Fujifilm X-T100 Photographic Dynamic Range (PDR) at PhotonsToPhotos

bclaff wrote:

tradesmith45 wrote:

...

Let me restate what I think you're saying & what the data says regarding use for astro. I'll use XT100 vs XT20.

We may be wandering off topic since this is not the astrophotography forum

Single stage amplification & invariance means the XT100 probably should be used differently from the XT20. To match read noise levels (not always important for astro when shot noise dominates), the XT100 must be set to ISO 318 & boosted in post to match the XT20 @ ISO 800. At ISO 318, the XT100 will have a bit more DR but less?? shadow detail?

You may want to look a Input-referred Read Noise rather than Read Noise in DNs.

If you click on cameras in the legend you'll get a table with some relevant information.
At ISO 318 the X-T100 has a capacity of 15,248e- with an Engineering Dynamic Range (EDR) of 12.2
At ISO 800 the X-T20 capacity is only 6,065e- with a slightly higher EDR of 12.3

So by giving up capacity you get a little deeper into the shadows.

Thanks, that helps me understand this better.

This is an area where translating from detailed data to practical visibility can be difficult. Having to struggle more to reveal shadow detail & retain star color for my XT2 compared to a rented XPro2, seems to me differences around 0.5 EV are meaningful for astro. But this also brings up issues of copy variation & measurement error. For example your charts of Shadow Improvement for an XPro2, XT2 & XT20 are slightly different - are those differences meaningfully accurate?

The auto-scaling of the charts makes them look more different than they are.
I'd say there's no meaningful differnence there.

Wow, that's really good to know!

Regarding FPN, its not clear to me that the short exposure test you use for read noise reveals the types of problems encountered with astro & much longer exposures. For example a comparison of FPN from the D5300 & D7500 over at Stargazers Lounge reached the opposite conclusion (D5300 better) from what your Sensor Heat map data shows. Your comments here would be helpful. I use your info often & simply want to understand the meaning.

My FPN testing is specifically for things like DSNU and PRNU.
You're probably more interested in dark current and amp glow; I don't measure those.

Here's my dumb (uncalibrated for black point) comparison of my XT10 & a rented XPro2. I can maybe see the horizontal vs vertical difference. In practice photo terms, the long -2-4 min.- exposures I use for starlit landscapes from the XP2 are fewer but more obvious compared to the XT10. I more often have to clone these out from my XT2.

Thanks again.