# Sony A7s II - THE DSLR Killer?



## rigrx (Jun 24, 2015)

Read this:



> We have expectation that it will come with the improvement over few sections compared to its predecessor Sony Alpha 7S then it will definitely gain better response from the users.
> 
> Resolution – We expect that it will come with larger resolution (possibly 20MP) comparative to its predecessor‘s so that it can deliver high quality images with superior clarity and sharpness.
> 
> ...



This text shown, is from this source: http://www.cameracomparisonreview.com/2015/06/21/sony-a-7sii-coming-soon/

I am a Canon user but I am waiting for the second generation of Sony A7S camera. They managed to triple the ISO sensitivity of the A7R camera and also managed increased resolution from 36 to 42.... by the implementation of BSI tech in FF sensor... A Sony a7s II with ISO 819200 would be crazy! What do you think? Do you think, that canon would compete with the 5D IV? 

Also see Sony managers interview here - http://thenewcamera.com/sony-a7s-ii-aroma-coming-from-sony-managers-interview/

I want to buy a new camera this year and there are 3 cameras which would be in my list. The 5D IV, when it is as good a the a7r II with less mp and better ISO performance, the a7r II and the a7s II. What do you think? Which one to get? Would be the a7s II also a DSLR killer? ???

EDIT: Another really informative article from Sony Senior General Manager Kimio Maki: http://www.sonyalpharumors.com/tele-fe-and-brighter-primes-are-high-on-the-priority-list/


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## 9VIII (Jun 24, 2015)

It's going to be interesting seeing what resolution the A7SII is going to be, and whether they implement IBIS, which ruined the high ISO performance of the A7II (it's more than a stop worse than cameras like the 6D).
A jump from 12MP to 20MP would reduce low light performance by just about a stop, I almost think they would be better off keeping it at 12MP, if you're going to make a dedicated low-light camera you may as well go all the way. You also get native 4K recording at 12MP. It still seems like the right choice for the moment.


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## m (Jun 24, 2015)

We need a new system for ISO, these numbers are getting silly.


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## bedford (Jun 24, 2015)

m said:


> We need a new system for ISO, these numbers are getting silly.



We need a new topic, these postings are getting silly.

I'm really getting tired of reading about "DSLRs killers" and that Canon is ******* and that we all need the DR only Sony's EXMOR can deliver, etc.. These postings are not informative any more (we've read the contents a thousand times before) and they're not even entertaining.

Why is it that people on the Internet have to make a holy war out of everything? In the real world I don't get bashed for using a Canon DSLR.

It is getting quite senseless to visit sites like dpreview and canonrumors. Nothing to be learned anymore which might be relevant to my photography.

<end of rant>

Oliver


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## tolusina (Jun 24, 2015)

bedford said:


> ....Why is it that people on the Internet have to make a holy war out of everything?....


Hmmm......
There's a perspective that causes me to suddenly appreciate the DR flame wars etc..
There's no blood drawn here, no lives senselessly lost, compare to a real holy war.
---
Back on topic, sure, mirror slappers will become obsolete, but it's going to be a while yet, don't be anxious or impatient.


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## 3kramd5 (Jun 25, 2015)

"
It is expected that the ISO sensitivity should be at least double or triple"

By whom? Are they just taking the increase from the 7R to 7R2 and assuming it will apply equally to the 7S2?

Meh, silly article to match the silly title.


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## unfocused (Jun 25, 2015)

I wish we could consolidate all these Sony fanatic threads into one, that way they wouldn't clutter up this forum. 

One thing that's amusing is that clearly these Sony lovers don't even read the interviews with the Sony executives. Read carefully the interview with Sony Senior General Manager Kimio Maki. His message can be summed up like this: "Yeah, our cameras aren't as good as DLSRs yet, but someday they will be. And, yeah, our lenses aren't as good as Canon, but hey, we are trying to get better."

Then, yesterday I got a copy of Popular Photography which was packaged with a special Sony advertising magazine. I looked through it and thought: these pictures sure look grainy and soft. If this company is supposed to have such magical sensors, the pictures sure don't show it. You would think that if they are trying to showcase their technical superiority, they would make sure the images were technically the best that could be achieved with their camera. But then again...maybe those *were* the best that could be done with their camera.


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## 3kramd5 (Jun 25, 2015)

9VIII said:


> I almost think they would be better off keeping it at 12MP, if you're going to make a dedicated low-light camera you may as well go all the way. You also get native 4K recording at 12MP. I



It's crippled if it doesn't have internal 6k raw uncompressed video.


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## Mt Spokane Photography (Jun 25, 2015)

dilbert said:


> 9VIII said:
> 
> 
> > ... I almost think they would be better off keeping it at 12MP, if you're going to make a dedicated low-light camera you may as well go all the way. You also get native 4K recording at 12MP. It still seems like the right choice for the moment.
> ...



The BSI tech is beneficial for very tiny photosites, where the traces between the miniscule photosites take up a disproportionate amount of space, so a 12 MP sensor would have to be a really tiny one to benefit.

The Stacked technology was another one that Sony claimed would benefit tiny pixels. 

From what I've read, a large photosite sensor like the 12 mp one would have a almost negligible benefit.


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## 3kramd5 (Jun 25, 2015)

Mt Spokane Photography said:


> dilbert said:
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> > 9VIII said:
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From a geometrical standpoint it (BSI) is certainly a question of diminishing returns as pixel size increases. Whether it's negligible remains to be seen, but as I read the following, it appears Sony management thinks they've reached the point at which pixel area is irrelevant. I suspect he's just blowing gas, since physics would seek to contradict him, but maybe that's their position, and any improvements will come from deeper wells.



> Sony Senior General Manager of the Digital Imaging Business Group Kimio Maki:
> We wanted to overcome the idea that has been prevalent since as long as there have been digital cameras, that you can have one virtue [resolution] or the other [sensitivity] but you can never have both.


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## emko (Jun 25, 2015)

unfocused said:


> I wish we could consolidate all these Sony fanatic threads into one, that way they wouldn't clutter up this forum.
> 
> One thing that's amusing is that clearly these Sony lovers don't even read the interviews with the Sony executives. Read carefully the interview with Sony Senior General Manager Kimio Maki. His message can be summed up like this: "Yeah, our cameras aren't as good as DLSRs yet, but someday they will be. And, yeah, our lenses aren't as good as Canon, but hey, we are trying to get better."
> 
> Then, yesterday I got a copy of Popular Photography which was packaged with a special Sony advertising magazine. I looked through it and thought: these pictures sure look grainy and soft. If this company is supposed to have such magical sensors, the pictures sure don't show it. You would think that if they are trying to showcase their technical superiority, they would make sure the images were technically the best that could be achieved with their camera. But then again...maybe those *were* the best that could be done with their camera.



you sound very salty, "But then again...maybe those *were* the best that could be done with their camera." haha come on man you really think that? when we all know the Sony sensor is currently the best please don't tell me those images would of had turned out better on a Canon. In shots where you can use ISO 100 and don't need the DR Canons 5Ds will be sharper i bet, but once you need some ISO A7rIi is going to look better and the DR.


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## emko (Jun 25, 2015)

Sorry i don't think DSLR is going to die i mean look at the A7rII its almost the same as a DSLR in size, the lenses are not that much smaller. Maybe DSLR will get some hybrid viewfinder so we get best of both worlds but i think DSLR will last at least 10 more years. Maybe batteries will have such high capacity that EVF cameras will be just as good as DSLR.

Is it more expensive to produce a DSLR? if a EVF becomes very very good i think they just might replace them but i am not sure if the cost is that much.

Then again EVF cameras will have increased frame rates that might get the sport shooters guys to switch over and force Canon to produce a EVF camera for them?


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## Hillsilly (Jun 25, 2015)

Yes, the A7sii will definitely kill the DSLR. All the people who would otherwise be buying <$1k Canon DSLR with 2 kit lens kits are probably very excited about the prospect of dropping $6k+ on the Sony and a couple of lenses.


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## JohnDizzo15 (Jun 25, 2015)

Hillsilly said:


> Yes, the A7sii will definitely kill the DSLR. All the people who would otherwise be buying <$1k Canon DSLR with 2 kit lens kits are probably very excited about the prospect of dropping $6k+ on the Sony and a couple of lenses.



Exactly. LOL. I love what Sony is doing with regard to lifting the whole (tech) boat, but to think that what they are doing with their high end is going to kill the DSLR is illogical. 

People will continue to buy the box at Costco, Target, Best Buy, Walmart, Sam's, etc. A complete setup for the average income family for under 1k is not in the same market position as a setup where the body itself will start at a minimum of $3200 before we get to lenses. Based on the pricing scheme from the first round, I'd imagine the a7s2 will actually be a few hundred more than that.


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## mistaspeedy (Jun 27, 2015)

I recently got an ancient Canon 20D. I have been able to take some nice images with it during the past few months. However, since the Sony A7s II was announced, literally overnight, I noticed that my camera would no longer take good images, and that my 20D is basically 'dead'.

This is how the Sony A7s II killed my DSLR.

I'm sure that the millions of other DSLR users out there have had exactly the same experience with their cameras being killed overnight, and that their only option to ever take a good photograph again is to buy the Sony A7s II.

I am also sure that the millions of Canon, Nikon and other camera body and lenses in the world right now will simply disappear overnight and that everyone will jump to Sony mirrorless.

Personally, I don't even think that the Sony A7s III or Sony A7s IV - no matter how good they might be, will 'kill' the DSLR during the next few years... we're not there yet.


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## wockawocka (Jul 2, 2015)

Amusing to see the same rants and flames going on.

Look at the bigger picture, Sony are pushing boundaries of camera tech, good luck to them. Hopefully other manufacturers will get a spanking and up their game making it better for everyone.

The biggest issues I have with the A7 series is the lack of dual card slots, build quality and compressed raw files. Mines already got issues 4 weeks into ownership.

But it's something I'm willing to live with in a few cases as only this camera will do the job I need it to. Like 135L handheld in a church at 1/60 sec.

Each to their own.


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## Mt Spokane Photography (Jul 2, 2015)

I'd be more interested in this camera than the A7s, which is a flop. My local camera dealer has them sitting unsold. I'd be even more interested if Canon made one with their higher reliability and better customer service. I could reliability use my Canon lenses on it too.


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## benperrin (Jul 3, 2015)

wockawocka said:


> Amusing to see the same rants and flames going on.
> 
> Look at the bigger picture, Sony are pushing boundaries of camera tech, good luck to them. Hopefully other manufacturers will get a spanking and up their game making it better for everyone.
> 
> ...


What issues have you had with them? This is one thing I'm unsure of. My 5dsr is taking ages (or at least it feels like it) to come in so I considered cancelling and getting the a7rII. I made a list of pros and cons and decided that the 5dsr was a better fit for me but I'd love to hear more about the ergonomics and potential issues the Sony's might have as I'll probably add one to my collection at some point.


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## wockawocka (Jul 3, 2015)

benperrin said:


> wockawocka said:
> 
> 
> > Amusing to see the same rants and flames going on.
> ...



Hi Ben, I took my 645z and A7ii to Iceland and put it through their respective paces. About halfway through the trip when I went to view an image on the A7 it started to flick through the images all by itself (suggesting water ingress) and the wheel at the back of the camera that can click left, right, up and down to confirm pressure no long does it on the left side.

Sure, not everyone is going to shoot waterfalls with it but it's not weather sealed. Lots of fabulous features on the camera that means it's worth keeping but is absolutely and without question NOT a professional build camera. The worst it was subjected to was heavy mist. I never changed the lens on it either.

Making a 42mp camera and targeting landscapers who shoot in all weathers is a bit silly imho. So I'm probably going to hold out for the A9 if it turns out to be a true rumor. It's not so much about the size of the body for me but how robust it is. 

I'm ready to jump brands but I need something secure to jump to. Right now the Sony's fall over at the most important step for me, build quality, dual card slots and jog dial AF selection points. (rather than their current more convoluted way).


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## IglooEater (Jul 3, 2015)

wockawocka said:


> benperrin said:
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Hmm, I'd be interested in knowing if it was indeed water that got into your camera. I've had a 60d (not weather sealed) with a non-weather-sealed lens out in pouring rain for a couple hours shooting a waterfall and never had an issue. I thought Sony pretty much just had battery life to work out before getting my money, but maybe there's more to it..


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## jrista (Jul 3, 2015)

3kramd5 said:


> From a geometrical standpoint it (BSI) is certainly a question of diminishing returns as pixel size increases. Whether it's negligible remains to be seen, but as I read the following, it appears Sony management thinks they've reached the point at which pixel area is irrelevant. I suspect he's just blowing gas, since physics would seek to contradict him, but maybe that's their position, and any improvements will come from deeper wells.



From what I have read about Sony's BSI technology, it is about more than simply increasing photodiode area. The design of putting all the logic and wiring on the opposite side of the photodiodes, and having more room within which to layout all that circuitry, has apparently allowed them to improve the electronics as well, signaling and current & voltage levels and things like that, making the electronic signal that drives the sensor less noisy. The noisiness of the signals that drive the electronics affect noise in the image as well, so BSI is important for other reasons than increasing light sensitivity. Apparently, it also improves SNR by lowering noise.


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## 3kramd5 (Jul 3, 2015)

jrista said:


> 3kramd5 said:
> 
> 
> > From a geometrical standpoint it (BSI) is certainly a question of diminishing returns as pixel size increases. Whether it's negligible remains to be seen, but as I read the following, it appears Sony management thinks they've reached the point at which pixel area is irrelevant. I suspect he's just blowing gas, since physics would seek to contradict him, but maybe that's their position, and any improvements will come from deeper wells.
> ...



Right, there is a lot more going on that *just* BSI. Still, his statement implies that Sony users need not trade sensitivity for resolution for sensors using this tech. I imagine a future product will prove him wrong.



benperrin said:


> My 5dsr is taking ages (or at least it feels like it) to come in so I considered cancelling and getting the a7rII.



I bet you'll get the 5DSR before I get my A7R2. When I pre ordered it on June 17, the confirmation (BH) said "New Item - Coming Soon", and the website estimated a ship date of July 29. It now says August. Sony's website says August 26, and others say August 30.

I updated my BH order, and the new confirmation changed the verbiage to "New Item, Available for pre-order 08/01/15." I don't know if that means they aren't taking *new* pre-orders until August.


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## jrista (Jul 3, 2015)

3kramd5 said:


> jrista said:
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Once the entire sensor surface is light sensitive, then technically speaking he is correct. Fill factor is no longer a concern with BI designs. On a normalized basis, the full sensor surface is going to gather the same amount of light for a given subject framing, regardless of what size the pixels are. Now, if Sony manages to overcome noise scaling (which they seem to have done to a small degree so far in some of their cameras), then it is possible that larger pixels may have better DR and SNR (because they have a larger FWC). In that circumstance, larger pixels would still be better for low light photography.

If the A7s II hits with big pixels, and ~3-6e- RN at ISO 100, then I'll believe Sony has indeed overcome noise scaling issues, and the A7s II would probably be the best low light performer on the market. At the moment, the A7s has higher starting read noise, so I'm not sure that bigger pixels will actually perform better than smaller pixels on a normalized basis with a BSI design.


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## 3kramd5 (Jul 3, 2015)

jrista said:


> 3kramd5 said:
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BSI essentially maximizes fill factor, but it doesn't negate he charge capacity of a large pixel vs a small pixel of the same technology. In any case, future Sony products will show whether his statement is accurate or not. If there is a forthcoming product (A7S2 or whatever) which has a 135-format frame, similarly-designed BSI sensor with copper traces, less than 42MP, which offers more than 100k ISO, his statement is false. If I were a betting man, i would bet on that being the case. Time will tell. It doesn't matter much to me, but I bet an A7S2 with low RN BSI pixels and high framerate would be great for Astro. 

Edit: they do seem to be marketing with the same notion. See attached: I read that as "you get resolution without compromising (sensitivity)." Perhaps there won't be a 7S sequel, or perhaps it won't have better sensitivity but rather better video (unbinned full frame 4k high framerate or whatever).


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## benperrin (Jul 4, 2015)

wockawocka said:


> Hi Ben, I took my 645z and A7ii to Iceland and put it through their respective paces. About halfway through the trip when I went to view an image on the A7 it started to flick through the images all by itself (suggesting water ingress) and the wheel at the back of the camera that can click left, right, up and down to confirm pressure no long does it on the left side.
> 
> Sure, not everyone is going to shoot waterfalls with it but it's not weather sealed. Lots of fabulous features on the camera that means it's worth keeping but is absolutely and without question NOT a professional build camera. The worst it was subjected to was heavy mist. I never changed the lens on it either.
> 
> ...



Thanks for the info. I'm not convinced yet that these round of Sony cameras are better than DSLR's just yet. The dual card slots is an issue for me but the rumour is that the a7rII can't use a single focus point when using a third party adapter with Canon lenses instead it has to use all the points (if that makes sense). Seems like there are compromises with either system. Also all the Sony marketing shots I've been able to find are at iso 100. I feel like I can't trust the Sony Artisans to be even slightly objective either. So at this point the 5dsr is ahead for me but I'll probably add an a7rII at some point.


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## jrista (Jul 4, 2015)

3kramd5 said:


> BSI essentially maximizes fill factor, but it doesn't negate he charge capacity of a large pixel vs a small pixel of the same technology.



No, it does not negate the charge capacity differences. However, in a normalized comparison, charge capacities are moot anyway. If we assume we have two BSI sensors, FF, one with 10 micron pixels and the other with 5 micron pixels. Let's assume we have normal noise scaling as well, so 12e- RN for the 10 micrin and 6e- RN for the 5 micron. If we downsample the image from the sensor with smaller pixels to the same size as the image from the sensor with larger pixels, there will be ZERO difference in SNR. 

Here's the proof. The formula for SNR:


```
SNR = (PixelSignal * AveragedPixelCount)/SQRT(AveragedPixelCount * (PixelSignal + ReadNoise^2))
```

If we apply this formula for our two sensors, we would have to assume that the 10 micron pixels get four times the signal. If we are talking 18% gray midtones, that may be 50ke- for the 10 micron pixels, which leaves us with 12.5ke- for the 5 micron pixels. Then we have:


```
SNRsmall = (12500e- * 4)/SQRT(4 * (12500e- + 6e-^2)) = 223.29:1 = 49.98dB
SNRlarge = (50000e- * 1)/SQRT(1 * (50000e- + 12e-^2)) = 223.29:1 = 46.98dB
```

For a subject, framed the same, exposed the same, at the same ISO, scaled to the same output magnification (larger image downsampled to the same size as smaller image)...there is no difference in the amount of light gathered. With an FSI sensor, you would have to knock off some percentage of the maximum signal, and factor in a small loss of light from vignetting in the physical pixel well from the wiring and transistors (even with a microlens). With BSI, you don't have those problems (you can have other problems, like color crosstalk, but that's different.) Without the fill factor issue, it doesn't matter if you have large or small pixels. The total SNR from both sensors on a normalized basis is the same.


In any case, future Sony products will show whether his statement is accurate or not. If there is a forthcoming product (A7S2 or whatever) which has a 135-format frame, similarly-designed BSI sensor with copper traces, less than 42MP, which offers more than 100k ISO, his statement is false. If I were a betting man, i would bet on that being the case. Time will tell. It doesn't matter much to me, but I bet an A7S2 with low RN BSI pixels and high framerate would be great for Astro. 

Edit: they do seem to be marketing with the same notion. See attached: I read that as "you get resolution without compromising (sensitivity)." Perhaps there won't be a 7S sequel, or perhaps it won't have better sensitivity but rather better video (unbinned full frame 4k high framerate or whatever).
[/quote]


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## 3kramd5 (Jul 4, 2015)

But in downsampling to normalize, you have specifically traded resolution for that SNR. Verifying that Sony has overcome pixel pitch when it comes to sensitivity must be done at native resolution.


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## jrista (Jul 5, 2015)

3kramd5 said:


> But in downsampling to normalize, you have specifically traded resolution for that SNR. Verifying that Sony has overcome pixel pitch when it comes to sensitivity must be done at native resolution.



That's not actually true. You traded image dimensions for SNR. You have not, however, traded resolution. Resolution and image dimensions are not the same thing.

Have you ever downsampled a larger image to smaller dimensions? Blurring occurs at certain frequencies. In the case of a bayer array, it's going to occur at roughly 3x the pixel pitch. The amount of blurring that occurs in my hypothetical 10 micron sensor, which is greater than the amount of blurring that occurs in my hypothetical 5 micron sensor, is BAKED INTO the signal. You can try to deconvolve, but that will only get you so far. You sampled the original information at a lower level, and you can only recover so much. Information you never had in the first place...well, no amount of code will ever 'restore' that. 

The higher resolution sensor, however, DID gather more information, at a finer scale. That finer scale is not really lost when you downsample. It's refactored, the greater amount of information is redistributed, but it is not lost. Compare the downsampled 5 micron image to the original 10 micron image...the SNRs will be the same, but the higher resolution sensor DID have more fine scale information, and that information is factored into the downsampled results. It WILL look sharper, clearer, and more detailed than the 10 micron image.


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## 3kramd5 (Jul 5, 2015)

jrista said:


> 3kramd5 said:
> 
> 
> > But in downsampling to normalize, you have specifically traded resolution for that SNR. Verifying that Sony has overcome pixel pitch when it comes to sensitivity must be done at native resolution.
> ...



But that's true of all sensors, from brand new full frame exmor R to decade-old canon 500nm FSI sensors. Sure, maybe that's what he was getting at, but in the context of promoting new tech that would be a fairly disingenuous.


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## jrista (Jul 5, 2015)

3kramd5 said:


> jrista said:
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What? ???

Were talking about the benefits of a BSI sensor design in a full frame camera. The benefit is that it eliminates fill factor as an issue. With BSI, that is no longer a concern. Therefor, pixel size is effectively immaterial. If you want the sensitivity of a lower resolution sensor, no problem: downsample. If you want maximum resolution, no problem...you already have it. 

What's the complaint here? Big pixels, small pixels...with BSI, normalized SNR is going to be the same regardless. Therefor, why would you ever opt for smaller pixels? They are less flexible. You cannot magically get more information out of the charge accumulated by larger pixels, however you can redistribute the information in smaller pixels to get more SNR.

The benefits are greater than that, though. You don't just gain die space for the light sensitive side. You also gain die space for the circuitry side. You don't have to pack all the circuitry into the borders between photodiodes. You can consume the entire die space. That opens up a whole lot more possibilities beyond simply greater sensitivity. Multiple pixel memories for increased dynamic range, per-pixel CDS or even per-pixel ADC, better wiring layouts to improve signaling efficiency and performance, who knows what else. There is absolutely zero reason not to use a BSI design if it's possible, regardless of the size of the sensor.


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## 3kramd5 (Jul 5, 2015)

So with FSI sensors, is the only advantage of larger pixels the higher fill factor? In other words, is well capacity irrelevant? Will RN always scale directly with pixel size?

I know we were discussing BSI, but everything you've laid out with respect to downsampling and its affect on SNR applies to all sensors; it is not unique to BSI, whereas I read his statement as an advantage afforded by BSI, not merely by the maths of downsampling.

If he meant "if you want high resolution, here it is. If you want higher SNR, just downsample the image," is that not some Mayeda could also say of the 5DS, for example?



jrista said:


> The benefits are greater than that, though. You don't just gain die space for the light sensitive side. You also gain die space for the circuitry side. You don't have to pack all the circuitry into the borders between photodiodes. You can consume the entire die space. That opens up a whole lot more possibilities beyond simply greater sensitivity. Multiple pixel memories for increased dynamic range, per-pixel CDS or even per-pixel ADC, better wiring layouts to improve signaling efficiency and performance, who knows what else. There is absolutely zero reason not to use a BSI design if it's possible, regardless of the size of the sensor.



Agreed, hence buying one sight unseen once a FF option surfaced


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## jrista (Jul 6, 2015)

Well capacity is much less of an important factor than you may think. So long as noise does scale as expected (and, in some cases, it may scale *better *with larger pixels), then you wouldn't see any difference in dynamic range or SNR. The reason for that is smaller pixels are seeing a smaller portion of the subject. A 10 micron pixel may be resolving a 2 by 2 arcsecond area of your subject. A five micron pixel, on the other hand, would only be resolving a 1 by 1 arcsecond area of your subject. The smaller pixel has less area, and thus lower FWC...but it's also only getting a quarter of the light. The whole entire system scales...so, assuming equivalent technologies in both sensors, well capacity isn't really a factor.

Yes, downsampling does affect every image, even from FSI sensors. The key factor with BSI is that fill factor no longer applies. Canon cannot say that about the 5Ds...and worse, Canon's fabrication process is still using 500nm, so the fill factor concern is very significant the smaller Canon's pixels get. With the 5Ds, despite having nearly 4.1 micron pixels, may not even have 3 micron photodiodes because there would be at least a 1 micron border around them, the space consumed by 500nm wiring and transistors. Sony could have the same light gathering diode area with 3.36 micron FSI pixels, which in FF would be a 10000x6667 pixel 66.7mp monster. With BSI, the pixels would need to be marginally larger than 3 microns, which would be a whopping 12000x8000 pixel 96mp behemoth.

Because fill factor does not apply with BSI, big pixels or small pixels, it doesn't really matter. Everything scales, so your gathering the same total light, any given unit-area of sensor has the same photon flux, and dynamic range is the same on a normalized basis. There may be some slight real-world nuances that result in very small differences, but in general...there would be little reason to choose bigger pixels over small if you had two cameras to pick from and that was the only difference. 

Now, there is more to the A7s than big pixels. It's been demonstrated that the A7s uses some kind of technology similar to Aptina's DRPix technology. DR Pix is dynamic range enhancement technology, operating along similar lines as MagicLantern's dual exposure (only better, more efficiently, and in the hardware). It doesn't kick in until after ISO 1600, however once it does kick in, it enhances dynamic range at higher ISO, which is why the A7s performs like a friggin powerhouse at ISO 400k. If the A7r II does not use this DR Pix like technology, then it is doubtful it would perform as well at high ISO. That said, we would once again be comparing apples and oranges...because there would be technology differences, rather than the same technology.


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## 3kramd5 (Jul 6, 2015)

jrista said:


> Because fill factor does not apply with BSI, big pixels or small pixels, it doesn't really matter. Everything scales, so your gathering the same total light, any given unit-area of sensor has the same photon flux, and dynamic range is the same on a normalized basis. There may be some slight real-world nuances that result in very small differences, but in general...there would be little reason to choose bigger pixels over small if you had two cameras to pick from and that was the only difference.
> 
> Now, there is more to the A7s than big pixels. It's been demonstrated that the A7s uses some kind of technology similar to Aptina's DRPix technology. DR Pix is dynamic range enhancement technology, operating along similar lines as MagicLantern's dual exposure (only better, more efficiently, and in the hardware). It doesn't kick in until after ISO 1600, however once it does kick in, it enhances dynamic range at higher ISO, which is why the A7s performs like a friggin powerhouse at ISO 400k. If the A7r II does not use this DR Pix like technology, then it is doubtful it would perform as well at high ISO. That said, we would once again be comparing apples and oranges...because there would be technology differences, rather than the same technology.



Interesting. Thanks for your thoughts!


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## benperrin (Jul 7, 2015)

jrista said:


> Now, there is more to the A7s than big pixels. It's been demonstrated that the A7s uses some kind of technology similar to Aptina's DRPix technology. DR Pix is dynamic range enhancement technology, operating along similar lines as MagicLantern's dual exposure (only better, more efficiently, and in the hardware). It doesn't kick in until after ISO 1600, however once it does kick in, it enhances dynamic range at higher ISO, which is why the A7s performs like a friggin powerhouse at ISO 400k. If the A7r II does not use this DR Pix like technology, then it is doubtful it would perform as well at high ISO. That said, we would once again be comparing apples and oranges...because there would be technology differences, rather than the same technology.



Hi Jon,

Have you decided to go with a Sony camera for your next camera or are you getting something else? I would love to hear your thoughts from an astro photography perspective. I haven't seen any high ISO examples from the a7rII which I would need to see before purchasing one. My 5dsr is still on pre-order with no release date given so I might consider the a7rII but at this stage the 5dsr is slightly ahead on paper for my needs.

Cheers,
Ben


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## Dylan777 (Jul 7, 2015)

1. a7rII with high MP and slower fps
2. a7sII lower MP, higher fps and higher ISO(more like 1Dx)

Forgot to mention. It WILL NOT kill DSLR


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## 3kramd5 (Jul 7, 2015)

benperrin said:


> I haven't seen any high ISO examples from the a7rII which I would need to see before purchasing one.



(Supposed) A7RII pics, heavily downsized.

Either it's way way way pre-production (EXIF date = january 1), it's got screwy firmware, or it's fake. Either way, nothing to make any judgments from.


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## benperrin (Jul 7, 2015)

3kramd5 said:


> benperrin said:
> 
> 
> > I haven't seen any high ISO examples from the a7rII which I would need to see before purchasing one.
> ...


Yeah, as you say still not much to go on. I'm sure it'll perform well at high ISO I'd just like to see it for myself before making any rash decisions.


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## jrista (Jul 7, 2015)

benperrin said:


> jrista said:
> 
> 
> > Now, there is more to the A7s than big pixels. It's been demonstrated that the A7s uses some kind of technology similar to Aptina's DRPix technology. DR Pix is dynamic range enhancement technology, operating along similar lines as MagicLantern's dual exposure (only better, more efficiently, and in the hardware). It doesn't kick in until after ISO 1600, however once it does kick in, it enhances dynamic range at higher ISO, which is why the A7s performs like a friggin powerhouse at ISO 400k. If the A7r II does not use this DR Pix like technology, then it is doubtful it would perform as well at high ISO. That said, we would once again be comparing apples and oranges...because there would be technology differences, rather than the same technology.
> ...



I am definitely getting at least one Sony camera. I would already have the A6000, however the rumors keep cropping up about the A6100 or A7000, and the specs for the AF on the newer model sounds amazing, so I've been holding out. If the A6100/7000 is pushed out too much longer, I'll probably just get a used A6000.

I am also pretty certain that an A7r II is going to be my landscape camera. I am not sure that I would spend $3200 on it...not because I don't think it's worth it, but because I simply have too many things I need to buy, and my money can only go so far.  I am hoping it will drop to $2800 or around there soon enough, and I'll probably pick one up. 

There are a number of reasons I'm so interested in Sony. I met a guy, Mike Malik, on an astro forum. He does DSLR and mirrorless astro modifications, so he's inside cameras from several brands all the time. He started modding Canon DSLRs, and was fairly impressed with the 6D. However, once he got his hands on a Sony (A7s I believe it was), he said on several occasions how blown away he was by the quality of them. The design, the internal layout and construction...he stated it was quite superior to how Canon builds their DSLRs. Not all the materials were ideal in some of the external cases, like the mount, but internally, apparently Sony cameras are EXTREMELY well built. 

On top of that, once A7s vs. 6D comparisons started to show up, the differences were STARK. The A7s trounces the 6D, hands down, no contest, game over. With 50% more, even double, the integration time in 6D images, compared to short exposures at quite high ISO on the A7s , the A7s produces far cleaner results, with deeper exposure, than the 6D can deliver. Results at ISO 2000 and 3200 from the A7s look at least as good as ISO 100 in your average daytime photography. It's just mind boggling how good the A7s is for astro.

Now, the A7 and A7 II...they don't seem to be delivering quite the same IQ. They are good, but only marginally better than the 6D. We think the primary difference is that the A7s uses that dynamic range enhancement technology at high ISO (something similar to Aptina's DRPix technology), whereas the A7/A7 II do not. The A7r also seems to do quite well, and it certainly delivers the resolution, but even on a normalized basis, it's still not quite as good as the A7s for astro. At the moment, I think the A7s is hands down the best ILC on the market for astro, especially when astro modded. Cleanest, deepest results you can get without going to full CCD (and even then, CCD cameras require more integration time to produce similarly clean results....the CCD advantages are thermal regulation and cooling, and being mono most of the time, so they support LRGB and narrow band filtration.) 



For the record, I have not seen Sony's lossy compression exhibit as a problem for astro very often. In very rare cases, you might find some compression artifacts around stars, but for the most part, the data once integrated appears very clean.

If you are interested in a Sony camera for astro, I would skip the A7/A7 II. Those will deliver marginally better quality than the 6D...and the 6D tends to be a much better buy. The A7s is really where it's at for astro on the Sony side. Phenomenal quality. We just recently had a discussion about using drizzle integration to increase the resolution of A7s images. The big pixels are great for high resolution imaging (bigger, longer scopes), but undersample with shorter scopes. Shorter scopes are much easier to image with, though. With drizzling, you can gain 50% or more resolution if you get enough subs, and process correctly. So you can get both the really clean results, as well as good resolution, by pairing the A7s with drizzle integration.


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## jrista (Jul 7, 2015)

Here are a couple of examples:

http://www.cloudynights.com/uploads/monthly_06_2015/post-205769-0-45448000-1435261812.jpg
http://www.cloudynights.com/uploads/monthly_06_2015/post-205769-0-36074400-1435261831.jpg

The top is the A7s, bottom is 6D. The A7s is 42 minutes of exposure at ISO 1600. The 6D is 60 minutes of exposure at ISO 1600. The 6D subs were gathered under darker skies, by about a factor of 1.6x, which is 1 2/3rds stops BETTER than the skies the A7s subs were gathered under. The 6D was modded with a "full spectrum" mod, which totally opens the sensor up to as much light as possible by entirely removing all the filters. The A7s was only a partial mod, which removed the primary IR cutoff filter, but left all the other filters in place, so there was still some filtering occurring. 

This scenario gave EVERY advantage possible to the 6D. The 6D has longer integration time by 43% (half a stop). The 6D was a full spectrum mod so it had no filtering of any kind, whereas with default filtering it doesn't even get 20% of the primary Hydrogen emission, Ha (hydrogen alpha) while the A7s still had it's first LPF filter in place which filteres out some Ha. The 6D was used under darker skies (nearly a pristine dark site, 21.2 mag/sq"), which reduces extra unwanted light signal, which reduces photon shot noise, whereas the A7s was used under skies that had a moderate amount of light pollution (20.0 mag/sq"). 

This all gives the 6D at least a two stop, if not a two and a half stop, advantage...and DESPITE all those advantages over the A7s...the A7s still produced a cleaner image, with more stars, with better colors, less background noise, and a deeper exposure.

Don't know about anyone else, but that is pretty telling to me. The technology Sony is packing into their cameras, whether all the external factors are perfect or not (lot of people on this forum bring up Sony's plastic mount as a major issue, for example), is truly phenomenal stuff.


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## StudentOfLight (Jul 7, 2015)

jrista said:


> Here are a couple of examples:
> 
> http://www.cloudynights.com/uploads/monthly_06_2015/post-205769-0-45448000-1435261812.jpg
> http://www.cloudynights.com/uploads/monthly_06_2015/post-205769-0-36074400-1435261831.jpg
> ...


Couple of questions:
1) Why do the two images have different magnification?
2) What do the histograms of the integrated files look like?


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## 3kramd5 (Jul 7, 2015)

StudentOfLight said:


> > The 6D was modded with a "full spectrum" mod, which totally opens the sensor up to as much light as possible by entirely removing all the filters. ...
> >
> > This all gives the 6D at least a two stop, if not a two and a half stop, advantage...and DESPITE all those advantages over the A7s...the A7s still produced a cleaner image, with more stars, with better colors...
> 
> ...



One more, possibly a stupid one, but that's fine:

3) If all the filters were removed, weren't the colors added in post (and thus is it fair to really compare them)?



benperrin said:


> Yeah, as you say still not much to go on. I'm sure it'll perform well at high ISO I'd just like to see it for myself before making any rash decisions.



Here are some raws: http://we.tl/X6ACE5UQem , https://www.dropbox.com/s/ub2jagdhl9blg5x/DSC09049.ARW?dl=0


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## jrista (Jul 7, 2015)

StudentOfLight said:


> jrista said:
> 
> 
> > Here are a couple of examples:
> ...



I don't have the original files, so I cannot say what the histograms look like. The images were processed with PixInsight, and integration radically changes the histograms. Pre-stretch, in linear mode, histograms look all bunched up to the left. Post-stretch, it would depend on the processing to some degree. The thing is, that's all in 32-bit float space, so that has little to do with the camera. A more reasonable question would be what do the histograms of the individual RAW images look like, as that would be closer to the hardware...but I don't have that information either.

The magnification differs very slightly. The image scales were normalized as much as possible, but we don't have zoom telescopes, so getting 100% identical image scales is basically impossible. They are off only by a small fraction, however, and as comparable as two deep sky images can be.


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## jrista (Jul 7, 2015)

3kramd5 said:


> StudentOfLight said:
> 
> 
> > > The 6D was modded with a "full spectrum" mod, which totally opens the sensor up to as much light as possible by entirely removing all the filters. ...
> ...



The filters of the filter stack OVER the sensor were removed. The CFA itself as not removed, these were not mon-modded cameras, only astro modded cameras. Astro modding just removes the IR cutoff filters (which these days are built into the low pass filters, so the low pass filters are removed as well), which enhances the sensors sensitivity to the full visible spectrum. Without the mod, red sensitivity is SIGNIFICANTLY diminished. 

These sensors were both still bayer CFA sensors, though, still both full color.


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## 3kramd5 (Jul 7, 2015)

jrista said:


> 3kramd5 said:
> 
> 
> > StudentOfLight said:
> ...



Gotcha. I was really impressed that someone disassembled their sensor subassy


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## StudentOfLight (Jul 7, 2015)

jrista said:


> StudentOfLight said:
> 
> 
> > jrista said:
> ...


You mentioned the two stacks were shot in different locations, so does magnification change by the latitude where shots are taken? Or does it change due to atmospheric conditions or how close an object is to the horizon maybe or some other reason? 

I didn't think of telescopes needing to zoom.

The reason I asked about magnification is that I noticed the 6D stack shot looked smaller than the A7s shot. I guess I expected the 6D shot would be look larger due to the higher native resolution. You also mentioned something called drizzle to increase resolution. Did you use this technique when doing this comparison and can you point me to a good resource so I can read up more about drizzle? Sounds interesting.

Thanks


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## jrista (Jul 8, 2015)

I'm not exactly sure what you are referring to. Magnification isn't talked about much in astrophotography. We are more concerned with image scale, or the number of arcseconds per pixel. Image scale is affected by focal length and pixel size. With the same scope, the image scales with these two cameras would differ quite considerably. The difference in image scale with these two images is actually fairly small. I don't know exactly what scopes were used, but the fact that they only differ by so little is actually fairly surprising. Their image scales have to be quite similar.

Image scale effectively tells us photon flux, the rate of photons incident on each pixel. With similar image scales, the photon flux is similar. That's an "equivalent" (or nearly so) situation in astrophotography. That reduces the comparison to differences in hardware and sky darkness. 

Star sizes differ usually because of differences in seeing, which blurs detail. But detail isn't the most important factor we are interested in here. We are interested in how much noise there is, and how deep the exposures are. For similar image scale, and with the 6D having significant advantages over the A7s both in terms of integration time and sky darkness, the A7s image is still BETTER. It's cleaner and has a deeper exposure (more faint bits show up.) That's a heavy win for the A7s, regardless of the small difference in image scale. 

The A7s wins here primarily because of higher Q.E. It's 65% Q.E. for the A7s, 47% Q.E. for the 6D. That is a MASSIVE difference. It's the reason the A7s pulls ahead despite all the advantages for the 6D. The A7s, despite a very similar photon flux per pixel, is converting more of those photons to charge. That's how it's able to build up a stronger signal in less time, and with less total integration. It's mainly converting more photons to charge in each pixel. On the other end of the spectrum, the A7s extremely low dark current noise (about an order of magnitude lower than the 6D), and similar read noise to the 6D. The lower dark current results in deeper background exposure, which picks up some more faint stars and renders a cleaner background.

Some of these technological differences don't mean as much for daytime photography. Certainly the noise characteristics of the A7s make it an amazing camera for low light photography...the low read noise and dark current and large pixel capacities result in image signals at ultra high ISO settings that are nearly devoid of electronic noise (read noise is sub-electron, dark current is so low that for most high ISO images you wouldn't even get 1ADU...so effectively zero dark current noise). These technological differences are quite huge when it comes to astrophotography, however. All the low noise and high sensitivity means very good signals with shorter exposures and less total integration time than other cameras.

The only real drawback with the A7s is the lossy compression in the RAW images. That can sometimes result in artifacts. However it does not seem to actually result in artifacts very often, and real-world results are usually exceptional. Hopefully at some point soon here Sony will "fix" their RAW issue with a firmware update, and lossy compression will no longer be a problem. Then there is essentially nothing negative I could say about the A7s as an astro camera.


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## psolberg (Jul 8, 2015)

I'm still hoping they will not bump the MP on the S. My preference would be an 8K readout that scales to 4K just as they are doing with the 5k? readout that scales to 4K on the A7RII. No line skipping pixel binning or whatever crap caused the soft 5DmkIII video. I doubt this will be a full sensor readout, but hey, this is sony. They are the leader in this stuff so why not dream?

Even if they have to crop to APS-C, I would prefer that to the super 35 crop of the RII model just to achieve that shallow DOF look easier without the excessive crop.


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## benperrin (Jul 9, 2015)

Thanks Jrista for your response by the way. Sorry it took me a while to reply. I think I'm going to cancel my 5dsr pre-order as I have no idea when it's going to arrive (company won't even give me an estimate). I'm going to purchase the a7rII and the commlite adaptor and I'll probably be using manual focus most of the time. Then later on I'll either purchase a 5dsr or 5d4 depending on what comes up. If the sony ends up being terrible I'll just return but at least this way I can find out if it is right for me. I see this more as adding a camera to my Canon kit rather than ditching Canon for Sony. Thanks for everything you write on this forum even if some of it goes over my head.


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## benperrin (Jul 9, 2015)

By the way for anyone interested some a7rII high iso shots have been posted. Pity the photographer didn't know how to focus the thing.
http://www.cameraegg.org/sony-a7rii-new-100-crop-sample-image-at-iso-25600-and-full-size-raw-image-at-iso-6400-w-fe-pz-28-135mm-f4-g-oss/
http://www.cameraegg.org/first-high-iso-12800-25600-sample-images-of-sony-a7rii

Hard to tell everything when the full size jpg/raw files weren't provided for some but it does give an overall estimation. These are the same pics that 3kramd5 was able to find it's just that now 100% crops have been added.


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## 3kramd5 (Jul 9, 2015)

benperrin said:


> By the way for anyone interested some a7rII high iso shots have been posted. Pity the photographer didn't know how to focus the thing.
> http://www.cameraegg.org/sony-a7rii-new-100-crop-sample-image-at-iso-25600-and-full-size-raw-image-at-iso-6400-w-fe-pz-28-135mm-f4-g-oss/
> http://www.cameraegg.org/first-high-iso-12800-25600-sample-images-of-sony-a7rii
> 
> Hard to tell everything when the full size jpg/raw files weren't provided for some but it does give an overall estimation. These are the same pics that 3kramd5 was able to find it's just that now 100% crops have been added.



Not bad for 1600. I'd call that more than usable.


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## benperrin (Jul 9, 2015)

I'm thinking up to iso 12800 is usable from the a7rII. Wouldn't want to use it all the time but in a pinch it would be acceptable I think.


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## 3kramd5 (Jul 9, 2015)

benperrin said:


> I'm thinking up to iso 12800 is usable from the a7rII. Wouldn't want to use it all the time but in a pinch it would be acceptable I think.



I'll wait for mine to deliver to make that call. The 12.8k photo is questionable, but I can't decide whether it's the camera's fault or the operator's.


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