Because you don't have the flash in manual mode
The best flash options for a Nikon D3100 camera are the Nikon SB-700, SB-500, and Yongnuo YN560 IV. These flashes offer good compatibility and performance for the D3100's capabilities.
Flash battery grip different lenses
Yes. Be aware that it is a manual flash, so you have to set the power settings manually.
In low light conditions, it is recommended to use the Nikon D3100 flash with a higher ISO setting, a wider aperture, and a slower shutter speed to capture well-exposed images. Adjusting these settings will help to properly illuminate the subject while minimizing noise in the final image.
Yes it does just got one in the mail today. Tried it out and it works fine.
flashdrive
To mount a flash on a tripod, you will need a flash bracket that attaches to the tripod. Secure the flash onto the bracket and adjust the angle as needed. Make sure the flash is securely attached before using it.
I think a stroposcope is a flash for photography not attached to the camera that pro photographers use.
A flash bridle is just a snaffle bridle with a flash hinge and flash strap attached to the noseband. Flash Bridles should always be applied with care as many people over tighten them and cause the horse stress and pain.
yes it is
Yes, you can, but it will be in manual mode only. Go and take a load of test shots to see which flash setting works best. That's a bonus with digital photography , you can easily delete the bad shots from your card.
you can find all the usb attached to linux by lsusbcommand in terminal !