Personal item or carry-on?

I'm flying on allegiant air next month and i was wondering if my nikon d3000 would be considered a carry-on or personal item if i'm taking a bag with other stuff in it. Would both be able to fit under the seat? Sorry if this sounds confusing

Added (1). Thanks everyone

The information on their site is a bit unclear, but it does say you can take one personal otem in addition to your carry on. The following is from their site;
"1. 1+1 Rule: Per TSA guidelines, each passenger is allowed to carry on the aircraft one carry-on bag (fees apply) plus one personal item.
2. The carry-on bag must be under 25 pounds (11 kilos) and the exterior dimensions must not exceed 9" H x 14" W x 22" D. (22.9 cm x 35.6 cm x 55.9 cm). The carry-on bag must fit in the overhead compartment.
3. The personal item must not exceed exterior dimensions of 7" H x 15" W x 16" D (17.8 cm x 38.1 cm x 40.6 cm) and must fit under the seat.
4. These measurements include wheels, pockets, handles and decorations. Please measure your bags carefully.
5.In addition, passengers may bring mobility aids or assistive devices, necessary medical equipment such as diabetic supplies, a coat, jacket, diaper bag, or umbrella onboard the aircraft without charge".

Without knowing the dimensions of both noone can say if they will fit under the seat.

You can carry.

If both items can fit under the seat in front of you, then it is a personal item. I suggest you put the camera in the other bag and then take it out once you are in your seat.