faberryman
Member
Are photon transfer curves available for the major cameras so you can compare them? I've never seen one referred to, but then I've never gone looking for them.
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Check out Bill Claff’s meticulous work:Are photon transfer curves available for the major cameras so you can compare them? I've never seen one referred to, but then I've never gone looking for them.
The results of this experiment depends on the brightness of the image. As the image gets brighter, the number of steps that can be seen discreetly increases. It is also affected by the tone curve of the RGB color space in which the experiment is conducted. If you simulate photon noise, the number of steps deceases. The color of the ramp affects the results.This whole issue with bits and gradations is a very easy experiment to conduct for the human visual system.
I did something like this when I was selecting monitors.
Make a photoshop file in a rectangular format that is 256 pixels long.
Create a black to white gradient with the start at end points at each end of the rectangle.
You will get 1 linear pixel length per step, and see if your eyes can pick it apart or get banding.
I have tried this and I could see banding in 256 steps.
<snip>
That's right. It's basically 15-bit unsigned integer plus one state. They did that to get a convenient middle value.Another interesting note I found is Photoshop limits its 16 bit values to 0-32,768.
So in Photoshop you are essentially limited to a 15 bit file.
Here's a link right to the PTC's. You can pick your camera from the list on the right and see them:
Makes my head hurt. I am asking myself whether it worth investing the time to understand it? Am I going to use the information in deciding which new camera to purchase? For example, is lens selection more important, or will photon transfer function trump it? Or is photon transfer function more fun facts to know and tell? I guess you can't have too much information.
This will have nothing to do with the optics. Basically, there is no point to understanding it, except for maybe in conversations like this. Most of what it is saying can be described in easier ways. It will not help in your workflow or, more to the point, you can intuitively come to the same results without that detail. For those that like the technical aspect of digital imaging, it is interesting. For the type of photography that people do here, it is not helpful for most.Makes my head hurt. I am asking myself whether it worth investing the time to understand it? Am I going to use the information in deciding which new camera to purchase? For example, is lens selection more important, or will photon transfer function trump it? Or is photon transfer function more fun facts to know and tell?
Most cameras are good enough these days that DR is not the long pole in the tent when it comes to picking a camera. In the film days you could pick film and developers without knowing your posterior from your elbow about H&D curves, color shift with exposure, or the Zone System. Those folks that understood that stuff thought it made them better photographers, but there were plenty of top-notch photographers who didn't understand it, didn't care, didn't process their own work, and were very successful.Makes my head hurt. I am asking myself whether it worth investing the time to understand it? Am I going to use the information in deciding which new camera to purchase? For example, is lens selection more important, or will photon transfer function trump it? Or is photon transfer function more fun facts to know and tell? I guess you can't have too much information.
There are a lot of steps from that 14 and 16bit capture to an image on a piece of paper, and lot of very complex calculations and manipulations going on.The discussion is about the perception of the final image. The human visual system cannot distinguish between a 14-bit image and a 16-bit one.
Hi Jim,Thanks for the kind words. It's quite freeing to not feel I have to a) read every post on that forum, b) not correct statements that are objectively, verifiably wrong there, and not be drawn into what seem like endless, circular, acrid, logic-free, no-testing allowed, tribal discussions.
View attachment 142002
Jim
Hi,Makes my head hurt. I am asking myself whether it worth investing the time to understand it? Am I going to use the information in deciding which new camera to purchase? For example, is lens selection more important, or will photon transfer function trump it? Or is photon transfer function more fun facts to know and tell? I guess you can't have too much information.
Not to perpetuate this aside to the title of this thread, but 16 bits vs 14 bits could be helpful when purposefully underexposing a scene with a large dynamic range, then pulling the shadows in post by several stops. I routinely shoot trees this way, and recently compared a 12- vs. 14-bit image of the same scene post-processed this way, with much better results pulling the detail in the shaded trunk without creating a sea of noise from the 14-bit image.
Whole scene (14-bit):
View attachment 142216
Trunk crop at 100% (post-processed from 14-bit):
View attachment 142218
Trunk crop at 100% (post-processed from 12-bit):
View attachment 142217
(No, that's not moss that only appears in a 12-bit workflow... it's noise which I tried (and failed) to post-process to look more moss-y )
Admittedly, this isn't a perfect example for the 14 vs 16-bit argument because it's 12 vs. 14, and because I post-processed each image by hand independently so the process wasn't identical. And the difference is magnified by the fact that the trunk was SO underexposed that there were probably only a handful of bits of value depth within the trunk. But it's a vivid demonstration to me of how a couple extra bits of shadow values can make a difference in the final photo.
Now I propose we return this thread to discussion of the GFX100
I could not agree more. Oddly enough, that was my main critique that simply stating shoot at 16-bit is going to result in a perceptually different result than a 14-bit file was an oversimplification itself. I certainly would not suggest not using technology for its benefits. I also think the these improvements are having diminishing returns and their significance is not being understood. If someone asks me if buying a 16-bit camera is going to improve the quality of their images from the 14-bit camera they have now, I could not state it would.I might agree that differences of a simple gradient on a print derived from a 14 bit vs 16 bit image might not be resolvable by the human eye, but I think that’s an over simplification of what’s going on with a digital sensor and system.
Even better, if you ever have the chance to rescan this on a modern system (e.g. DT Film Scanning Kit) I think you'll be shocked how much more there was on the film than a Flextight or drum scanner was able to extract, especially when it comes to deeply saturated colors in a shadow area. My appreciation for film and the lab coats that engineered film emulsions has definitely increased over the past few years of doing R+D on modern approaches to film scanning.Not to... well, whatever, I love the Portland tree! So @onasj, this is Hasselblad SWC Ektar 100 (I think)
Clearly moss . Full view
Flextight 848 scan. We now return you to the scheduled GFX100 discussion.
There is no doubt that a 16-bit image has advantages over a 14-bit one. But what exactly is it? Car companies make Supercars that cost millions of dollars that are amazing machines. But they still will not get me to work any faster than my Toyota--there are practical limits to speed. I can also get the fastest computer available, but it will not change the efficiency of my email correspondence. And as you said, it is complicated. Engineers tend to simply focus on performance in an absolute sense without the actual implications on the final result (I know, I worked with the engineers at a camera company). And seriously, how many here will be able to take advantage of a 100MP sensor? Even with a 42" printer, these images will be idling.
Yup, you can show all kinds of advantages with quantitative data. The problem is images are finally filtered through the human visual system. That is a similar problem of putting your Supercar on a crowded road with a posted speed limit of 35mph. (Or rounding your tax returns to four decimal places.)
Lets not forget, engineers are incentivised to produce better products. If any one of them come out and simply states the current products are fine and we can stop development, they might be out of a job.
I am all for developing photographic tools, but I also think photographers need to understand what those developments mean in real terms.
I believe it! I will save up $ for a test scan!Even better, if you ever have the chance to rescan this on a modern system (e.g. DT Film Scanning Kit) I think you'll be shocked how much more there was on the film than a Flextight or drum scanner was able to extract, especially when it comes to deeply saturated colors in a shadow area. My appreciation for film and the lab coats that engineered film emulsions has definitely increased over the past few years of doing R+D on modern approaches to film scanning.
Very excited about the GFX100S, but I don't think this is the camera for me. Hopefully, I will manage to bide my time here and see what Fuji (and Hasselblad) does next. I'd be much more interested in a GFX50S Mark 2 right now.