File latitude to manipulation

[AreBee]

All,

What provides Medium Format files with a greater ability to hold up under heavy post-processing than 35mm format files?

[Bart_van_der_Wolf]

All,

What provides Medium Format files with a greater ability to hold up under heavy post-processing than 35mm format files?

Hi Rob,

It's usually due to a better MTF response because the detail can be captured at a larger magnification factor. Better MTF results in more subtle tonality differences, which can then be exploited in postprocessing. But the differences with good quality lenses for smaller formats is not all that large. It's there, but its magical qualities are also exaggerated a lot.

Cheers,
Bart

[Doug Peterson]

Like many things, it is an oversimplification to point toward one thing. Generally post processing does two things:
- exaggerates issues in the file (e.g. pushing contrast or sharpening will increase the perception of chromatic aberration)
- stretches data

Depending on the MFD being discussed, some of the factors involved in what I'd call "malleability"

- Dynamic Range
- Quality of the Color Profile (e.g. linearity of the color)
- Bit Depth of the Color
- Dark Frame Quality
- Raw Processing and Hardware that are codeveloped
- Better Lenses (sharper detail, requiring less sharpening)
- Better Lenses (lower chromatic aberration)

[Endeavour]

I did a quick unscientific test this weekend, pitting my P30+ on a Hasselblad H1 with 80mm lens against a Canon 5d2 with a 17-40mm L lens

What amazed me most, apart from the shear level of details the P30 captured - was that the MF image was great corner to corner. Really sharp
The 5D's resolve was far softer around the edges of the frame.

Now I know we are talking about apples & oranges with Prime lens vs zoom. But the differences in image quality were far greater than I imagined (and gave me a warm fuzzy feeling after just paying for the P30)

so to answer the OP - my MF images seem to give me a lot more freedom to crop whilst still retaining excellent levels of detail over my 35mm images

[AreBee]

Bart,

It's usually due to a better MTF response because the detail can be captured at a larger magnification factor. Better MTF results in more subtle tonality differences...

If I understand correctly:

1. The larger physical size of a Medium Format sensor compared to a 35mm format sensor means that a longer focal length lens is required to return the same field of view.
2. By definition the magnification of a longer focal length is greater than a shorter focal length.
3. Greater magnification increases MTF.
4. File bit-depth sets a limit on the tonality that can be captured - a 16-bit file may retain 100% of the tonality inherent in an image (depending on the image content) whereas an 8-bit file may curtail it.

Is this correct?

[Bart_van_der_Wolf]

Bart,

If I understand correctly:

1. The larger physical size of a Medium Format sensor compared to a 35mm format sensor means that a longer focal length lens is required to return the same field of view.
2. By definition the magnification of a longer focal length is greater than a shorter focal length.
3. Greater magnification increases MTF.

Correct. Assuming similar Fields of View, the larger magnified detail is 'lower spatial frequency' detail on the MTF curve and thus has a better preservation of the original subject contrast, and as a consequence more tonality to work with.

4. File bit-depth sets a limit on the tonality that can be captured - a 16-bit file may retain 100% of the tonality inherent in an image (depending on the image content) whereas an 8-bit file may curtail it.

It's the ability to discriminate between subtle tones. A 16-bit/channel file can encode more intricate detail/tonality for post-processing. It's then up to the postprocessing to enhance or reduce those differences, depending on the intended effect.

Is this correct?

Yes, that's my take on it. Of course, as Doug pointed out, there are more factors like lens quality, but when all other factors are more or less the the same, MTF still makes the difference, makes the files more malleable. That's what it boils down to, IMHO.

Cheers,
Bart

[AreBee]

Folks,

I had been under the impression that file bit-depth alone determined what Doug referred to as malleability, and couldn't understand what it was that apparently made Medium Format files more malleable than 35mm format files, all else being equal. I have read the claim many times, but my understanding is that modern 35mm format files have the same bit-depth as Medium Format (excluding the IQ3 100MP), hence my confusion.

Thank you.