Hello, host. If you use in inside, the dome camera is ok. and how long between the camera and DVR is not important, the most important is that:
1. Do you need to see color or B/W object
2. how long of the distance you need to be?
it depend on the Focal lens also. the focal lens larger, you will be see wider and longer a little.
3. What is the Horizontal Resolution you need ? 420TVL, 480TVL, 500TVL 520TVL.... or more
If you need, you can reference the below camera is interesting you?
http://www.lbtech.com.cn/en/product_more1.asp?id=286&pid=12 (long distance camera ).....
More information ,you also can contact me : cindy@lbtech.com.cn or MSN: cindyliu172217267@163.com . We are the camera factory..............