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How much does Dynamic Range matter?

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So I was shooting on an F900 for a year, it had it's age related problems, but the build quality and sensor is superb.

 

Just had my first shoot with this new URSA Mini Pro, the one thing that stands out as awesome to me is an extra 3-4 stops of DR from what I'm used to. Also capable of INTERNAL recording which makes life super easy.

 

However, I don't like the native gamma curve (I've been working it in Davinci, but still), moire everywhere, color science doesn't blow away a camera 18 years older, ugly FPN, and the body itself feels CHEAP.

 

I guess I'm asking, what do you value more? Dynamic range and internal recording? Or overall ergonomics free of miscellaneous visual blunders?

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It just really depends on how you shoot. Dynamic range doesn't matter in all cases. And if people are lighting for cinematic contrast they will kill half their dynamic range anyway. It only matters when the story calls for pleasant rolloff in high latitude scenes. For most controlled scenes you wouldnt be able to tell a 13 stop camera from a 14 stop. Plus since modern cinematography is pushing into the darks bit depth probably matters more for clarity than the stops of dr the sensor can handle. Highlight retention is easy to handle on most cameras now especially if your already 1.5 under for key and have some nd gel.

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It really isn't just about total DR, but how well the medium in question handles its breaking points.

 

Look at Canon DSLRs for example. They've got thoroughly unimpressive DR, a good 3-4 stops down from what Nikon and Sony are doing. But they rolloff into their white clip point very gracefully. In the video world, the Sony F35 is a good example of the same thing, and in film, positive transparencies have similar characteristics.

 

And ultimately, the significance of a wide latitude is directly related to your ability to control the contrast range in your composition with lighting. The more control you have, the less significant the need for a wider latitude is.

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And ultimately, the significance of a wide latitude is directly related to your ability to control the contrast range in your composition with lighting. The more control you have, the less significant the need for a wider latitude is.

I beg to differ here. Adjusting the lighting to match a low DR capture is a significantly different look. DR does matter, even with a truck load of lighting gear.

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And ultimately, the significance of a wide latitude is directly related to your ability to control the contrast range in your composition with lighting. The more control you have, the less significant the need for a wider latitude is.

 

I always believed this, especially after years of shooting transparency film day in and day, mostly in a studio setting. Talk about dynamic range - 4 stops!

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nes par..? ...

If that's your schoolboy French, you must have gone to borstal ;) .

Edited by Mark Dunn

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If that's your schoolboy French, you must have gone to borstal ;) .

 

 

Borstal was considered the Posh school where I grew up Sir.. only the soft lads went there..

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The better/wider DR you can capture just has to better for post/grading nes par..? ...

 

I would say color depth, not so much dynamic range, makes for more options during grading. It's funny how we want as much range as possible when we ultimately end up compressing the dynamic range anyway.

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I would say color depth, not so much dynamic range, makes for more options during grading. It's funny how we want as much range as possible when we ultimately end up compressing the dynamic range anyway.

 

Capturing 14 stops dr and compressing to 7 or w/e rec 709 is much different then capturing only 7 stops to begin with

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By starting out with more dynamic range we can smooth out the rate of clipping to something more natural and elegant plus adjust the occasional hot window or lampshade separately from the faces. Its true that we need sufficient bit depth to avoid banding on gradients.

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Capturing 14 stops dr and compressing to 7 or w/e rec 709 is much different then capturing only 7 stops to begin with

 

Of course, but who's still shooting on MiniDV anymore?

 

 

By starting out with more dynamic range we can smooth out the rate of clipping to something more natural and elegant plus adjust the occasional hot window or lampshade separately from the faces. Its true that we need sufficient bit depth to avoid banding on gradients.

 

I was going to say "as long as highlight clipping was prevented or minimized" but I thought that was obvious :-)

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Someone please correct me if I'm wrong, but my understanding about DR is there are two bottle necks, full well capacity and bit depth. Which ever of the two has less stops of DR, thag is the actual DR of the camera. So 8 bit cameras have 8 stops. You can double the code values 8 times before you max out at 256 per channel. 10 bit has 10 stops, and 12 bit has 12 stops. Thats why 8 bit cameras can be so muddy underexposed, since the bottom three stops only have 14 code values per channel in total. Almost half the stops of DR the camera can see has very little color information. With less info the chances that the eye can tell the difference between the stops is low. Hence ETTR to utilize the top 4 stops that have over 80% of the color information the camera can capture.

 

With a 12 bit camera the additional code values are added to the highlights and middle grey is reset higher giving the darks near middle grey 4 times the color info. Visually theres an increase in clarity and spacial fidelity. I feel like the canon c200 is a good example. If anyone has seen the difference between the 8 bit capture and the 12 bit, the darks have more "DR." When two camera have the same bit depth but one has a higher full well capacity its obvious which one will look slightly better, but from my understanding bit depth in many casing can be the largest variable in DR.

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No, it'd be like this if cameras all recorded in linear without any internal processing and their sensors were completely noiseless.

Shortly, DR is mostly a sensor/encoding issue usually not connected with recording bit depth.

 

Less shortly...

The analog part's DR is limited not only by full well capacity but by thermal (Ikegami used Peltier elements to cool their CCDs which provided for a lowest-noise camera back in the day) and shot noise (which makes a difference at tiny currents inside there) as well. Then there's a preamp circuit.

In CMOS - a huge lot of MOSFET transistors (or even differential amps) which are impossible to get precisely matched and off course add their own noise. I don't know of any CMOS camera that used anything nonlinear in the sensor to compress the range before digitization. Kodak designed a sensor with two amps per pixel with different gain. A technology used in Alexas and Varicams now.

CCDs have an advantage (not only) here: they need a single preamp, which can be much more elaborate (we're not trading off real estate on silicon for more amp transistors) and include complicated nonlinear stuff like pre-knee.

This means what gets sampled by A/D isn't necessarily a ful-range signal - it can be compressed, it can be two signals, and there's always noise which makes redundant bit depth, well, redundant.

Then I guess you mixed up A/D converter bit depth with recording bit depth. I doubt there has ever been a pro camera with 8-bit A/D converters - 25 years ago they were already all 10 bit. Bit depth of A/Ds is generally such that lower bit(s) contain nothing usable. On cameras that output encoded video (either 709 or log) there's gamma correction taking place before bit depth gets lowered for recording. And if we're recording uncompressed raw, we're basically going straight from the A/D.

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Someone please correct me if I'm wrong, but my understanding about DR is there are two bottle necks, full well capacity and bit depth. Which ever of the two has less stops of DR, thag is the actual DR of the camera. So 8 bit cameras have 8 stops.

 

The only thing that determines the upper limit on dynamic range is the well capacity. The bit depth doesn't have any affect on the well capacity, and therefore no affect on dynamic range.

 

The bit depth just determines how many levels you can measure in each well. You can have a two-bit sensor with 16 stops of DR even though the only values you'd get out of it are empty, 1/4, 1/2/, 3/4, and full. Double the A/D to four bits, and you get 16 levels instead of just four. And so on.

 

This is of course over simplified, but the point is that bit depth is an encoding thing, not a determinant of dynamic range.

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The bit depth just determines how many levels you can measure in each well. You can have a two-bit sensor with 16 stops of DR even though the only values you'd get out of it are empty, 1/4, 1/2/, 3/4, and full.

It won't be a 16-stop sensor then :) Since 4-6 (or up to 11 if there's pre knee) stops of highlights will be all rendered as white (full). The same for shadows.

You do need sufficient A/D bit depth to utilize the full range of photosites. Recording bit depth, on the other hand, has little to do with latitude.

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Yea I was talking about recording bit depth, not the A/D. I guess my question is if you have a camera like the C series cameras that are 12bit sensors that are lowered to 8bit when encoded, is there no reduction in dynamic range after going down to 8 bit? If a lower A/D bit depth can effect the DR, why does the recording bit depth have no effect when theres less code values to distinguish stops especially on the lower end?

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It won't be a 16-stop sensor then :) Since 4-6 (or up to 11 if there's pre knee) stops of highlights will be all rendered as white (full). The same for shadows.

You do need sufficient A/D bit depth to utilize the full range of photosites. Recording bit depth, on the other hand, has little to do with latitude.

 

You're still wrong; it's still a 16-stop sensor. It's just going to be recorded as a coarse 16-stops. Yes, it's probably too coarse to be a useful for a 16-stop sensor, but that doesn't have any affect on the brightness range that it can handle, which is what the dynamic range is.

 

And that's why bit depth matters. It's not a determinant of dynamic range, but the bigger the dynamic range, bigger your buckets are for a given bit depth.

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