Luminous Landscape Forum
Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: wellcome86 on April 14, 2020, 01:40:06 pm
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Hi there,
Im a cinematographer and I'm searching a long time for a good still photography camera to jump from analog to digital but I'm just disappointed. What is your experience?
I made a practical Dynamic Range test with the best digital cameras available. Please judge by yourself and tell me if Im wrong. But the Phase One IQ3 100 has never ever 15 stops of dynamic range.
Cameras:
PHASE ONE IQ3 100 (2017)
- 35.000€
- 8984x 6732
- 15 Stops
- IIQ 16 Bit Compressed RAW / around 120MB
VS
Arri Alexa LF ( Sensor technology age 2008)
- 30.000 € - 90.000 €
- 4448 x 3096
- 14 Stops +
- Uncompressed 12 Bit / ARRI RAW / 20,9 MB Per Frame
Pictures are shown in an logarithmic Curve ( Log C) instead of linear, so we can see what informations are stored in the frames.
IQ3100 VS ALEXA -6 to +/-0
(http://www.sebastian-thaler.com/Link2Pictures/ALXEA VS IQ3100 002.jpg)
IQ3100 VS ALEXA +1 to +9
(http://www.sebastian-thaler.com/Link2Pictures/ALXEA VS IQ3100 001.jpg)
As you can see, with the PHASE ONE IQ3100 you already lose information when you just overexpose the image by 2 stops. Thats insane no? I thought that's best photo camera? Ok there is now the IQ4 150 but I doubt that the dynamic range improved.
My thoughts on that: I don't need 100MP if I can't overexpose by two stops or lets say it like that: anything what has 18% grey can't be over exposed by 2 Stops.
By the way, film holds up to +9, not losing any information.
I'm open for discussions :)))
thanks
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Hi there,
Im a cinematographer and I'm searching a long time for a good still photography camera to jump from analog to digital but I'm just disappointed. What is your experience?
I made a practical Dynamic Range test with the best digital cameras available. Please judge by yourself and tell me if Im wrong. But the Phase One IQ3 100 has never ever 15 stops of dynamic range.
I think there are some major misunderstandings in this post about the nature of dynamic range in a digital camera. For example, regarding over exposure, this is entirely a decision of the manufacturer of how much they want to underexpose "by default" in order to leave headroom. Neither camera tested can tolerate any actual overexposure (both will hard clip when they reach their maximum exposure), but they may have different approaches to how much they typically underexpose by when showing you a "normal" histogram or "normal" exposure evaluation tool.
I'm not clear how you generated the remaining visuals here, so can't comment further. But unless you used Capture One to do the processing and leveraged the available tools to boost/normalize exposure it's a moot point. Capture One can take advantage of the dark frame information in the raw and will do a better job of shadow recovery than other raw processing software.
In any case, if you're really driven toward the best possible dynamic range the Frame Averaging and Dual Exposure+ features of the IQ4 leave all other cameras far far far behind.
https://www.dtcommercialphoto.com/dual-exposure/
https://www.dtcommercialphoto.com/the-phase-one-iq4-now-has-automatic-frame-averaging/
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You may also enjoy the Maximizing Dynamic Range webinar (free) that the Head of R+D of Phase One made during our Project Lemonade Series: http://dtculturalheritage.com/dt-launches-project-lemonade-during-the-covid-19-crisis/ (scroll to bottom)
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I'm not clear how you generated the remaining visuals here, so can't comment further. But unless you used Capture One to do the processing and leveraged the available tools to boost/normalize exposure it's a moot point. Capture One can take advantage of the dark frame information in the raw and will do a better job of shadow recovery than other raw processing software.
Hi Doug,
thank you for your reply.
Its a very simple set up. I illuminated the chart, took my light meter set the base iso of the camera on the light meter and measured in front of the chart the hitting light.
so when I got my F-Stop and Shutter to the base ISO, I started to under and overexpose the chart by a full stop.
I think there are some major misunderstandings in this post about the nature of dynamic range in a digital camera. For example, regarding over exposure, this is entirely a decision of the manufacturer of how much they want to underexpose "by default" in order to leave headroom. Neither camera tested can tolerate any actual overexposure (both will hard clip when they reach their maximum exposure), but they may have different approaches to how much they typically underexpose by when showing you a "normal" histogram or "normal" exposure evaluation tool.
Im not sure if its a miss understanding or a lie or a cheap trick from some companies. to reduce the noise. let me explain:
lets take Kodak and analog film. if its written the film stock has 200 ASA, I know that my 18% Grey will be exposed as 18% also on film when I expose the film with the right settings. But what I also know is that my Dynamic range goes from -6 to +9 stops. (of course there are variations in the film stocks) the noise is given by the grain size.
when it comes to digital and the Arri Alexa, its the basically the same as analog film. the Base ISO is 800 and my 18% Grey is 18% Grey at 800 Iso with the correct settings according to the light meter. but I know that my 18% grey in the dynamic range of the Alexa is set quite in the middle of the range at base iso. and I have always 14+ stops no matter what ISO I choose I just shift the 18% Grey
please se the image:
(http://www.sebastian-thaler.com/Link2Pictures/Alexa.png)
the thing is, the base is should have a good Noise / ISO ratio to each other. and everybody wants low noise.
But ARRI made it very clear and I have full control and knowledge about what the sensor does.
for example, when make a frame indoor and my brightest spot outside a window is 8,5 stops over my base F-Stop (@800 ISO I have 7+ stops up), I can push the ISO from 800 to 1600 and I can shift my 18%grey one stop down of the dynamic range Scala and close my lens by one stop, so I get all my information outside and a correct preview. I don't win a stop but I know where my borders are.
With all other still photo cameras, its a mystery what is going on. how the sensor or the tech behind it is handling the data.
If I would translate the tech from the ARRI Alexa to the IQ3 100 the Base is must be much higher. But if they would set the Base ISO higher, the noise would be I guess quite bad for a medium format camera right?
The thing is if I rate the IQ3 100 @ 50 ISO I know my over expose limit is 2 stops. so I have to under expose bei 5 Stops to get lets say +7 as a peak captured. But doing that, I will never See in the back in the wild a normal looking picture.
And As I understood IIQ Format is not really a RAW where I can reset the ISO Setting. its not just metadata right? its more like a tiff format right? so there is a difference if I set the iso in camera to 400.I can't se it back in CO back to base of 50 ISO? at least its with my P65+ like that.
does that make all sense?
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by the way the Arri Alexa makes dual readout for the higher dynamic range
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Arri’s dual readout was there to circumvent the limitations of the 14 bit converter. At that time there was no sufficiently fast 16 bit converter available but nowadays there is, as applied by PhaseOne.
For the rest the comparison is apples and oranges to me as Arri has much fatter pixels andlower quantity. You’d get far more similar results if you:
- Apply also 800 ISO setting at the PhaseOne camera => increased highlight handling, especially in the range of 18% grey till saturation / clipping.
- Scale down the resolution of the PhaseOne 100Mpix camera to Arri’s 13 Mpix => increased lowlight handling / noise reduction.
Regards,
Jaap.
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Im not sure if its a miss understanding or a lie or a cheap trick from some companies. to reduce the noise.
This tells me you still misunderstand how digital exposure is working under the hood of *literally any* digital camera (still or motion).
All digital cameras clip the same way; all that varies is:
1) how far under that clipping point their histogram and ISO rating suggest you expose
2) how far into the shadows you can still extract usable/pretty visual information
In cinematography (and as you mention, in most traditional neg film) the tendency is to rate the ISO such that there is lots of highlight room. In still photography the tendency is to leave less highlight room. This is primarily because in the capture of motion imagery there is a greater likelihood of an "unexpected" highlight somewhere during the course of a given shot, whereas in still photography there is a greater likelihood of understanding the scene's tonal range in absolution for that specific capture. In either case, you can get the results of the other simply by changing the way you expose and push/pull (as you could with film by rating it differently before processing).
I'd suggest watching the Project Lemonade webinar on Dynamic Range by Lau: http://dtculturalheritage.com/dt-launches-project-lemonade-during-the-covid-19-crisis/
Simply put: a Phase One IQ4 produces an in-camera raw file with more usable dynamic range than any other camera on the market (stills or cinema). It's really not even close.
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This tells me you still misunderstand how digital exposure is working under the hood of *literally any* digital camera (still or motion).
All digital cameras clip the same way; all that varies is:
1) how far under that clipping point their histogram and ISO rating suggest you expose
2) how far into the shadows you can still extract usable/pretty visual information
Hi,
Believe me, I know what Im talking about when it come to motion picture digital cameras. still photography is a mystery.
Did you see the Exposer Index Chart from Arri for the Alexa that I posted in my previous post?
what you say is right, but what the point is: there is lack of information or communication from the manufacturer. Because I expect if somebody says your base is ISO 50 for the best balance between highlight and shadow coverage, then I expect that my image is not clipping the 18% grey when its 2 stops over.
coming from cinematography, my understanding is different. to get the advice to underexpose at base ISO to avoid clipping which is just 2 stops over is strange, technically and because my preview on the camera is dark. that's missing the point of a preview and of the describe "best performance of the sensor at base ISO"
and that's misleading when it comes to noise. sure if you make a picture that has no extrem highlights and you photograph it with low ISO, sure its the best looking image when it comes to noise. but if you stop down the f-stop to cover the highlights and push your image or lets say it better push the ISO to 400 or 800 to compensate the underexposer, your noise level increases. that logical. so maybe the given base ISO is just false, and should be higher, this of course kills the low noise level.
do you get my point? I just want to know where I have the sweet spot in the dymnamic range. I just want to know, when I have 7.5 stop headroom in the highlights and 7.5 stops in the shadows. what ISO? Like ARRI tells you very simple. And my preview image looks just fine and is ready to.
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do you get my point? I just want to know where I have the sweet spot in the dymnamic range. I just want to know, when I have 7.5 stop headroom in the highlights and 7.5 stops in the shadows. what ISO? Like ARRI tells you very simple. And my preview image looks just fine and is ready to.
Absolutely. I understand that you come from the world of Motion and expect the world of Still to provide identical workflows and equipment behavior despite presenting fundamentally different needs and shooting situations.
Still photographers, especially in high end applications, simply do not need “equal highlight and shadow flexibility” – they want the cleanest shadows without overexposing. It’s a different medium with different challenges that call for different expectations, tools, and workflows.
I suppose you still have not watched the webinar that is on this exact topic?
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I suppose you still have not watched the webinar that is on this exact topic?
Hi Doug,
thank you for discussing that topic with me:)
Sure I watched it. I know exactly that we should always expose to the right to fill the sensor with photons because the sensor just capture the light linear.
The sensors captures more information in upper area than in the lower end. we do that as well in the film industry. that's standard.
But the the webinar does not explain how much headroom I have at base ISO. how much is it? 5 stops? 4 Stops? What I also do not understand is, If I capture a RAW file in the IQ3 Back, why can't I change the ISO in POST? and As I understood If I change ISO in the camera its backed in. I can push and pull in CO the data by 4 stops, but that means for me that this is not a RAW file.
In my understanding, a RAW file is a File that represents a snapshot of the Sensor during the capturing. Un-debayed, un-manipulated Sensor Data. As I remember from my P65+ that's not the case, because I can set the suffix to .IIQ or .tiff. I do not remember how that is on the IQ3 100.
(http://www.sebastian-thaler.com/Link2Pictures/ARRIRAW.png)
The Webinar also mentions the Preview Images, but its exactly the problem that I describe. For collecting as much as possible of usable data from a high contrast scenery, I should use the "RAW" histogram. But then I get unusable Preview images.
And the higher ISO settings are not well explained. yes its brighten your image, but happens with the dynamic range? A sensor can just capture ( lets keep it simple) for example values from 0 - 1024. everything beyond is clipping. So setting higher ISO in the still photography universe is just doubling some informations but not shifting the 18% grey from value 500 to 200 in my example. is that so? when yes why?
thanks
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Hi to all,
here is a link, for the download of all files, ALEXA and IQ3100. for the arri RAW I included mac and win apps for viewing and playing.
just look at the picture 011 Exposuer +3.
with phase one the image is clipped and there is no highlight recovery possible anymore.
with the alexa all patterns are visible and good.
please play around:)
ARRI:
(http://www.sebastian-thaler.com/Link2Pictures/ARRI +3 Recovery.png)
IQ3 100:
(http://www.sebastian-thaler.com/Link2Pictures/IQ3 100 +3 Recovery.png)
LINK for DOWNLOAD:
https://we.tl/t-CoE62119sx
thanks
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Sure I watched it. I know exactly that we should always expose to the right to fill the sensor with photons because the sensor just capture the light linear.
The sensors captures more information in upper area than in the lower end. we do that as well in the film industry. that's standard.
But the the webinar does not explain how much headroom I have at base ISO.
The webinar explained the tools on the IQ3 and IQ4 that allow you to see where (not just how much) data is being retained in the highlights, across at least two channels (clipping one channel is actually not the end of the world in modern raw files with modern raw processing). Because one channel can clip, the amount of headroom cannot be described simply in number of stops. For example, a blue sky can be quite clipped and still result in excellent color/tone fidelity because the red and green channels, plus some fancy math, are used to restore the blue sky in Capture One. Hence whether they chose the cinema or stills approach to defining, displaying, and working with ISO vis a vis headroom vs shadowroom the answer would still not be a simple number, and the tool-based approach (raw histogram, clipping warning) would still be preferable.
However, if you *really* want to replicate your current/motion-based approach you can do so in the IQ4; simply have your dealer walk you through adding an ISO-adaption style to the IQ4 preview/histogram, and the back will treat a setting of ISO 50 as if it was ISO 800 as regards visual feedback and headroom.
If I capture a RAW file in the IQ3 Back, why can't I change the ISO in POST? and As I understood If I change ISO in the camera its backed in. I can push and pull in CO the data by 4 stops, but that means for me that this is not a RAW file.
In my understanding, a RAW file is a File that represents a snapshot of the Sensor during the capturing. Un-debayed, un-manipulated Sensor Data. As I remember from my P65+ that's not the case, because I can set the suffix to .IIQ or .tiff. I do not remember how that is on the IQ3 100.
Common misunderstanding. For historical reasons the Phase One Raw file is wrapped in a TIFF container, and for a few years P1 backs allowed you to select a file extension of .TIF if you wanted, but that's purely a technical/backend/pedantic thing. Every Phase One back ever made has only ever had the capability to capture a true raw file (despite the confusing file extension in some cases).
What is the source of this historical curiosity of crossed/confusing file extensions, you might ask? Phase One started doing raw capture in the late 90s, which was well before Lightroom, Aperture, and well before operating systems themselves started supporting basic things like thumbnails for raw files. Therefore, at that time, the only way for Phase One to write a raw file that would include a visual thumbnail at the OS level was to make their raw file technically compliant with the TIFF standard. The written specification for the TIFF format allows a form of "notes" to be attached, so if you open up the binary of a Phase One Raw file, what you'll find is that there is a very very small (IIRC something like 320x240 pixel) TIFF image with a very very very large "note" that contains the raw data. In order for the OS to see this as-intended (to show the small thumbnail sized image) the file had to end with .tif, which was confusing as heck since that is almost always associated with a raster/outputted file. So to (very partially) alleviate that confusion they made the Phase One Raw File extension ".TIF" (in capitals) since the overwhelming majority of files that make/save/edit tiff files use a lower case ".tif" extension. Of course people still (rightly) got confused, and over the years that followed operating systems generally smartened up to show thumbnails of raw files, so with the underlying motivation no longer relevant, Phase One switched to using the .IIQ file extension which is what they still use today.
I would encourage you to start working with a Phase One dealer that can provide expertise on deeper technical topics like this. That will help avoid the misunderstandings and misassumptions that lead to incorrect conclusions. If you're in the USA we would be glad to be that dealer.
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This tells me you still misunderstand how digital exposure is working under the hood of *literally any* digital camera (still or motion).
All digital cameras clip the same way; all that varies is:
1) how far under that clipping point their histogram and ISO rating suggest you expose
2) how far into the shadows you can still extract usable/pretty visual information
—/snip—-
Simply put: a Phase One IQ4 produces an in-camera raw file with more usable dynamic range than any other camera on the market (stills or cinema). It's really not even close.
Doug,
You may be “assuming” something about the Alexa.
Remember, there were sone digital cameras eg from Fuji with multiple sensels?
I suggest you do some research on the Arri Alexa before you embarrass yourself.
My feeling is the OP will not find a still camera with the DR of the Alexa, at least not in a still photo camera, although some machine vision cameras have crazy DR.
Edmund
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Doug,
You may be “assuming” something about the Alexa.
Remember, there were sone digital cameras eg from Fuji with multiple sensels?
I suggest you do some research on the Arri Alexa before you embarrass yourself.
My feeling is the OP will not find a still camera with the DR of the Alexa, at least not in a still photo camera, although some machine vision cameras have crazy DR.
Edmund
Hi Edmund,
Thank you for comment. I already had the feeling that nobody wants to see the difference.
Or is telling me that I’m technically on a low level and just making things up.
Which is just not truth.
Best regards
Sebastian
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I was trying to find info about the cameras and this is all I found: https://www.photonstophotos.net/Charts/PDR.htm#Phase%20One%20IQ3%20100MP Perhaps it helps give an idea of the DR and the actual ISOs of the IQ3.
Bill
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I was trying to find info about the cameras and this is all I found: https://www.photonstophotos.net/Charts/PDR.htm#Phase%20One%20IQ3%20100MP Perhaps it helps give an idea of the DR and the actual ISOs of the IQ3.
Bill
Hi Bill,
thank you for the page. that's really interesting how different the numbers are from DXO. Almost all are around 11 stops... why everybody wants more resolution? I don't get it.
The most interesting thing for me is that with higher ISO you loose DR. that's a very strange thing for me.
thanks for that input.
Sebastian
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Hi Sebastian,
The PDR is more conservative than the engineering DR. Most companies state the engineering DR.
I'm wondering if the Arri Alexa might have a bit more DR than the IQ3. Arri seems to use dual gain pixels for more DR and even though it is an older sensor the dual gain would help a lot.
Bill
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Hi Edmund,
Thank you for comment. I already had the feeling that nobody wants to see the difference.
Or is telling me that I’m technically on a low level and just making things up.
Which is just not truth.
Best regards
Sebastian
Sebastian,
Don’t worry, Doug is a very serious and competent dealer who knows eveything about medium format digital, but he has no experience in cinematography. He got a bit confused, it happens.
You will find that the DxO site is useful to compare DR between existing still cameras, but these cameras tend to be optimised for resolution rather than DR because historically they are tools intended for captures that will be displayed as paper print after some tone curve is applied.
Edmund
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I suggest you do some research on the Arri Alexa before you embarrass yourself.
Thanks for the concern Edmund.
Please carefully read every post I've made in this thread and point to a single thing that was not accurate :).
And honestly "before you embarrass yourself" is a really boorish thing to say.
My feeling is the OP will not find a still camera with the DR of the Alexa, at least not in a still photo camera, although some machine vision cameras have crazy DR.
Repeating myself from earlier in this thread... "In any case, if you're really driven toward the best possible dynamic range the Frame Averaging and Dual Exposure+ features of the IQ4 leave all other cameras far far far behind. That raw file is now the gold standard, and nothing else comes close."
Don’t worry, Doug is a very serious and competent dealer who knows everything about medium format digital, but he has no experience in cinematography. He got a bit confused, it happens.
I do get confused, often. In this case I am not.
However, based on the conversation so far, it seems unlikely that my further participation in this thread will lead anywhere positive, so I'm out.
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Hi Sebastian,
The PDR is more conservative than the engineering DR. Most companies state the engineering DR.
I'm wondering if the Arri Alexa might have a bit more DR than the IQ3. Arri seems to use dual gain pixels for more DR and even though it is an older sensor the dual gain would help a lot.
Bill
HI,
yes the Arri uses dual read out of the sensor since the alexa was introduced in 2008, Up to 200 frames a second. I can confirm from my experience of shooting a lot of features. I didn't come along any other camera yet that had really 14+ Stops of DR.
I was just wondering why there is such a difference between needs in Cinematography and Photography.
Both coming from an analog age where film had (has) the best DR possible. Resolution is important but I would love to have a back with just 60MP but the DR of the Alexa than 150MP.
Question for Doug:
How this Dual exposer works? Can it be use in handheld with moving objects? or just from the tripod and with static objects?
thanks
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“I would love to have a back with just 60MP but the DR of the Alexa than 150MP.“
I’m sure you would, as the fat pixel Alexa is only 13MP. A modern PhaseOne back equipped with a 16 bit ADC should easily provide similar or better images with a single exposure, provided you set the ISO accordingly and resize the image in post to 13 MP.
One thing about expected dynamic range from 18% grey level till saturation level. This is mathematically 2.5 stops, noting more, nothing less. So if the camera realizes 3 stops then the sensor well saturation level scaled to the A/D converter is correctly incorporated. In case you’re wondering where all the remaining dynamic range lives, whether it is 7 or 10 stops, that is all below the 18% level.
Regards,
Jaap.
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“I would love to have a back with just 60MP but the DR of the Alexa than 150MP.“
I’m sure you would, as the fat pixel Alexa is only 13MP. A modern PhaseOne back equipped with a 16 bit ADC should easily provide similar or better images with a single exposure, provided you set the ISO accordingly and resize the image in post to 13 MP.
One thing about expected dynamic range from 18% grey level till saturation level. This is mathematically 2.5 stops, noting more, nothing less. So if the camera realizes 3 stops then the sensor well saturation level scaled to the A/D converter is correctly incorporated. In case you’re wondering where all the remaining dynamic range lives, whether it is 7 or 10 stops, that is all below the 18% level.
Regards,
Jaap.
Hey Jaap,
Did you download my files? Please do that and have a look.
In my understanding an clipped pixel is an clipper pixel. If ist 1 pixel or 100. The amount of MP does not matter.
But when it comes to downsizing. Yes there it’s relevant. It makes sense when there is a need to reduce the noise. But downsizing can’t give you back clipped highlights. So therefore
the Alexa Sensor gets even more impressive for its age and DR and tech behind compared to the IQ3 100.
Please play around with files. It would be very interesting to know you opinion.
Please don’t judge the quantity of the pixels but the quality))
That would be really interesting.
Thx
Sebastian
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HI,
yes the Arri uses dual read out of the sensor since the alexa was introduced in 2008, Up to 200 frames a second. I can confirm from my experience of shooting a lot of features. I didn't come along any other camera yet that had really 14+ Stops of DR.
I was just wondering why there is such a difference between needs in Cinematography and Photography.
Both coming from an analog age where film had (has) the best DR possible. Resolution is important but I would love to have a back with just 60MP but the DR of the Alexa than 150MP.
Question for Doug:
How this Dual exposer works? Can it be use in handheld with moving objects? or just from the tripod and with static objects?
thanks
Here is some more info on the Dual Exposure option for the IQ4:
https://captureintegration.com/phase-one-labs-dual-exposure/ (https://captureintegration.com/phase-one-labs-dual-exposure/)
I have found the Dual exposure can handle slight motion (subject matter moving due to wind), much better than the Frame Averaging option. The results I was able to get before the shut down in my state, were impressive. I like what this option offers for my work. Frame Averaging could not handle any subject matter movement, but offered excellent image quality. Dual exposure also offers an huge range in exposure DR, and give the photographer an excellent starting point. You would need to have a tripod for either frame averaging or Dual exposure.
Paul C
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Here is some more info on the Dual Exposure option for the IQ4:
https://captureintegration.com/phase-one-labs-dual-exposure/ (https://captureintegration.com/phase-one-labs-dual-exposure/)
I have found the Dual exposure can handle slight motion (subject matter moving due to wind), much better than the Frame Averaging option. The results I was able to get before the shut down in my state, were impressive. I like what this option offers for my work. Frame Averaging could not handle any subject matter movement, but offered excellent image quality. Dual exposure also offers an huge range in exposure DR, and give the photographer an excellent starting point. You would need to have a tripod for either frame averaging or Dual exposure.
Paul C
Hi Paul
Thanks for the info, that’s a bit of a disadvantage, if some motion is not possible.
Hm... it needs testing again.
So I guess ocean and waves are not possible??
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One can probably process a short clip from the Alexa and get super-resolution.
Edmund
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Hi Paul
Thanks for the info, that’s a bit of a disadvantage, if some motion is not possible.
Hm... it needs testing again.
So I guess ocean and waves are not possible??
That is a good question on Ocean waves. I work with water all the time, but I am usually looking for the blurred effect, which I believe the dual exposure will work with. However due to the current situation in the US, I have not been able to get out and test it at all.
Hopefully as time goes by, some more test shots can be posted.
Paul C
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That is a good question on Ocean waves. I work with water all the time, but I am usually looking for the blurred effect, which I believe the dual exposure will work with. However due to the current situation in the US, I have not been able to get out and test it at all.
Hopefully as time goes by, some more test shots can be posted.
Paul C
Hi Paul,
Thank you that would be so great to see.
all the best
Sebastian
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The most interesting thing for me is that with higher ISO you loose DR. that's a very strange thing for me.
You're joking, right? I mean, come on! Before getting all huffy and puffy, maybe, just maybe, you should educate yourself on the basics of camera sensors, noise issues like amplifier noise, read noise, pre- and post-amplifier noise, how noise impacts dynamic range, etc. etc.
For instance, you may want to read this thread: https://forum.luminous-landscape.com/index.php?topic=56906.40
I fully understand why Doug Petersen bowed out.
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You're joking, right? I mean, come on! Before getting all huffy and puffy, maybe, just maybe, you should educate yourself on the basics of camera sensors, noise issues like amplifier noise, read noise, pre- and post-amplifier noise, how noise impacts dynamic range, etc. etc.
For instance, you may want to read this thread: https://forum.luminous-landscape.com/index.php?topic=56906.40
I fully understand why Doug Petersen bowed out.
Im not joking, If you look at the Arri DR chart that I posted earlier? then you will understand what I mean by that.
I know enough about sensors and the noise ratio etc.
But how the still photography workflow works right now, is for me a bit foggy and strange. Nothing is Clear. Its guessing while shooting.
With the ARRI Alexa workflow or RED workflow its totally clear. I get my base ISO and the Company tells me how much head room I have . that's it. I take My light meter and know where my limits are. And I don't loose any DR when changing the ISO. and when I change the ISO the company tells me again how my DR looks like. I collect always the same data no matter what Iso I set.
with the Example of the IQ100. I go out in to the field, take my light meter and it says me a proper setting. But things are blown out because everything that has 18% grey and is 3 stops over is clipped. So what do I do? I make a series of shots to find the right exposure. that's not professional that's guessing by try and error.
With the Arri Im not guessing what the sensor will capture, I know it. So Im not putting any energy in the philosophy of the right exposure, I concentrate on the shot it self.
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I know enough about sensors and the noise ratio etc.
But how the still photography workflow works right now, is for me a bit foggy and strange. Nothing is Clear. Its guessing while shooting.
I don't loose any DR when changing the ISO.
I collect always the same data no matter what Iso I set.
So Im not putting any energy in the philosophy of the right exposure, I concentrate on the shot it self.
I myself know next to nothing about anything, but... It's clear that you need to learn - a lot - about sensors, amplifiers, noise, etc. DR is not a constant, independent of ISO; headroom is not the same as DR; read up on it with an open mind; read the thread I linked to; read posts by experts like Andrew Rodney (digitaldog), Guillermo Luijk and others.
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I go out in to the field, take my light meter and it says me a proper setting. But things are blown out because everything that has 18% grey and is 3 stops over is clipped. So what do I do?
Use a camera with a live histogram and/or zebras.
Jim
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Use matrix metering and - if you are really into understanding the fine detail - use a program like Rawdigger to get a feel for how much headroom you have when using it. And, at the risk of repeating myself ad nauseam, learn to understand the difference between dynamic range/signal-to-noise-ratio and headroom.
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Hi,
The clue is that you use ISO 800 on the Arri and 100 on Phase One. Still cameras normally expose midtones like 3-3.5EV under saturation. Vid log video, it seems that higher ISO is used, which mostly means that the image is exposed say 6 EV below saturation.
Question is how the camera handles the intentional underexposure. If you expose at 800 ISO on a stills camera, chance is that the camera just multiplies the raw values with 8, throwing down DR. It is possible to shoot at 100 ISO, but underexpose 3 EV and push exposure 3EV in post. On an 'ISO less' camera the result would be the same as shooting at 800 ISO, but yielding 6EV of positive DR.
There may be an other factor. The pixels on the Arri may be larger. Per pixel, larger pixels will have higher DR than smaller pixels. The Arri is probably highly optimized for the intended image size, with antialiasing filters optimized for the requirements.
A stills camera is not optimized for motion. As an example, something like 40 MP is needed for 8K. If Arri has an 8K camera, the sensor is probably sized for 8K. The 8K image from the IQ 100 needs to be scaled down to 8K.
Stills and video are two different playing fields.
Best regards
Erik
Hi there,
Im a cinematographer and I'm searching a long time for a good still photography camera to jump from analog to digital but I'm just disappointed. What is your experience?
I made a practical Dynamic Range test with the best digital cameras available. Please judge by yourself and tell me if Im wrong. But the Phase One IQ3 100 has never ever 15 stops of dynamic range.
Cameras:
PHASE ONE IQ3 100 (2017)
- 35.000€
- 8984x 6732
- 15 Stops
- IIQ 16 Bit Compressed RAW / around 120MB
VS
Arri Alexa LF ( Sensor technology age 2008)
- 30.000 € - 90.000 €
- 4448 x 3096
- 14 Stops +
- Uncompressed 12 Bit / ARRI RAW / 20,9 MB Per Frame
Pictures are shown in an logarithmic Curve ( Log C) instead of linear, so we can see what informations are stored in the frames.
IQ3100 VS ALEXA -6 to +/-0
(http://www.sebastian-thaler.com/Link2Pictures/ALXEA VS IQ3100 002.jpg)
IQ3100 VS ALEXA +1 to +9
(http://www.sebastian-thaler.com/Link2Pictures/ALXEA VS IQ3100 001.jpg)
As you can see, with the PHASE ONE IQ3100 you already lose information when you just overexpose the image by 2 stops. Thats insane no? I thought that's best photo camera? Ok there is now the IQ4 150 but I doubt that the dynamic range improved.
My thoughts on that: I don't need 100MP if I can't overexpose by two stops or lets say it like that: anything what has 18% grey can't be over exposed by 2 Stops.
By the way, film holds up to +9, not losing any information.
I'm open for discussions :)))
thanks
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Arri’s dual readout was there to circumvent the limitations of the 14 bit converter. At that time there was no sufficiently fast 16 bit converter available but nowadays there is, as applied by PhaseOne.
This is incorrect. It is not just a "dual readout". It is simultaneous dual gain readout from each pixel.
Arri's ALEV III Dual Gain Architecture sensor is designed to increase dynamic range and reduce noise by optimizing the signal amplification for both highlight and shadow for each pixel simultaneously, producing HDR images in a single exposure.
"The Dual Gain Architecture simultaneously provides two separate read-out paths from each pixel with different amplification. The first path contains the regular, highly amplified signal. The second path contains a signal with lower amplification to capture the information that is clipped in the first path. Both paths feed into the camera's A/D converters, delivering a 14-bit image for each path. These images are then combined into a single 16-bit high dynamic range image. This method enhances low light performance and prevents the highlights from being clipped, thereby significantly extending the dynamic range of the image."
https://www.arri.com/en/learn-help/technology/alev-sensors (https://www.arri.com/en/learn-help/technology/alev-sensors)
When physics professor Dr. Emil Martinec proposed this type of sensor design in 2008 it was just a theoretical hoped for advance in technology. Just two years later, Arri turned the theory into reality with the first Alexa in 2010.
"What one would like is to somehow be able to use ISO 100 to keep all the highlights, while at the same time using ISO 1600 to recover all the shadows. But how can one have two ISO settings at once? By having two separate amplifiers fed from the same sensor data, running in parallel. Suppose that the sensor signal is sent to two separate processing paths, each path an amplifier and an ADC, with one amplifier set to ISO 100 and the other to ISO 1600. The ISO 100 path keeps all the highlights but has noisy shadows; the ISO 1600 path loses the top four stops of highlights but has much better shadows. Quantizing each, one can then combine the image data in a manner similar to HDR processing to yield an image with all 14 stops that the sensor is capable of recording. What would the result look like? Well of course, no such camera is currently made, but one can get an idea of the possibilities by shooting two successive images, one at ISO 100 and another at ISO 1600, and combining the two"
"As an aside, now that one is recording all the data that the sensor has to give, there is no reason to have a variable ISO gain, just the fixed 100/1600 parallel channels (or whatever two fixed amplifications optimize the data extraction). The ISO setting can be put into metadata like white balance is, a suggestion from the camera's metering to the raw converter as to what exposure compensation to apply in order to develop the image. As discussed on page 3, so long as noise sufficiently exceeds quantization step, there is no difference between amplification in hardware during the capture process, and amplification after the fact during raw conversion."
https://www.photonstophotos.net/Emil Martinec/noise-p3a.html (https://www.photonstophotos.net/Emil%20Martinec/noise-p3a.html)
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The Alexa is a remarkable camera. I frequently work side-by-side on commercial film sets with the Alexa (with my Phase One or Mark IV), and it is difficult to achieve a similar look with stills cameras as to what comes straight out of the Alexa.
The Alexa produces a very attractive image in poor conditions and low light, and holds highlights better than anything I've seen.
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Hi,
Most sensors are not limited by ADC but by sensor DR. Sensor DR is full well capacity, divided by readout noise.
Cameras intended for photography have sensors designed for high resolutions and the pixel size often limits full well capacity to something like 50000 e-. I would guess that readout noise may be around 4e- at base ISO, that gives 50000/4 -> 12500 which converts into 13.6 EV, fairly typical of high end sensors. Covering 13.6 EV requires about 13 bits, so 14 bit representation is a perfect fit.
If you don't need high resolution and use a proper OLP filter it would be possible to use larger pixels. These larger pixels may have larger full well capacity, say like 200000 e-. Now, readout noise increases with pixel size, as it reduces the voltage swing caused by the captured electron charges.
If we assume that we have a 24x36 mm sensor with say 10 MP (that would be needed for 4K) we may have a full well capacity of say 200000 e-. We may assume that readout noise is still 4e-, although that would probably increase with larger pixels. But, with 4e- readout noise DR would be 50000, that is 15.6 EV. You may need 15 bits to handle that.
In reality, the increase in DR would be small, as you could bin four high resolution pixels into one. But that would make huge demands on the processing pipeline.
In the end, the Arri approach may make sense. But of course, we don't know how that implementation exactly works. Marketing speak often differs from reality.
The huge difference is that a video camera needs to scan the sensor at high rate. It is not possible to scan a 100 MP sensor at the same rate. But, the IQ3100 is intended to deliver 100 MP of detail at 1FPS while the Arri delivers like 12 MP detail at say 60 FPS.
So, the devices are very different animals. Doing a proper comparison of DR, I would guess that the IQ 3100MP would deliver around 14.5 EV of engineering DR. I would guess that the Arri would deliver something similar. But it would deliver it at high FPS.
Best regards
Erik
This is incorrect. It is not just a "dual readout". It is simultaneous dual gain readout from each pixel.
Arri's ALEV III Dual Gain Architecture sensor is designed to increase dynamic range and reduce noise by optimizing the signal amplification for both highlight and shadow for each pixel simultaneously, producing HDR images in a single exposure.
"The Dual Gain Architecture simultaneously provides two separate read-out paths from each pixel with different amplification. The first path contains the regular, highly amplified signal. The second path contains a signal with lower amplification to capture the information that is clipped in the first path. Both paths feed into the camera's A/D converters, delivering a 14-bit image for each path. These images are then combined into a single 16-bit high dynamic range image. This method enhances low light performance and prevents the highlights from being clipped, thereby significantly extending the dynamic range of the image."
https://www.arri.com/en/learn-help/technology/alev-sensors (https://www.arri.com/en/learn-help/technology/alev-sensors)
When physics professor Dr. Emil Martinec proposed this type of sensor design in 2008 it was just a theoretical hoped for advance in technology. Just two years later, Arri turned the theory into reality with the first Alexa in 2010.
"What one would like is to somehow be able to use ISO 100 to keep all the highlights, while at the same time using ISO 1600 to recover all the shadows. But how can one have two ISO settings at once? By having two separate amplifiers fed from the same sensor data, running in parallel. Suppose that the sensor signal is sent to two separate processing paths, each path an amplifier and an ADC, with one amplifier set to ISO 100 and the other to ISO 1600. The ISO 100 path keeps all the highlights but has noisy shadows; the ISO 1600 path loses the top four stops of highlights but has much better shadows. Quantizing each, one can then combine the image data in a manner similar to HDR processing to yield an image with all 14 stops that the sensor is capable of recording. What would the result look like? Well of course, no such camera is currently made, but one can get an idea of the possibilities by shooting two successive images, one at ISO 100 and another at ISO 1600, and combining the two"
"As an aside, now that one is recording all the data that the sensor has to give, there is no reason to have a variable ISO gain, just the fixed 100/1600 parallel channels (or whatever two fixed amplifications optimize the data extraction). The ISO setting can be put into metadata like white balance is, a suggestion from the camera's metering to the raw converter as to what exposure compensation to apply in order to develop the image. As discussed on page 3, so long as noise sufficiently exceeds quantization step, there is no difference between amplification in hardware during the capture process, and amplification after the fact during raw conversion."
https://www.photonstophotos.net/Emil Martinec/noise-p3a.html (https://www.photonstophotos.net/Emil%20Martinec/noise-p3a.html)