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Author Topic: If its not megapixels what is it?  (Read 51477 times)

feppe

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Re: If its not megapixels what is it?
« Reply #120 on: May 21, 2011, 05:30:53 pm »

I don't change still cameras quickly because I don't' have clients asking for any different file sizes, though with motion the 4k buzz is now taking over and that has become a request.

OT, but I'm curious: who is requesting 4k, and are they actually displayed at 4k? Nobody has 4k TVs or projectors in the real world, and we're at least 5 years away from appreciable market penetration even in the bleeding edge home cinema crowd. Video displays playing ads in stores, bars, restaurants, etc. are invariably consumer TVs.

I'm sure there are special applications at sports venues and conventions and some corporate events - is that the intended audience?

Graham Welland

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Re: If its not megapixels what is it?
« Reply #121 on: May 21, 2011, 05:43:59 pm »

With a bayer pattern of 1 row RGRGRG.. and the next GBGBGB.... etc this means that even with an 80M pixel sensor then captured resolution for the green channel is 40 M pixels the Red is 20M pixels and the Blue 20 M Pixels. Any "resolution" above that, with a single shot sensor and a bayer pattern, is down to software and interpolation. Why then should we be surprised that a difference can be seen with the higher resolution sensor. At A2 360dpi, 80M of bayer pattern pixels is still not enough to resolve each colour without interpolation.

I have to declare that I have not seen prints from the new sensor and that the above is theortical. However it does lead me to trust those that have seen a difference in prints and suggests a reason why such a difference may be visible. It also suggests why comparisons with a 24 MP sensor (6Mp Red, 6Mp Blue and 12MP Green) may be futile.

I am happy to be corrected if my assumptions above are incorrect.

Dave


Dave

I think you're dead right about this. We are comparing rendered down pixels and downrezzing an 80mp image that has been Bayer mapped and interpolated back to RGB @ 80mp is going to have more information than starting with a lower res original. The fact that this is visible isn't surprising to me at all. We may not know what to call it but it's easy to understand that there will be some difference in color /detail rendering even if you sampled down the 80mp image to the same size as the smaller image.
« Last Edit: May 22, 2011, 03:38:50 am by Graham Welland »
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fredjeang

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Re: If its not megapixels what is it?
« Reply #122 on: May 21, 2011, 06:25:07 pm »

No, I didn't mean to imply that about 4k footage.  I just meant that mentioning RED and 4k from either my or the client's side is the only camera or format I've seen mentioned in years.

Now still digital capture is usually just takent for granted that most professional cameras from 22mp on will comfortably do the job.

(and before any medium format guys get their panties in a wad, that doesn't mean you shouldn't or wouldn't use something larger).

The RED is interesting to me because it shoots raw and has a thick file, less interesting to me because it takes more multiple steps in workflow.

But I guess if I have a point, for any image maker that works for commerce it should be understood that medium format still cameras don't just compete against each other or Canon and Nikon.

They compete for all professional spending dollars, like computer systems, the RED, continuous lighting, etc. etc. etc. and all this stuff is not cheap.

Even a 5d/7d outfitted properly can get into 10 grand without glass, so what was once our business of owning a few formats of still cameras and some lights has now moved on to broader but more expensive territory to compete.

IMO

BC
Thank you for this precision James,

I understand now your post and it makes all sense.  I wish sometimes my english was better.

Really, keep a sweet eye on the Avid with Red because indeed, with the Avid's capability to devellop the source Raw file in the timeline and apply any Raw correction(s) it is a powerfull workflow and time saver.
It does need computer power, without any doubt, but in the end not more than what you already need for working the Red's.
Arri's also very easy with MC.

I was thinking that with the Epic's (but the deliveries are long), 4K at RED's prices, RED is probably the best investment price/capabilities/reward, that 4K is going to be the "standart" very soon in that sense.

It's always good to be able to downsample from such files.

Out-of-topic: On the Canon's side, and Panasonic, there's a guy who transform the 7D to fixed PL mount removing the mirror etc... Shopping the Bastille boulevards for Angenieux optics and you have a bomb for cheap. (for the people who are interested on PL, do not try the PL mount on a 5D2 or you'll have vigneting but the Panasonic works perfectly. I'm saying that because I've seen some PL adapters on the marquet for the 5D2 and it makes no sense and some have bought them expensive for nothing, unless they want to crop)

I agree 100% that the MF are also competing with the RED, even ALEXA etc...

« Last Edit: May 21, 2011, 06:28:20 pm by fredjeang »
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bcooter

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Re: If its not megapixels what is it?
« Reply #123 on: May 21, 2011, 06:30:41 pm »

OT, but I'm curious: who is requesting 4k, and are they actually displayed at 4k? Nobody has 4k TVs or projectors in the real world, and we're at least 5 years away from appreciable market penetration even in the bleeding edge home cinema crowd. Video displays playing ads in stores, bars, restaurants, etc. are invariably consumer TVs.

I'm sure there are special applications at sports venues and conventions and some corporate events - is that the intended audience?

No I don't believe there is an exact need for 4k as most video has web view.  Then again the ceo of Netflix predicts 4k streaming soon and you'll see 4k on computer screens and in corporate projection rooms probably a lot faster than you'll see it on the networks.

I would imagine 4k first on your computer, 2nd in corporate and maybe instore, 3rd, the cinema.

The thing 4k and RED is a catch phrase with clients.  Red does a good job of marketing and keeping up the myth and a lot of it is deserved because they are in that sweet spot of raw file, 4k, 30 grand.  Nobody is there yet.

Then again regardless of the pixel peepers few people in the print world are asking for 80mpx capture though before it's all done I would imagine Phase will at 180mpx capture because that seems to be the way medium format goes. 

With stills the world has flip flopped and sending out the file sizes we do the only request I ever have now is make it smaller!

But back to 4k motion because there is a parallel between RED and Arri and medium format.

If Canon or someone does raw 4k at 15 grand and does it without line skipping then the rules will change.  Just like it did with stills.

But your right, today we all cut in 2k at the most probably display at 1000k, though in computer streaming land things change quickly, though I predict soon all nle's will be 4k capable.

The only thing that holds our studio up sticking with fcp is #1 we know it and I've got 8 years working it, #2 Apple could produce a world beater with fcp X or a bomb, Avid can produce anything but price points are hard to beat knowing that the next fcp is $299.

Money talks.

IMO

BC
« Last Edit: May 21, 2011, 06:36:03 pm by bcooter »
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fredjeang

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Re: If its not megapixels what is it?
« Reply #124 on: May 21, 2011, 07:05:06 pm »

With stills the world has flip flopped and sending out the file sizes we do the only request I ever have now is make it smaller!

I'm so happy to hear that! Few months ago I was about to write exactly the same in this forum but didn't dare because people would not take me seriously and I did not want to be interpretated as provovative.

But in my assistance experience, let's say from last Sept + or -, that is all we hear: make it smaller, make it smaller!! And I'm talking about long time big clients that in the past used to say "could it be bigger?".

That is to the point that the last time I was trying to incite the boss to take the Blad (in fact it was a strategy of me to be able to play with it...) it kind of looked at me nervous: "don't talk to me about those devices, I want a clean set, if nobody cares anymore" (refering to clients).

By the way, all the campaigns shooted with Gisele Bundchen, Bar R, Erin W etc...not one MF was involved at any time. In fact, he did MF for gallery exhib that nobody cares. For me those are the best shots and works, but they do not sell.

It's not romantic thinking numbers and workflow, it's cold and pragmatic. But I've learned this: this is why he is the boss and not me.


Things have changed.
« Last Edit: May 21, 2011, 07:19:41 pm by fredjeang »
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bcooter

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Re: If its not megapixels what is it?
« Reply #125 on: May 21, 2011, 07:58:33 pm »

(in fact it was a strategy of me to be able to play with it...) it kind of looked at me nervous: "don't talk to me about those devices, I want a clean set, if nobody cares anymore" (refering to clients).

By the way, all the campaigns shooted with ..........

Things have changed.

I'm sure your boss would be happy if he could go out on the day and have the exact usability with his blad that he does with other less expensive cameras.

In fact I'm sure your boss would be happy if it was back to the world where 350 line screens was the only number we really thought about and a day of shooting still images for commerce was a day of shooting still images, maybe a few set ups, maybe a few more for yourself, with no mention of make it horizontal and vertical, make it wide and tight, make it in still and motion, make it fast and btw, deliver it in the morning.

The world has changed and early on when I invested in digital backs, I was damn sure going to use them for about everything.  I almost beat myself silly shooting the world's fastest man with a Leaf, one of the world's fastest women with a Phase.  I did the thing of quick, let me get to the computer so I can check focus, or hold it,  I'm at 1/30th so  . . . ok . . . hold it, don't move, click, now move and yea that's beautiful, hold that . . . click.

In some ways I'd love to not to know the difference between a cross transition vs. a push, what codec means and why I should debayer at half or full.

So, I understand your boss, I somewhat understand you and fortunately or unfortunately (depending on where you sit) I've come to understand some of the world.

I also understand that if I don't get the list that's sitting in everyone's Iphone completed, if I don't make it look natural, if I don't shoot it so the people that hire me bosses go wow, then the resolution of the camera means nothing.

Early this year I tried it.  I went back to my backs (hmm does that rhyme?) and it was smaller jobs, some editorial.  I was bound and determined to shoot them like I shoot my Canons and Nikons and just shoot the way I enjoyed working. 

It worked, the images ran, people were pleased and as much as I could see a deeper more workable file, Ialso saw some stiffness in the subjects, some slowdown in the shooting and less options.  We also ran to the very maximum of the schedule and worried us and the people around us, so I now use the backs only when it's appropriate and I have a lot of light an easier schedule, or when I'm just shooting for me.

But your boss want's a clean set?  

I want a clean brain.

IMO

BC
« Last Edit: May 21, 2011, 08:26:56 pm by bcooter »
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fredjeang

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Re: If its not megapixels what is it?
« Reply #126 on: May 21, 2011, 08:25:30 pm »

I'm sure your boss would be happy if he could go out on the day and have the exact usability with his blad that he does with other less expensive cameras.

In fact I'm sure your boss would be happy if it was back to the world where 350 line screens was the only number we really thought about and a day of shooting still images for commerce was a day of shooting still images, maybe a few set ups, maybe a few more for yourself, with no mention of make it horizontal and vertical, make it wide and tight, make it in still and motion, make it fast and btw, deliver it in the morning.

The world has changed and early on when I invested in digital backs, I was damn sure going to use them for about everything.  I almost beat myself silly shooting the world's fastest man with a Leaf, one of the world's fastest women with a Phase.  I did the thing of quick, let me get to the computer so I can check focus, or hold it,  I'm at 1/30th so  . . . ok . . . hold it, don't move, click, now move and yea that's beautiful, hold that . . . click.

In some ways I'd love to not to know the difference between a cross transition vs. a push, what codec means and why I should debayer at half or full.

So, I understand your boss, I somewhat understand you and fortunately or unfortunately (depending on where you sit) I've come to understand some of the world.

I also understand that if I don't get the list that's sitting in everyone's Iphone completed, if I don't make it look natural, if I don't shoot it so the people that hire me bosses go wow, then the resolution of the camera means nothing.

Clean set?  I want a clean brain.

IMO

BC
Correct James.

Paradoxically, I think we are more prepared now than years before and even if it all looks like a mess, it is maybe more easy to smell where the wind is blowing and anticipate-understand the market, clients and industry in their big lines.

The thing is that in the last decade, tech has made such huge steps and revolutionated the profession from the very roots. Softwares and electronics, data storage, computer power have evolved to a point that it brought unthinkable power to smaller structures and the financial-economical crisis have exhacerbated the all process as well as media displays and social behaviours.

We are now IMO in between 2 worlds, we are living one and enter a new one. There is a lot of pressure as you pointed. But when I read for example your regular comments on Lu-La about how you see the short-medium future, I think that your descriptions are correct in their general lines. It can fluctuates of course but we kind of know where all this is going.

Personally speaking, I have now more fun than ever, but I'm under extreme pressure and tired. Maybe more difficult than the codecs, I find that time management and efficiency vs hollidays-decompression is the real chalenge.

So yes, I understand you perfectly when talking about Avid, you don't want to add more complications and a new learning process and stays with a solution that you and your team already mastered. We have enough to mess with testings etc...

Cheers.
« Last Edit: May 21, 2011, 08:44:57 pm by fredjeang »
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bcooter

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Re: If its not megapixels what is it?
« Reply #127 on: May 21, 2011, 08:51:43 pm »


Paradoxically, I think we are more prepared now than years before and even if it all looks like a mess, ..........snip..............

So yes, I understand you perfectly when talking about Avid, you don't want to add more complications and a new learning process and stays with a solution that you and your team already mastered. We have enough to mess with testings etc...

Cheers.

Fred,

This is my brain on Saturday morning after all of us pulled 18 hour days for weeks.   So mess, yea man it's a mess.



Effective, but non the less a mess and last night hit the deadlines and decided to sit down on my office sofa for a few minutes.  I woke up 11 hours later.

IMO

BC
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ChristopherBarrett

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Re: If its not megapixels what is it?
« Reply #128 on: May 21, 2011, 11:24:37 pm »

To say that it's an insane time in our genre is nothing if not an understatement, but with the anxiety comes exhilaration.  

It's the weekend.  I want to spend time with my family.  I've still got stills to retouch, two days of footage to edit and Monday I'm on a plane to take workshops at Red Studios.

Yeah, it's a little crazy.  This week we spent two days in Herman Miller's studio on a new project.  We had Ford sending models from Chicago and New York.  We were doing the kind of work we'd never done before and I didn't make a single photograph.  The Canon and the Arca stayed at home.  I billed what I always do and never touched my 60 megapixel digital back.  I had no idea what I was doing and when it was all said and done everybody was thrilled.

Yeah, it's a little crazy.

But you know what?  I love it!  I love the Red.  I love dollies and jibs and sliders and Kinos.  I love composing not for a perfect singular image but imagining a scene where the camera is tracking left to right, a chair that fills the frame rotates to reveal another chair in the distance and as I rack focus to bring that chair into sharpness a beautiful woman enters from the left with perfect body language... and the clients release a collective sigh as it all comes together.

Ahh... that's good shit.

Yeah, I don't know where I'm at anymore.  I love my Arca.  The P65+ makes beautiful images, but motion is sooo seductive.  Screw depth of field, give me Cookes wide open and an actress that melts you to the core.

Heh... I remember when I was an architectural photographer.  I have no idea what I am anymore and I love that.

CB
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fredjeang

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Re: If its not megapixels what is it?
« Reply #129 on: May 22, 2011, 06:39:29 am »

Yeah, it's a little crazy.

But you know what?  I love it!  I love the Red.  I love dollies and jibs and sliders and Kinos.  I love composing not for a perfect singular image but imagining a scene where the camera is tracking left to right, a chair that fills the frame rotates to reveal another chair in the distance and as I rack focus to bring that chair into sharpness a beautiful woman enters from the left with perfect body language... and the clients release a collective sigh as it all comes together.

Ahh... that's good shit.

Yeah, I don't know where I'm at anymore.  I love my Arca.  The P65+ makes beautiful images, but motion is sooo seductive.  Screw depth of field, give me Cookes wide open and an actress that melts you to the core.

Heh... I remember when I was an architectural photographer.  I have no idea what I am anymore and I love that.

CB
So do I !!

I think I've never been so exited and even if there is a serious learning curve and my daily rythm has tripled while my personal life is almost unexistent today, I enjoy like never before and this mist you are describing, not really knowing how to "label" one self anymore, photo or video grapher, is creatively reinventing us and the way we express, and it does it in a very exiting and rewarding way.

I feel free. Sounds strange because of the pressure, but I feel more free now. We have wonderfull versatile tools unthinkable 10 years ago.

When we started to hear about convergence, it was clear that this would also apply to the artistic expression also.
Frontiers, labels, do not count any more.

The learning of  some "accessible" post-prod softwares like Autodesk Smoke or Flare have really brought a dimension in my post-prod workflow that I often take the extra work with such enthousiasm because they are bloody peices of softwares and it is a pure delight.
Learning them is hard, lots of hours, but then (sorry to say it but that is really what I'm feeling) when I'm back in PS, or in whatever Raw dev not to mention this or that brand, they simply look like unfriendly toys. I try to avoid them now as much as I can.

I'm evaluating Sratch because Smoke is on Mac and I want a continuous PC solution on a middle term and it's really like I could spend 15 hours on that stuff, I'm tired but it's sooo fun and bloody efficient.

Suddenly, what could catch my interest not a long time ago in some still configuration just vanished, because the "problems" we have to deal with in motion are far more complicated but at the same time, IMO, far more stimulating.

Ps for Cooter: James, looking at this desktop, indeed it's a monitor mess!!! (I'm sort of teasing) Compared to the perfect organised red rack. I've noticed that when I want to clear my head, external clearing helps a lot. But that's just me. I did a sort of reduced "mission control" disposition and I noticed the workflow faster and costing less time. It sounds crazy but having less possible objects arround, distracting cables etc...has an impact.
I think it's interesting because we are into that. I visited this company: http://www.gesab.es/eng.html and realised how important are those details when it comes to motion, and they are relatively easy to do.  

Those guys have long experience building control centers all over the world for various industries and I've been talking with one of the executive. The most important factor seems to be the spacial disposition monitors etc..and very important: no objects visualy that have nothing to do with the workflow. I first thought "come on guys, you're exagerating aren't you". But it changes a lot the tiredness impact.  

  
« Last Edit: May 22, 2011, 07:23:42 am by fredjeang »
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bcooter

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Re: If its not megapixels what is it?
« Reply #130 on: May 22, 2011, 10:37:16 am »

Fred,

That's not the usual look of my workstation, though it was pretty funny for me to wake up and look at it.  Kind of like a guy on a two week bender that wakes up and finds his car in the swimming pool.

Actually, after I finished two videos, I was uploading and also cloning a new computer over to another and pulled the powerbook over to check retouching from our team in NY.

The 4th computer is a Mac tower that is only used for coloring RED dailies in cine-X with a RED Rocket card.

Usually I start the day much neater, but  . . .

IMO

BC
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ctz

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Re: If its not megapixels what is it?
« Reply #131 on: May 22, 2011, 10:54:33 am »

OMG, there are 40 to 50 LaCie Rugged in there...
I just have one LaCie.
And oh, my IKEA chair is the very same model as yours;)
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bcooter

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Re: If its not megapixels what is it?
« Reply #132 on: May 22, 2011, 11:09:01 am »

OMG, there are 40 to 50 LaCie Rugged in there...
I just have one LaCie.
And oh, my IKEA chair is the very same model as yours;)

Upstairs there are 14 Lacie Raid 5's, off site 210 something 3.5" drives and enclosures, under the workstation is 6 terabytes in Raid 0 for video editing.

With our retouchers there are 100 something drives.

When out of LA the 14 Raid 5's go online and I can access them through remote desktop.  

But those Lacie Ruggeds, now that they come in 1 terabyte are a godsend.  I'm slowly getting done with Raid 5's, as we just shoot to the drives, back them up, ship one to the retoucher, keep two on site and one off site.
They're tiny, self powered and so easy to plug and play.

I really do consider them to be the best invention for digital in 5 years and with all I have bought and use only two ever stopped working.  One because it looked like TSA or someone in the air travel food chain bashed it and another because someone stepped on it (not me well maybe me, not sure).

I know a lot of people have issue with LaCie but I've been lucky with them with few issues.   I start every video project with two Lacie 2 or 4 terabyte drives set to raid 0 that are syncronized for backup.

At the end of the project I copy everything over to a third drive for shipping to one of our other studios, or to carry if the project is still in progress.

I kind of have a rule.  I don't buy any drives I can't find in a Mac Store or At Samys.

But to keep this on topic, raw file sizes are important.  One thing about Phase I like is the ability to shoot a smaller raw, I think they call it IQ or IC or something, but it's fine unless your in very low light.
Compared to my previous leaf backs I could get twice the images on a drive which changed our set up considerably.


IMO

BC

P.S.  The funny thing is when I started shooting digital I did it early and in a way thought it was kind of like a fad.

I really believed in my heart and soul that someone would finally say, stop it, we want film, but it never happened and all of a sudden we had a hundred terabytes of data.

I didn't have a dam system, so I kind of built our own using a pdf that we updated.  It grew to 9985 pages and on a slower powerbook took 20 minutes to search out a file name.

Obviously this wasn't going to work so now we have a system and can find anything quick, but I never once dreamed that I would have so much data.  I don't think anyone thought so.

I've been fortunate I've never lost a job, only a few files when the new at the time 1ds2 would corrupt files.  

The biggest scare I had was one saturday I was in our Dallas studio and for once in a long time didn't have a deadline.  I set up the recliner and decided to lay on the patio and get some sun.  I felt like I'd been given a weekend pass from Riker's Island when the phone went off and a client had to have a series of retouched files for Monday.

I went to our drives and found the job and the folders were empty.  Went to the backup same thing.  Went off site, same thing.  My heart sank.  I called our retoucher, made her go back into Manhattan and she did have the complete drive, this time with images.  Turned out a digital tech I hired somehow during backup started dragging in folders, but they were empty and he over wrote the file folders.  

Other than that no problems, yet.


« Last Edit: May 22, 2011, 11:45:32 am by bcooter »
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cunim

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Re: If its not megapixels what is it?
« Reply #133 on: May 22, 2011, 12:46:31 pm »

Odd how this thread has mutated from the value of subtle improvements in an old field (MF still) to the excitement and challenges of working in the new (motion).  Never mind.  It's encouraging to see a group of young (and not so young) photographers applying their skills and talents in a hot market.  The difficulties you mention provide the significant entry barrier which defines a protected profession.  That's a refreshing change from the gloom in commerical photography.

Wonder how many of you will transition from the small shoots to the really lucrative entertainment end of it.  Seems to be a natural progression from motion photography to cinematography. Of course, the logistics are a bit different.
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ChristopherBarrett

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Re: If its not megapixels what is it?
« Reply #134 on: May 22, 2011, 01:46:39 pm »

I wonder as well.  I have no idea at all what I'll be doing 5 years from now.  The crew thing was the biggest change.  My largest Still shoots have maybe 10 people on set with clients and all.

We had a cast and crew of 15 on this little indie / art film.  At the end of our last day shooting at my house we had to cancel our final shots at an exterior location because of thunderstorms.  Everyone was bummed to say the least. 

Our previous scene had been a triumphant and heart wrenching moment.  I did a quick transcode of that, streamed it to the AppleTV downstairs and gathered everyone to watch... it was a hugely emotional scene that created a final bonding amongst the crew that I've rarely experienced on still shoots.

In the scene the actress is singing softly as she contemplates her impending divorce and the take actually wrapped with her in tears... it just melted me to the core.

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DaveRichardson

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Re: If its not megapixels what is it?
« Reply #135 on: May 23, 2011, 07:08:33 am »


1. Is there any proof that 360 ppi is really needed?
2. Is there any proof that current printers actually have a brick-wall response all the way up to 360 ppi for each color channel separately?

As printer have only one or a few output "bits" (either spit a drop of ink, or dont), they all (to my knowledge) use heavy dithering to give the appearance of 8-bit or even 16-bit gradations. This means that even if the distance between any two drops of ink is minute, the real spatial detail level is more limited.

-h

My reference to printing at 360 dpi came from tests with my own printer and it's driver (An Epson 3800 set to Superfine photo 2880 x 1440 dpi). A test pattern of vertical lines; horizontal lines and a checkerboard - each 1 pixel wide is reproduced perfectly at 360 ppi but suffers from artifacts at 359ppi or less or at 361ppi or more. (Sending 720 ppi does not reproduce correctly either).
 
If the pixels can be reproduced on paper, as per the above test, then they are potentially visible when looking at the image (depending on viewing distance). They therefore can have an impact on perceived image quality, that is why I picked 360 ppi. Other printers/drivers may produce different results.

Dave
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hjulenissen

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Re: If its not megapixels what is it?
« Reply #136 on: May 23, 2011, 07:32:32 am »

My reference to printing at 360 dpi came from tests with my own printer and it's driver (An Epson 3800 set to Superfine photo 2880 x 1440 dpi). A test pattern of vertical lines; horizontal lines and a checkerboard - each 1 pixel wide is reproduced perfectly at 360 ppi but suffers from artifacts at 359ppi or less or at 361ppi or more. (Sending 720 ppi does not reproduce correctly either).
 
If the pixels can be reproduced on paper, as per the above test, then they are potentially visible when looking at the image (depending on viewing distance). They therefore can have an impact on perceived image quality, that is why I picked 360 ppi. Other printers/drivers may produce different results.

Dave
Thank you for your reply. I like arguments based on empiry!

How did you conclude that 360dpi prints was reproduced perfect? Using your eyesight closeup, a scanner, a camera using macro lense? Is it safe to conclude that the clean, apparently unaliased image that resulted was the result of an end-to-end 1:1 pipeline, or could it be that you were actually viewing an aliased image that happened to give you clean patterns similar to the input (at e.g. an integer multiplum lower frequency)?

For this test, it was possible to generate content tailormade for the printer input resolution, where pixel-to-pixel difference is 100%. For realistic scenarios, one will grab a e.g. 20 megapixel image from camera, and decide on some physical print size (e.g. A3). Then content would have to be resampled at least once, meaning that bar-code patterns will loose some acuity.

One could imagine that your particular printer/driver does something stupid for any input resolution except 360dpi, without necessarily using image information to its fullest at 360dpi. One test for that may be printing high-resolution material at 360dpi, then taking the same material downscaling it to a resolution corresponding to 180dpi, then upscaling it back up to 360 dpi (choosing scaling and sharpening methods judiciously) before printing just like the high-res original. What is the visual/technical difference then?

I agree that your test seem to indicate that there is that for your setup some gain in choosing 360dpi as output format. Whether your images can use that gain, and whether any given human can perceive it at any given print size/distance is open for debate.

-h
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Bart_van_der_Wolf

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Re: If its not megapixels what is it?
« Reply #137 on: May 23, 2011, 08:15:58 am »

My reference to printing at 360 dpi came from tests with my own printer and it's driver (An Epson 3800 set to Superfine photo 2880 x 1440 dpi). A test pattern of vertical lines; horizontal lines and a checkerboard - each 1 pixel wide is reproduced perfectly at 360 ppi but suffers from artifacts at 359ppi or less or at 361ppi or more. (Sending 720 ppi does not reproduce correctly either).

Hi Dave,

That sounds suspect. Could it be that resampling was used to reach the 359 / 361 PPI? If so how was the resampling done?

The same goes for the 720 PPI, which is the native resolution of your printer (when using glossy paper and the appropriate driver settings). Others report superior resolution at 720 PPI vs 360 PPI.

Cheers,
Bart
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DaveRichardson

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Re: If its not megapixels what is it?
« Reply #138 on: May 23, 2011, 08:48:49 am »


How did you conclude that 360dpi prints was reproduced perfect? Using your eyesight closeup, a scanner, a camera using macro lense? Is it safe to conclude that the clean, apparently unaliased image that resulted was the result of an end-to-end 1:1 pipeline, or could it be that you were actually viewing an aliased image that happened to give you clean patterns similar to the input (at e.g. an integer multiplum lower frequency)?


Thanks for the response.

My use of the word "perfect" is incorrect. With my eyes, wearing reading glasses, I could percieve a pattern of lines and dots at 360 dpi. It took a magnifying glass to show that this was a reproduction of the 1 pixel patterns I had sent and did not appear to show any particular artifacts.

For the 359 and 361 ppi tests - the artifacts were visible with the naked eye at 8-10 feet - they appeared as a repeating pattern of dark / light lines. It would seem that the printer driver is doing some resampling.


For this test, it was possible to generate content tailormade for the printer input resolution, where pixel-to-pixel difference is 100%. For realistic scenarios, one will grab a e.g. 20 megapixel image from camera, and decide on some physical print size (e.g. A3). Then content would have to be resampled at least once, meaning that bar-code patterns will loose some acuity.



I agree - to get through the end to end chain of camera to my printer, with no resampling (which with the exception of some specific integer sizes, will always introduce some impact on the image, and for an A2 print would require a 50MP sensor that samples each colour at each pixel site. My original point was that even the 80M sensors that exist today are not capable of doing that due to the use of the bayer pattern.



I agree that your test seem to indicate that there is that for your setup some gain in choosing 360dpi as output format. Whether your images can use that gain, and whether any given human can perceive it at any given print size/distance is open for debate.

-h

In the real world, it is rare that we do produce images that are not scaled (or have not used specific integers for up-scaling). However the thinking behind my original comment was that there is printable data from the 80Mp sensors that is not being captured in smaller sensors, and even with the 80Mp sensor we have not yet reached the point where we are capturing more data than is printable at A2, even on my old printer. I totally agree that it remains debatable what can be seen in printed images from normal viewing distances - but not having had the good fortune to see images from these sensors directly I was only able to hypothesise on why those who have used the sensors might be seeing a real difference.

Dave
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DaveRichardson

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Re: If its not megapixels what is it?
« Reply #139 on: May 23, 2011, 09:09:31 am »



That sounds suspect. Could it be that resampling was used to reach the 359 / 361 PPI? If so how was the resampling done?


Cheers,
Bart

Hi Bart
I was careful not to resample when I resized the image from 360ppi to 359/358/361/362 and 720 ppi for testing. This was confirmed with no impact on screen only the reported image dimensions changing. Then I just sent each image to the printer driver.
It looks like my driver (Epson) is doing some internal resampling at resolutions other than 360 dpi

I just repeated the 720 dpi test to ensure I had not made a mistake. I was using Premium Glossy paper and had the printer set to 2880 x 1440dpi (Superfine). The  printer did not reproduce the fine horizontal and vertical lines that were seen when sending 360 dpi. Just solid areas of white and black. It may be that another setting in the driver may be required for 720 dpi.

Dave
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