I am a 50 year old man. Recently, I noticed that the amount of semen I release per ejaculation is quite little. Is this a symptom of a serious problem?

Check with your doctor.

How often do you ejaculate? Can effect the amount.

Your 50, so maybe your not producing as much.

Oh so many questions...

Actually you can't see the seamen, you see the fluid, you would need a microscope to see the actual

Since you're entering your 50's, if you haven't already it would be a good idea to go to a urologist for a checkup. It is possible that you may have an enlarged prostate and experiencing retro ejaculation with your semen going back into the bladder instead. A specialist could help you determine what the cause is and it's not always age.