldn't load it.

RustierOne continues:

It looks like you were discussing MP4s > AVI, not JPGs - my mistake. I'm using Registax V6, but its been a few months since I've used it on the Moon. I know it does have a limit, but I've fed it over 17,000 AVI frames (640 X 480) with no problems.

One thing I've noted on Moon stacking: I usually don't like many of the alignment points that Registax picks. So I delete these (right-click) and place my own points in high contrast points. I don't really know if it works any better, but it makes me ​think​ I'm in more control.

Prism Video Converter will convert AVCHn saD files as well as MP4's.

jmac698 says the video stream exist of key frames that contain a full image followed by a number of frames that just contain the changes then followed by another key frame. The key frames on their own should be much better quality and he says he knows a way to extract those. Only about 1 in every 15 are key frames but you are still going to get a couple per second and saves the shutter. I've sent him a couple of my videos so will keep you posted. Take a look through this thread for more details: Full Moon - Stacked

That looks promising. And yes, keep us posted. Regarding shutter wear, one forum member says he has gotten over 1/4 million shutter activations since February on two Sony NEX-5Ns:

http://forums.dpreview.com/forums/post/50326237

So I'm not going to fret too much over it. I'll just limit my JPGs to the nights with best seeing.

I just love Moon images and have really enjoyed your full Moon shots. I haven't shot many of the full Moon, but it's certainly full of detail, especially all the ejecta rays and bright craters. The other Moon phases are also enjoyable since the shadows really emphasize the elevation differences. Here's an interesting shot of that type (best 146 of 304 JPG images stacked with Registax, using Sony NEX-5N camera, 2.8 MP, cropped from 8 MP).

C-11, 2790mm F.L. @ f/10, Mare Imbrium, Eratosthenes (Lt.) , Plato (Rt.), 6/27/12

By the way the LPOD website (lpod.wikispaces.com/ ), Lunar Photo Of the Day, by Charles Wood is an interesting resource, since he gives insight on the physical processes going on in the Moonscapes. He also writes a monthly column in ​Sky and Telescope​ magazine "Exploring the Moon".

Best Regards,
Russ

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Railton
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Re: Sony NEX-7 / Registax - Video vs Stills for Lunar Photography
In reply to RustierOne, Dec 7, 2012

Good news on the activations, I have a long way to go before I get to 250k!!

Regarding point setting I either pick by hand or let Registax pick then scale back the ones actually used to the strongest 10 or 20.  I also crop my images first to minimise the amount of movement Registax has to deal with.

I love your close-up.  With my setup the focal length is 1875mm (including crop factor).  I've just got a 2x barlow and have taken some initial shots but not had a chance to process them yet.  If it works well then I might get a x3 and stack them.  With x6 I might have issues with vibrations so we will see.

Thanks for the website link, there are some great shots on there!!

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