「① I'm not an expert」は「私は[専門家](https://eikaiwa.dmm.com/uknow/questions/12065/)ではありません」、すなわち「[あんまり](https://eikaiwa.dmm.com/uknow/questions/43540/)詳しくないです」。これでお求めのニュアンスが得られる、自然な言い回しです。
使い方:
I know about Charles Dickens but I'm not an expert.
ジュリアン
I'm not familiar with it.
I'm (contraction) - I am
'I' and 'am' are combined to form 'I'm'.
Therefore, you may say 'I am not very familiar with it'.
It is, however, more common to use contractions when speaking casually to someone.
'Not familiar' means that you do not have a good knowledge of a particular thing, activity or person.
Example
A: I know all the Harry Potter spells.
B: I'm not familiar with it.
________________________________________
I don't know much about it.
Don't (contraction) - do not
Therefore you can make use of 'I do not know much about it'
'Do not know much' shows that you know little about a specific thing, person or activity.
I'm not familiar with it.
I'm - I amの省略形
'I' と 'am'は、一緒にして'I'm'の形になります。
ですので、'I am not very familiar with it' と言う事が出来ます。
しかし、カジュアルな会話をしている時は、省略形をよく使います。
'Not familiar'とは、馴染みのない、不慣れなと言う意味で、人や物などにな対して使います。
例
A: I know all the Harry Potter spells. (ハリーポッターの呪文をすべて知っています。)
B: I'm not familiar with it. (私はよく知りません)
________________________________________
I don't know much about it. (あんまりよく知りません)
Don't - do notの省略形
ですので、'I do not know much about it'を使うことが出来ます。
'Do not know much'とは、特定の事や人の事を少ししか知りませんと言う意味になります。
I saw it but wasn't paying much attention at the time.
It's great that you can participate in the conversation about the film! But maybe your memory is not so good. Maybe you were with your boyfriend or girlfriend and were discussing something while the film was on. Maybe you were drunk! There are a million reasons why you cannot recall the details. The three expressions given are stock responses for this situation :-)
"I'm don't really know much about ______" and "I'm not very familiar with _____" is a good way to tell someone that you don't have much knowledge about the topic.
If you want to discourage more conversation about the topic you could say "I'm not really into _____" to show that you don't know much about it and you're not interesting in talking about it without being rude.
"I don't really know much about ______"
"I'm not very familiar with _____"
特定の話題について十分に知らないことを相手に伝える表現です。
その話題について、もうあまり話したくないときは、
"I'm not really into _____"
と言うことで、その話題について十分に知らないことと、
その話題に興味のないことを、相手に失礼にならない範囲で伝えることが出来ます。
I have seen/watched it but I do not really know the details.
Although I have seen it I don't really know much about it.
"I have seen/watched it but I do not really know the details." This explains that you have watched the movie but you do not know much about the details of it.
"Although I have seen it I don't really know much about it."
"Although" Is used when comparing two things
This explains that even though you have watched the movie you know very little about it.
"I have seen/watched it but I do not really know the details."
(それは観たことがありますが、詳細はよく知りません。)
その映画を観たことはあるけど、詳細はよく知らないということを述べています。
"Although I have seen it I don't really know much about it."
(それを観たことはありますが、よく知りません。)
"Although"(~けれども)は 、2つのことを比べるときに使われます。こちらの文は、その映画を観たことはあるけど、その映画について本当に少ししか知らないということを述べています。
I don't know much about it
I know very little about it.
I don't have much knowledge about it.
I'm not very familiar with it.
I don't know much about it
そのことをあまり知らない。
I know very little about it.
そのことをほとんど知らない。
I don't have much knowledge about it.
そのことについてあまり知識がない。
I'm not very familiar with it.
そのことをよく知らない。
I have watched the movie but I don't really understand it.
*I have watched the movie (I have seen the movie)
---> You use but to introduce something which contrasts with what you have just said, or to introduce something which adds to what you have just said. (conjuction)
*I don't really understand it (I don't really know much about it)
*I have watched the movie (I have seen the movie)
その映画を見たことがある。
--->butを使うことで、何か言ったことと相反することを導入するときに使います。
また、接続詞として何か追加で言いたいことがあるときなどにも使えます。
*I don't really understand it (I don't really know much about it)
よくわからなかったよ。
I watched it but I'm afraid I'm still not familiar with it.
I'm not well versed with it.
"I hardly know anything about it." means that you have little knowledge about the subject or matter.
"I watched it but I'm afraid I'm still not familiar with it." this is a polite way to express that even though you watched the movie, your knowledge of it did not improve and hence you have no knowledge.
"I'm not well versed with it." is another way of saying you have no experience or familiarity of the movie or subject.
"I hardly know anything about it."は、それについてほとんど知らないという意味です。
"I watched it but I'm afraid I'm still not familiar with it."(見ましたけど、残念ながら詳しくはありません)
これは、その映画を見たけど詳しくはないと伝える丁寧な言い方です。
"I'm not well versed with it."(あまり詳しくありません)
これも、それ(その映画)についてあまり詳しくない、経験がないという意味です。
I know I watched it ... but I am not sure of all the ins and outs;-)
"The ins and outs...: is a well used idiom and it refers to .... "the detailed or complicated facts of something"
"I know I watched it ... but I am not sure of all the ins and outs;-)"
「the ins and outs」はよく使われるイディオムで、「(~の) 詳細、複雑なところ」を表します。
"I know I watched it... but I am not sure of all the ins and outs;-)"
(見たことはあるけど... 詳しくは知らない)
I have seen the movie but I was not paying a lot of attention
if you are referring to a topic then you could say "I know of it but I am not a expert"
however if you are referring to a movie then you could say "I have seen the movie but I was not paying a lot of attention"
話題についていうなら、"I know of it but I am not an expert"(知っているけど詳しくはない)と言えます。
映画についていうなら、"I have seen the movie but I was not paying a lot of attention"(映画は見ましたが、あまり真剣に見ていませんでした)と言えます。
"This looks familiar"
For something to be familiar is something that you have seen/heard before. you may or not know it well or not.
"I can't remember what happens"
Casual statement, referring that you don't know what happens but you have seen or heard it before.
"This looks familiar"(これは見覚えがあります)
"familiar" は「見たことがある/聞いたことがある」の意味です。それについて詳しいこともあればそうでないこともあります。
"I can't remember what happens"(内容は覚えていない)
カジュアルな言い方です。内容は分からないけど、見たことあるいは聞いたことはあると伝えています。
I don't know much about it.
私はそれについてあまり知りません。
I'm not an expert.
私は専門家ではありません(詳しくないです)。
上記のように英語で表現することができます。
not an expert は「あまり詳しくない」というニュアンスで使うことができる英語表現です。
お役に立てれば嬉しいです。
またいつでも質問してください。