It's just marketing spin.
They are taking a higher resolution stream (e.g., 1080p) and then only sending out a subsection of the visible FoV (e.g., 720p).
This feature has been around for a while (called digital cropping in the past), but has never really become prominent because you are not zooming, you are simply losing resolution.
Sony explains this process here:
The other big problem is very limited 'zoom' range that this offers. This is roughly equivalent to buying a 3-4.5mm varifocal camera, so there's not much flexibility in 'zooming' and, again, you have to drop down in resolution to get it.
You might as well just buy a real 1080p optical varifocal camera, get the full resolution and be able to adjust the FoV much more flexibly. These Sony cameras cost about $500 each. Here are 76 real varifocal 1080p cameras under $500.
This is the entire point of the E-Varifocal, to achieve the capability of a 720p camera at a lower cost. The List Price is in fact $500, for non SSPR Sony partners, but is not anywhere near the true cost. This camera was design to offer similar capabilities of a quality camera manufacturer, at a lower cost. I highly recommend you demo this camera, before comparing with any lower priced manufacturer.
Thank you for your response.
As a Sony Salesperson, I want to clarify and clear any confusion about the product and it's features. You are referrancing the XM637 & XM632, which are both outdoor Sony Cameras with E-Varifocal at the List price of $798. The XM631, which is for indoor use, and is sold at LIST price for $498 as shown Here.
I do in fact agree with you that E-Varifocal is not a new invention and can easily be accomplished by other manufacturers, but is not currently offered by them. The benefit is still there by purchasing the Sony XM Series Cameras and utilizing the E-Varifocal Feature, but who is to know which manufacturers will have this feature offering in the near future.
We are an SSPR Sony Partner and obviously, we install a lot of Sony cameras because of the real features that work as advertized. Practically all of these features are included in this camera in question, For our customers, it is quality over price and the value added features in these cameras are generally worth the few extra $$$.
The XM631 Sony camera includes:
Sony's XDNR Dynamic Noise Reduction
Sony's Visibility Enhancer (VE)
Sony's DEPA Advanced analytics with face detection
Sony's View-DR technology (which has out performed in our testing) just about every other camera on the market.
- All this with a minimum illumination at 0.3 lux Color and B/W
- Not bad for a sub $500 MSRP camera!
Would this feature be better received if the 1080P camera using it did not output a 1080P stream, but was intentionally limited to stream only 720P?
It certainly shouldn't be; that would be counterintuitive, but it still might be an easier sell.
To be clear, technically what I mean is that:
When using its full FOV mode (non-e-varifocal), it would use all the pixels of its 1080P sensor, but then would downscale the stream (but not the FOV) to 720p before going out the wire.
Everything else would remain the same, namely that:
When using an e-varifocal FOV of say 1280x720, it would crop that corresponding part of the 1080P sensor, and send out only that region without downscaling.
Why would this seem better? For the simple reason that now the e-varifocaled FOV would show more detail than the full FOV mode would, and therefore people would think it acted more like a real optical zoom, seemingly increasing resolution.
Even though it's not optical, but you can't tell because you never get to see the whole sensor at full resolution...