IQ3100 and tech wides: why crosstalk effects are difficult to evaluate

[ErikKaffehr]

Hi,

I would suggest that it is beneficial to be aware of possible issues and guys like Torger, yourself and the guy formerly known as Voidshatter do a great job of informing us. Raw images, like the ones from Capture Integration and Digital Transitions are most helpful.

Now, that the issues are know, the potential buyer is well informed and is aware of the possible pitfalls and also hopefully about some workarounds.

Clearly, both advantages and disadvantages may be a bit overblown. Not long ago some folks claimed that digital backs had a six EV advantage in DR over DSLRs and still many users believe in the benefits of 16 bit representation of 13 bits worth of data. Now, with the new Sony sensor, MFD actually seems to be able to deliver almost 15 bits worth of data. So, you get great high ISO capability and can pull a lot of shadow data. Small pixels and microlenses cure a lot of moiré but may not work that well with symmetric wide angles or even mildly retrofocus designs.

I would say that folks like Anders (Torger), Voidshatter, yourself,  Ray Ondebanks, Jim Kasson, Bart van der Wolf, Luke Klaven, BJanes, Bill Claff, Jack Hogan et al. made great contributions to inform us, separate info from hype and perhaps helping some of us to educated decisions.

Best regards
Erik

I guess the big question is, will you see it in post?

The IQ150, when shifted to 15mm with a 40 HR-W was basically pure red on the last 6mm or so of shift so much that when I first viewed it, I was sure that the 50MP chip just would not work.  However when the LCC was applied it's not bad at all.  In fact, what I found, was that the 40 HR-W had more issues with my IQ260 on a blue sky than the 50MP IQ150.  C1 has to me a lot of trouble getting a pure blue to work on a shift from the 260 as there always seems to be a residual red cast, which has to be fixed. 

The 150 only really showed me one issue on shifts, the light/faint blotchy vertical banding on solids.  This also showed up on the IQ3100 on the Alpa test where they shot a blue sky. 

I guess to me, it's not a show stopper, wasn't on the IQ150, only the crop factor was really.  If you are working in Art reproduction I guess it might for sure.  But in my outdoor work, I was very pleased with what Phase One was able to accomplish with the IQ150/250 and movements.

I am of course a bit disappointed that since all this was known about from the 150/250, that Phase did not attempt a better fix for the wides, but I guess that is just not possible?   Maybe the next chip? 

But from what I have seen on of the LCC's from Capture Integration on the 10mm shift with the 32 Rodie and 15mm of shift on the 40, the LCC's outwardly do not show as much red color, no where near as much, when compared to the IQ150 LCC.  Right now it's also hard to really compare with the LCC's since C1 is not processing the LCC for the 3100 without the green cast.

I realize that the LCC doesn't correct crosstalk, but on the 50MP chip it did a darn good job of getting all the red out and bring back the correct looking colors.

Just one opinion of many.

Paul C

[torger]

I have not personally seen any residual red issue in the skies with the Dalsas, and I don't have a technical explanation as to why it would occur. I haven't used Capture One extensively though so it could be some sort of LCC algorithm bug, or may even a profile issue. But of course, what you see is the end result and that is what matters.

The issues I and many others did observer with the 6um Dalsa is tiling and ripple, but it's in most cases a correctable problem. The Dalsas did have significant crosstalk issues on the Schneider symmetrical wides, and the 80MP does have significant issues also with the Rodenstocks when you do large shifts. The P45+ was really the last back in the Phase One line that was designed to work with technical wide angle lenses without issues.

The Dalsas really made people used to accepting a set of issues and figuring out various more or less time-consuming workarounds. With the Sonys we again get a set of issues, of a different kind. Personally I think the Sony issues are worse as the crosstalk thing is the one thing that is hardest to correct in software. But while I can make my own custom software to correct stuff that Capture One doesn't do, any normal user is dependent on what Capture One chooses to fix in their LCC algorithm.

A well-made LCC algorithm for Sony is surely providing a better end result than a poorly made LCC algorithm for Dalsa. With the P45+ and also the Kodak I have myself you didn't have to make a special LCC algorithm, the simplest will cancel out all color cast and there's no residual artifacts as the sensor was designed for handling these lenses, and that is how I think it should be, but it will probably never be like that again.

[gebseng]

Panasonic to the rescue?

http://www.43rumors.com/press-panasonic-announces-first-organic-sensor-with-global-shutter/

"Panasonic Corporation today announced that it has developed a new highly functional global shutter[1] technology for CMOS image sensor using organic photoconductive film (OPF)*1."

"Wide incident angle (60 degrees), high sensitivity, high saturation and highly-functional circuits due to a unique feature of OPF, in which an OPF for photoelectric-conversion and a readout circuits are independent."


best,

Gebhard

[torger]

Thanks for the link. Very interesting technology, with light sensitive area so thin there's further improvement of angular response. 60 degrees is quite much. I'm not sure what the old Kodaks had, the KAF-39000 (P45+) had +/-39 = 78 degrees in "critical crosstalk" angle but that's the angle when light leaks over to the next pixel, due to light shields the maximum angle that actually gets registered in he right pixel is considerably less, maybe 60 degrees or a little less.

This likely means that Panasonic's OPF technology could deal with even the SK28XL. That lens delivers light at even lower angles but you can push the limit some and still get good results.

What's a little suspicious in the diagram is that the OPF pixel is larger than the color filter above.

While it may seem like the "extreme" symmetric lens designs are dead in MFD segment, it should still be interesting for compact camera makers as you can make very compact wide angle cameras with high image quality if you have a sensor that can handle it. So I think there's still an interest to make wide angular response sensors in some segments, unfortunately I don't think MFD is one of them. Since Kodak stopped making sensors it's very clear that the tech cam segment have no influence on sensor design. We get what we get and have to do the best out of it.

If the technology proves successful and superior also in dynamic range and other factors it will eventually bubble up I suppose, but looking historically and projecting forward it could be 8+ years from now. That's a long time in digital photography...

[eronald]

They are talking 2020 for this tech.

I think at that point I'll be thinking cataract surgery ...

Edmund

Thanks for the link. Very interesting technology, with light sensitive area so thin there's further improvement of angular response. 60 degrees is quite much. I'm not sure what the old Kodaks had, the KAF-39000 (P45+) had +/-39 = 78 degrees in "critical crosstalk" angle but that's the angle when light leaks over to the next pixel, due to light shields the maximum angle that actually gets registered in he right pixel is considerably less, maybe 60 degrees or a little less.

This likely means that Panasonic's OPF technology could deal with even the SK28XL. That lens delivers light at even lower angles but you can push the limit some and still get good results.

What's a little suspicious in the diagram is that the OPF pixel is larger than the color filter above.

While it may seem like the "extreme" symmetric lens designs are dead in MFD segment, it should still be interesting for compact camera makers as you can make very compact wide angle cameras with high image quality if you have a sensor that can handle it. So I think there's still an interest to make wide angular response sensors in some segments, unfortunately I don't think MFD is one of them. Since Kodak stopped making sensors it's very clear that the tech cam segment have no influence on sensor design. We get what we get and have to do the best out of it.

If the technology proves successful and superior also in dynamic range and other factors it will eventually bubble up I suppose, but looking historically and projecting forward it could be 8+ years from now. That's a long time in digital photography...

[voidshatter]

Panasonic to the rescue?

http://www.43rumors.com/press-panasonic-announces-first-organic-sensor-with-global-shutter/

"Panasonic Corporation today announced that it has developed a new highly functional global shutter[1] technology for CMOS image sensor using organic photoconductive film (OPF)*1."

"Wide incident angle (60 degrees), high sensitivity, high saturation and highly-functional circuits due to a unique feature of OPF, in which an OPF for photoelectric-conversion and a readout circuits are independent."

best,

Gebhard

I guess organic sensor could be the next breakthrough. They are advertising 128dB of dynamic range, which is 100 times better than the current sensors. It could surely make the IQ3 100MP completely obsolete.

[torger]

Organic sensors have been discussed for a while, and if I remember right Sony has some work in that area too. If it's 4 years until this reaches the consumer market, maybe someone else will be ahead?

It will be extremely interesting to see where high resolution wide angle photography will be in just 5 years. It's hard to predict.

[Bart_van_der_Wolf]

Organic sensors have been discussed for a while, and if I remember right Sony has some work in that area too. If it's 4 years until this reaches the consumer market, maybe someone else will be ahead?

It will be extremely interesting to see where high resolution wide angle photography will be in just 5 years. It's hard to predict.

Hi Anders,

My guess is that it will evolve in the direction of retrofocus design lenses that are used non-shifted, with a high enough sensor resolution that perspective corrections can be done in postprocessing (more accurately than on a small camera LCD, maybe taking camera orientation sensors into account to automate this).

The keystone correction by sensor rotation, as some smaller IBIS sensors offer, may also play a role but it will remain a challenge to match radially decentered microlenses with non-centered lens projections. BackSide Illuminated (BSI) sensors will be difficult to manufacture for large format sensors, and may negatively impact dynamic range.

Cheers,
Bart