The 'MF look' and high ISO CMOS backs

[narikin]

Just passing along that great as the new CMOS backs are at 400/800/1600 asa, for me, that 'MF look' gets lost as the ISO increases.

I needed to shoot at 400 the other day, and something was bothering me when I looked at the files. I think it was simply this: the buttery smoothness of a large resolution back is lost, and you are starting to look at the 'grain' structure, rather than the thing itself: skin, metal, glass, sky - do not have 'grain' after all.  A key part of the MF look for me is that complete smoothness you have on a large print that has not been upsized, or pushed in any way, allowing the true surface/textures to come through. You see it at asa 35/50 on the CCD backs, and 100/200 on the CMOS ones. Above that it starts to look closer to a small sensor pushed. Strange how these subtle things play out.

Very happy still to have this high ASA option to hand - there are things you simply must have 400/800/1600 for, and it's great it's truly usable, unlike CCD backs which fall apart really fast, but...  it's still not without a cost.

 

[AlterEgo]

for me, that 'MF look' gets lost as the ISO increases.

you actually mean that 'MF look' gets lost as the exposure (exposure time + aperture) decreases and you can't saturate your sensel wells... unless you are about OOC JPG.

[Paul2660]

I would agree it could be better at 400 on up and I had expected a bit better.  I have realized that there is a bit more headroom in the higher ISO Ranges and have started exposing more to the right as the highlights do do blow out as fast as I thought.

I am also finding that it appears that ISO 50 may have less room than 100 and the 50 is like 50 on the Canon sensors i.e. Your base is 100 but there are a few lower settings but your DR will not be as good as with the base. So I feel the base is really 100  ISO

Paul C

[william]

There seems to be quite a bit of ambiguity as to what the true native/base ISO is on Phase CMOS backs. 

http://www.getdpi.com/forum/medium-format-systems-and-digital-backs/58498-real-base-iso-phase-one.html

http://www.getdpi.com/forum/medium-format-systems-and-digital-backs/58494-iq3-100-vs-iq-180-test-comparison.html

I would agree it could be better at 400 on up and I had expected a bit better.  I have realized that there is a bit more headroom in the higher ISO Ranges and have started exposing more to the right as the highlights do do blow out as fast as I thought.

I am also finding that it appears that ISO 50 may have less room than 100 and the 50 is like 50 on the Canon sensors i.e. Your base is 100 but there are a few lower settings but your DR will not be as good as with the base. So I feel the base is really 100  ISO

Paul C

[Bart_van_der_Wolf]

you actually mean that 'MF look' gets lost as the exposure (exposure time + aperture) decreases and you can't saturate your sensel wells... unless you are about OOC JPG.

That's right, nothing beats real photons. With more photons, the overall Signal to Noise ratio of the file data is better at all tones and colors are more precise (less random), and the files are more robust for postprocessing. Even if the scene is of low enough contrast to easily fit inside the dynamic range capabilities of the sensor, ETTR helps (assuming the Rawconverter doesn't introduce shifts when virtually pulling the exposure).

Cheers,
Bart

[Steve Hendrix]

I would agree it could be better at 400 on up and I had expected a bit better.  I have realized that there is a bit more headroom in the higher ISO Ranges and have started exposing more to the right as the highlights do do blow out as fast as I thought.

I am also finding that it appears that ISO 50 may have less room than 100 and the 50 is like 50 on the Canon sensors i.e. Your base is 100 but there are a few lower settings but your DR will not be as good as with the base. So I feel the base is really 100  ISO

Paul C

Actually, the base ISO is 86.

Ok, not really. I don't know for sure. But that's my theory. It is not 50 and it is not 100, but it's somewhere in between, and probably closer to 100 than 50.




Steve Hendrix/CI

[Steve Hendrix]

Just passing along that great as the new CMOS backs are at 400/800/1600 asa, for me, that 'MF look' gets lost as the ISO increases.

I needed to shoot at 400 the other day, and something was bothering me when I looked at the files. I think it was simply this: the buttery smoothness of a large resolution back is lost, and you are starting to look at the 'grain' structure, rather than the thing itself: skin, metal, glass, sky - do not have 'grain' after all.  A key part of the MF look for me is that complete smoothness you have on a large print that has not been upsized, or pushed in any way, allowing the true surface/textures to come through. You see it at asa 35/50 on the CCD backs, and 100/200 on the CMOS ones. Above that it starts to look closer to a small sensor pushed. Strange how these subtle things play out.

Very happy still to have this high ASA option to hand - there are things you simply must have 400/800/1600 for, and it's great it's truly usable, unlike CCD backs which fall apart really fast, but...  it's still not without a cost.

True - and I get what you're saying.

There's no free lunch or get out of jail free card or reality distortion field that provides for grainless files at higher ISO, unfortunately.

That would be amazing! But it's not here yet.

With that said, I also agree with you that the capability to shoot and produce excellent files at these ISO levels is great. And while that subtle true detail doesn't quite come through the same as a base ISO capture will, the resulting quality still is a beautiful file with wonderful grain structure, sharpness, and detail that can scale to extreme sizes. Just not quite as well as the base ISO files, in terms of surface detail retention.

But still - ISO 1600 file attached, a great accomplishment at 100 megapixels.


Edit: Note the grain structure looks much finer and there is less coloration in the raw file, as opposed to the attached jpg.


Steve Hendrix/CI