Why so low ?

you cant gain 2 stops more DR by using an extended gain. its not possable.

Just kidding but there's saying here in Texas "if yew had'na tole me that, ah would never have known" ...

Indeed. For example: those who hate blown skies or are into HDR ... "If ah had'na tole you that etc." ... 😉

you dont gain 2 stops useing extended iso's 50 vers 100 just tested my a7iv ,in fact as it should you loose dr and information, its suptle but you can see the difference at 3000 % i wouldnt hesitate useing iso 50 on my a74 if needed though as its nearly identical.

thats where your wrong, i did shoot a 100% DR shot and this is in the middle tones 😁 why ? because thats where DR is most important ,in mid tones, and you can clearly see camera manipulation to the file ☺im tired of seeing in camera raw file manipulated shadow noise and squashed highlights that everyone posts.

have a good think about what you just posted. your not looking at the big picture (pun)
do you actually think DR is black, or white. 😉
a small sensors black is a large sensors grey ,and a small sensors white is a large sensors grey, colours play out the same.

+1

Donald, please read and understand:

ChatGPT:

The dynamic range of a digital camera refers to the range of luminance values that it can capture, from the darkest shadows to the brightest highlights, without losing detail. It's typically measured in stops, with each stop representing a doubling or halving of the amount of light. The wider the dynamic range, the greater the ability of the camera to capture details in both very bright and very dark areas of an image simultaneously.

I think you're missing the context of Bob's metric. He is only looking at "safe" and "standard/normal" highlight ranges that pretty much are available with all cameras and ISOs, and so the bottom of his DR is measured relative to standards, not the highlight limits of the RAW file. It's just like DPR's special versions of the Studio Comparison Tools that compare under-exposures; DPR never looked at the raw clipping point, and used that for a reference; they use an exposure standard, so they are demonstrating what happens with exposures in an absolute sense, rather than relative to raw highlight clipping levels.

When you allow the wild card of variable headroom into the picture, then you don't know how much of the DR is "footroom", which is a better proxy for exposure-referred noise, which is why I tell people not to use Bill's "PDR" as any kind of proxy for absolute noise. PDR attempts to tell you what you can fit (aesthetically) into the raw levels, independent of absolute, exposure-referred noise.

from my experience with cameras with multipul size sensors. is if shooting a scene the FF sensor with a wider/larger DR it streches the colour gamet over the whole image recorded where the smaller sensor squashes the colour gamet ( muddy images) including the mid tones, the mid tones are not the same between tiny and large sensors. the larger sensor will always produce a smoother graduation due to wider dynamic range.

i just took a very contrasty image with my xz1 and the a7iv, amazing little ccd camera the xz1.

What have you done to separate the effects of total light from the effects of sensor size, in your decades-long photographic epidemiology?
What have you done to separate the effects of pixel size from the effects of sensor size?

If you can only know about either total light or sensor size, which would you choose if you wanted to predict the smoothness of gradation?

"Contrasty" is a function of scene, lens veiling glare, and conversion math, as virtually all sensors are very close to linear in response over most of the raw range of digitized values.

neither "larger pixels" which is why i chose the 33 meg a7iv over the 60 meg a7r5 the whole crop factor is just to justify lack of practical sence.
i can shoot extreme macro with my 24 meg apsc a6300 and crop mode a7iv at 14 meg and no one could ever tell the images apart. even viewing at 200%

define "capture". do you capture 9 stops from camera which is my thinking of DR capture. or do you manipulate the file in Ps and guess what is aceptable noise and call that DR. you have 1 choise, lets see which is right 😁

If true, that's a corner case that has no relevance to most detail-prioritizing photography. It may be more like shooting at f/64 at typical distances with the range of pixel densities from the m43, APS_C, and FF formats, all of which should be well into in the "oversampling" range for f/64.