Can someone explain digital and optical zoom?

MACTEN said:

My zulus just says 5-20 but not how much optical or digital. Now I'm seeing other night vision scopes that advertise they have X optical IE 6 or 8, and X digital zoom, Do these numbers combine or are they stand alone? In other words, are you only either on 6 or 8 optical zoom or does it combine with the digital for 6 or 8 times digital?
Very confused,

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There should be a distinction made between the two. Obviously, the more opticle zoom, the higher the clarity. Digital zoom is somewhat like zooming in on a flat screen where the more zoom, the bigger the pixels appear.

MACTEN said:

So if one is advertised at 8x optical and 1-3 digital..Does that mean 3 times the 8 (24) or another 3 power added?

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Yes, that's basically acceptable for the industry. True zoom is optical. The lenses actually change the way light bends on to the sensor. Digital zoom is exactly like cropping a photo in the computer. For the practical purposes of a scope, digital zoom is ok.

MACTEN said:

So a 8 power optical zoom with digital turned up is 24X then? or 11X?

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Yes, you would add it like you said in your previous example. So 8x optical zoom with a 3x digital zoom will be marketed as 24x zoom *digital*

Ok... I think I just understood what you were asking... actually now you're making me question it as well. I have to think about it a little bit... But I've always believed it's multiply the two instead of adding them because when you already have 8x'ed the image through the lens, and then 3x that in the digital, it should give you 24x the size of the original.

MACTEN said:

That's what it seems to be but some aren't advertised as like that (multiply) just X optical and X digital . I would be able to know for sure if I had one but of course... I don't which is why I'm trying to figure it out.

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When advertised at "total zoom", one has to be careful. 8x optical with 3x digital is 24x total. We're it 12x optical and 2x digital, it would still be 24x "total zoom", but with more clarity because the optical zoom is higher.

I’m not sure about electronic scopes, maybe they are different or something , that multiplication part isn’t the way I thought zoom worked in general. Once you reach your max optical zoom the digital takes over 3 x optical zoom produces a picture that 3 times larger or closer that doesn’t lose any quality. once you exhaust your optical then digital takes over and your then zooming in electronically and the more you zoom in the more quality you lose, digital simply starts where optical ends. This is the way I’ve always thought zoom worked when you have both optical and digital. Maybe that’s not correct though after reading this thread.

I’m pretty sure you are spot on and it’s how these digital optics magnification statements are kind of misleading. Oh wow that scope has 24 or 52x and then you buy and wonder why it looks like dog through the scope and you are on like 6 or 7x. Lol.

From what I can tell about the zulus hd 5-20x, there is NO mention of optical zoom anywhere. It appears to be a 1080p camera that is zero optical zoom and 5-20 digital zoom. That's it.

With cameras (still or video), normally they would say something like "20x (12x optical)" for example. This would mean that once you have zoomed in to 12x, you have maxed out the optical zoom. When you zoom beyond 12x, it is a digital zoom being applied to the already maxed out 12x optical zoom. So in this example 20x would be full 12x optical then digitally scaled to get the total of 20x. In digital cameras I used to totally dismiss the digital zoom part of any specifications. I assumed it would just be trying to make silk out of a sow's ear -- no real gain in resolution -- and usually that was true. But then I got a higher-end panasonic video camera that was 20x (12x optical). To this day I am still amazed that the digital zoom part of it is actually giving more resolution -- as if the camera sensors had more pixels than needed at 12x optical and then started providing that additional "info" once I exceeded 12x.

My point is, unfortunately, a mixed bag of "digital zoom sucks", but sometimes it doesn't. The camera sensors used can make a big difference. Some cameras brag about using sensors that have a ton of pixels -- more than enough, but the size of the sensor is so small that light from one pixel bleeds over to adjacent pixels, which kind of defeats the purpose of lots of extra pixels on the sensor. Larger sensors get more light and avoid the bleeding if they don't cram too many pixels onto it.

In the case of optical zoom in darkness, the more "optically" zoomed in you are, the less light you are letting in which means less light for the sensor to "sense". Yikes -- we don't want to starve the sensor(s), but we want zoom too. This makes it really difficult, as a consumer, to judge a night-vision rig by only optical vs digital zoom specs.

stovepipe

The Zulus has a fixed 5x base magnification (or 3x for the new model). Base magnification is determined by the sensor's physical size and the lens' focal length. The digital zoom is 1x to 4x. I've seen photos of the prototype ThermNight where the display showed the actual digital zoom rather than the total magnification.

Yes the Zulus does not have an optical zoom, it is a fixed lens digital scope. All zoom capabilities are digital only.