I left my nikon D3100 outside with the tripod and i forgot to get it,then suddenly it got wet from the rain,what will i do?

Look here for specs: Nikon D3100

I do not have a D3100, but if it is like other Nikons, you slide the memory card door open (located on right side of the camera body). You will see the edge of the memory card. The retaining mechanism is spring loaded. Push in on the edge of the card and it should release the card which will spring outward. Now just pull the card out. There should be no resistance. To replace the card, open the door; face the card with the label toward you and with the copper contacts on the left side facing away from you. Push the card inward until it clicks into place and close the door.

See if you can reset the electronics and restore the unit to factory defaults. If no result and if Nikon does not have a hidden code to fix situation you will either have to live with the situation, replace the camera, fix the camera (not cost effective.) Your choice.

The best tip is to use a tripod or other camera support. That is, unless you want the blur from camera motion.

Other than that, it depends on what you're photographing, and what you want that photograph to say to the viewer.

Hi
to shoot in the dark use a good tripod, select a smaller aperture and longer shutter time.

hope this helps

If your SD card is not large in size (mb's) it will oniy hold so many pictures
either format or use another empty card

The filters go on the back of the lens (the end that connects to the camera). If you detach the lens and look inside, you'll see a threaded ring. Simply screw the filter on, similar to how you put filters on the front end of other lenses.

Due to the great magnification ratio of this lens, you absolutely need to have it on a tripod or other stable support. Even the slightest camera shake will be magnified.

The lens also has very little depth of field, so you must focus precisely. Since you're mounted on a tripod, you might want to activate the LiveView feature and zoom in the subject while you focus.

You didn't specify the make of the lens. Assuming the lens has a Nikon mount then yes, it will mount on a D3100. The big question is whether it will autofocus on the D3100. The D3100 does not have an autofocus motor, relying on the lens to have one. Not all lenses do. Nikon designates lenses with an autofocus motor as AF-S. Other manufacturers use different designations.
If you need further assistance, feel free to reply to this post and give the make of the lens.

Remove the battery imediately, the memory card and the lens. Place the camera body, lens and memory card in a warm dry and place for several days to dry out completely.
When the camers is dry, insert the battery, lens and memory card, turn on the camers and set the date and time.
If the camers does not work charge the battery and try again.
If it still does not work then you need to send it to the Nikon service centre for repair.

I found this site that has the service manual: nikon d3100 service manual Download Pdf nikon d3100 service manual Find...