just started out dslr a while back.. pardon me as im still learning.

however, i noticed when i want to shoot another object(black color) which i put on my desk, it just can't autofocus on it.
image will turn out blur. tried with auto mode and some adjustment on autofocus area but to no avail.
if i use my smartphone, it can autofocus easily.

i tried with d3100 and d5100 with kit lens but same result.
any advise ??

much thanks !

it is not macro object. for instant, im shooting my wallet using my dslr.
it can't really focus and always blurred out, however shooting using phone can autofocus easily pretty fast
that makes me confuse ..