Very soon after, I mark the transition into the first jhana (J1) with tingling that starts in my hands and arms, and progresses to shivers/buzzing in my body. The latter either comes in waves or, when I get a good lock, a continuous buzz. For me, I equate this to the "rapture" factor, because it does feel like elation, excitement. Significantly, while I am well locked onto the breath, it continues to be coarse, and I need to make an effort to stay with it. This I take as the "applied and sustained attention" factor of J1.
If I stay with the breath through this, the rapture continues as does the coarseness of breath. When I start to think that this effort is really getting tiresome (usually after about 5 minutes now), it goes into this phase of being really coarse -- not quite hyperventilating, but pretty deep breathing -- and then suddenly it nearly vanishes. I become really, really still, and my breath is dramatically finer. And the buzzing that was present in J1, but overshadowed by the breathing effort, becomes, with the stillness, the two major sensations.
This I take as the transition to the second jhana (J2), because classically (as well as in MCT

, it is the dropping of "applied and sustained attention" that seems to be the signpost. The first time this happened, I was really surprised that my breath just started to "amp up" on its own, and I was locked in just following it. Some kind of weird positive feedback loop or something.
Anyhow, in this new calm, I notice my eyes are now not looking down, nor are crossed. This removes the pressure from my forehead and, because I am now looking "forward" and the amount of light coming in is more, it seems "brighter" and the FOV somewhat larger. The breath is still there, but is very light and while I follow it, the rapturous buzzing gives a really pleasant feeling counterpoint to the utter stillness. [cont'd...]