How to fix the focus on the camera?

I should know how to do this, having done photography since 2010 with D-SLRs, but I'm not yet accustomed to my newest lens which is a 50mm Nikkor lens. I use a Nikon D3100, so the auto-focus feature isn't available. I manually focus and I have done enough practice to understand that when a green light comes on in the corner, it's focused on part of the subject.

Well, last night it wouldn't work. That green light was flashing on and off and I looked it up. I fixed it, or so I thought. It doesn't flash on and off now and flashes when the viewfinder focuses; the picture would look sharp and exactly the way I'd want it.

Then I take the picture and it comes out blurry…
Added (1). I forgot to mention that for right now, I'm shooting on Auto. I shoot Manual, too, but for now I'm shooting on Auto.

Read more: How to fix the focus on the camera?

Good Camera under 500 dollars Canadian?

What is a good interchangeable lens camera that is under 500 dollars Canadian? My basic requirements are HD video, WiFi, good low light performance, Bulb, and fast burst speeds. (around 10 fps)

I was thinking of things like the Canon t5i, and the Nikon d3300

My previous camera was a sony a5000

if you can leave links for amazon or something, please make it Canadian

Read more: Good Camera under 500 dollars Canadian?

I want to know what camera I should buy for Photography 101 class?

I want to know what camera I should buy for Photography 101 class?

Read more: I want to know what camera I should buy for Photography 101 class?

In terms in size and bulk which one big in size the canon 5d mark 3 or Nikon d810?

In terms in size and bulk which one big in size the canon 5d mark 3 or Nikon d810?

Read more: In terms in size and bulk which one big in size the canon 5d mark 3 or Nikon d810?

When you first buy a new nikon d810 body what are the best absolutely sharpe lens to buy?

When you first buy a new nikon d810 body what are the best absolutely sharpe lens to buy?

Read more: When you first buy a new nikon d810 body what are the best absolutely sharpe lens to buy?

Is a cobra auto 210 flash gun compatible with a Nikon d3300 camera?

Is a cobra auto 210 flash gun compatible with a Nikon d3300 camera?

Read more: Is a cobra auto 210 flash gun compatible with a Nikon d3300 camera?

Which lens are the best for all rounds 24-70 24-120 nikon lens?

Which lens are the best for all rounds 24-70 24-120 nikon lens?
Added (1). Which lens are the best for all rounds 24-70 2.8 24-120 4g nikon lens?

Read more: Which lens are the best for all rounds 24-70 24-120 nikon lens?

How to take off the minutes of of a Nikon Coolplix L320 to make a longer video?

How to take off the minutes of of a Nikon Coolplix L320 to make a longer video?

Read more: How to take off the minutes of of a Nikon Coolplix L320 to make a longer video?

Which 2 lenses should I bring?

I m traveling to Strasburg tomorrow and I m not sure which lenses to bring. I haven t traveled much outside the country with my camera yet. I have a Nikon D3200 camera and a Nikon DX 35MM 1.8, Nikon DX VR 18-55 45-5.6 and a Sigma 70-300mm 4-5.6.

Read more: Which 2 lenses should I bring?

How to make background blur?

I have Nikon D5200 with Tamron AF 18-200mm (IF) Macro F/3.5 - 6.3
How to make background defocused in portrait?

Read more: How to make background blur?