I've modified my Holga 120 to take 35mm film and I know that you can't wind the film back, you have to open the back of the camera (in a darkroom) to rewind the film.
1-2	I've	_	_	_	_	_	_	_	_
1	I	I	PRON	PRP	Case=Nom|Number=Sing|Person=1|PronType=Prs	3	nsubj	3:nsubj	_
2	've	have	AUX	VBP	Mood=Ind|Number=Sing|Person=1|Tense=Pres|VerbForm=Fin	3	aux	3:aux	_
3	modified	modify	VERB	VBN	Tense=Past|VerbForm=Part	0	root	0:root	_
4	my	my	PRON	PRP$	Case=Gen|Number=Sing|Person=1|Poss=Yes|PronType=Prs	5	nmod:poss	5:nmod:poss	_
5	Holga	Holga	PROPN	NNP	Number=Sing	3	obj	3:obj	_
6	120	120	NUM	CD	NumForm=Digit|NumType=Card	5	nummod	5:nummod	_
7	to	to	PART	TO	_	8	mark	8:mark	_
8	take	take	VERB	VB	VerbForm=Inf	3	advcl	3:advcl:to	_
9	35	35	NUM	CD	NumForm=Digit|NumType=Card	10	nummod	10:nummod	SpaceAfter=No
10	mm	mm	NOUN	NN	Number=Sing	11	compound	11:compound	_
11	film	film	NOUN	NN	Number=Sing	8	obj	8:obj	_
12	and	and	CCONJ	CC	_	14	cc	14:cc	_
13	I	I	PRON	PRP	Case=Nom|Number=Sing|Person=1|PronType=Prs	14	nsubj	14:nsubj	_
14	know	know	VERB	VBP	Mood=Ind|Number=Sing|Person=1|Tense=Pres|VerbForm=Fin	3	conj	3:conj:and	_
15	that	that	SCONJ	IN	_	19	mark	19:mark	_
16	you	you	PRON	PRP	Case=Nom|Person=2|PronType=Prs	19	nsubj	19:nsubj	_
17-18	can't	_	_	_	_	_	_	_	_
17	ca	can	AUX	MD	VerbForm=Fin	19	aux	19:aux	_
18	n't	not	PART	RB	_	19	advmod	19:advmod	_
19	wind	wind	VERB	VB	VerbForm=Inf	14	ccomp	14:ccomp	_
20	the	the	DET	DT	Definite=Def|PronType=Art	21	det	21:det	_
21	film	film	NOUN	NN	Number=Sing	19	obj	19:obj	_
22	back	back	ADV	RB	_	19	advmod	19:advmod	SpaceAfter=No
23	,	,	PUNCT	,	_	19	punct	19:punct	_
24	you	you	PRON	PRP	Case=Nom|Person=2|PronType=Prs	25	nsubj	25:nsubj|27:nsubj:xsubj	_
25	have	have	VERB	VBP	Mood=Ind|Number=Sing|Person=2|Tense=Pres|VerbForm=Fin	19	parataxis	19:parataxis	_
26	to	to	PART	TO	_	27	mark	27:mark	_
27	open	open	VERB	VB	VerbForm=Inf	25	xcomp	25:xcomp	_
28	the	the	DET	DT	Definite=Def|PronType=Art	29	det	29:det	_
29	back	back	NOUN	NN	Number=Sing	27	obj	27:obj	_
30	of	of	ADP	IN	_	32	case	32:case	_
31	the	the	DET	DT	Definite=Def|PronType=Art	32	det	32:det	_
32	camera	camera	NOUN	NN	Number=Sing	29	nmod	29:nmod:of	_
33	(	(	PUNCT	-LRB-	_	36	punct	36:punct	SpaceAfter=No
34	in	in	ADP	IN	_	36	case	36:case	_
35	a	a	DET	DT	Definite=Ind|PronType=Art	36	det	36:det	_
36	darkroom	darkroom	NOUN	NN	Number=Sing	27	obl	27:obl:in	SpaceAfter=No
37	)	)	PUNCT	-RRB-	_	36	punct	36:punct	_
38	to	to	PART	TO	_	39	mark	39:mark	_
39	rewind	rewind	VERB	VB	VerbForm=Inf	27	advcl	27:advcl:to	_
40	the	the	DET	DT	Definite=Def|PronType=Art	41	det	41:det	_
41	film	film	NOUN	NN	Number=Sing	39	obj	39:obj	SpaceAfter=No
42	.	.	PUNCT	.	_	3	punct	3:punct	_
