GFX 100 RF on the way

[tex]

Of course we all want to see your controlled tests. But I hope you take it out for a ride; your "street" photography is pretty excellent.

 

[JimKasson]

Of course we all want to see your controlled tests. But I hope you take it out for a ride; your "street" photography is pretty excellent.

Thanks, but difficult for me with my present mobility constraints.

 

[tex]

Sorry to hear it hasn't

 

[Lukacs85]

Hardest thing will be to send it back.

 

[Lukacs85]

Microcontrast.

 

[marc aurel]

I would appreciate comments on sharpness and distortion across the frame in the various crop modes. Presumably it will be better the tighter the crop. Joe

Thank you Jim for asking the community.
In addition to jbrs question I would like to ask if you could check if you see the same problem as I:

That the jpg out of the camera are mostly free from distortion, but that the raws developed in Lightroom or Capture One show barrel distortion (not extreme, but noticable).

 

[JimKasson]

Microcontrast.

My definition of microcontrast is MTF at a quarter or a third of a cycle per pixel. You okay with that definition?

 

[jhunna]

LensRentals notified me today that they're shipping me a GFX 100 RF for testing and that it should arrive next week. Sorry it's taken so long. Anything special you folks want me to check on?

I plan to test the lens, comment on the ergonomics, make sure the sensor works the same way as the one in the GFX 100 II, look for odd bokeh from the leaf shutter,

You'll have to find the bokeh first!

I don't think I've ever seen bokeh artifacts at f/4 and 1/2000 sec., but if you find them, that will be interesting.

Note that the leaf shutter will only do 1/4000 sec. at f/8 or smaller. At apertures wider than that, the shutter can't move fast enough to expose at 1/4000 sec. and cross the entire image circle, so it will force you to a 1/2000 sec. max shutter speed. To observe this, set the shutter mode to MS only, switch the top dial to 1/4000 sec. and the aperture to f/4. The shutter speed display on the LCD/EVF will be in red, meaning it's out of range. If you fire the shutter in this situation, it will expose the image at 1/2000 sec. Now keep opening the aperture, and you'll see that at f/8, the shutter speed display turns blue again, meaning 1/4000 is now allowed.

So if one really needs 1/4000 sec to shoot in bright light at wider apertures, make sure the shutter mode is set to MS + ES so it can switch over as needed. Of course that only works for still subjects due to rolling shutter with ES, so 1/4000 + apertures wider than f/8 + fast subject motion is out of scope for this camera.

From the manual:



I would like your take on the true base ISO of the 100RF. Reid Reviews says it's actually ISO100 according to their testing (as is the GFX100SII he also says), but P2P shows ISO80 is not outside of the normal analog range for the 100SII.

test flash synch, and anything else I can think of while it's in my hands.

Jim

This is a really good observation! Thanks for sharing, and yes I second the desire to find out the true base iso.

 

[jhunna]

LensRentals notified me today that they're shipping me a GFX 100 RF for testing and that it should arrive next week. Sorry it's taken so long. Anything special you folks want me to check on?

I plan to test the lens, comment on the ergonomics, make sure the sensor works the same way as the one in the GFX 100 II, look for odd bokeh from the leaf shutter, test flash synch, and anything else I can think of while it's in my hands.

Jim

First off thanks for this, and while I don't have anything specific, I hope you don't mind some suggestions for more subjective thoughts, in addition to the formal tests.

1. How long do you have the camera?
2. A few questions about ISO:
   1. What is the base iso?
   2. Is the camera ISO invariant?
   3. Is there dual iso in video?
3. I saw mention that you will not be able to take it out (sorry to hear that and I hope it is a temporary situation), however, I hope you take the opportunity to take keep the camera on you and take as many spontaneous pictures as possible. I would be interested on the settings you use that add speed to your actual photography process.
4. Play with the zoom and ratio features and the jpeg. I would be interested in your thoughts on that functionality.
5. Anything you can share around flash output performance, if you can try to get one of the newer Godox flashes like the it30pro and/or the v480. (I have to admit I do like the tt350 on it as a good compromise, but it uses AA cells).
6. Thoughts on the viability and practicality of using a medium format sensor for everyday, spontaneous shooting.

I have put alot here, pick and choose as you have the time/desire, but I do think the longer you have the RF, the better it gets. So I hope you have it for more than a week. For me it took about a month or two to get it, but with your experience with Fuji and MF, I suspect you will adapt a lot faster.

Thanks, really looking forward to your tests!

 

[highdesertmesa]

I would appreciate comments on sharpness and distortion across the frame in the various crop modes. Presumably it will be better the tighter the crop. Joe

Thank you Jim for asking the community.
In addition to jbrs question I would like to ask if you could check if you see the same problem as I:

That the jpg out of the camera are mostly free from distortion, but that the raws developed in Lightroom or Capture One show barrel distortion (not extreme, but noticable).

The lens corrections in Capture One and Lightroom have always been more conservative than the Fujifilm JPEGs from the camera. This goes way back to the 50S days. What we don't know is if that's Capture One and Adobe's choice or is Fujifilm providing less accurate correction instructions in the RAW files – or is the language used in the RAW files inadequate to ever match the JPEGs (meaning that complex distortion may require more nuance than the code allows for).

Correcting the 100RF files perfectly is critical for some applications such as architecture or anything with straight lines along the long edge of the frame, so if Jim could help figure out where the fault lies, that would help the rest of us know who to complain to.

 

[DavidMillier]

I would appreciate comments on sharpness and distortion across the frame in the various crop modes. Presumably it will be better the tighter the crop. Joe

Thank you Jim for asking the community.
In addition to jbrs question I would like to ask if you could check if you see the same problem as I:

That the jpg out of the camera are mostly free from distortion, but that the raws developed in Lightroom or Capture One show barrel distortion (not extreme, but noticable).

The lens corrections in Capture One and Lightroom have always been more conservative than the Fujifilm JPEGs from the camera. This goes way back to the 50S days. What we don't know is if that's Capture One and Adobe's choice or is Fujifilm providing less accurate correction instructions in the RAW files – or is the language used in the RAW files inadequate to ever match the JPEGs (meaning that complex distortion may require more nuance than the code allows for).

Correcting the 100RF files perfectly is critical for some applications such as architecture or anything with straight lines along the long edge of the frame, so if Jim could help figure out where the fault lies, that would help the rest of us know who to complain to.

Darktable uses the Lensfun database for lens correction but it also lets you do your own measurements on your own lens under as many conditions as you like. Potentially this could allow you to correct distortion, vignetting and CA specifically for your own lens.

 

[JimKasson]

LensRentals notified me today that they're shipping me a GFX 100 RF for testing and that it should arrive next week. Sorry it's taken so long. Anything special you folks want me to check on?

I plan to test the lens, comment on the ergonomics, make sure the sensor works the same way as the one in the GFX 100 II, look for odd bokeh from the leaf shutter, test flash synch, and anything else I can think of while it's in my hands.

Jim

First off thanks for this, and while I don't have anything specific, I hope you don't mind some suggestions for more subjective thoughts, in addition to the formal tests.

1. How long do you have the camera?

Three weeks.

1. A few questions about ISO:
   1. What is the base iso?

Tell me how you define base ISO, and I'll answer the question.

1. Is the camera ISO invariant?

No. It has dual conversion gain. It is ISO invarient above the point where the high conversion gain kicks in. I will check that, but I expect it will be the same as the GFX 100II.

1. Is there dual iso in video?

I don't test video.

1. I saw mention that you will not be able to take it out (sorry to hear that and I hope it is a temporary situation), however, I hope you take the opportunity to take keep the camera on you and take as many spontaneous pictures as possible. I would be interested on the settings you use that add speed to your actual photography process.

That's not how I test cameras.

1. Play with the zoom and ratio features and the jpeg. I would be interested in your thoughts on that functionality.

I'm assuming that it works as designed, and I will check. I don't test JPEG performance of cameras.

1. Anything you can share around flash output performance, if you can try to get one of the newer Godox flashes like the it30pro and/or the v480. (I have to admit I do like the tt350 on it as a good compromise, but it uses AA cells).

I will test it with a Godox flash.

1. Thoughts on the viability and practicality of using a medium format sensor for everyday, spontaneous shooting.

I think every knowledgeable photographer can judge for themselves by looking at the specs of the camera. I don't see what I have to add there. I will comment on the ergonomics.

I have put alot here, pick and choose as you have the time/desire, but I do think the longer you have the RF, the better it gets.

It has been my experience that the camera doesn't change with extended use. It's the photographer who changes.

So I hope you have it for more than a week. For me it took about a month or two to get it, but with your experience with Fuji and MF, I suspect you will adapt a lot faster.
Thanks, really looking forward to your tests!

See my post here about my testing philosophy.

 

[JimKasson]

This will be old news for many, but for the new folks here, my testing philosophy follows.

• I only test things that make a different to me personally. No JPEGs, no video, no auto-everything shooting.
• I concentrate on testing things that others don't test. There are plenty of tests on the web which are long on opinions and short of facts.
• I try to do quantitative testing when possible.
• I strive to make my results reproducible.
• I try to define the terms I use.

 

[jhunna]

1. A few questions about ISO:
   1. What is the base iso?

Tell me how you define base ISO, and I'll answer the question.

Never thought too deeply about the base iso outside that I assume it is the lowest iso marked in the camera. I also assume this is where you get the best performance from the sensor, ie lowest grain/noise most DR, etc... I raise the question because the lowest marked iso is 80, however I have seen that it may actually be 100. My guess is that 80 offers slightly less performance in some metric. (my guess would be in higher noise/grain or lower DR, but I really don't know).

So if you have a way of confirming that ISO improves from 80 to 100, that may be what I am truly asking.

 

[JimKasson]

1. A few questions about ISO:
   1. What is the base iso?

Tell me how you define base ISO, and I'll answer the question.

Never thought too deeply about the base iso outside that I assume it is the lowest iso marked in the camera.

WIth that definition and the camera in hand, you have your answer.

I also assume this is where you get the best performance from the sensor, ie lowest grain/noise most DR, etc...

With the GFX 100II, that's ISO 80, but with an asterisk, since the black point subtraction is done in-camera at ISO 80, and only at ISO 80. I expect the GFX 100RF will do the same. I'll test for that.

I raise the question because the lowest marked iso is 80, however I have seen that it may actually be 100.

Take a look at your camera to see what the lowest marked ISO is.

My guess is that 80 offers slightly less performance in some metric. (my guess would be in higher noise/grain or lower DR, but I really don't know).

See above.

So if you have a way of confirming that ISO improves from 80 to 100, that may be what I am truly asking.

Define improves. I need a metric for that. You must have one in mind if you're asking the question and you have the camera.

--
https://blog.kasson.com

 

[jhunna]

1. A few questions about ISO:
   1. What is the base iso?

Tell me how you define base ISO, and I'll answer the question.

Never thought too deeply about the base iso outside that I assume it is the lowest iso marked in the camera.

WIth that definition and the camera in hand, you have your answer.

I also assume this is where you get the best performance from the sensor, ie lowest grain/noise most DR, etc...

With the GFX 100II, that's ISO 80, but with an asterisk, since the black point subtraction is done in-camera at ISO 80, and only at ISO 80. I expect the GFX 100RF will do the same. I'll test for that.

I raise the question because the lowest marked iso is 80, however I have seen that it may actually be 100.

Take a look at your camera to see what the lowest marked ISO is.

Kind of confused by your line of thoughts/questions. I mentioned that 80 is the lowest iso marked, however some say that ISO 100 is actually the base iso. Maybe I need their definition, but for my workflow, I generally see the lowest noise/grain and better DR at the base iso.

[SNIP]

So if you have a way of confirming that ISO improves from 80 to 100, that may be what I am truly asking.

Define improves. I need a metric for that. You must have one in mind if you're asking the question and you have the camera.

For me it would be in lower noise or grain in the file or greater Dynamic Range, but there may be other criteria such as sharpness and rendering (I hesitate to use rendering as I don't have standard definition, but I know when I see a preferred rendering vs a rendering that is not as good).

 

[JimKasson]

1. A few questions about ISO:
   1. What is the base iso?

Tell me how you define base ISO, and I'll answer the question.

Never thought too deeply about the base iso outside that I assume it is the lowest iso marked in the camera.

WIth that definition and the camera in hand, you have your answer.

I also assume this is where you get the best performance from the sensor, ie lowest grain/noise most DR, etc...

With the GFX 100II, that's ISO 80, but with an asterisk, since the black point subtraction is done in-camera at ISO 80, and only at ISO 80. I expect the GFX 100RF will do the same. I'll test for that.

I raise the question because the lowest marked iso is 80, however I have seen that it may actually be 100.

Take a look at your camera to see what the lowest marked ISO is.

Kind of confused by your line of thoughts/questions. I mentioned that 80 is the lowest iso marked, however some say that ISO 100 is actually the base iso.

You have said that your definition of the base ISO is the lowest marked ISO, so the answer to your question is determined.

Maybe I need their definition, but for my workflow, I generally see the lowest noise/grain and better DR at the base iso.

You will see lower photon noise if you give a correspondingly more generous exposure. You will also see lower read noise, but that's mostly due to the in-camera black point subtraction, which is kind of a cheap trick. That assuns the camera works like the GFX 100 II.

[SNIP]

So if you have a way of confirming that ISO improves from 80 to 100, that may be what I am truly asking.

Define improves. I need a metric for that. You must have one in mind if you're asking the question and you have the camera.

For me it would be in lower noise or grain in the file or greater Dynamic Range, but there may be other criteria such as sharpness and rendering (I hesitate to use rendering as I don't have standard definition, but I know when I see a preferred rendering vs a rendering that is not as good).

If you know what you're looking for in the way of rendering and you have the camera, you can answer your own question.

 

[SrMi]

1. A few questions about ISO:
   1. What is the base iso?

Tell me how you define base ISO, and I'll answer the question.

Never thought too deeply about the base iso outside that I assume it is the lowest iso marked in the camera.

WIth that definition and the camera in hand, you have your answer.

I would define base ISO as ISO "with the cleanest image with the least noise and maximum dynamic range," and without any shenanigans (assuming maximized exposure).

 

[JimKasson]

1. A few questions about ISO:
   1. What is the base iso?

Tell me how you define base ISO, and I'll answer the question.

Never thought too deeply about the base iso outside that I assume it is the lowest iso marked in the camera.

WIth that definition and the camera in hand, you have your answer.

I would define base ISO as ISO "with the cleanest image with the least noise and maximum dynamic range," and without any shenanigans (assuming maximized exposure).

Then ISO 100 is your answer for the GFX 100 II.

 

[jhunna]

Kind of confused by your line of thoughts/questions. I mentioned that 80 is the lowest iso marked, however some say that ISO 100 is actually the base iso.

You have said that your definition of the base ISO is the lowest marked ISO, so the answer to your question is determined.

Just for clarity, I asked chatgpt to define base and extended iso, and I am in agreement with the answer. Does this work for you?

========================BEGIN CHAT GPT==================================

Base ISO

• Definition: The lowest native sensitivity of the camera sensor.
• How it works: It’s the ISO at which the sensor performs optimally without any digital manipulation.
• Benefits:
  • Maximum dynamic range (captures the widest range from shadows to highlights).
  • Lowest noise.
  • Best color depth.
• Example: On many modern cameras, base ISO might be ISO 100 (some medium-format and cinema cameras have base ISO 200 or even dual base ISOs like 800 & 2500).

Extended ISO

• Definition: Artificial ISO values below or above the native range, created by the camera’s image processor.
• How it works:
  • Low extended ISO (e.g., ISO 50): Achieved by overexposing at base ISO and then digitally pulling the exposure down.
  • High extended ISO (e.g., ISO 51,200+ on many cameras): Achieved by pushing the signal beyond the sensor’s native gain.
• Trade-offs:
  • Low extended ISO: Reduces highlight detail (you lose dynamic range in bright areas).
  • High extended ISO: Increases noise and reduces detail.

Rule of thumb:

• Use base ISO when you want the highest image quality (landscapes, portraits, studio work).
• Use extended ISO only when you need it (e.g., ISO 50 to shoot wide open in bright sunlight, or ISO 102,400 in a dim venue).

=====================END CHAT GPT =======================================

So using these definitions I would want to know if 80 iso an extended iso or base iso. And if 80 is an extended iso, where does the base iso begin?

Maybe I need their definition, but for my workflow, I generally see the lowest noise/grain and better DR at the base iso.

You will see lower photon noise if you give a correspondingly more generous exposure. You will also see lower read noise, but that's mostly due to the in-camera black point subtraction, which is kind of a cheap trick. That assuns the camera works like the GFX 100 II.

I didn't know there were two types of noise, so will need to do some additional work on how these different noise types show up in the photo.