As usual with this kind of question, you have to define what you mean by "worth". It's probably (rather: it's surely) not the first book that you should refer to for photography. On the other hand, it is a book of enormous importance in the history of mankind, so it is worth, in the sense that a masterpiece is always worthwhile.

In this vein, have you already read Galilei's works? They are (in my opinion) rather enjoyable even for modern readers and they surely are masterpieces (scientific and literary ones).

UPDATE, as requested

From a brief search on Amazon, here are some links. I don't know about the quality of the editions, since I read them in the original version.

• Dialogue Concerning the Two Chief World Systems
• Sidereus Nuncius
• Discoveries and Opinions of Galileo (contains the sidereus nuncius)

As a minimum, Galilei is relevant if you are interested into astronomy. The use of the telescope is also quite relevant... and now I will stop arguing about the relevance of Galilei, since he certainly doesn't need me :-)