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Sony A7s - New Low-Light Camera - Wow!

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#101 mpgxsvcd

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Posted 20 June 2014 - 07:54 AM

A7s looks VERY, VERY, VERY promising.

http://www.dpreview....8=lowlight&a...

#102 GJJim

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Posted 20 June 2014 - 08:33 AM

In the A7S it looks like Sony has matched the sensor noise characteristics of the Canon 6D - no small feat. Now if they would release a SDK, their cameras might become useful for astrophotography. :tonofbricks:

#103 bwallan

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Posted 20 June 2014 - 09:15 AM

... Now if they would release a SDK, their cameras might become useful for astrophotography. :tonofbricks:


How so? I use the A7R quite successfully for astrophotography and nightscape photography w/o their SDK...

bwa

#104 bwallan

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Posted 20 June 2014 - 09:17 AM

A7s looks VERY, VERY, VERY promising.


It does indeed!

bwa

#105 GJJim

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Posted 20 June 2014 - 09:32 AM

How so? I use the A7R quite successfully for astrophotography and nightscape photography w/o their SDK...
bwa


Useful in the sense of having the camera integrated with an imaging system. Look at apps like MaximDL, BYEOS, TheSkyX -- they all support cameras as part of a system that includes the camera, a mount, scheduling, focusing, etc.

I'm sure the Sony control app is a fine intervalometer for the camera, but beyond that it is limited.

#106 RandyC

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Posted 20 June 2014 - 12:44 PM

What is the difference between RAW and Jpg in the Studio Scene? Is it a simple conversion to JPG? It's much better.

#107 DonBoy

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Posted 20 June 2014 - 02:16 PM

What is the difference between RAW and Jpg in the Studio Scene? Is it a simple conversion to JPG? It's much better.



Noise reduction in .jpg

#108 Relativist

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Posted 20 June 2014 - 02:40 PM

In the DSS thread in this forum I asked about A7 series compatibility, and the raw files are not natively supported. This is something that once the A7s comes out and is confirmed to be worth it we should probably petition Sony for if it helps our use case.

#109 Moromete

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Posted 20 June 2014 - 03:16 PM

What I am waiting to see is if this new Sony A7S will need to remove the stock filter and use just a UV/IR filter for detecting Ha emission nebulas or is the ISO good enough on really high amounts to pull this nebula through the stock filter. If it needs to be modified then I cannot see many doing this to a full frame expensive camera.

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Hey Chris, have a look here http://www.youtube.c...h?v=elz2mMPoFKE and here http://www.youtube.c...h?v=elz2mMPoFKE .

Please note that those are in video mode with a shutter speed of 1/4s which is true video astronomy!

#110 Chris A

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Posted 20 June 2014 - 03:49 PM

Thank you very much Moromete for that excellent link and I loved it! Now were starting to talk real-time DSO observing. This was so cool seeing the different ISO settings at 1/4 sec and I liked it very much up to 40000 ISO but it is nice with that very fast f/1.4 lens :)

What filter was he using a IDAS-P2 or something else? Do you know if the stock filter was replace with a UV/IR filter? If not then that is amazing!! Seeing those Satellites whip by in real-time was fantastic to say the least.

I might be considering the purchase of one of these cameras also but will wait to see how others find it. Thank you again!!

Cheers,

Chris A

#111 bwallan

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Posted 20 June 2014 - 07:32 PM

...

What filter was he using a IDAS-P2 or something else? Do you know if the stock filter was replace with a UV/IR filter? If not then that is amazing!! Seeing those Satellites whip by in real-time was fantastic to say the least.

...

Cheers,

Chris A

I suspect an "RS Mod" is a full spectrum mod, i.e.: filters replaced with clear glass (or nothing).

The HEUIB (Ha Enhanced UV/IR Blocking) II is a Hutech filter that gives very close to normal white balance to full spectrum images while at the same time passing RGB and Ha. I use both the 48mm and clip-in HEUIB II filter; love it!

I sort of agree with your ISO40000 limit; however, darn hard to tell from YouTube!

I'd like to get my hands on the original video and process it (align and stack the frames) to see what can actually be extracted?

bwa

#112 bwallan

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Posted 20 June 2014 - 07:36 PM

Thanks for the link; interesting.

Do you know if one can download a good copy of this video to try some postprocessing on it? YouTube quality is a little shaky...

bwa

#113 RandyC

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Posted 20 June 2014 - 09:12 PM

I suspect the 1/4sec video output is RAW and not fully BIONZ NR processed for JPG output. Using the BIONZ Image Processor, the entire ISO range should be utilizable. Most of us would be going beyond 1/4sec anyways, geez how's 25seconds.

#114 Chris A

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Posted 20 June 2014 - 09:18 PM

Thank you bwa for the helpful information, I really appreciate it. If the stock filter is removed and a clear glass is replaced then I could see the camera lens reaching focus but without the glass will there not be focus issues with camera lenses? That Hutech filter that allows for Ha and RGB sounds great and for me the clip in would be the way to go. Yes if you could get a copy of the original video that would be great to stack and process the data.

Cheers,

Chris A

#115 Relativist

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Posted 20 June 2014 - 10:00 PM

Looks like some clouds show up after 40000 ISO, so does not seem to fair comparing after that. That said you can see sections with extra noise, so some on the fly adjustment or stacking is probably required. Really looking forward to whats to come with this camera. :)

#116 RandyC

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Posted 20 June 2014 - 10:26 PM

This is funny. We are already getting into the same stacking versus processing discussion that we had in Mallincam. Sony has built a high-end image processor with the Bionz. There shouldn't be that strong of a need to stack. Unless you prefer long exposure imaging which will get the halos and background objects better. For live "video", the BionZ should take care of the noise, as long as you convert from Raw.

#117 bwallan

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Posted 20 June 2014 - 11:22 PM

This is funny. We are already getting into the same stacking versus processing discussion that we had in Mallincam. Sony has built a high-end image processor with the Bionz. There shouldn't be that strong of a need to stack. Unless you prefer long exposure imaging which will get the halos and background objects better. For live "video", the BionZ should take care of the noise, as long as you convert from Raw.


I view the A7S primarily as an imaging camera, much like the A7R but with better sensitivity. 30 seconds images off the A7R @ ISO3200 are darn good, I'm expected an improvement off the A7S. It might work for video (it would be great if it does!) but this is not my intended usage of the beastie. Stacking is really the only way I know of really improving the signal-to-noise ratio to get great images. If you want Mallincam type images, go for it; been there, done that!

What "halos" are you talking about?

bwa

#118 bwallan

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Posted 20 June 2014 - 11:28 PM

Looks like some clouds show up after 40000 ISO, so does not seem to fair comparing after that. That said you can see sections with extra noise, so some on the fly adjustment or stacking is probably required. Really looking forward to whats to come with this camera. :)


Yes, the sky conditions may have got worse OR at the higher ISO's it might just be easier to see the clouds? That's why I'd like to get my hands on the original video...

bwa

#119 RandyC

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Posted 21 June 2014 - 11:46 AM

Hi bwa, You have a lot of experience with the Sony A7 and am sure you have a good idea of the A7S capabilities. When I look at this camera, I see a sensor and image processor cam. When I think "video", it means exposures of about 1 minute, maybe as high as 3. My hunch is the BionZ processor will reduce the noise to make the high ISO settings useable. At least it appears so in the studio comparisons posted. It's very exciting to think of adjusting the ISO versus exposure time to get something in the 1-3 minute range for "video". The analog to digital conversion has been a difficult issue, as the world is analog but displayed digitally. Low light situations, in particular, struggle with the conversion because there are less photons to go around. It looks pretty good for Sony as they invested in an underlooked area. ps: I was referring to galaxy halos visible in long exposure imaging.

#120 chasing photons

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Posted 21 June 2014 - 12:18 PM

I view the A7S primarily as an imaging camera, much like the A7R but with better sensitivity. 30 seconds images off the A7R @ ISO3200 are darn good, I'm expected an improvement off the A7S. It might work for video (it would be great if it does!) but this is not my intended usage of the beastie. Stacking is really the only way I know of really improving the signal-to-noise ratio to get great images.



I have little interest at this time in using video for near real time observing of deep sky objects. Unless the photons from a cataclysmic event happen to reach your optics at that particular moment, the patch of sky you are looking at will appear exactly the same next month, let alone a second from now. I also see software stacking as the way to go to improve the signal to noise ratio.

Cameras with higher sensitivity help for near real time observing by reducing the exposure times for individual images. This eliminates the need for guiding - a BIG plus. If the exposures are kept short enough, the stacking software may not even have to align the images. Also, even a good alt-az mount can be used as field rotation would not be a concern. In addition, a higher sensitivity image sensor can allow for optics with longer focal lengths without the typical use of such drastic focal reduction. The potential use of slower focal ratios allows for a broader choice among usable OTAs for near real time observing.

The Sony A7S is a good step in the right direction for near real time observing with a mirrorless/dslr consumer camera. Its large pixels and state of the art Exmor CMOS technology, combined with a relatively low pixel count, makes it a great choice for an astro camera. Another good use for moderately higher pixel counts is the ability to offer instant 2x-10x 'zoom' by simply cropping the area of interest in the image. But a full frame sensor is a huge chip and begs for expensive optics that can deliver a large, flat imaging circle. Sony also lags behind in camera features and available supporting software.

Before I jump in and spend $5K+ for a near real time observing system consisting of OTA, mount, camera and software/UI, it will have to capture useful individual images in under 60 seconds (hopefully much shorter) and stack/process on the fly in a clean and simple manner. The various technologies are improving and slowly merging, and I think MY dream system might be available in a year or two. Whether a CMOS consumer camera or a dedicated, cooled astro CCD camera ends up in that system, I really couldn't say at this point. In the mean time, I will continue to entertain myself as I watch for the technology improvements and follow the results of the more adventuresome individuals that frequent this forum.

#121 RandyC

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Posted 21 June 2014 - 12:34 PM

Hi, My guess is the Bionz image processor combined with the Exmor CMOS high ISO range will advance near real time imaging. We are talking about really high ISO values. If it's usable, then a game changer.

#122 bwallan

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Posted 21 June 2014 - 04:02 PM

...
When I think "video", it means exposures of about 1 minute, maybe as high as 3. My hunch is the BionZ processor will reduce the noise to make the high ISO settings useable. At least it appears so in the studio comparisons posted. It's very exciting to think of adjusting the ISO versus exposure time to get something in the 1-3 minute range for "video".

The analog to digital conversion has been a difficult issue, as the world is analog but displayed digitally. Low light situations, in particular, struggle with the conversion because there are less photons to go around. It looks pretty good for Sony as they invested in an underlooked area.

ps: I was referring to galaxy halos visible in long exposure imaging.


When we talk about "exposures" greater than about 1 sec (1 fps) I don't normally equate this with video (unless you come from a Mallincam environment)... I consider this the realm of imaging. And with multiple subs I can align and stack them to greatly improve upon the signal-to-noise ratio (SNR) I would normally find in a single image. I'm not talking about increasing the brightness of the image (i.e.: additive stacking); I'm talking about astronomy stacking which doesn't increase the brightness but DOES improve the SNR.

If the A7S would let me capture even marginal video at its reported max. exposure of 1/4 sec (4 fps), five minutes of video would yield 1200 frames of video, i.e.: 1200 subs, which when aligned and stacked equates to almost a 35x improvement in SNR over that of a single frame. Now that is something to get seriously excited about! Normal astronomy imaging would entail taking 20-50 five to 20 minute subs with a CCD and processing these to a final image. If this process could be reduced from a multi-hour or multi-night process of gathering long'ish subs to five to ten minutes of video, it would be a paradigm shift for amateur astro-imagers! No longer would you have to worry about great mount tracking, precise polar alignment, fantastic guiding, equipment flexure or even using an EQ mount.

Ok, I've got my heart rate up just thinking about the possibilities... Now to wait for the delivery of my A7S and see what it can actually do!?

"galaxy halos" sort like: Sombrero Galaxy - M104 - 30x30 sec exposures with an A7R @ ISO3200 on a Astro-Tech 65EDQ scope, unguided.

bwa

#123 Relativist

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Posted 21 June 2014 - 04:06 PM

So I was looking at the other forum where the A7s is discussed and apparently there is a SDK available.

https://developer.so...evelop/cameras/

Really looking forward to July 4th weekend when hopefully more than one broadcaster will be live on NSN showing us what this camera can do.

#124 bwallan

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Posted 21 June 2014 - 04:15 PM

I view the A7S primarily as an imaging camera, much like the A7R but with better sensitivity. 30 seconds images off the A7R @ ISO3200 are darn good, I'm expected an improvement off the A7S. It might work for video (it would be great if it does!) but this is not my intended usage of the beastie. Stacking is really the only way I know of really improving the signal-to-noise ratio to get great images.



...
I also see software stacking as the way to go to improve the signal to noise ratio.

Cameras with higher sensitivity help for near real time observing by reducing the exposure times for individual images. This eliminates the need for guiding - a BIG plus. If the exposures are kept short enough, the stacking software may not even have to align the images. Also, even a good alt-az mount can be used as field rotation would not be a concern. In addition, a higher sensitivity image sensor can allow for optics with longer focal lengths without the typical use of such drastic focal reduction. The potential use of slower focal ratios allows for a broader choice among usable OTAs for near real time observing.

The Sony A7S is a good step in the right direction for near real time observing with a mirrorless/dslr consumer camera. Its large pixels and state of the art Exmor CMOS technology, combined with a relatively low pixel count, makes it a great choice for an astro camera. Another good use for moderately higher pixel counts is the ability to offer instant 2x-10x 'zoom' by simply cropping the area of interest in the image. But a full frame sensor is a huge chip and begs for expensive optics that can deliver a large, flat imaging circle. Sony also lags behind in camera features and available supporting software.

Before I jump in and spend $5K+ for a near real time observing system consisting of OTA, mount, camera and software/UI, it will have to capture useful individual images in under 60 seconds (hopefully much shorter) and stack/process on the fly in a clean and simple manner. The various technologies are improving and slowly merging, and I think MY dream system might be available in a year or two. Whether a CMOS consumer camera or a dedicated, cooled astro CCD camera ends up in that system, I really couldn't say at this point. In the mean time, I will continue to entertain myself as I watch for the technology improvements and follow the results of the more adventuresome individuals that frequent this forum.


Well stated!

I believe the A7R has already opened up (high resolution) astro-imaging for under 60 sec exposures, at least it has for me (NM Album). The A7S can only improve upon this. The A7R gives me the same image quality at IS06400 as my Canon 60D at ISO1600. If the A7S pushes this to ISO25600, I'll be shooting 7.5 sec subs, or going deeper with 15-30 sec subs, or using a longer scope, whatever. If the A7S performance at ISO51200 is as good as the marketing hype, I'll be totally impressed :).

Astro-imaging is the wild west at the moment; probably has been since the invention of the digital camera...

bwa

#125 jdbastro

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Posted 21 June 2014 - 05:47 PM

Before I jump in and spend $5K+ for a near real time observing system consisting of OTA, mount, camera and software/UI, it will have to capture useful individual images in under 60 seconds (hopefully much shorter) and stack/process on the fly in a clean and simple manner. The various technologies are improving and slowly merging, and I think MY dream system might be available in a year or two. Whether a CMOS consumer camera or a dedicated, cooled astro CCD camera ends up in that system, I really couldn't say at this point. In the mean time, I will continue to entertain myself as I watch for the technology improvements and follow the results of the more adventuresome individuals that frequent this forum.


Since you are in the USA, for an extra $2500 ($2K intensifier, $500 housing), you could add a Gen 3 modern image intensifier and housing into the mix and get 100's of DSO's in well under 30 seconds with this new camera attached to the output of the intensifier.

Real-time video will also be within reach for very many DSO's.

This is my plan for the A7S. I already have tried this with a GH3 and A7. The added sensitivity of the A7S over the A7, A7R, GH3, & GH4, should dramatically improve real-time video. And the A7S' improved 1080p video codec should make for cleaner real-time video over the A7/A7R cameras.

A Gen 3 image intensifier and A7S camera should be a marriage made in heaven. And the wedding can be in July-2014, not several years from now.


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