With the ever-changing world of large-sensor cameras, it is becoming difficult to know when to "pull the trigger" on a particular camera. Just when you think you have found the perfect solution, another new product is announced that has even better features. If you are needing a DSLR or other camera on just a few shoots a year, you might consider the rental houses that have popped up online recently.
Sites such as BorrowLenses.com and ATS Rentals have a great selection of cameras, lenses and even accessories for super low rates. One of my favorites because of their great service is The Lens Depot. For less than $300/week, you can be shooting with a Canon 5dMKII, 7D or 60D and a number of super fast lenses that will yield amazing images. So far, I have not seen anyone offer true cinema lenses (such as the Zeiss Compact Primes) at discount prices, but I imagine someone may in the not too distant future.
In my experience, these discount places are actually easier to rent from than local rental houses as far as the paperwork goes, and the shipping process is quite painless. Give them a try for your next shoot--or just use them as a way to "try before you buy" a particular camera system.
