TAKOBOTO

if
If it's from outside, I don't mind.

そとからならとってもいいよといわれたので，そとにでてさつえいしました。

I was told that if you're taking it from outside I don't mind so I went out and took the shot.

のるならのむな。

If you drive, don't drink.

じぶんのしんねんをかくすくらいならしんだほうがましだ。

I would rather die than conceal my belief.

よんどころないりゆうでさんかされないのならまえばらいきんはおかえしします。

If you cannot attend for unavoidable reasons, we will refund your advance payment.

ごつごうによりさんかされないのならまえばらいきんはおかえししません。

If you cannot attend for reasons of your own, the advance payment will not be refunded.

そのしごとがだめだとおもうなら、やめればいいとおもうよ。

If you think the job is no good, then I think it is best if you quit.

せんだいにきていたなら、でんわをしてくれればよかったのに。

If you were in Sendai, you should have called me.

かれがくるならこのパーティーにはしゅっせきしなかったのに。

If I knew HE was coming, I wouldn't have attended this party.

「うちあわせのじかんは７じどうですか。」「じはだめですが、じならいいですよ。」

uHow about meeting at 7 o'clock?」「7 is bad for me, but 8 is fine.」

ちゅうごくにいくなら、こうくうけんをはやくしといたほうがいいですよ。

If you go to China, you should book your ticket early.

there are a few if/when constructs:

[nara] is similar to -[eba]
formed with verb-plain form + nara
　行くなら分かる = if/when you go you will understand

[to] is used when the action is expected to happen, rather than use the english 'if' use 'when...'
formed with verb-plain form + to
　行かないとまずい = it will be bad if you dont go

[eba] is used when PEOPLE do the actions or suggesting an action. masu-stem + ba
　行けばいいよ　= its ok to go

[tara] is used in the other cases
寒かったら行かない = if its cold i won't go

dc

〜なら：１．もし (if) ; 辞書形 +（の,optional)なら

2.勧告(advice); 辞書形 + (の,optional)なら

3.話題を出す時; (Speaking of.../ For...) ; 名詞 +（の,optional)なら

誠

(GOOD)冷蔵庫を閉めた（な）ら　電気が消えますか。
I cannot exaplain the difference usage in [tara] and [nara]

dc

であれば is closely realted to なら.

bamboo4

nara is similar to -eba
eba is used when PEOPLE do the actions or suggesting an action.
tara is used in the other cases
and to is used when the action is expected to happen, rather than use the english 'if' use 'when...'

KotatsuSama

KS - I added your comment as a "note" on the above...

dc

I also thought -tara had a bit more "when" whereas -eba was a bit more if.
行ったら： when you go
行けば： if you go

although there is much more overlap than english

dc

行ったら is more like "when you get there" and 行くなら would be "if you go." 行けば is either soft command or archaic "when you go."

bamboo4

なら is used in the context of suggestions, commands, violitional sentences and such. (One example of each above ;-)

Amatuka

Therefore なら can't be used in sentences like the following where no such elements are present.
(BAD) 冷蔵庫を閉めるなら電気が消えますか。
(GOOD) 冷蔵庫を閉めると電気が消えますか。
If(when) you shut the fridge does the light go out?

Amatuka

「なら」と「たら」の違い
例：「山田さんが来たら、私は帰ります。」の場合には、
山田さんが来てから私が帰るという意味であるが、「山田さんが来るなら、私は帰ります。」の場合には、山田さんが来る前に私が帰るという意味になる。
うふふふ、朝飯前わね＾＾

フリザ

と can also mean " that..."
行かないとまずい " It is not good that (I/you/one) don't go"

誠

〜なら／ならば、．．．、although なら is more common and usually, appear in conversations.

誠

One cannot use と(if/once)、with 意志形、命令形、ください、but instead use たら、なら、〜えば according to the respective situations or sentence.

誠

Agree with フリザさん.
「ここは禁煙です。煙草を吸うなら、外へ出てください。」→　外へ出てから、煙草を吸っては構いません。

「煙草を吸ったら、入ってもいいです。」→ 煙草を吸ってから、入っても構いません。

誠

誠さん、解釈の日本語変だと思いますが…。

Miki

Correctly, 外へ出てから、煙草を吸っても構いません。

bamboo4