Within the last year I've been working quite a bit with the new dSLR's for indie films and shorts. First with the 7D and then recently the 5DmkII. I use a lot of older manual lenses because that is what I have. I've grown quite happy with some of the little quirks each one has. For example, my Super-Takumar 50mm f1.4 has a wonderful highlight bloom at 1.4 which virtually disappears at f1.8. I've used this effect for an entire dream/flashback sequence because I've never seen such a beautifully organic effect done in post.
I've even used old Canon FD mount lenses via an adapter ring (non optical) for macro use.

The thing I have noticed with some older lenses is their lower-contrast characteristic. I don't have a video dSLR of my own yet to test this, but I'm wondering what effects these might have on dynamic range. From the recent footage I shot earlier this month, I've noticed that shadow details are a bit more apparent with the older lenses, verses the few shots taken with the 24-70mm L we were using for wider angles. That lens has much higher contrast compared to the older Takumar, and I'm wondering if using lower contrast lenses might compress more information down to the sensor. Just some food for thought.

-Nathan

My photography market has 1000s of old lens, guess it might make sense to check em out. thanks!

Nathan,
Many lenses made decades ago had lower contrast glass or coatings in order to play nice with the high contrast black-and-white stocks of the time. Pentax screw mount is not exception-- I've got that 50mm and some others from my old spotmatic set, and the results are gorgeous with hi-con film (and on a digital body as well).

This idea does of course translate to DSLRs-- for instance, try shooting a test with a Zeiss prime (C/Y or newer) then with a nikkor prime- same stop, same frame- and look at the results. You will most likely see more highlight information from the nikkor because the zeiss have a higher contrast. Not necessarily a good or bad thing either way, but definitely something to note. I tend to shy away from the Canon L glass for DSLR video because the low end and dark detail is rendered very murky IMO... same shot with a zeiss or nikkor and the low end opens up with detail. (I will however gladly welcome the 70-200L..... that lens is something special!)

So your notion is right- lower contrast lenses put more information down the barrel, resulting in more *effective* dynamic range in your footage.