How much ff resolution to not be "weak link" with Otus?

l_d_allan said:

My understanding is that the very expensive Zeiss 55mm f1.4 Otus is pretty much state-of-the-art for lens quality, including line-pair resolution.

I also have the impression that the Otus has more resolution than even the Nikon D800e with 36mpx can resolve. In that sense, the Nikon sensor is the "weak link".

Click to expand...

Here's another way to look at the "weak link" question. I started with a MTF50 plot of a simulated Otus on a simulated Bayer-CFA (RGGB) camera with no AA filtering, varying the lens aperture from f/2.8 to f/16, and the sensel pitch from 2 um to 5.7 um. The next-to-coarsest sensel pitch is about the same as that of the D800E.



I scaled the grid by taking the log base 2 in both directions, so the points were evenly spaced, and took the first difference of MTF50 with respect to both pitch and f-stop. Then I calculated the direction of steepest ascent at all but the highest-resolution points on the grid as arrows, with the length of the arrow proportional to the slope of the MTF50 curve in the direction of steepest slope. I then plotted all the arrows on a linear grid:


Vertical axis_ sensel pitch; Horizontal axis, f-stop.

Here is a rather facile way to read the plot. If the arrows point mostly horizontally, then the lens resolution can be considered the "weak link". If the arrows point mostly up and down, then the sensor's resolution can be thought of as the "weak link".

Of course, I could change the direction of the arrows by changing the scaling of the axes. That's an intellectual problem. MTF50 might be the wrong metric, especially because sharpening is likely to be used on these images. Still, I hope that this is useful to some of you all.

More here.

Jim

JimKasson said:

Vertical axis_ sensel pitch; Horizontal axis, f-stop.

Click to expand...

Good one. According to the way the arrows are pointing the answer is f/6

Some people have said that, since we routinely sharpen our raw files, MTF10 is a better metric for resolution than MTF50. Here's a couple of plots of the simulated Otus's performance with MTF10 as the metric, rather than MTF50. Because MTF10 can occur at spatial frequencies greater than the Nyquist frequency, when that happens I've substituted the MTF at the Nyquist frequency, since in those cases that is the highest spatial frequency where the MTF is free of aliasing.

The simulated camera has no AA filter, and a Bayer CPF with an RGGB pattern. Demosaicing was with bilinear interpolation. sfrmat3 was used to generate the curve from which i interpolated MTF10 using linear interpolation.

Here's a surface plot, with MTF10 the z axis, sensel pitch in um coming towards you, and f-stop across the bottom:



And here's a quiver plot, with the arrows pointing in the direction of steepest ascent, and their lengths proportional to the slope in that direction:



Using MTF10 as a metric makes increased sensor resolution even more important than it was with MTF50, There is hardly any place on the surface where improving the lens resolution by changing the f-stop helps as much as increasing the sensor resolution.

Of course, the arrow angles still depend on the scaling chosen, and anyone is free to suggest a better scaling.

Jim

--

http://blog.kasson.com

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Better late than never, huh?

JimKasson said:

Better late than never, huh?

Click to expand...

That's a big 10/4, good buddy. ;-)

And ...

Happy Martin Luther King Day!

Have you smiled and said "Hi!" to another human being yet today? Including one of each color ... red, white, blue, brown, black, green, yellow, purple with orange racing stripes, pink, olive, albino, checkered, ... and for extra credit ... brown+white, brown+black, white+brown, [fill-in-the-blank], etc.

The weakest link is always your technique. I just shot with the Otus 85mm last week and if you want to get the most out of it, you need a real tripod from a real camera store, and a very solid floor. My clients were walking around while I was shooting and the slightest vibration takes away every bit of resolution you're paying for.
You also need a way to minimize mirror slap and shutter vibration. Luckily, they're easy to focus but that's important too.

You'll get amazing results from the lens regardless of the body on which you use it, as long as you keep the camera steady.

" color artifacts around high-contrast edges, which is due to aliasing."

I thought color artifacts around edges were strictly green and purple fringing. Are you saying there's another type of color artifact due to aliasing? And if so, what in heaven's name can we fix it when it shows up in our photos?

xpatUSA said:

xpatUSA wrote on April 29, 2014:

BTW, has anyone answered the original question to your satisfaction yet?

Click to expand...

Thanks for "rattle'ing my cage".

As of your post 3+ years ago, I had neglected to click on the Answer Check-Mark, and write to my shame that most replies were over my head.

As of Jan 16, 2018, I've clicked a pair of "Answer Check-Marks", and numerous thumbs-up appreciations.

Thanks for all the patient members moving the discussion to something like:
At least 500 Mpx from 2.71 micron sensor lines on full frame sensors.

--------------------------------------------------------------
tl;dr ? sorry

My understanding is that the sensors in late 2017 premium smart-phones are well past that pitch. A two dimensional mosaic of 4x4 or 5x5 or [fill-in-the-blank] of such dinky sensors seems technically feasible.

Or not?
---------------------- Jan 3, 2018 status ------------------------------
Two weeks ago (early Jan, 2018), OmniVision announced their family of 0.9 micron sensors .

OV24A1Q fits high 24Mpx resolution into the slim 1/2.8" smartphone form factor for front-facing selfie cameras.

Eventually, those numbers seem like they could feasibly scale up to something like ~2.5 billion pixels (BPx?) on a full-frame sensor.
---------------------
24 Mpx * 2.8 reciprocal * 2.8 reciprocal * rectangular aspect ratio of 36x24 = 2.82 billion pixels, if I did the math correctly (for once)

Or not?

-----------------------------------------------------------------

And equivalent Otus IQ down-scaled lenses for such "dinky sensors" would seem to be an order of magnitude lower in price than the mighty Otus .... $5000 >>>> $500 in large quantities with robotics rather than hand-assembly and hand-inspection?

Member said:

<unknown member> in heading
Joe Pineapples wrote:

That ain't necessarily so. At some level, everything discrete is really analogue, and at another level everything analogue is really quantised. More than that, harmonic analysis unifies the two views.

J.

Click to expand...

FWIW:
I'm curious how J. Pineapples with 2200+ posts can show up as an "Unknown Member" in the prologue of the immediately previous post to which I'm replying. Is he no longer members? Probation? Banned? Virtually deceased?

I wonder if I can send him a PM and invite back ... ?
...

nope ... Joe has left the building

Mark Scott Abeln said:

In industrial engineering,

Click to expand...

and also such as Engineering Econ, and considerations so that the Otus would remain viable for 2 to 5+ years without a "back to the drawing board" re-design.
__________________

Drat, my MSIE degree with OpResearch emphasis from 43 years ago ... 1975 ... is haunting me. I should have paid more attention. Don't get old ;-)

War story? Back in the day, we curmudgeons calculated correlations by hand before being allowed to use a simple +-*/ calculator with four functions.

And we later wrote SPSS or SAS programs on punch cards. The very pricey HP 65 didn't come out for several years later.

You kiddos got it easy?

Austinian said:

Along those lines, Goldratt's "The Goal" was required reading at the last company I worked for.

Click to expand...

Thanks. Here's a link to it's Wiki entry ... written in 1984. I'll check if our local library has a copy, or can do an ILL (inter-library loan).

OK ... reserved so I can pick it up later this week, on "Date Night" with the TAGAL Mrs. Allan. (Talented And Gifted And Lovely)

Mark S Abeln said:

Mark Scott Abeln wrote:
the final image will likely be soft but clean.

Click to expand...

Does this mean something close to "low contrast"?

Like a target captured at dusk? Lower MTF like MTF-100+?

Or am I still "fuzzily unclear on the concept"?

JimKasson said:

Some people have said that, since we routinely sharpen our raw files, MTF10 is a better metric for resolution than MTF50.

Click to expand...

Hmmmmm ....

For my "use cases", I suppose for:

• Panoramas: I want high IQ across the frame.
  ...
• Individual portraits with shallow DOF: highest IQ near the center 16mm x 16mm for the face, and everything else can deteriorate to relative fuzziness. Also, I can apply selective sharpening in post processing to the eyes, lashes, lips, teeth and leave the skin alone.
  ...
• Couple or small group: highest IQ near the middle 20mm x 20mm with some negative space OOF at the top, bottom, and sides.

Or not?
_____________________
Hmmmm ... I wonder if the Lytro light field camera might conceptually have allowed moving the "sweet spot" of the lens around dynamically. Is it still around, or too far ahead of its time to be economically viable?

rfsIII said:

The weakest link is always your technique.

Click to expand...

Your relative lack of stability and ability to stabilize the camera and freeze subject motion "always" lowers the maximum possible contrast between neighbor pixels, at least infinitesimally, especially with high pixel densities. However, lower pixel densities limit detail concretely and predictably, regardless of camera and subject stability.

rfsIII said:

The weakest link is always your technique. I just shot with the Otus 85mm last week and if you want to get the most out of it, you need a real tripod from a real camera store, and a very solid floor. My clients were walking around while I was shooting and the slightest vibration takes away every bit of resolution you're paying for.

Click to expand...

I've had my ultra-res Sony a7R2 with 42 MPx on the lower floor slab. With 12.5 magnification, you can see the vibration from walking around.

It was even more of a factor on the upper floor.

Outside on a tripod, the camera can sometimes detect trucks driving by ... the LCD viewfinder is visibly vibrating at 5x and especially 12x magnification.

l_d_allan said:

rfsIII said:

The weakest link is always your technique. I just shot with the Otus 85mm last week and if you want to get the most out of it, you need a real tripod from a real camera store, and a very solid floor. My clients were walking around while I was shooting and the slightest vibration takes away every bit of resolution you're paying for.

Click to expand...

I've had my ultra-res Sony a7R2 with 42 MPx on the lower floor slab. With 12.5 magnification, you can see the vibration from walking around.

It was even more of a factor on the upper floor.

Outside on a tripod, the camera can sometimes detect trucks driving by ... the LCD viewfinder is visibly vibrating at 5x and especially 12x magnification.

Click to expand...

I do my resolution testing with the camera stand or tripod resting on vinyl tile over 8 inches of concrete-on-grade located a mile from the nearest road. Not everyone can get a setup that vibration-free, but I'm glad I can.

Jim

Apparently, the OP just emerged from a 40 month cryogenic state.

Perhaps DPR should yellow the corners of posts in white-background mode, by age, going to brown for 15-year-old-posts.

Strange thing is, I read most or all of the older posts back when they were written, and all of them, including my own, were colored in threaded view as if I never read them.