About 30 feet 

The Olympus 100-400mm IS lens size is 72mm, please reconfirm the number mark as "ø" (diameter) symbol, if the number is 72, just need to order same 72mm size filter ,thanks. 

First, you need to check whether the camera battery is sufficient. When the battery is below 30%, you cannot take pictures at night. You can see the battery in the lower right corner of the camera screen; then format the memory card; find the delay in the menu Take pictures, note that the factory default setting is 30 seconds, but if the animal stays in front of the camera for less than 30 seconds, the picture will not be taken. You can try to set it to 8 seconds, 5 seconds, etc. 

Unfortunately this is for adapting lenses to Olympus' modern digital Micro 4/3 cameras. It won't work with the Pen FT or similar half-frame film cameras, and you most likely won't find anyone making adapters for these. 

This means that the magnification can be adjusted from 10 to 30 times, the objective lens is 50mm, a great telescope, light and durable.