SF Kang Sir,
Thankyou so much for your experience advise,
Fast lens (F2.8) not affordable that why bought only Sigma 120-400mm F4.5-5.6
Good tripot, I got a reasonable SIRUI 2205
Setting, need to learn more on this aspect.
I shall try harder and hopes that I can get what I wish to see (Sharp and reasonable details image for birding)