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Ever larger sensors.


Stuart Brereton

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I've just completed my first ever 5D narrative shoot. I've used them before on music videos etc, but never for a proper piece of drama. Despite being pleasantly surprised by the quality of images from the new 5D MkIII with my old Asahi primes, I have to say that the DoF is a real pain in the ass. My preferred stop is generally around f2.8. I feel this has a great DoF, while still giving my 1st AC a chance. In Full Frame terms, this is something like a f5.0 or 5.6, and that's quite a stop to light to even with a reasonable package, particularly on night exteriors.

 

With new sensors like the RED Dragon, I can see this being a trend that develops into the professional world, and I wonder about the implications, not just for focus, but also for the size of our lighting packages.

 

Thoughts...?

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Well who knows, maybe it'll bring us back towards hard lighting, and really controlling things, as opposed to just throwing up a nice soft side source. Could be interesting.

In truth, though I also think whomever makes a good noise reduction plugin will be making some good coin as we keep upping our ISOs to save our asses when we realize we backed ourselves into a corner with an overly large sensor and underwhelming lighting package.

Another perhaps side effect is we will go back a bit towards wider lenses, and wider shots-- which could be interesting. I think we often get close up overload.

 

Then again, perhaps it will just be that productions will be once bitten twice shy. I'm not sure if the Dragon has a window mode-- but that may come into play, and/or people will just gravitate towards S35mm imagers more often.

 

Or maybe, we'll all get llucky, and by the insane need for practice and razor thin DoF, ACs will become true jedi.

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Well, think of it this way, if you had a chance to shoot in 35mm anamorphic or 65mm spherical, wouldn't you take a chance and deal with the shallower depth of field?

 

Not to say that it isn't a problem. However, as cameras get more sensitive, you can also stop down more.

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I think the depth of field difference between full frame and crop/super 35 is approximately 1 1/3 stops - I worked that out using a dof calculator but may have got it wrong.

However, larger sensors tend to have lower noise, so you can shoot at higher ISO, and I think the difference is usually at least a stop.

 

So with a 5diii you can have the same dof as a 7d (by going 1 1/3 stops narrower aperture and upping the iso by a stop or so), but you also have the option of having a shallower dof.

 

It's a choice, not a problem. If you never choose to go for the super shallow dof a full frame sensor allows, then the other disadvantages over crop (size, cost, weight) may make full frame not a good option.

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Generally speaking, though larger sensors also have higher resolution, which tends to decrease their dynamic range-- but that's only speaking generally, so you still get into situations where you start needing more light to cajole things into the dynamic range you have.

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Couldn't agree more.

 

It is a bit relative, though. Recently shot a very small project which was, among other things, an education in the difficulty of working with even s35-sized sensors under less-than-ideal circumstances (not to take anything away from the crew, but there weren't enough of us or enough gear). It would have been better shot on 2/3" video - anyone with an IQ greater than their shoe size can control depth of field on B4 lenses that open up to 1.4 anyway. I'm sure the concerns over full frame 35 sensors apply to a full crew with proper gear.

 

But in general, yes. I wish that all high-res big-chip cameras, such as the Blackmagic 4K, had HD sensor windowing modes.

 

P

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David, I would love to shoot some 65mm, but I'd assume that with the budget to shoot it would come a lighting package that was appropriate. I'm used to working at 800asa, at around f2.8. That translates roughly as f1.8 on FF. I don't believe that the 5D is sufficiently quiet at 2000asa to compensate for the difference.

 

I do like the look of Full-Frame, I just foresee a time (much like when the RED first appeared) when producers will try to force a FF camera package on me, because it's the new fashion, or they own one, or VFX have requested it. Those same producers will look at me blankly when I try to explain why I need more lights, or why there are more focus buzzes than usual.

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That never bothered me. I've spent my life shooting so many different formats that I must admit I've never been able to normalise my instincts to a particular focal length representing a particular field of view or suitability for a particular shot. And I'm normally shooting on zooms, anyway, so it's tweakable. I know that on 2/3" we need one that goes down into the single digits and on super35 sensors we don't, but that's about as far as my head goes - call me a rank amateur.

 

And in any case, knowing the size of the sensor might not be that much help. The relationship between diagonal size and field of view isn't exactly counterintuitive but it is rather nonlinear, and 2/3" sensors aren't actually two thirds of an inch across in any case. There are many confounding factors.

 

P

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Super-35 is a cinema format and is 24mm wide; "Full-Frame 35mm" refers to the original size of 35mm still film, which is 8-perf horizontal, not 4-perf vertical, and is 36mm wide. VistaVision is the equivalent of Full-Frame 35mm.

 

Not to be confused with Full Aperture, which just refers to the largest possible area that can be captured on the particular film format.

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