One important part of my journey from post-production lackey to camera assistant is one I need to be sure I don't neglect: studying. Whereas with post production, you can get by fairly well if you understand the most common formats and programs, the world of cameras is exceptionally vast. There are so many different models with so many different accessories to be used in so many kinds of situations--and if I want to be successful at this, I need to be able to take anything that comes at me and know at least something about it.
So I ventured into the world of lenses today. First up is a rarity I expect to never see on the job, but is AWESOME for all the reasons I would hate to actually use it:Catadioptric lenses.
This isn't a lens, it's a fucking rocket ship launcher. That outer glass is about to fall back and reveal the shaft of the ship in the center and it will take off in a fiery blast of mirrored glory.
Actually, I'm still in the process of figuring this thing out, because you can delve pretty far into the physics of it and I've forgotten most of physics from high school because my teacher was a senile old man who wore the same turtle neck every single day. But here are the basic points as I understand them...
The way catadioptric lenses are set up, they allow for extremely long focal lengths in a much smaller size lens. The above picture is of a Sony 500mm. If you've ever seen a similar length telephoto lens, you know they can get pretty damn big. Comparatively, this thing is tiny.
There are a lot of pros to these lenses when it comes to image quality, the one most important to me being the lack of chromatic aberration.
This, by the way, is chromatic aberration. As best as I understand it, the wavelengths have to travel so fucking far they get pissed off, I don't even know.
Anyway, catadioptric lenses don't do that, which is sweet. But the HUGE downside is the big, GLARING fact that theydo not have aperture controls.You buy a lens with a specific f-stop and that's it. No changing it. This means that the only way you can change your exposure is to throw ND filters in front of the lens, which if you're trying to really get exactly the exposure you want, is going to be an enormous, expensive, annoying pain in the ass. It also means that you're going to have no control over your depth of field, so you better be a damned good focus puller.
Catadioptrics were manufactured mainly in the later part of the 20th century, and Sony is the only major manufacturer remaining that even offers a single model...and that's the one pictured above. I can understand why. With the way things are shot now, no one's got any patience for that shit.
So honestly, I hope I never run into one of these on an actual job, at least not before I'm some kind of seasoned pro in 1000 years. But if I do, I'd better learn to calculate exposure vs ND filters in my head REAL quick.