Page 2 of 2

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Tue May 23, 2017 4:15 pm
by Gene Kochanowsky
Johan Cramer wrote:
Gene Kochanowsky wrote:According to the Sony specs, the RX100M5 and a6500 output 4:2:2 10 bit on their HDMI ports.

No, they don't. No Sony consumer camera does. You're definitely mistaken.


I see that now. I conflated 4:2:2 with 10bit when in fact it was only 8bit.

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Tue May 23, 2017 5:10 pm
by John Brawley
Gene Kochanowsky wrote:
John Brawley wrote:
Uli Plank wrote:IMHO the best way to measure it is shooting a Xyla 21 from DSC.
Unfortunately that thing is expensive and needs a pitch black studio.


Yes.

It needs to be done properly. Not only that, but you'll still get differences in opinion on what's acceptable noise. Some will see 14 stops and some will see 12.

DR is a subjective measure. One mans noise is another mans shadow range.

I personally think that noise should also be evealuted in MOTION. Your perception of noise changes from a still frame to one that's moving but no one ever shoots DR charts like that either.

JB


John, What do you think of this experimental setup? It will be crude but I think it will be effective.

1. Using the following set of nd filters construct a test apparatus similar to the Xyla21
https://www.bhphotovideo.com/c/product/ ... y_Gel.html
2. Since I'll be using gel ND filters the chart will be illuminated from behind using a light constructed from one of these:
https://www.amazon.com/gp/product/B01DX ... UTF8&psc=1
3. Aluminum foil painted black will be used for the opaque parts of the apparatus.
4. I will setup the apparatus so that it will flip up and reveal the light so an image can be taken of the light intensities illuminating the gels.
5. Then an image will be taken of the apparatus back illuminated.
6. Steps 4 and 5 will be repeated a dozen times or so to take a statistical sample to examine variation in light values over the course of the test.
7. I will use a program that will allow me to review the frames and measure light intensities in bit values. (Not sure if Resolve has this functionality)
8. All this will be recorded in a spreadsheet for analysis.
9. Maybe I'll write up a paper and post it on the board.

If light uniformity is in question I could construct a slit in the light and move it across the apparatus to use the same light source for all stops.


Hard to answer from set on an iPhone.

It's not the way I do it but it seems fine if you want to emulate the test chart model.

I prefer to shoot a person in controlled lighting.

I put a range of lighting into the scene. Aim for say 5 stops.

I'll also put what I call an exposure ramp. Take a Fres type lamp and run it along a wall in the background. The point closest to the lamp will generally meter f22 on a spot and it peters off to nothing at the end of the beam.

Then I'll get a light trap. A light tight shoe box enclosed and painted black on the inside. Cut a small hole in one end and face to camera. This is your "true" black. This is an important reference for the noise floor. This black is always black no matter how far you lift it. It helps tell you when you've lifted the exposure too much.

THEN

You do bracketed exposure takes. Make what you decide is the zero "correct" exposure. Then do +1 stop, +2 etc for as much as you need or want. Then do -1 and -2 etc.

THEN

Grade your zero exposure how you like it. Distribute the 5 stops.

THEN try to match each exposure bracket to the same grade. By trying to recover the gradual under or overexposed images you get to see the DR clips (add the bracket to the different 5 stop scene exposure readings) plus you're also testing the recoverability of your bit deapth / codec combo.

Many times you can have an 8 bit codec that looks OK out of camera. But as soon as you try to reposition something that sits at 80% on the vector down to 35% you'll find it technically can do it but it looks like total crap. Plus this way you're testing a shot in motion.

So that's how manufactures can have high DR claims but it's all BS until you shoot in the real world and work with it.

By the way, I think the lessor known Arri test chart is better if that's what you want to replicate b

https://www.arri.com/arriajax?mod=produ ... roduct=263

JB

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Wed May 24, 2017 2:07 am
by Denny Smith
The Panny GH4 was the first consumer type camera that I am aware of, to offer a 10-bit output, as does the GH5. All Sony and Canon still/video consumer cameras are 8-bit output, to force you to buy their Pro video cameras to get 10-bit output/recording.
DS

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Wed May 24, 2017 2:18 am
by Uli Plank
Well, Leica was the first, but the tech was coming from Panasonic.
Of course, that Arri device is a viable alternative. But since no manufacturer is giving you linear data, rather they all apply different sorts of curves, I like how the Xyla 21 shows you at one glance what the whole ramp looks like.
Exposure bracketing needs more experience to interpret it correctly and to compare cameras. The whole aspect of subjectivity stays valid, not only for noise, but colors too.

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Wed May 24, 2017 4:52 pm
by Denny Smith
Thanks Uli, but we're discussing "consumer/prosummer" level still/video cameras, I consider high end Leica and Arri to be Pro gear, so I would expect 10 to 14-bit image processing.
Cheers

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Wed May 24, 2017 5:40 pm
by Rakesh Malik
Johan Cramer wrote:No, you only get 8bit wrapped in 10bit ProRes.


That part is correct. Sony's consumer video cameras only process 8-bit video, so the "10-bit" output is just padded from 8 to 10 bits with extra zeroes, rather than with additional data.

And that dynamic range will only be preserved when you record in Slog for which 8bit doesn't provide sufficient color depth.


That's also not entirely accurate; you CAN get 12 (or even 14) stops of dynamic range with 8-bit color, but there's not enough detail available for much grading latitude, because the lower bit depth limits the quantization accuracy.

The size of the bucket (i.e. maximum amount of luminosity before clipping) is the same; the difference is like using an 8-oz cup to measure the value (where a cup with a little water in it has the same value as a cup that's almost but not quite overflowing) instead of using a teaspoon with the same all-or-nothing restriction. (This is in reality how quantization works; that's why it's called "quantization.") Oversimplified yes, but still valid.

So if you're recording with an 8-bit imaging system, you have less room for fixing exposure or color balance problems in post than if you're recording with a higher bit depth imaging system.

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Wed May 24, 2017 5:49 pm
by John Brawley
Which is why 10 bit is a large order of magnitude better than 8 bit.

And guess what...

12 bit is a giant leap again over 10 bit.

This is the true secret of why these cameras perform so well in my view. Not high DR but high bit depth couple with little or no compression.

JB

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Wed May 24, 2017 6:33 pm
by Rakesh Malik
John Brawley wrote:Which is why 10 bit is a large order of magnitude better than 8 bit.

And guess what...

12 bit is a giant leap again over 10 bit.

This is the true secret of why these cameras perform so well in my view. Not high DR but high bit depth couple with little or no compression.


Not that the dynamic range hurts of course... but yeah, it doesn't SOUND like much to go from 8 to 10 or from 10 to 12 bits, but since they're exponential, the increase in the number of quanta available is huge.

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Thu May 25, 2017 12:38 am
by Uli Plank
Leica doesn't make pro motion cameras, only lenses for those.
But, there are consumers like you and me and then there are consumers who can afford to show off a red dot on their photo cameras when hanging around with other rich folks ;-)
Panasonic is doing the electronics for these cameras.

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Thu May 25, 2017 9:57 pm
by John Brawley
I was under the impression Sony made the sensor in the Leica SL.

Panasonic have a relationship with Leica over some lenses and they also sell some Leica branded Panasonic made cameras at the very low end point and shoot camera end.

As someone that owns severa Leicas my experience is has always been one of imaging satisfaction. I often try and use other cameras but find I drift back to Leica M's.

There's no way they can justify the cost but there is something special about them. They're also very unreliable ! Me Leica M-E is 4 years old and has had to have he shutter replaced AND the sensor. The new sensor has problems but I love the damn camera so much I can't bear to part with it for repair till I wrap on this job I'm on now.

I'm in the very long and overdue pre-order q for the new Leica M.

They have terrible Q A and service. But I can't be without them.

Most of the recent images in my Flickr stream are Leica.

https://www.flickr.com/photos/johnbrawley/

JB

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Fri May 26, 2017 5:35 pm
by Denny Smith
Yes John, there is something special about Leica top end cameras, and their lenses are a amoung the best.
The old mechanical Leica Ms (film cameras) were among the best ever made, unlike the new digital cameras, very reliable, my M4/5 never failed me in a job.
Cheers

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Fri May 26, 2017 5:38 pm
by John Brawley
Denny Smith wrote:Yes John, there is something special about Leica top end cameras, and their lenses are a amoung the best.
The old mechanical Leica Ms (film cameras) were among the best ever made, unlike the new digital cameras, very reliable, my M4/5 never failed me in a job.
Cheers


Ha. You have an M5 ? Is the meter still working ? ;-)

I have a single stroke M3 that I use daily and it's simply amazing. The serial indicates mid 60s and it takes great photos. Also have an M7 and I just bought an MP (film) because they really are amazing mechanical perfection !

Sorry for the off topic !

JB

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Fri May 26, 2017 5:45 pm
by Denny Smith
John, yes the M5 meter was still working when I sold it several years ago. When I shoot film today, I am using a Rollie 6003 Pro (last model made) with the rotating 654 back. I preferthe larger negative, more "bit depth" :roll:
Cheers

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Fri May 26, 2017 6:08 pm
by John Brawley
Denny Smith wrote:John, yes the M5 meter was still working when I sold it several years ago. When I shoot film today, I am using a Rollie 6003 Pro (last model made) with the rotating 654 back. I preferthe larger negative, more "bit depth" :roll:
Cheers


Well I just go to the Mamiya 7 for the medium format "Leica" experience :-)

JB

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Sun May 28, 2017 5:13 pm
by Denny Smith
Yes, the Mamiya 7 is a nice MF option too, along with the Fujifilm MF rangefinder cameras.
For my "Leica" small/light MF camera experience, I also have a custom rebuilt Graflex XL Wide Angle camera with a 47mm Schneider Super Angulon XL lens for landscape shots.
Cheers

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Mon May 29, 2017 7:08 pm
by Leon Benzakein
Please see this post.
viewtopic.php?f=14&t=59942
:ugeek:

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Tue May 30, 2017 1:27 am
by Denny Smith
Funny Leon... :lol:
Cheers

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Tue May 30, 2017 2:53 am
by Leon Benzakein
Denny Smith wrote:Funny Leon... :lol:
Cheers


Thank you Maestro. :ugeek:

The BMPCC RULES!

Re: Future Pocket Cam is a New Cinema Camera

PostPosted: Tue May 30, 2017 4:56 pm
by ryancheng2000
Just keep the form of bmpcc, let's make it interchangeable mount, better / sturdy output slot, decent audio and higher frame rate!

don't join the resolution race in this form of camera, the d-range and picture quality are best weapon of this cam!