Correlation between camera digital zoom and distance to object?

For me to get a decent picture of a person from a distance and still capture detail such as skin tone or capture a bird perched on a tree or animal grazing a distance away far enough not to scare it using a domestic camera such as the Nikon L830 what would be the maximum distance on average i would have(or rather I CAN BE) to be from object(person, bird or grazing animal) i don't want a defitive answer of course but i want to have an idea like say 100m? 500m? Or should it just be 50m? Or closer?

I would suggest that you forget using the digital zoom feature on your camera and do the cropping later using your photo program on your computer.

Your camera has a fine 34x optical zoom. For the highest quality images at a distance, set the camera to its longest focal length and use the camera highest resolution. Using the lens at the equivalent of a 765 mm lens, far exceeds the focal length that professional wildlife photographers and birders use.

If you are too far away using the lens at that focal length, you have two choices. Learn how to get closer to the birds nest without frightening it or shoot the bird and then using your computer, do the cropping there.

When I shoot birds in the wild, I use a 300 mm lens and that is good enough. It was expensive enough at $6.300. The 800 mm lens for my camera costs over $18,000

As the user of a camera, it is really up to you to determine the answers to this kind of question. Had you ventured out into the wild and made some tests, you would already know the answer

To get the BEST picture possible your camera should be on a tripod (for stability)and as close to the subject as possible WITHOUT using any zoom. With that said the rest (settings, etc.) is just practicing and learning your equipment. Animals are tricky because you don't know how close they will allow you to get without getting skittish and taking off or worse, like attacking you. For zoom shots, the higher your OPTICAL zoom the better. Digital zoom doesn't do anything but make your pixels larger, you're not really getting closer. I set my cameras on the highest resolution possible and I don't shoot DZ. I recommend you don't also. However, you may want to experiment and shot a couple of DZ shots to see if you like the effect. If I were to give you any more tips it would be to shoot your keeper pictures in TIFF format because there's no quality loss when you make a copy (save to file, DVD, etc. Most people don't know that when you make copies of jpg files the quality decreases with every copy.

Gee I would just buy the bridge camera that is the most comfortable to hold at maximum magnification. I just can't see where all this math will affect the end result=a quality picture which you can be proud of.-Sorry.