Rob de Loe
Veteran Member
True, but my point was that back in the misty dawn of time when I was relying on this camera -- 2018 -- 10 stops of DR was not holding me back.
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Cropping in the GFX 100RF and the effects on dynamic range
- Thread starter JimKasson
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Rich42
Senior Member
Contact sheets always used to look so promising. Glistening with detail and range.
Then the enlargements always looked so flat.
Ap0ll0n
Senior Member
Fyi, in my tests (at 35mm) ibis was fully effective only about 1 stop - so much for the 8 stop advantage of the 100S ii.
It is a drawback for sure but I would still take compact medium format without IBIS instead of compact full frame or crop format with ibis/ois. Totally personal preference and kind of besides the point
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Apollon
http://www.flickr.com/photos/apollonas/
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Ap0ll0n
Senior Member
3.5 stops - 2 stops mf advantage = 1.5 stops, right? Also, I think these lenses need to be compared to the likes of 55mm 1.7 or 80mm 1.7 instead of a very compact 100RF. Just my two cents.
SeeingSomeThingsMissingMany
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One of the attractions of faster glass as f/1.2 for me is how they render wide open compared slower glass. There is a magical look in certain scenes.
Faster glass can be utilised on Gfx 100/50 series with adapter demonstrated on this forum. It's one of the things I intend to do when I get round to picking up a Gfx.
Fuji X70 fixed lens 28mm f/2.8 camera would be more appropriate comarison in someways.
https://www.dpreview.com/products/fujifilm/compacts/fujifilm_x70
Still a f/4 lens has its own magic if it's a decent enough lens attached to a decent sensor : utilised for their strengths.
Since this 100Rf toing and froing I been looking more into my Sigma DP1 28/4 photographs I took 2010 2011. Was a lowerDR, ISO100 camera although I did utilise ISO200 when I had no other choice. DP1 has its own magic in certain scenes. I cropped various times in post from its .X3F RAW. Looking at these DP1 photos I just wished it wasn't only 4.9MP.
If I had 100Rf I'd love to return to some of these scenes locations interior and exterior.
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Photography after all is interplay of light alongside perspective.
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Crispy_Bee
Forum Enthusiast
And how effective is it for 2 stops? 3 stops? 4 stops?Fyi, in my tests (at 35mm) ibis was fully effective only about 1 stop - so much for the 8 stop advantage of the 100S ii.
It is a drawback for sure but I would still take compact medium format without IBIS instead of compact full frame or crop format with ibis/ois. Totally personal preference and kind of besides the point
Most likely you'll still find IBIS helpful in these cases, surely not 100% effective but maybe 75%, 50%, 30% 25%,....
And if you can save 2 or 3 stops and still have a bigger chance of getting a sharp image than without IBIS at a higher ISO, it's a pretty clear verdict. There's a reason why compact medium format cameras with a 100MP sensor are all equipped with IBIS and why pretty much all high-res fullframe cameras are also equipped with IBIS - and it's not "just" one stop.
SrMi
Veteran Member
How did you calculate that one-stop improvement?
FWIW, the number of effective stops should be based on the ratio of your safe handholding shutter speed (100% sharp images) without IBIS to the safe handholding speed with IBIS.
It is a drawback for sure but I would still take compact medium format without IBIS instead of compact full frame or crop format with ibis/ois. Totally personal preference and kind of besides the point
SrMi
Veteran Member
It would be nice if we had measurements to confirm your analysis. It could then apply also to Leica Q's digital crop.I now realize that my thinking was simplistic. It's not possible to compute the curves precisely without going back to the photon transfer curves and recalculating from there, which I'm too lazy to do at this point. So I've redone the curves with a heuristic that I derived from Bill's data.I would expect 70mm (2x from 35mm) to "cost" two stops of PDR instead of only one. When we compare FF with m43 PDRs (2x difference), we see a difference of two stops of PDR.Fuji is recommending cropping as a method to ameliorate the limitations of a fixed lens in the GFX 100RF. That will affect dynamic range. I've calculated that, using BIll Claff's Photographic Dynamic Range measurements from the GFX 100S II.
Here it is:
The vertical axis is PDR in stops. The horizontal axis is ISO setting. The equivalent focal length for a 33x44mm sensor is shown for each line.
I will be happy to take questions and comments in this thread.
Where is my thinking wrong?
Here's the modified formula:
The heuristic is 1.1. I also added a column for a focal length of 48mm, which gives the FF pixel height, and checked it against BIll's numbers.
I also changed the 60mm line to a 63mm line, to match the Fuji crop selection.
Here's the corrected graph.
I can't justify the heuristic on theoretical grounds, so take this with a grain of NaCl.
To deal with your question about the slopes, the SNR slope in read noise limited regions is different than that in the photon noise limited regions. PDR is affected by both kinds of noise.
T
The Hat
Guest
Fyi, in my tests (at 35mm) ibis was fully effective only about 1 stop - so much for the 8 stop advantage of the 100S ii.
It is a drawback for sure but I would still take compact medium format without IBIS instead of compact full frame or crop format with ibis/ois. Totally personal preference and kind of besides the point
Crispy_Bee
Forum Enthusiast
Why would it?
Ap0ll0n
Senior Member
Ap0ll0n
Senior Member
I will go back do some more testing with different focal lengths but at 35mm, my findings, for my technique and the way I viewed the images here , were pretty consistent. Perhaps IBIS is more effective on speeds under 1/30, which is the slowest I measured, but probably (though not hopefully) much lower than 50% effective.In my experience IBIS is much more effective and i usually get 3, 4 stop of improvement in lowlight handheld situations. I don't know why you only get 1 stop better performancesFyi, in my tests (at 35mm) ibis was fully effective only about 1 stop - so much for the 8 stop advantage of the 100S ii.
It is a drawback for sure but I would still take compact medium format without IBIS instead of compact full frame or crop format with ibis/ois. Totally personal preference and kind of besides the point
--
Apollon
http://www.flickr.com/photos/apollonas/
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Ap0ll0n
Senior Member
If you happen to own a 100MP GFX with IBIS, then it would be interesting to see what you find based on your tests. Mine are totally based on my technique and my perception of what is equally sharp based on the pics I posted. The later part can be double checked. I do need to go back and measure effectiveness for 2 or more stops but I suspect it will be far from the above percentages you provided. TBD.And how effective is it for 2 stops? 3 stops? 4 stops?Fyi, in my tests (at 35mm) ibis was fully effective only about 1 stop - so much for the 8 stop advantage of the 100S ii.
It is a drawback for sure but I would still take compact medium format without IBIS instead of compact full frame or crop format with ibis/ois. Totally personal preference and kind of besides the point
Most likely you'll still find IBIS helpful in these cases, surely not 100% effective but maybe 75%, 50%, 30% 25%,....
And if you can save 2 or 3 stops and still have a bigger chance of getting a sharp image than without IBIS at a higher ISO, it's a pretty clear verdict. There's a reason why compact medium format cameras with a 100MP sensor are all equipped with IBIS and why pretty much all high-res fullframe cameras are also equipped with IBIS - and it's not "just" one stop.
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Stan Disbrow
Veteran Member
Hi,
And that rear element has me thinking they have microlenses of varying angles to match that rear element. Something that can be done for a specific (fixed) lens.
But I may never know for sure.
Stan
And that rear element has me thinking they have microlenses of varying angles to match that rear element. Something that can be done for a specific (fixed) lens.
But I may never know for sure.
Stan
Rob de Loe
Veteran Member
I have a couple lenses that stick almost that far back into the sensor cavity. On a BSI sensor there would be strong lens cast, but on the 100 MP FSI sensor they're fine.
Because it's a fixed lens and Fuji's own design, they should have control over all the issues I have to wrestle with using wide symmetrical lenses on GFX that relate to the thick sensor cover glass.
jturn00
Forum Enthusiast
Quick question, I saw the chart of the focal lengths, what are the possible crop focal lengths SOOC? Are those FF equivalent or medium format focal lengths?Fuji is recommending cropping as a method to ameliorate the limitations of a fixed lens in the GFX 100RF. That will affect dynamic range. I've calculated that, using BIll Claff's Photographic Dynamic Range measurements from the GFX 100S II.
Here it is:
The vertical axis is PDR in stops. The horizontal axis is ISO setting. The equivalent focal length for a 33x44mm sensor is shown for each line.
I will be happy to take questions and comments in this thread.
Thanks,
Jeff
SrMi
Veteran Member
For most meaningful results I suggest this approach:
Rules of thumb for handheld shutter speed - the last word
When you first learned about photography, right along with the Sunny Sixteen rule, I'll bet you learned this one: When shooting hand held, set the shutter speed to at least as fast as one over the focal length of the lens. That rule was originally promulgated for 35mm cameras. Should you scale...
blog.kasson.com
Ap0ll0n
Senior Member
Thank you. I believe I followed all of these steps except "analyze for horizontal edge and vertical edge MTF50 in Imatest". I may look into that in the future but if I can't perceive a difference at 100% zoomed in, right now, that is good enough for me. The stdev with IBIS on was very low, again based on 100% zoom in, so I didn't find the need to take 16 shots and I thought 5 were more than enough.For most meaningful results I suggest this approach:
https://blog.kasson.com/the-last-word/rules-of-thumb-for-handheld-shutter-speed/
Macro guy
Veteran Member
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I'm thinking that the interpolated data reduces the need to zoom in on the pixel at a given print size, thus reducing the noise perception. I don't know if that's the case or not, but that's what I was wondering.
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