I think it looks pretty good. I'd want the flame to be flickering a bit more. As it is, it seems a little too still for all of the wind that's around it, but everything else looks fine.
I think it's awfully flat. What time of day is this supposed to be? Black and white is an art that takes time to master. This shot just looks like the saturation was removed. You should be boosting the red channel and pulling down the blue to give it a look like it was shot with a Wratten #8 at least. Wratten number - Wikipedia
A good understanding of how to shoot Black and White film is necessary if you are going to take color video and process it as black and white. The tonal quality is extremely important to the story.
I would take a picture, even a still photo with a candle in the shot around the time of day you are trying to portray and then experiment with some black and white filtering techniques. Then make your video look like the sample image. That's how you make composites believable. Unless you have years and years of experience this is the best and most accurate way to color grade a film.
Sorry I forgot to mention that there is no color grade applied, this is added effect to the raw footage from the camera ... I want to do color grading after all the effects are done.
But thank you guys for the advice and I will apply all techniques that you recommended.
Color grading is part of doing a successful composite. You can't judge the composite until you color grade the footage unless you want to spend a bunch of time in the color grade isolating the candle and the lighting effects it is going to have to make it look like it's really there. You'll want to establish at least a base color grade for the entire project using a few shots then at least start with that color grade.
There is an overall grade for the whole project. Many times you change the color grading depending on the scene, but the base should always be there. If that shot is supposed to be night or evening then trying to put the candle in the shot and then grade the composite after it is rendered is going to be very difficult. I'd get the shot looking like it should look without the candle then add in the candle and then add in the lighting effects, the glow, the fall off, and any lens flare you want to the composite so you have a shot that is pretty close to the final look of the film. When you are grading your final project you'll have a lot less to fiddle around with.
I cant argue back for you answer Rick, thank you for great advice and I will apply it for sure because now that I look at it, it makes completely sense.
Are there any other problems in the shot that I should solve? besides colorgrading ...