Actually, we need even more resolution.

[BernardLanguillier]

16 stitched Betterlight captures

Jim,

Interesting, that's something I have been considering trying to. How did you move the camera/back?

What that spherical stitching or did you use shift? If you used shift, what lens did you use with such a coverage? One of the mega schneider monsters covering 11x14?

Cheers,
Bernard

[Bart_van_der_Wolf]

This can be approached by introducing arguments and references to relevant theory, or introducing real-world side-by-side tests that confirm or fail to confirm your view. Simply claiming "because... physics" is not very fruitful.

I agree. Moiré is just one manifestation of aliasing, it is not restricted to Bayer CFA false color artifacts (which are mostly caused by different under-sampling densities between Red/Blue and Green, and how the Raw converter handles that).

There is aliasing in any sampling system as long as the input signal has a bandwidth >= fs/2. Man-made sampling systems might include some kind of "anti-aliasing" prefiltering (explicit or implicit), but like any man-made filters they won't have infinite attenuation in the stop-band. What might be realistic (for some systems/cases) is for this aliasing to be sufficiently attenuated to levels where they are no longer a big problem. There is no need for the signal to be periodic, by the way. A single impulse (think single-sensel-size star against a black sky) contains a wide range of frequencies and may cause aliasing.

Correct, a sharp edge will aliase 'just fine', especially with sensors that have low fill factors. Multi-sampling with half sensel offsets will increase the apparent fill factor and sampling density, and full sensel offsets will eliminate the unequal Bayer CFA sampling densities. It will not eliminate aliasing, just reduce its most visible effects to more acceptable levels.

With the CFA used in "Bayer" sensors, the 3 sampling frequencies are simply shifted downwards. If you prefilter at this new minimum fs/2, I believe that there will be no Bayer artifacts (and Debayering will be a very simple linear operation). One reason that we don't do such pre-filtering is that the sensel density is simply not high enough. The resulting (luminance) resolution would simply be too low, and the artifacts from the CFA pre/post processing are often surprisingly small anyways. The current level of prefiltering and postprocessing may be a compromise that works well for current sensel densities and print sizes/viewing distances.

The most objectionable kind of aliasing is false color aliasing caused (but not exclusively) by repetitive subject patterns with high spatial frequency when projected on the sensor. Some 'nice' examples here. This kind of aliasing can be made less obvious with the right tools, but the residual luminance aliasing is harder to reduce once it is created.

Prevention is better than cure, and increasing the sampling density (over-sampling) is one way to reduce aliasing. That can be achieved by either using relatively smaller sensels (exploiting over-sampling or optical blur), sub-pixel offset sampling, or by using more projection magnification (which increases the size of the image features that are projected on the sensor array), or pre-filtering.

Cheers,
Bart

[bjanes]

Hi,

This paper is a good read: http://www-isl.stanford.edu/~abbas/group/papers_and_pub/pixelsize.pdf

The impression I have is that the papers says that 4-5 microns is optimal with 0.18 micron technology, but I also feel that the pixel model in the paper is a bit dated. Modern pixel designs use shared transistors and utilise the pixel area better than older designs.

Best regards
Erik

Not only that, but the analysis is for monochrome, not Bayer array sensors, and it does not take microlenses into account. I didn't read the whole article, but I'm not sure if it applies to per pixel dynamic range or to down sampled DR for high pixel density sensors (screen vs. print DR in DXO terminology.

Bill

[Torbjörn Tapani]

Monochrome, no microlenses and assuming a CRT display.

[Ken R]

Ok, enough of the tech talk.  

Anyone want to see how much resolution is enough? or required?

Go to a Rodney Lough JR Gallery (las Vegas or San Fran (the Wharf)) and look at some of the VERY large prints on display. Get close. Yes, real close, no, 50cm is not close enough. Get your nose to almost touch the glass. See the detail? Yes, you can count the blades of grass on a wide angle shot. Count every leaf. Those prints do not leave you wanting for more resolution. Only color prints I have seen that large that do that. Almost every print is just stunningly well made and look amazing even under close scrutiny.

The Peter Lik prints are almost as good but not quite. He gets a touch sloppy on some although most are awesome also.

Again, I am talking color prints.

Google what kind of gear they use and techniques.

[jerome_m]

Rodney Lough JR used a 8x10" view camera for much of his work and presently uses an RL3d with an IQ180 back. His maximum print size appears to be 45" (114cm) on the shorter side. The prints are probably about 180-200 dpi.

[Theodoros]

Ok, enough of the tech talk.  

Anyone want to see how much resolution is enough? or required?

Go to a Rodney Lough JR Gallery (las Vegas or San Fran (the Wharf)) and look at some of the VERY large prints on display. Get close. Yes, real close, no, 50cm is not close enough. Get your nose to almost touch the glass. See the detail? Yes, you can count the blades of grass on a wide angle shot. Count every leaf. Those prints do not leave you wanting for more resolution. Only color prints I have seen that large that do that. Almost every print is just stunningly well made and look amazing even under close scrutiny.

The Peter Lik prints are almost as good but not quite. He gets a touch sloppy on some although most are awesome also.

Again, I am talking color prints.

Google what kind of gear they use and techniques.

"Use your  magnify lens"... "Makers are stupid"! "P1 is right for being the only one that has moved (a little) below 6microns"... "We know better"... "We know everything !" ..."You need prints to be captured at 300dpi"! ..."Move closer"! ..."Less ppi is because there is a conspiracy against the public"! ..."Gursky is overrated because he doesn't use enough ppis"... "I close examined that expensive print and it was rubbish"... "I watch prints to judge them at less than 50cm no matter the size of them"... I want, I want, I want... I know, I know, I know... 

I wonder why the industry doesn't employ the posters, or acts against their "results", ...and still survives?! ...I really wonder if a maker makes an 180mp back (as it was mentioned earlier) with Bayer pattern... If ANY of the posters would buy it... Who is the "customer"? ...lets see the "preorders list"... Is there a man that would put his money on a 4microns MFDB? ...let's see the "hands up" and their "declaration of purchase"... Saying "I want this to be made ...for others to consume it", sounds ...(@#$%!&^)  whatever to me... It's easy to talk on (wrong) theories with your pocket not involved! 

[Theodoros]

Rodney Lough JR used a 8x10" view camera for much of his work and presently uses an RL3d with an IQ180 back. His maximum print size appears to be 45" (114cm) on the shorter side. The prints are probably about 180-200 dpi.

Actually It's 44" Jerome..., but them being at 180-200ppi, wasn't your O/P about someone needing 300ppi?

[ErikKaffehr]

Hi,

That would be 185 PPI, pretty consistent with the suggestion that 180 PPI is needed for a very good print. Pretty much consistent with this article of my.

It is also consistent with the observation in above article that high contrasts texture and line patterns need higher resolution to avoid aliasing and pixelation.

So, I guess we are in a race between good enough and more is even better.

Yes, I am a bit split on the issue. My experience is that 180 PPI is good enough to view normal objects in prints, but higher resolution is needed for high contrast texture and even more resolution is needed to eliminate fake details.  

This image shows the advantage of high resolution clearly:


While this is much less clear:


Both crops correspond to 180 PPI in an A2 size print.

The images here are all from Imaging Resource.

Best regards
Erik

Rodney Lough JR used a 8x10" view camera for much of his work and presently uses an RL3d with an IQ180 back. His maximum print size appears to be 45" (114cm) on the shorter side. The prints are probably about 180-200 dpi.

[Theodoros]

It is also consistent with the observation in (my) above article that high contrasts texture and line patterns need higher resolution to avoid aliasing and pixelation.

So, I guess we are in a race between good enough and more is even better.
Best regards
Erik

I still fail to see the race... the two new CMOS sensors (the latest in technology) for MF (Leica & Sony - the only ones that are expected to sell on some numbers at "next day's future")... are with 6microns (Leica) and well above 5 microns (Sony)... where is the "race"?

[Jim Kasson]

Interesting, that's something I have been considering trying to. How did you move the camera/back?

What that spherical stitching or did you use shift? If you used shift, what lens did you use with such a coverage? One of the mega schneider monsters covering 11x14?

Bernard, it's a little complicated, and all is not what it seems to be. I can explain.

The idea behind this series, which I call Timescapes, is one dimension of the image is distance, like a normal photograph, but the other dimension is time, quite unlike a normal photograph, but like the images from finish-line cameras at racetracks. I use a Betterlight Super 6K back on a Linhof Master Technica, and occasionally an Ebony field camera, which provides a delicious combination of old=tech and high-tech.

There is a rotating platform available for the Betterlight back that allows it to be used to make panoramas. When the camera software is in panorama mode, the sensor goes to the center of its travel and stays there, expecting the rotating platform to provide the scanning. In this mode, the back can make images of up to 6000x64000 pixels with no interpolation.

So how do I get the camera to make the Timescapes pictures? I lie to the software. I tell it that the camera is on a rotating platform, but it's firmly attached to the head of a normal tripod. Therefore, any changes visible in the picture that results are the result of subject motion. To get multiple exposures for stiching, I use the camera software's built-in intervalometer.

Now, about this image.

I have some succulents that my wife propagated from a cutting Don Worth (yes, that Don Worth; AA's assistant and, with Jack Welpott, creator of one of the great photography education programs) gave to me. The succulent was created by Don — it’s a hybrid of Echeveria Shaviana and Echeveria Subrigida, and it’s called Echeveria Afterglow.

Slit scans need some motion to rise above banality, and succulents are not known for their athleticism. I figured, if I can’t get the plant to move, I can at least get the light to change. In fact, since I’m taking the photographs in direct sunlight, I can’t get the light not to change. So I made a series of images with long exposures. When the slit was vertical, I had time run from right to left, and with the slit horizontal, time goes from top to bottom.

You can see more of the series here.

Jim

[EricWHiss]

Eric, I'm thinking finer pitch. My reasons:

We can get lots of pixels that way more cheaply, by riding on the coat tails of CMOS processes developed for other, higher-volume purposes.

We are nowhere near using all the available performance of the best lenses, at least, if my simulation results are right.

There's a lot of small pixel work being done for cellphone cameras.

Much bigger sensors means much bigger cameras and lenses, with cost and portablility issues.

Of course, I've been wrong before...

Jim

Hi Jim,
I see your logic, and probably this is the way the tech will go since devices such as cell phones will push for smaller pixels and higher quality small optics.   It's an interesting dilemma because that route will be one which pushes the glass to be shorter, faster, smaller and higher cost for the reasons of diffraction etc.  Going to a smaller pixel will up the cost of lenses, and also affect range of DOF the photographer can use on both sides -  Shallow DOF will not be as easy since format is smaller and faster glass not so easy to come by, and deep DOF not possible because diffraction limits are found sooner when stopping down because of the smaller pixels. Technology on small pixels is still developing but the limits of physics are there - smaller pixels will ultimately have less dynamic range than larger pixels - all else being held equal.

On the flip side, a larger sensor will be more costly because of lower yields in manufacturing, and the cameras will be larger and heavier as you pointed out.   So you'd put your money into the sensor instead of the glass.   The glass is less stressed and the photographer could have more range of DOF control available because a larger sensor would not necessarily need smaller pixels.   Also worth noting - when you are working with a larger sensor the magnification/compression of the image is much less and this can be apparent in the image.  The glass does not have to work as hard to transfer a large range of frequencies in the image scene at high contrast either.

For these reasons, I tend to see the future heading towards very small and perhaps just cell phone cameras, but with a small niche market for a very high end larger sensor camera platform for those that need the control.   

[jerome_m]

That would be 185 PPI, pretty consistent with the suggestion that 180 PPI is needed for a very good print. Pretty much consistent with this article of my.

Actually, my experience of large prints has been that ~200ppi are fine, but the quality visually deteriorates below 200 ppi. How much depends on the subject. Still: apparent sharness definitely improves between 200 ppi and 300 ppi.

300 ppi for 60" x 80" is 18000 x 24000 pixels, 200 ppi for 60" x 80" is 12000 x 16000 pixels.

We can discuss whether 200 ppi or 300 ppi is needed all day long, the fact remain that the 60" printers demand resolution that cannot be attained by present cameras for best output. Which was always the point of this thread.

This thread started tongue in cheek about the realisation that available inkjet printers are better than any camera on the market today and, therefore, that the idea that digital MF cameras have too high a resolution is absurd. It then evolved about out of my control about bizarre theories about printing, optimal pixel size, moire and lenses, etc... But this was never my intention.

My intention was always about large prints and large printers. I have printed somewhat big and reached the limits of my cameras of the time (24 mpix 24 x 36). I have been to galleries and museums and have experienced large prints, both analogue and digital. I know perfectly well what can be done, because I have tested it myself. And I know just as well that few photographers can produce large prints which appear sharp when looked up close, because I have been to galleries and museums and watched prints up close.

(Edit: corrected dpi to ppi.)

[Jim Kasson]

I see your logic, and probably this is the way the tech will go since devices such as cell phones will push for smaller pixels and higher quality small optics.  

If FF is "small", we're already there with the Oti (is that the plural of Otus?), the Sigma ART series, the Coastal Optical 60mm macro lens, and some others. We could have  2um pixels and not run out of lens resolution with those lenses.  It's interesting as the lens quality for FF lenses increases, the lenses themselves get much larger, until they are almost as big as some MF lenses. That's not always true: the Coastal 60 and the Leica 50 f/2 APO are counterexamples.

It's an interesting dilemma because that route will be one which pushes the glass to be shorter, faster, smaller and higher cost for the reasons of diffraction etc.  Going to a smaller pixel will up the cost of lenses, and also affect range of DOF the photographer can use on both sides -  Shallow DOF will not be as easy since format is smaller and faster glass not so easy to come by, and deep DOF not possible because diffraction limits are found sooner when stopping down because of the smaller pixels.

Within reason, that all sorts itself out: http://www.josephjamesphotography.com/equivalence/

But your original question was about sensor getting bigger than they are, and they're already a bit under 56mm in the long dimension. I think they could get a little bigger -- I'd sure like to see a 56mmx56mm sensor, but I don't expect to see 4x5 inch and 8x10inch sensors as standard photographic tools in my admittedly limited prospective lifetime.

Technology on small pixels is still developing but the limits of physics are there - smaller pixels will ultimately have less dynamic range than larger pixels - all else being held equal.

Smaller pixels have more limited dynamic range per pixel, but if you take a sensor of a given physical size, making the pixels smaller doesn't reduce the dynamic range of the captured image as a whole.

Good luck with Rollei!

Jim

[ErikKaffehr]

Hi,

My view is that thriving for large usable apertures makes for large and expensive lenses. Personally I am an f/8 shooter, so making medium aperture lenses like f/2.8 makes a lot of sense to me. Those lenses can be small and reasonably priced.

Right now I feel quite inspired with the Zeiss Loxia lenses, the ZM series recalculated for 2mm cover glass. If Sony makes a camera within the 36-54 MP range with an electronic first curtain I would certainly be one of the first ones to buy.

Best regards
Erik

If FF is "small", we're already there with the Oti (is that the plural of Otus?), the Sigma ART series, the Coastal Optical 60mm macro lens, and some others. It's interesting as the lens quality for FF lenses increases, the lenses themselves get much larger, until they are almost as big as some MF lenses. That's not always true: the Coastal 60 and the Leica 50 f/2 APO are counterexamples.

[Torbjörn Tapani]

Going to a smaller pixel will up the cost of lenses, and also affect range of DOF the photographer can use on both sides -  Shallow DOF will not be as easy since format is smaller and faster glass not so easy to come by, and deep DOF not possible because diffraction limits are found sooner when stopping down because of the smaller pixels. Technology on small pixels is still developing but the limits of physics are there - smaller pixels will ultimately have less dynamic range than larger pixels - all else being held equal.

But all else is not being held equal. Thinking about smaller feature size, different layout, copper, microlenses and so on.

Diffraction is not a limit on aperture. When we are diffraction limited wide open you are free to worry about what the image need for the intended viewing size. 1:1 pixel view is going to be soft anyway.

[Theodoros]

Actually, my experience of large prints has been that ~200dpi are fine, but the quality visually deteriorates below 200 dpi. How much depends on the subject. Still: apparent sharness definitely improves between 200 dpi and 300 dpi.

300 dpi for 60" x 80" is 18000 x 24000 pixels, 200 dpi for 60" x 80" is 12000 x 16000 pixels.

We can discuss whether 200 dpi or 300 dpi is needed all day long, the fact remain that the 60" printers demand resolution that cannot be attained by present cameras for best output. Which was always the point of this thread.

This thread started tongue in cheek about the realisation that available inkjet printers are better than any camera on the market today and, therefore, that the idea that digital MF cameras have too high a resolution is absurd. It then evolved about out of my control about bizarre theories about printing, optimal pixel size, moire and lenses, etc... But this was never my intention.

My intention was always about large prints and large printers. I have printed somewhat big and reached the limits of my cameras of the time (24 mpix 24 x 36). I have been to galleries and museums and have experienced large prints, both analogue and digital. I know perfectly well what can be done, because I have tested it myself. And I know just as well that few photographers can produce large prints which appear sharp when looked up close, because I have been to galleries and museums and watched prints up close.

There is no print than can be made as low as 200dpi or even 300dpi Jerome... Not on a Canon or an Epson printer anyway... Perhaps you mean ppi and just confused it with printer's dpi.... is that what you mean?

[ErikKaffehr]

Hi,

Yes, PPI and DPI is often mixed up. I am quite tolerant about that.

Best regards
Erik

There is no print than can be made as low as 200dpi or even 300dpi Jerome... Not on a Canon or an Epson printer anyway... Perhaps you mean ppi and just confused it with printer's dpi.... is that what you mean?

[ErikKaffehr]

Hi,

I would say that DR is more about sensor area than pixel size, equivalent technology presumed. But, I don´t really think that DR is decisive for image quality, I would say that less than 0.1% of my 70000 images are affected by DR.

Would I grade causes of bad image quality, the causes would be:

1) Subject choice
2) Bad cropping
3) Wind
4) Lack of DoF
5) Bad focus
6) Aliasing
7) Diffraction
…
..
DR

Best regards
Erik

But all else is not being held equal. Thinking about smaller feature size, different layout, copper, microlenses and so on.

Diffraction is not a limit on aperture. When we are diffraction limited wide open you are free to worry about what the image need for the intended viewing size. 1:1 pixel view is going to be soft anyway.

[Theodoros]

Hi,

I would say that DR is more about sensor area than pixel size, equivalent technology presumed. But, I don´t really think that DR is decisive for image quality, I would say that less than 0.1% of my 70000 images are affected by DR.

Best regards
Erik

What one judges as priority to him... is obviously personal... PHOTOgraphy though, is not personal... it's by definition a print that involves lighting difference and the treating of lighting difference... by definition! ..That's what a PHOTOgraph is!