making histogram from data vs time

It is not clear to me exactly what you want in the graph.

Creating a histogram makes me think of couting "how many entries have time stamps in each bin" so that column A is not even considered in building the histogram. Is that correct? Assuming that is correct, I am surprised that you had trouble with the histogram tool, because it should have done just fine with that task (unless your "bin" numbers were completely different from you "time stamps"). Since I would rarely use the histogram tool, here's how I would build this histogram (I'm still not sure this is exactly what you want).

1) Enter "bins" data in a column.
1a) Enter 0:15:00 in row 1 of bins column (column E for example).
1b) Enter =E1+30/24/60 and copy fill down for as many bins as needed. If you are unfamiliar with how Excel stores dates/times, review something like this: http://www.cpearson.com/Excel/datetime.htm#SerialDates
2) With the bins array in place, enter the FREQUENCY() function in the adjacent column https://support.office.com/en-us/art...7-fd9ea898fdb9 Note that the FREQUENCY() function is an array function and must be entered accordingly.
2a) If you have trouble with the FREQUENCY() function, a series of COUNTIFS() functions will accomplish the same purpose.
3) Insert Column chart using the bins array as the horizontal category axis data and the FREQUENCY() column as the values/series data.

If I understand what you are looking for, that should do it. If I do not understand, the basic idea should still work. Figure out in step 1 what you want for the "horizonatal" x axis data and enter that into a column, then figure out what you want for the vertical y axis data and enter that into an adjacent column. Then use those two columns to create a column chart.
Where do you get stuck?