What is f- means in digital camera? - 1

I have Nikon n90, Many times when I want to take picture, the camera does not allow me to do anything and it show: f--
What should I do what is wrong?

What is f- means in digital camera?

I have Nikon n90, Many times when I want to take picture, the camera does not allow me to do anything and it show: f--
What should I do? What is wrong?

What do I need to do to capture the same purple in the photograph from a purple object?

In most of the settings I use, the purple comes out as blue in varying tones and sometimes with a tinge of purple, maybe pale purple as well. What can I do to overcome this problem and the camera settings I use?
I use a Nikon D500 camera.

I have no idea what I'm doing?

So this summer I plan to take up longboarding and buy a camera to start photographing landscapes, along with a bit of action photography. I have a decent eye, so I'm willing to pay a good amount of money for a camera. I'm thinking about a Nikon D600, if you think there's a better choice for what I'd like to do, go ahead and let me know. For longboarding I was wondering if anyone could recommend good brands. I would love to start doing downhill.
(Yes, I've asked this, just in a different category)

Added (1). I would also like to film videos if that matters at all

Cheap Nikon dslr camera?

I want a Nikon dslr camera under 300 dollars that takes clear pictures. I haven't been able to find one. If you know about any please answer.
Oh and also I would like the camera to have a flash and record videos.

Free NEF file conversion on a Mac?

I have a Nikon DSLR and I've been told shooting in RAW is the best. This saves the photos as a NEF file type, and Photoshop (CS4) doesn't seem to want to open it for editing. Is this something I can change in PS, or is there a free method of converting the pictures so I can edit them in Photoshop?

AND, if I do convert them prior to editing in Photoshop, is it still going to have the benefits of shooting in RAW, or should I just save the time and keep shooting in JPG?

I primarily want to experiment with HDR photos, and I use Photomatix to fuse them together - and this does open NEFs. But for single images I want to be able to use Photoshop.

Good camera to vlog with?

I want to start vlogging, but I don't know which camera to get. What do most vloggers use? Nikon? Canon?

Are cameras allowed to a Justin Bieber concert?

There has been some confusion with whether or not I would be allowed to bring my DSLR Nikon camera to the Justin Bieber concert on November 5th. I was just wondering if I could or if they do not allow those kinds of cameras at his concerts.

My Adobe photoshop 7.0 won't open high quality images?

Hi, I bought a Nikon 5100 camera recently and I have adobe photoshop 7.0 because i had the disk for it and i didn't want to buy the new ones. Photoshop can open up images just fine but when i try to open up the images from this nikon camera just a blank screen opens up but with no image on it. If anyone knows what's wrong and how i can fix it please answer. And btw i don't have any plugins or anything i'm sort of a begginer with photoshop i used another program before it.

Nikon or Cannon camera? - 1

Any good camera suggestions? Nothing way too pricey, but good quality.