DSLRs and lenses...

Film-making is a unique pursuit in that it combines, as no other, the technical with the artistic.  It contains elements of theater, music, photography, literature, and - increasingly - computer simulation. No other art form can claim such an eclectic mix of disciplines.

For our project, the technical stuff begins with a Canon DSLR - the EOS Rebel T2i.  Given our budget, it's probably the best choice: it's essentially a 7D, internally, but packaged in a less expensive form factor - so much less expensive, that it's fairly astonishing what you get for your money.  The level of quality for the price is unbeatable.  We're also running Magic Lantern, which allows us some creative options well beyond the standard firmware, including ISO settings at multiples of 160, focus peaking, false color exposure monitoring, and even HDR recording, if we want it.

Where we spent a little more is on a set of Canon prime lenses: 20mm/f2.8, 50mm/f1.8, and 85mm/f1.8.  There are several reasons to select primes over the kit zoom lenses, but the major ones, in descending order of importance, are:

• The primes are faster (meaning able to take in more light) by anywhere from half a stop to two-and-a-half stops, depending on the focal length.  This is very significant when shooting at night, and our third act takes place mostly in the dark.
• The manual focusing rings stay put.  On the barrels of the less expensive zoom lenses, they ride with a section of the lens that "telescopes" as the focus and/or focal length changes.  This makes using a proper follow-focus rig difficult or impossible, depending on the lens.  Keeping the focus ring in place is more mechanically complex and therefor more difficult to manufacture.
• Primes are sharper.  This has always been true, though - admittedly - modern zoom optics (even on the lower-end models) have gotten so good it almost doesn't matter.  Still, when you're shooting at 1080 x 1920, every little bit helps.
• The front lens element does not rotate on better primes, which expands the range of filter options available.  For example, the use of a graduated filter or split-field diopter requires that the filter remain rotated at the same angle throughout the focusing range, or the effect gives itself away.

So if you're considering using a DSLR to film a movie, you should consider renting or buying a couple of good prime lenses.  We are going to keep higher-end 24-85mm/f3.5-4.5 Canon zoom around in the kit, just in case, but we don't expect to use it often, if at all.