Learn Hardcore Japanese: watasitati ha zenin de syasin wo torimasu.

は is the topic marker. In 私たちは, it tells the listener “as for us…,” setting 私たち (“we”) as what the sentence is about. It’s different from the subject marker が, which directly identifies the doer of an action.

Why does 全員 have で after it, making 全員で? What nuance does this convey?

The particle で turns 全員 (“all members”) into an adverbial phrase meaning “together with everyone” or “as a group.” 全員で emphasizes that the action is done collectively by every single person.

What role does を play in 写真を撮ります?

を marks 写真 (“photo”) as the direct object of the verb 撮ります (“take” in polite form). So 写真を撮ります literally means “(we) take a photo.”

Why is the verb 撮る in its polite form 撮ります here? Could we use a different form?

撮ります is the polite -masu form, appropriate for formal or polite conversation. In casual speech you would use the plain form 撮る, as in 写真を撮る. You could also use the past polite 撮りました (“took a photo”) if you’re talking about something already done.

Does 撮ります indicate present tense or future tense?

Japanese -masu forms cover both present and future actions. Context tells you which one. In this sentence, the context is “we will take a photo,” so it’s future.

Can I replace 全員で with みんなで? What’s the difference?

Yes. みんなで写真を撮ります is perfectly natural and more casual. 全員で is slightly more formal and focuses on literally “every single member.” みんなで feels friendlier and less formal.

Why is 私たち used instead of 僕たち or 俺たち?

私たち is gender-neutral and polite, suitable for any situation. 僕たち is more masculine and casual, and 俺たち is even more rough or informal—often used among close male friends.

Is the word order in Japanese flexible? Could I say 私たちは写真を全員で撮ります?

Japanese word order is relatively flexible, but common flow is: Topic → Adverbial phrase (全員で) → Object (写真を) → Verb (撮ります). 私たちは写真を全員で撮ります is understandable but sounds less natural than 私たちは全員で写真を撮ります.