Don't buy the lens, rent it!

And once you have tried it and see the results you can always decide whether it is worth for you to invest in buying it, depending on how often you use it. Don't let not owning the best equipment to stop you delivering the best results possible! You can rent the lens, many cities offer the possibility to do so. Some photographers add the renting gear to their invoice and others include it in their fee. Also, if you are thinking of buying one anyway, I still suggest to try different ones out and then evaluate your choice once you have tried them! Last time I rented a wide angle lens that in theory was great and so were the reviews but it did not deliver amazing results as I expected. But I learnt it. Later on, I rented one that surprised me with the most amazing results that made my vision come across and do my job right. So I will buy that one over the other one even if it is more expensive but it is an investment in quality while the other one would just not be worth. If you live in The Netherlands you can rent photography gear at Budgetcam.nl which has many locations across the country. For cinematography and more offer there are many other sites such as "The Window", etc.