Sony A7-II: XAVC-S, slog-2, and now... IBIS

James0b57 said:
Being able to switch perspectives by cropping would be a game changer.
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The *ONLY* thing that will change perspective in the photographic sense is physical movement of the camera relative to subject. (See http://en.wikipedia.org/wiki/Perspective_distortion_(photography) )

Photographically, that normally must be accompanied by something else, which is normally a change in the focal length of the lens if you keep the sensor size constant.

Imagine a photograph of someone standing in front of their house such that the framing is waist to top of head and their head is the same height in the photo as the house. You want to change the perspective such that the house is more prominent (let's say same height as the persons body), whilst the framing of the person remains the same. Adjusting focal length, cropping etc won't change perspective - won't change the apparent size of the house in the frame relative to the person.

To do that you'll first have to physically move the camera back to get the perspective you want - but then the framing of the person will be wrong (full length, say). So the physical move must be accompanied by something like a longer focal length lens.

I say "something like" because what you describe in terms of sensor cropping will indeed have the same effect. But surely the lens option is normally going to just be far easier than what you propose as there are no issues with changing resolution?
 
harddrive said:
I say "something like" because what you describe in terms of sensor cropping will indeed have the same effect. But surely the lens option is normally going to just be far easier than what you propose as there are no issues with changing resolution?
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Yes.

But from a more practical experience, having crop options is empowering. Having used every format from iPhone to ff35 extensively, they all have pros and cons to what can be done. Maybe as lens and sensor technology improves things will change, but currently each format offers different possibilities, which effect everything from aesthetic to perspective choices.
 
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Binning -> B&W

Binning -> B&W

harddrive said:
No, that doesn't necessarily follow - as I said earlier: "Binning the electric charge from 4 small photosites should give the same results as from a single photosite of 4x the area. , and as Samuel H puts it:

The whole point about what Samuel H and I are talking about is that it doesn't "downsample" at all - not in the generally accepted way anyway. If the sensor is an exact multiple of the frame dimensions (and ideally an even one) binning becomes a very valid technique. Each binned block directly corresponds to a single pixel of the output frame, so no need to do a conventional deBayer or scaling. That gives full video resolution with low power consumption because of the minimised processing.

The proof is in the C300, but because there it's only twice the frame dimensions in each axis it means "only" about 8.3Mpx. So great for 1080 video, rather low for stills. Next even multiple after 2x is 4x - which would indeed be capable of good video performance, but also high quality stills as well.

Yes to the comments from Celluloid Dream about true 4k (as opposed to quad-HD) needing 8192x5461, so yes - 44.7Mpx would be needed for that. But maybe that's looking at running before walking.....? For now I'd be happy to see such a 39Mpx 3:2 sensor with binning capability.
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"Binning" in the true sense only generates a B&W result. You need something like Kodak's proprietary sensor(s) to do color binning and that takes a chunk of processing power.

bwa
 
Yes, you need to bin same-color photosites together, not across colors. And in principle you can do that over the analogue signal, before converting on the ADCs, so you don't need any extra processing power. You do need some vias and transistors, and they are not "pool with a contiguous photosite" vias so yes, it's complicated. You'd probably want a stacked sensor for this, but Sony is good at making those... in small sizes, so far.
 
Meanwhile, the camera hit the store shelves in Japan already ... and no rumor site had it a week earlier.

Talk about keeping secrets.
 
My thoughts about the A7II:
If it has the same clean image as the A7s (I dont understand why the bigger sencor can be a problem in that aspect, Nikon D810 delivers a clean image from a bigger sensor...right?)
If it has a good low light performance (ok...not like A7S...but Im fine with a relatively clean 6400 ISO... and I believe it can be done)
If the faster AF has also a good impact on the video mode as well
And with that 5-axis IS and a price around 1600$...seems like a very good option to me...
 
Brian W. Allan said:
"Binning" in the true sense only generates a B&W result. You need something like Kodak's proprietary sensor(s) to do color binning and that takes a chunk of processing power.
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What is being suggested here is to have three "bins" for every 4x4 block - one for red, one for blue and one for green. Each frame, the charge from each photosite would be read into the appropriate bin, literally "binning" the electrons from the 4 red sites into the appropriate bin, and the same for the 4 blue and 8 green. Only then would the bins be read and fed to an A-D convertor.

So you'd end up directly with three sets (R,G, and B) of data corresponding to 1920x1080 pixels directly - without any complicated processing, deBayering or scaling. That's the beauty - but it relies on the used sensor dimensions being exactly 4x the output frame dimensions, and the sensor having the ability to bin the appropriate 16 sites into the appropriate 3 bins per block.
 
Sony Alpha Rumors posted excerpts from an official Sony PR release/road map with their plans for the next three years.

http://www.sonyalpharumors.com/sony-goes-for-ultimate-speed-sensivity-and-resolution/

Quite a few interesting things, IMO, the main one being an inference that Sony is not going to abide by the recent Canikon (2-3 year) product cycle standards but will instead dive head first into the future, bringing along whatever technological advancements their engineers are capable of. In other words, they want to dominate the image acquisition market.
 
A7II body is supposed to be somewhat thicker than the MK I's. I assume it's to allow some form of an internal 4K recording at some point on all of the 7-series models.
 
The Sony A7s has S-log at iso 3200,

DXO measuring the raw image, has the A7s at iso3200 rated at 10.5 stops DR.

So, that could, in some way mean that Sony is keeping them under 11stops DR, since this is all 8bit.
 
As I said on the other thread, I think ISO 3200 with slog is just like ISO 100 heavily underexposed and with shadows brought up big time. So you are using the electronic mode where the camera has the best DR.

But that IBIS is not tuned for video so... next!
 
A super-mini-quick comparison - A7 weighed in at 416 grams while A7II does at 556. A7s is 489, A7r is 407.

Where does the extra weight come from? Obviously, from the mechanical stabilization system, for one. But from where else?
 
Samuel H said:
As I said on the other thread, I think ISO 3200 with slog is just like ISO 100 heavily underexposed and with shadows brought up big time. So you are using the electronic mode where the camera has the best DR.

But that IBIS is not tuned for video so... next!
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Seems odd. The 1DC under exposed in C-Log, so, ISO 800 was closer to ISO 400,

While I understand the implementation of log, i do not understand the re-naming of the ISO.


In the case of the A7s, are you seeing you expose ISO 3200 in S-Log, as you would ISO 100?
 
I can understand it, if the shadows are being boosted, and so therefore the ISO is 'technically' higher, but in practical terms, as such in the case of the 1DC, ISO in C-Log versus other all the picture styles resulted in a lower exposure.
 
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