Faintness of Object of Meditation

I started meditating recently formally, after a while of non-formal meditation, and I'm realizing that the objects I meditate on, either the breath or an image, are extremely faint. In the case of the breath, I barely can tell whether I'm on the breath or some other object, and it is hard for me to switch my attention to the sensations at the nostrils. In the case of an image, it is extremely faint and hard to distinguish. My questions are as follows: 1) Should I continue with the breath, hoping it will become clearer despite not knowing if I'm truly focused upon it, or should I switch to a visual imagined object? 2) Should I keep meditating despite the faintness of these objects of focus or is there a way to dispel this dullness outside of formal meditation? Are there any tips or techniques to do so? Thank you in advance.