Take a photo of a very light plain subject close to the lens using long exposure and smallest aperture you have - over expose by a couple of stops
1	Take	take	VERB	VB	Mood=Imp|VerbForm=Fin	0	root	0:root	_
2	a	a	DET	DT	Definite=Ind|PronType=Art	3	det	3:det	_
3	photo	photo	NOUN	NN	Number=Sing	1	obj	1:obj	_
4	of	of	ADP	IN	_	9	case	9:case	_
5	a	a	DET	DT	Definite=Ind|PronType=Art	9	det	9:det	_
6	very	very	ADV	RB	_	7	advmod	7:advmod	_
7	light	light	ADJ	JJ	Degree=Pos	9	amod	9:amod	_
8	plain	plain	NOUN	NN	Number=Sing	9	compound	9:compound	_
9	subject	subject	NOUN	NN	Number=Sing	3	nmod	3:nmod:of	_
10	close	close	ADJ	JJ	Degree=Pos	9	amod	9:amod	_
11	to	to	ADP	IN	_	13	case	13:case	_
12	the	the	DET	DT	Definite=Def|PronType=Art	13	det	13:det	_
13	lens	lens	NOUN	NN	Number=Sing	10	obl	10:obl:to	_
14	using	use	VERB	VBG	VerbForm=Ger	1	advcl	1:advcl	_
15	long	long	ADJ	JJ	Degree=Pos	16	amod	16:amod	_
16	exposure	exposure	NOUN	NN	Number=Sing	14	obj	14:obj	_
17	and	and	CCONJ	CC	_	19	cc	19:cc	_
18	smallest	small	ADJ	JJS	Degree=Sup	19	amod	19:amod	_
19	aperture	aperture	NOUN	NN	Number=Sing	16	conj	14:obj|16:conj:and	_
20	you	you	PRON	PRP	Case=Nom|Person=2|PronType=Prs	21	nsubj	21:nsubj	_
21	have	have	VERB	VBP	Mood=Ind|Number=Sing|Person=2|Tense=Pres|VerbForm=Fin	19	acl:relcl	19:acl:relcl	_
22	-	-	PUNCT	,	_	1	punct	1:punct	_
23	over	overexpose	VERB	GW	Mood=Imp|Typo=Yes|VerbForm=Fin	1	parataxis	1:parataxis	_
24	expose	_	X	VB	_	23	goeswith	23:goeswith	_
25	by	by	ADP	IN	_	27	case	27:case	_
26	a	a	DET	DT	Definite=Ind|PronType=Art	27	det	27:det	_
27	couple	couple	NOUN	NN	Number=Sing	23	obl	23:obl:by	_
28	of	of	ADP	IN	_	29	case	29:case	_
29	stops	stop	NOUN	NNS	Number=Plur	27	nmod	27:nmod:of	_
