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Sony A7s - New Low-Light Camera - Wow!

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#326 Traian

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Posted 14 August 2014 - 02:01 AM

We had one heck of a good lightning storm last night:

Video extracts from 30 minutes of A7S video

Slide show using 12 frame captures from video

Don't beat me up on the image/video quality. I forgot to set manual focus and automatic focus wandered all over the place. These are the best segments... :(

There are four full sized frame captures following the video in the album.

bwa

Hello Allan,

 

 

I have some good news for you and other A7S owners!

 

It seems that you can get rid of the Amp Glow even at ISO 51200 if you use the Silent Shutter instead of the Mechanical Shutter. Look at the bottom of the page here http://3d-kraft.com/...Itemid=2#update.

 

Hope this helps you guys.

 

Can you test and confirm this finding when putting the A7S in long exposure mode?



#327 ccs_hello

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Posted 14 August 2014 - 05:07 AM

I'd guess it's due to lower spatial resolution and bit depth in video recording mode, which implies less time sensor is in readout mode and less time sensor is in fully activated state (less heat generated by non-sensel part of the circuitry.)

Clear Skies!

ccs_hello

#328 RandyC

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Posted 14 August 2014 - 09:53 PM

I can't remember seeing this astrophotography review video by Ian Norman. He goes from video to a 10sec exposure of the Milky Way at various ISO settings. I saw the write up but not the video. https://www.youtube....h?v=mctD-hu4s9U

 

I am still looking forward to seeing 60sec-90sec DSO exposure at ISO 6000-12000 with full noise reduction.



#329 chasing photons

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Posted 15 August 2014 - 08:52 AM

I can't remember seeing this astrophotography review video by Ian Norman. He goes from video to a 10sec exposure of the Milky Way at various ISO settings.
 
I am still looking forward to seeing 60sec-90sec DSO exposure at ISO 6000-12000 with full noise reduction.



This is rather impressive as the video clip shows still images of 10 seconds or less using moderately fast f-stops (f/4) that compare well with typical time lapse images of 20 to 30 seconds using other cameras with fast (f/2), wide angle lenses. Once the initial excitement of its night sky real time video capabilities (impressive as they may be) wears off, I think we will see more still images in the 15 to 60 second range at lower ISO numbers with very little noise. This is where the A7S could produce beautiful images for near real time observing using a moderately fast (f/4) OTA on a tracking equatorial mount with no guiding required.

#330 RandyC

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Posted 15 August 2014 - 11:44 AM

It will be a game-changer. The larger pixels and advanced Sony sensor allow gain to be pushed with little noise. I have no doubt in my mind, there is a sweet spot, where 1min-3min exposures will be unbelievable.



#331 Dom543

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Posted 15 August 2014 - 12:23 PM

I asked this earlier but haven't gotten any answer. Could someone, who has access to one of these cameras, please answer if there is any way to sequentially download images resulting from consecutive still exposures. This is what would be needed to use the camera for near-live observing.

As I understand, the software support for this camera is rather limited at this point. It has some kind of SDK but due to the novelty of the camera and to its high price independent software developers have not taken up on the opportunity.

Thank you,
--Dom

#332 bwallan

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Posted 15 August 2014 - 07:21 PM

 

We had one heck of a good lightning storm last night:

Video extracts from 30 minutes of A7S video

Slide show using 12 frame captures from video

Don't beat me up on the image/video quality. I forgot to set manual focus and automatic focus wandered all over the place. These are the best segments... :(

There are four full sized frame captures following the video in the album.

bwa

Hello Allan,

 

 

I have some good news for you and other A7S owners!

 

It seems that you can get rid of the Amp Glow even at ISO 51200 if you use the Silent Shutter instead of the Mechanical Shutter. Look at the bottom of the page here http://3d-kraft.com/...Itemid=2#update.

 

Hope this helps you guys.

 

Can you test and confirm this finding when putting the A7S in long exposure mode?

 

Amp glow is present to about the same degree with Silent Shutter as it is with Mechanic Shutter; at least my findings.

 

And since you cannot use Long Exposure Noise Reduction in Silent Shutter mode you can't even automatically remove the amp glow.  Long Exposure Noise Reduction does work with Mechanical Shutter and does a reasonable job eliminating amp glow but does double the time per exposure.

 

My personal feeling towards A7S Silent Shutter mode is that it was thrown in as an afterthought by Sony as the result of all the discussion around shutter vibration on the A7R (which I have yet to see!).  It is not at all well integrated into the A7S features or apps, in fact it doesn't work with the Time-Lapse Camera App or in Bulb Mode where it would be the most useful (at least for me).  As a result I have sort of forgotten about all the nice things that Silent Shutter was supposed to do and pretty much use Mechanical Shutter for most of my shooting.  It does work with both my wired remote timer and Trigger Trap; one redeeming quality!

 

bwa 



#333 bwallan

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Posted 15 August 2014 - 07:31 PM

Since this thread is in the EAA forum, I assume that the results of the successive exposures can be seen in near real time and continually updated. Either on an attached monitor or on a computer.

 

How does this exactly happen? Suppose I want to use 30 sec exposures and have a monitor or a computer. Does the camera have an output jack through which the image resulting from the most recent exposures are accessible? Or does it come with software to do this from a computer?

 

Thank you,

--Dom

I just connect an old computer monitor (1920x1200 resolution) to the HDMI port on the camera.  You get two different outputs:

1) Normally you simply see the LiveView screen output to the external monitor; same resolution as the liveview screen.

2) When you play back video you see the full resolution video on the monitor.

 

bwa



#334 bwallan

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Posted 15 August 2014 - 07:40 PM

Has anyone tried long exposures at the A7S base ISO? 

What is a "long" exposure?  And what is the A7S "base ISO"?

 

I have always taken "base ISO" and "native ISO" with a large degree of skepticism, and have always shot at ISO's that are well in excess of so called Native ISO's.  In fact it has been found astro-imaging subs are often considerably better at ISO's higher than base ISO's.

 

There was a recent discussion of this on the Yahoo ImagesPlus forum (Aug 14-15th).

 

bwa



#335 bwallan

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Posted 15 August 2014 - 07:46 PM

 

I can't remember seeing this astrophotography review video by Ian Norman. He goes from video to a 10sec exposure of the Milky Way at various ISO settings.
 
I am still looking forward to seeing 60sec-90sec DSO exposure at ISO 6000-12000 with full noise reduction.



This is rather impressive as the video clip shows still images of 10 seconds or less using moderately fast f-stops (f/4) that compare well with typical time lapse images of 20 to 30 seconds using other cameras with fast (f/2), wide angle lenses. Once the initial excitement of its night sky real time video capabilities (impressive as they may be) wears off, I think we will see more still images in the 15 to 60 second range at lower ISO numbers with very little noise. This is where the A7S could produce beautiful images for near real time observing using a moderately fast (f/4) OTA on a tracking equatorial mount with no guiding required.

 

Totally agree!  The camera excels at subs in the 15-60sec range and ISO's in the order of 3200-12800 (personal experience).  And I haven't had to fire up my guide system since I acquired either the A7R or A7S; lovely sense of freedom!!

 

bwa



#336 bwallan

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Posted 15 August 2014 - 07:59 PM

I asked this earlier but haven't gotten any answer. Could someone, who has access to one of these cameras, please answer if there is any way to sequentially download images resulting from consecutive still exposures. This is what would be needed to use the camera for near-live observing.

As I understand, the software support for this camera is rather limited at this point. It has some kind of SDK but due to the novelty of the camera and to its high price independent software developers have not taken up on the opportunity.

Thank you,
--Dom

You can (sorta) do this with the Smart Remote Control Camera App for the Sony A7 series.  It allows you set a few camera parameters, take a picture and have the image downloaded to the device being used, i.e.: a smart phone or iPad.  I've tried it with an iPad; works.  There are also two other Camera Apps that might be applicable to your question.  Take a look at https://www.playmemoriescameraapps.com/portal/.

 

I did take a look at the available SDK but found it is fairly limited, almost as if they don't want to give away any features they might develop in the future...?

 

bwa



#337 RandyC

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Posted 15 August 2014 - 08:08 PM

 

 

I can't remember seeing this astrophotography review video by Ian Norman. He goes from video to a 10sec exposure of the Milky Way at various ISO settings.
 
I am still looking forward to seeing 60sec-90sec DSO exposure at ISO 6000-12000 with full noise reduction.



This is rather impressive as the video clip shows still images of 10 seconds or less using moderately fast f-stops (f/4) that compare well with typical time lapse images of 20 to 30 seconds using other cameras with fast (f/2), wide angle lenses. Once the initial excitement of its night sky real time video capabilities (impressive as they may be) wears off, I think we will see more still images in the 15 to 60 second range at lower ISO numbers with very little noise. This is where the A7S could produce beautiful images for near real time observing using a moderately fast (f/4) OTA on a tracking equatorial mount with no guiding required.

 

Totally agree!  The camera excels at subs in the 15-60sec range and ISO's in the order of 3200-12800 (personal experience).  And I haven't had to fire up my guide system since I acquired either the A7R or A7S; lovely sense of freedom!!

 

bwa

 

Brian, I know you have your stacking way. When I get the chance, I am going to go for 120secs, full noise reduction and no stacking. I just bought a new mount so I am going to go slow with this purchase. But I am looking forward to it. You give us all something to look forward to.



#338 bwallan

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Posted 15 August 2014 - 08:15 PM

Super Moon - August 9-12, 2014 Album

 

The super moon of the past few days was a great time to test both the A7R and A7S for resolution, image quality and capabilities.  Two nights had close to excellent sky conditions.  Two not so good... but I could still see the moon (or at least moonlight).

 

The above album contains both A7R and A7S images with various combination of lens/telescopes, mounted/handheld.  The captions to the images provide the shooting details.

 

All the images in the above album were shot with either a Sony A7R or A7S.  With the exception of the two sunset images, all are shots of/under the Super Moon; either the moon itself or scenes under moonlight. No artificial lighting was used!  Some of them may look like they were taken in the daytime...  They weren't!

 

Almost all of the A7S images were shot handheld and consist of individual images (single & panoramas), aligned & stacked video or video frame grabs. ISO's range from 200 to 102400.  Most of the video was shot at 1/30sec exposure & ISO 51200 or 1/60sec & ISO 102400.

 

A few of them turned out not too bad. A lot of them are total crap BUT one has to try a few oddball (some would call them weird) shots to see what a camera will do...

 

Enjoy!

 

bwa



#339 bwallan

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Posted 15 August 2014 - 08:26 PM

 

 

 

I can't remember seeing this astrophotography review video by Ian Norman. He goes from video to a 10sec exposure of the Milky Way at various ISO settings.
 
I am still looking forward to seeing 60sec-90sec DSO exposure at ISO 6000-12000 with full noise reduction.



This is rather impressive as the video clip shows still images of 10 seconds or less using moderately fast f-stops (f/4) that compare well with typical time lapse images of 20 to 30 seconds using other cameras with fast (f/2), wide angle lenses. Once the initial excitement of its night sky real time video capabilities (impressive as they may be) wears off, I think we will see more still images in the 15 to 60 second range at lower ISO numbers with very little noise. This is where the A7S could produce beautiful images for near real time observing using a moderately fast (f/4) OTA on a tracking equatorial mount with no guiding required.

 

Totally agree!  The camera excels at subs in the 15-60sec range and ISO's in the order of 3200-12800 (personal experience).  And I haven't had to fire up my guide system since I acquired either the A7R or A7S; lovely sense of freedom!!

 

bwa

 

Brian, I know you have your stacking way. When I get the chance, I am going to go for 120secs, full noise reduction and no stacking. I just bought a new mount so I am going to go slow with this purchase. But I am looking forward to it. You give us all something to look forward to.

 

With a good mount you should be able to get good 1-3 min. subs with a reasonable polar alignment and no guiding, depending upon the focal length you're using.  Not too sure what focal ratio and ISO you're planning on using BUT a 120 sec. exposure should capture anything you want to shoot.  The maximum exposure I've ever used with the A7S is 60 sec and that is with an f/8 scope!

 

I would not recommend using High ISO Noise Reduction on any camera.  Long Exposure Noise Reduction does a reasonable job of replacing Darks but does double your time per image.  Multiframe Noise Reduction works quite nicely if your tracking is good.

 

I'm assuming you'll be using an A7S?  You'll have a ball...

 

bwa



#340 RandyC

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Posted 18 August 2014 - 03:02 PM

Could someone explain how you can mount this camera directly at the telescope rear cell (say C8, C11) and achieve focus. With an eyepiece or video camera, you have to have the correct spacing with either a diagonal or extender. thanks.



#341 jdbastro

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Posted 18 August 2014 - 11:39 PM

Could someone explain how you can mount this camera directly at the telescope rear cell (say C8, C11) and achieve focus. With an eyepiece or video camera, you have to have the correct spacing with either a diagonal or extender. thanks.

A t-mount to nex adapter should get you most of the way.  After that it's like any other kind of SLR/DSLR with a t-ring attached to the camera body.

 

Try this part for example.


Edited by jdbastro, 18 August 2014 - 11:40 PM.


#342 RandyC

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Posted 19 August 2014 - 08:21 AM

I was really wondering if you or someone can explain how it focuses without the extra spacing typically required with an eyepiece or video camera.



#343 Relativist

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Posted 22 August 2014 - 03:25 PM

It looks like this camera outputs Ultra HD resolution, so I was thinking, it might be worth trying it out with an Ultra HD, giving an eyepiece some decent competition. A shootout might be in order.  In addition, I've noticed that prices for 4k televisions in the smaller sizes have fallen quite a bit, for example this Samsung is ~$1000:

 

http://www.samsung.c.../UN40HU6950FXZA



#344 RandyC

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Posted 22 August 2014 - 08:46 PM

Video exposures are only a max of 0.5sec. You are better off using standard 12Mp resolution and outputting to a computer monitor. That way you can lengthen the exposures to a minute or two. I still am not sure if the camera will work on DSOs with simple short single exposures. 



#345 Relativist

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Posted 22 August 2014 - 08:55 PM

True Randy, but how does it compare to naked eye? Any improvement is welcome, and this would be a good way to share. Hopefully as time goes on we will have more capabilities. Can't the camera output what it has saved? With some smart control software scrolling through as images are taken we might get close. I wonder if the SDK allows for that.

#346 Dom543

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Posted 22 August 2014 - 10:38 PM

For a $2500 price tag that improvement better be substantial...

The high price will mean a smaller user base and hence not much incentive for software developers. Don't expect a BackyardA7S. Users will have to depend on (and hope for) software provided by Sony.

 

--Dom



#347 Relativist

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Posted 23 August 2014 - 12:57 AM

That's true Dom, I have PMed the BYEOS developer and he said no plans at this time.

I'm thinking more along the lines of either the DSS observer toolbar, or just simply using the SDK to allow for the output via HDMI or USB that we want.

As for the 4k view, it obviously can't go out to NSN but that's ok.

I wish I had budgeted for one, but I'm certainly rooting for those that are trying them out.

#348 bwallan

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Posted 23 August 2014 - 01:10 AM

I was really wondering if you or someone can explain how it focuses without the extra spacing typically required with an eyepiece or video camera.

It doesn't!

 

bwa



#349 bwallan

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Posted 23 August 2014 - 01:15 AM

Video exposures are only a max of 0.5sec. You are better off using standard 12Mp resolution and outputting to a computer monitor. That way you can lengthen the exposures to a minute or two. I still am not sure if the camera will work on DSOs with simple short single exposures. 

Not too sure what you mean by "I still am not sure if the camera will work on DSOs with simple short single exposures."  It definitely works or you couldn't take multiple subs for stacking.  As to the quality of individual subs, this is a personal call.  Personally I would not be happy with individual subs (as an end product) but they're far better than those I ever got off a Mallicam Xtreme but I'm talking about 30sec exposures not 5-7 sec.

 

bwa



#350 bwallan

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Posted 23 August 2014 - 01:26 AM

...

Can't the camera output what it has saved? With some smart control software scrolling through as images are taken we might get close. I wonder if the SDK allows for that.

All of the A7 Series cameras can output whatever is on the LiveView screen or captured video to the HDMI port for display or capture.  The camera can also be controlled by WiFi using a smart phone or tablet for both shooting and display of captured images.  So the SDK used by whoever developed the Camera App definitely allows this type of control/display.

 

bwa




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