Scanning LF Negative 4"x5"

mauro_franic · August 22, 2010

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mauro_franic · August 22, 2010

Here is the overlap (i missed by a pixel or two). It is easy to tell how some of the eyelashes or facial hair merges or gets distorted with the transition. More obviously the eyelashes are thicker than in the original.

http://sewcon.com/compare/index.php?photo1=+http%3A%2F%2Fstatic.photo.net%2Fattachments%2Fbboard%2F00X%2F00X82c-271883784.jpg&text1=1st&photo2=http%3A%2F%2Fstatic.photo.net%2Fattachments%2Fbboard%2F00X%2F00X82f-271883884.jpg&text2=2nd&B1=Submit

swilson · August 22, 2010

You can see a difference which shows that there is some more detail in the 4000 ppi scan then in the 2000 ppi, which is not a surprise for BW film. But the 4000 ppi scan is not making as good use of its pixels as the 2000 ppi image is. A good test for this is to take an image scanned at 2000 ppi and down size to 1000 ppi and back up and then to a compare.

As an example, and trying to keep this all about film, here is a film scan I down sized until it was very sharp, then compared the original to a copy that was down size to 50% and back up. The Difference is pretty striking.

The best was to really see how much of the possible detail a film scan is capturing would be to shot the best shot you can with a good sharp 50mm lens, then shoot the exact same scene with a 200mm lens. Scan both at 4000 ppi but down size the shot with the 200mm lens down to 25%. The shot with the 200mm lens will be dramatically sharper, what this shows again is that not all pixels are the same, a 300 ppi print from a 4000 ppi scan is not worth nearly as much as a 300 ppi print from a 2000 ppi scan. And of course if we go up to 300 ppi print from a 8000 ppi scan, well it is worth less than a 100 ppi print from a 2000 ppi scan.

Dave Luttmann · August 23, 2010

This is really easy. A straight 16 bit scan at 2400 ppi scans below grain thresholds, and provides for an approximate 240 output to print at 40x50. With film flatness and lens diffraction, you rarely obtain much more than this.

For a 16 bit file at 2400 ppi from 4x5, you get about 690mb....or 345 in 8 bit. Obviously, for the best tonality and to avoid scanner noise, it's best to scan in 16 bit....especially with consumer scanners.

An output to 300 or 360 ppi on print isn't necessary at that size....and the data is rarely real detail anyway....unles your shooting with B&W, not stopped all the way down, and using glossy papers.

mauro_franic · August 23, 2010

For 6x7 and 35mm there is a clear advantage to 4000 dpi. Here the bottleneck is the scanner, then the film then the lens.

As Dave said for 4x5 probably not. Here, at 4000 dpi the bottle neck is likely the lens with its limitations, aberrations and diffraction, then the scanner and lastly the film. At 2000 dpi the scanner is probably back to being the bottleneck.

Dave Luttmann · August 23, 2010

Agreed Mauro,

I do not recommend scanning below 2400 ppi. At that size, it's easy to go over 600mb in file size. The beauty of a 2400 ppi scan from 4x5 is that it's grainless with modern day films like Astia, Velvia, TMax 100, Delta 100, Neopan 100, etc.

For MF though, you need 3200ppi and up to get the details off the film as MF lenses typically are sharper, film is held flatter, larger apertures can be used while still maintaining DOF.

kelly_flanigan1 · August 23, 2010

Mauro RE:

"For 6x7 and 35mm there is a clear advantage to 4000 dpi. Here the bottleneck is the scanner, then the film then the lens."

Scanning 6x7 and 35mm at a 4000 dpi real film scanner pulls out about all the practical info these sizes hold.

There *IS* an advantage going to this 4000 dpi level with a tack sharp original; but really not much more as a practical matter.

The "bottleneck" is about never the scanner at this resolution. It might be in one out of 100 to 1000 scans for high end pros; or one out of a million to 1000 scans with an amateur. For a typical amateur who uses 800 iso color print films; I have yet to see where beyond 4000 dpi matters; most only needs about 2700 dpi film scan or way less.

When I look at actual many many many thousands of 35mm and MF I have done for pros and amateurs since 1989; here I can just say the "bottleneck" is almost NEVER the scanner at the 4000 dpi level ; it the the shooter's non perfect input.

A *real* dedicated film scanner is almost never the bottleneck at 4000 dpi; the bottleneck is the shooters sub perfect piece of film.

A film scanner at 4000 dpi is almost never the weak link.

Very little if any even pro stuff needs or warrants scans above 4000 dpi; ie one in 100 or 1 in 1000 inputs really warrants me to farm them out for a drum scan. One typically does this to please the customers ego; often there is really little or NONE extra captured; thus Mr Ego's bubble often gets popped when reality sets in; ie their masterpiece is not chock full of info past what a Nikon coolscan 4000 dpi device can capture.

With 35m and MF the most common bottleneck in the resolution chains is the shooters beloved original does not tax the limits of the 4000 dpi class real film scanner

Nikons 35mm film scanner of 1988 was about 4300 dpi device; later they DROPPED the dpi levels newer scanners to be 4000 and 2700 regions.

5400 dpi film scanners were a marketing flop; only a few makers ever made them.

With a Nikon 4000 dpi film scanner; it is going to capture about all the usefull details of folks:

*"culled out super sharp/great original pile"* ; maybe just maybe one can farm the few percent reculling best of the *"best of the best"* out for drum scans at 5400 to 8000 dpi. Then one has to really search most of the time really to see any practical benefit. You have to ask yourself is if really work cutting the yard twice; or polishing the riding mower to make if faster? To a math major; if the mower burns 1 millionth less gas it matters. To a resolution freak with scanning; if one out of 1000 folks can see the difference in the final print; it matters.

At the 4000 dpi scan setting level with a dedicated film scanner; one is already practically at most all folks limits for film already.

A 4000 dpi real film scanner is the bottleneck in only a few shots in folks lifetime; these can be farmed out for a high end drum scan if warranted.

kelly_flanigan1 · August 23, 2010

In drum scans of 4x5 stuff; a 3000 or 3200 dpi level often pulls out no more info than a 2000 one; except for the on axis stuff. Drum scans of 4x5 at the 2000 level are common; so are 2400 and 2800. drum scanning 4x5 at 3200 or 4000 is done way less; ones costs are skyrocketing and one picks up little extra info

***EXAMPLE relating to ones pocketbook: You have to ask yourself does one want to have five 4x5's drum scanned at 2000 dpi for 200 bucks; or have them all scanned at 4000 dpi for 1000 bucks???

What if one wanted 100 4x5's scanned? a 2000 dpi set is thus 4 grand; a 4000 dpi set just 20 grand Is 16 grand chump change to you or your client?

The "question" about whether to waste money sinks in more if that 1000 buck bill is revolving at 29.99 percent on ones own credit card; or you client or wife questions if the extra 800 bucks was needed.

As scan prices have dropped; folks ponder costs less. All photographers are loaded; and client pays one in gold bars too.

In commercial work; costs matter. There is a live real client that cares about costs. They do not want to pay extra for things that adds no value, Thus if an 80 buck 2800 dpi 4x5 scan is totally ok for all applications; they do not want 120 bucks wasted to make it a 4000 dpi scan. Folks on photo.net seem not to understand costs; or "what is good enough" so it does not matter.

If you have an unlimited budget; one can just have all ones 35mm and MF films high end drum scanned.

Since decent film scanners came out 21 + years ago; less stuff is high end drum scanned. This is because 4000 dpi class real film scanners practically pull out all the info in a 35mm original.

None of this is anything new; Nikon found this out with their first 35mm scanner when Reagan was President; this is older than Photo.net. It goes back to Barney Scan and Photoshops birth

Twenty years from now folks will be asking how much info is in a 35mm film original; the question will be asked forever

alan_rockwood · August 24, 2010

Kelly,

What you are basically saying is that very good is good enough for practical purposes.

However, it is an experimental fact that in some careful tests 100 lines per mm has been demonstrated for some camera-lens-film combinations, at least in 35mm. One of the photo magazines showed this some years ago. To faithfully digitize an image such as this would require a theoretical minimum of ~5000 true pixels per inch, and to avoid Moire patterns in some images, as well as to deal with the fact that technical limitations would limit the true resolution of an instrument to somewhat less than that which would theoretically be achieved at 5000 pixels per inch, one would have to scan at somewhat higher resolution than this.

While it is no doubt true that few practical images would reach this level of resolution, it is nevertheless true that it is possible to achieve this level, and it will be achieved in some images.

Therefore, to settle for an instrument with lower resolution is to accept the fact that you are settling for something less than maximum possible performance. Hence, your strategy is equivalent to saying that very good performance is good enough for most practical purposes. It is not equivalent to saying that very good performance is equivalent to good enough for all cases.

Then there is the rather complex issue of grain aliasing, which is a topic I admit I am not completely comfortable with and don't fully understand, but which seems to have something to do with the interaction between grain structure and sampling rate.

Dave Luttmann · August 24, 2010

Alan, in some case there is a benefit to higher resolution scanning. I have had some photographs that were printed at 40x50 that I printed to a fibre based Baryta paper. It was printed at 360 as opposed to 240 or less that would be normal for most uses. The film stock was Ilford Delta 100, processed in PMK Pyro. There was pretty much no grain. The scan at 3600 ppi should more detail at that print size than did the 2400 ppi setting. So yes, in some cases good isn't good enough.

There can be a greater perception to depth with a higher rez scan.

swilson · August 24, 2010

I have no issue with people scanning at 4000ppi to get a bit more detail. What I have an issue with is those people trying to claim that a large print needs 300ppi, based on a film scan at 4000ppi. Putting it very simply going from a 2000 ppi scan to a 4000 ppi scan does not allow you to print twice as large, in many of the scan I have seen you might be able to print 5% to 10% larger, in some cases a bit more but never close to 100% larger.

kelly_flanigan1 · August 24, 2010

Alan;

It is true that with a lab run/special test one can get high numbers with miles per gallon and what 35 mm film resolves.

I here have done these "what will it do" with about every scanner I buy. I have some ultra high glass etched test targets I had made over 2 decades ago

I too have gotten 52 to 102 miles per gallon in a 1980's Camaro. You just pump up the tires to 50 psi so they are about to pop. You have everything all warmed up for the test. You use a 4 cylinder model with a 5 speed. You find a flat road on in the California Desert in the middle of nowhere. You start the car and lug it an get it up to 45 MPH and cut the engine off and coast. You restart it about 20 mph and do it again.

In tests of Normal lenses for 35mm film cameras that I have done personaly; I have gotten a few with high numbers if I look back through 38 + years of tests over many dozens of lenses. I used Panatomic-X in microdol and a solid tripod; the lights are turned on and off for the exposure; thus there is no camera shake. I got 85 line pairs per mm at F5.6 with a Konica Auto S2; 93 line pair per mm with a 50mm F2 Summicron at F5.6. In the common 50mm F1.4 Nikkors for the Nikon F; I have had the peak data be as low as 58; and the high be 95 in one case; with many in the 65 to 78 region as the peak

In the camera magazines; I remember there was on case where a lens topped 100; the 90mm F2.5 Series I got 105 line pairs per mm at a close test distance. With my own three tests of the same lens; NONE breached 100 at close of far distances; the best of three peaked at 85 line pairs per mm.

Thus as a practical matter; I could buy 1000 lenses on ebay or new from B&H and test them all; and maybe find one that really hits 100 line pairs per mm on fine film.

The customers who have their lenses that they claim hit 100 on film; that I have tested just clock in at about 50 to 75 line pairs per mm on film at their best fstops. Folks either uses the wrong distance or use the wrong values for the group pairs.

I use to work on 35mm microfilm cameras for check sorters. With microfilm and a 1:1000 test target and if one varies the exposure by 1/3 stops; I have gotten over 100 line pairs per mm on film; ie 105 to 110 numbers. As a practical matter; with a colored check; with tolerances of the checks positions; the issue of exposure not being within 1/3 stop one usually gets about 1/3 the resolution numbers on a practical basis.

It is possible for folks to get 100 line pairs per mm on film. It is also possible that they have the same chance of winning a lottery; or that gold bars will arrive in the mail too.

Getting 100 line pairs per mm on pictorial film; of a pictorial object is as easy as getting 100 miles per gallon in the typical USA car or truck. IT CAN BE DONE! If one waks up to another at a gas pump and you tell another that you get 100 MPG with one's Ford Ranger; must folks will think you are nuts. One photo.net many folks preach " I saw where once somebody got 100 line pairs per mm on film" ; and most folks think it is easy; or practical; when it is about impossible.

Alan; it *IS* possible that tomorrow you will win the lottery; or get 100 line pairs per mm on pictorial film; of a pictorial object. In is also possible for Los Angeles to get 5 inches of rain in July too. But just think of what the odds are; one has 1/100 of an inch of rain as the 100 year average for JULYS for Los Angeles downtown. A Bookie in Vegas would think there are better odds for Brett Farve to play pro football for another 20 years.

Thus the issue is not whether one can get 100 line pairs per mm on 35mm film; or get 100 MPG in a 1980's 3rd generation Camaro. IT IS HOW OFTEN DOES IT HAPPEN IN THE real world.

Getting 100 line pairs per mm on film for a pictorial image is like getting a hole in one; it happens at times

Look at golf; even Tiger Woods "settles" that few are every going to get a mess of holes in one in one 9 or 18 hole game.

Look at Baseball; it is possible that games go into overtime; it happens a lot. The media does not plan that every game will go into overtime with scheduling

Kodak in San Diego did tests of how much info 35mm microfilm will record back in the later 1970's and early 1980's for digital storage usage. Kodak and the military did in too during World War II for microfilming of mail for GI's; ie VMAIL. Microfilm got mailed. Even in the 1920's and 1930's 35mm microfilm like Kodaks later Microfile microfilm would record fantasy high numbers under best case test conditions

Alan; a 4000 dpi real film scanner works well with most all folks super sharp originals; the best of the best can be thus farmed out if they want to chase more details. The quest is like not always worth it; ie vacuuming the floor 3 times instead of 2 times. ie one has a high cost versus what extra is captured. It is like mowing the lawn twice; taking a bath 3 times a day. About every single customer who wants stuff farmed out repeats the 100 line per mm tales; ie one camera out of 100 ever tested; Panatomic-X film shot of 1:1000 test objects.

It really is not a complex subject or even technical one either. It is one where lay folks believe their fairly sharp 35mm original hols more info than a common 4000 dpi Nikon film scanner; when it about always does not. It really one is of the customer has this insane belief that based on pure faith that a better drum scanner will MAGICALLY make details appear.

Thus by using just a 4000 dpi film scanner; there is really NOT just settling for results. The average Joe's sharp original often never breaches the scanners limit. Thus one just farms out their gems of gems for higher end drum scans. If one told them that many of their better stuff benefits from drum scanning; one has the issue that one is a darn liar; folks will resent being lied to; being ripped off; ie paying for higher costs services that buy one nothing at all.

Saying that going above 4000 dpi is warranted for a lot of stuff makes one look like a BSer; it really is consumer fraud from a customer relations standpoint. In the long run the smarter customers will resent being ripped off; ie paying for scans that add little if any extra details. After one DOES farm out Mr Egos gems of gems for high end drum scanning; the majority often go through this crisis. If it is an account customer they may balk at paying for their invoice; since the farmed out drum scans did not make the grassy knoll have gobs more details/info.

A typical customer who has it in their heads that a 4000 dpi film scanner is not good enough does have som stuff farmed out for drum scans. After awhile the numbers of slides/negatives that get farmed out drops off. ie they "grew up" ; ie the Honeymoon/Newbie phase is over. They weight the extra costs with not much if any gained.

It is as simple as paying to have ones lawn cut twice in one day; in theory it looks a bit better. After awhile the benefit to cost ratio looks poorer.

It is most common that folks with 35mm get fewer and fewer stuff framed out for drum scans; as they mature. 4000 dpi film scans are usually good enough. The bottleneck is their original is not some 100 line pairs per mm test negative; but more just a common sharp pictorial image

alan_rockwood · August 24, 2010

... which is a long way of saying that I am right when I say that you are of the opinion that very good (but not quite the best possible) performance is good enough most of the time.

The following is an excerpt from a post I made a couple of months ago on some experimental results of camera/film resolution:

Modern Photography, October, 1978.

Here are some of the results:

Summicron 50mm f/2 on Pan-X film: 88 lines/mm at f/4 Nikkor 50mm f/1.8 on Pan-X film: 88 lines/mm at f/4 Canon 50mm f/1.8 on Pan-X film: 86 lines/mm at f/4

Summicron 50mm f/2 on Tech Pan: 96 lines/mm at f/4 Nikkor 50mm f/1.8 on Tech Pan: 96 lines/mm at f/4 Canon 50mm f/1.8 on Tech Pan: 92 lines/mm at f/4

Summicron 50mm f/2 on High Contrast Copy: 105 lines/mm at f/4 Nikkor 50mm f/1.8 on High Contrast Copy: 105 lines/mm at f/4 Canon 50mm f/1.8 on High Contrast Copy: 102 lines/mm at f/4

Summicron on Kodachrome II: 86 lines/mm at f/4 Nikkor on Kodachrome II: 82 lines/mm at f/4 Canon on Kodachrome II: 80 lines/mm at f/4

Summicron on Micro-Ektachrome: 102 lines/mm at f/4 Nikkor on Micro-Ektachrome: 100 lines/mm at f/4 Canon on Micro-Ektachrome: 100 lines/mm at f/4

So, they got around 100 lines/mm using several different lens/film combinations, though with normal pictorial quality films they were not quite getting that high, more in the high 80's lines/mm.

Clearly, under optimal conditions there are certain film/camera combinations that can yield a resolution greater than that which can be resolved by a 4000 pixel per inch scanner, even for some pictorial films.

However, I am sure you are correct when you say that this is not needed in most cases.

On the other hand, to shift gears a little bit, a flatbed scanner capable of resolution equivalent to 2000 pixels per inch is definitely not good enough to pull all the detail out of a 4x5 negative. A lot of lenses for 4x5 cameras resolve 60 lines/mm or better (some up around 80 lines/mm), and these cameras are usually used on a tripod using good all-around technique.

alan_rockwood · August 24, 2010

One other comment, more of a philosophical comment than anything else, posed in the form of a question: What is better, to use equipment with performance reserve capable of handling all situations or equipment which is incapable of providing full performance under certain conditions? Answer that question and it may determine whether one believes it would be good to have a scanner with more than 4000 pixel per inch.

swilson · August 24, 2010

Alan,

If you truly find you need more resolution then what 4000 ppi gives you then you really need a larger piece of film not a higher resolution scanner. The extra detail going from 2000 ppi to 4000 ppi is most often very small, going past 4000 ppi means that you have push the size film you have much too far, IMHO.

kelly_flanigan1 · August 24, 2010

Alan; I have that issue too . The one test that got 100 line pair per mm (not lines like your text) was with High Contast copy film

Thus you used a film about none every use for pictorial usage. I still have my 150 foot roll of Kodak High Conrtast Copy film frozen; I got in in 1976. It is an ASA 6 film; a LITH film,

One cannot get micro-ektachrome anymore. Panatomic-x is gone too.,

Again; you are confusing high contrast best case conditions; with pictorial ones; dead wrong assumption most all make.

You are making the basic lay begineers assumption,

You want to believe that the best case test data with high contrast film and targets; matches pictorial subjects and films. It is just a small error of about 1.5 to TWO TO ONE!

You quote test data shot with high contrast films of high contrast 1:1000 USAF test targets.

In the real world of non bull dung; folks shoot images of people; sports, cars; children; buildings.

*******None of this stuff has 1:1000 contrast bars unless it has a referees jersey. This fact alone hacks the super best

case numbers down to the 70's or 60's.

*******THEN one has the fact that folks are using pictorial films; NOT high contrast stuff. This hacks the numbers typically down into the 50's.

Folks who want scans above 4000 dpi are obsessive compulsive folks; it truely is an insane behavour at times dealing with them as customers. They have a mindset that more is better; they are a dangerous lot in an uncontrolled project. They are the ones who waste gobs of money on things that usually not matter

One can re-shoot those best case 88 line pair per mm tests with special USAF targets with pictorial contrasts of 1:4, 1:10 and the numbers drop like a rock. ie sometimes in the 30's to 50's; and that is with Panatomic-X or Micro File microfilm.

My own Konica Auto S2 that bests at about the 85 line pair one mm with Panatomic-x at 1:1000 targets drops down to the 50's when MY special grey type USAF charts I used for check sorters. If I try 1/500 at F5.6 shooting grey targets by hand; and shoot many and cherry pick the best ones; you get 40's to 50. ALL the numbers get hammered down to reality. If I reshoot those 1:1000 targets with iso 800 superia; one gets not 85 but numbers in the 40s to low 50's. With grey targets ; tripod and iso 800 superia one gets 30's to low 40's

Thus you are barking up the wrong tree to think folks get even close to the lab data under pictorial conditions; about nobody gets into that region at all.

Thus from a customer relations standpoint; the lay want high end scans that usually gather no extra info at all. One cannot come out and tell them directly they are dumb/stupid/dolts/; you just have to advise that the higher end scan may not be warranted.; and it COSTS MORE.

It really is just thus an irrational thing; folks have stuck in their brains that 1978 best case 100 line pair per mm number with B&W film; timed lights; tripod; ASA 32 Panatomic-X. I have several hundred lens tests from magizines. Folks quote the best tests of the century.

The irrational part is their lens is worse; it was not at the best fstop, The whole autofocus thing with many cameras is called locked when one is good enough (about 40 line pairs); they use faster films; they use a kit zoom

One can say why not just drum scan everything; or wash ones hands 10 times; or have the yard cut 4 times in one day.

I did all this 35 years with microfilm cameras for checks. If a check has a micro USAF 1:1000 target and one has perfect exposure and perfect focus; you would get sky high numbers. The with just lower contrast you got reality.

The main point is most lay folks cannot understand transfer functions.

They believe that 1:1000 test data is about what they will get with pictorial objects.

Their brains are not wired to understand MTF's; or combos of MTF's.

Thus one has to let lay beginners learn by failure; you advise them to cover liability. You watch newcomers have stuff farmed out; that really does not tax the 4000 dpi film scanner. You have to let the unbeliever who is obsessive compulsive waste enough cash to where it hurts their pocketbook,You basically are like a parent with a know it all 18 year old who knows everything.

One can often just use a lightbox and tell in a second what scan level is required; after 2 decades it is easy. Folks really want that drum scan to polish their beloved image; one has to deal with the disappointment.

One customer the other day said that the 150 bucks worth of stuff I farmed out were not even drums scans; "BECAUSE THEY ARE NOT BETTER" thus one has dumbing down of folks understanding.

The philosophical part today is the public is dumber; you as a service bureau know nothing; they as a customer know everything. It is real common that folks today cannot grasp that if an original looks just fair on a lightbox; they might not even breach a flatbeds limits.

maybe it is because few project slides anymore; or few use an enlarger anymore.

From a philosophical standpoint having done 21 years worth of 35mm film scanning; a 4000 dpi real film scanner pulls about about all there is with about all folks stuff.

The average persons "sharp original" often really only needs a 2700 dpi scan level. There are gob of folks with Kodachromes that really only need a flatbed; or 2000 dpi film scanner.

Look at it this way; it 1 in a million slides needed a 8400 dpi drum scan instead of a 7000 dpi one; would you say that 8400 is required for all?

You have the situation where already the 4000 dpi film scanner has a VAST RESERVE; most folks do not tax these at all.

4000 dpi film scanners already have big reserve already.

One can use an micro etched glass 35mm test slide I had made and breach any scanners limit.

If folks believe that film scanners should be 5000 dpi; maybe 1 in 10 million will breach its limits

You have the situation where file size grows; and one picks on slide in the scanners MTBF will breach its limits.

The common 4000 dpi film scanner that is a couple decades old already has a lot of reserve; since little breaches it limits. Nikon learned this 25 years ago; that is why early units back in 1988 were 4300. Later coolscan units got down to 4000 and 2700.

As a Philosophical comment; If you want the ultimate; just pay the shot and have all ones 35mm stuff scanned at 8400 dpi on drum scans; since 1 out of 1000 to 5000 great sharp shots might be noticeable.

It is really a money issue; do you want to pay double to ten times more for something that can be noticed after a lot of hard looking; in one out of thousand scans

To an person that is irrational; that one crumb they find after 2 hours of vaccuming the Kitchen is "worth it"

Maybe the impass is folks do not consider costs. With 4x5 stuff drum scanning at 2000 dpi or even flatbed scanning at 2400dpi is very common. In pro work the costs matter. In amateur work costs do not matter; there is no client.

The most odd thing is many folks who want drums scans with 35mm have these slides of sunsets. There are NO sharp details at all. A 2000 dpi film scan is often overkill for details; one uses 2700 or 4000 and see which looks better of the three in the final print.

alan_rockwood · August 25, 2010

Kelley,

A few corrections and clarifications. First, most of the test results quoted above were 80 lines per mm (OK, "line pairs" smart aleck) or higher. There is not a 4000 pixel per inch scanner of the face of the earth that can resolve 80 line pairs per mm, let alone higher than that. Why? Because the Nyquist limit for a perfect sampling device with 4000 pixels per inch is 78.4 line pairs per mm, and a real scanner cannot reach perfection. (If a "4000" pixel per inch does reach 80 line pairs per mm then it is not truly a 4000 pixel per inch scanner but something higher than that.)

Second, it does not require non-pictorial film to exceed the limits of a 4000 line pair per mm scanner. Note that of the five films listed above that achieved >80 line pairs per mm two and one half of them are pictorial films. (I am counting Tech Pan as half-pictorial, since it has sometimes been used as a pictorial film.)

Third, the results were not limited to monochrome film. Some results for Kodachrome exceeded 80 line pairs per mm, and I believe some of the more modern films exceed Kodachrome in resolution.

Fourth, I have the article in my hand and it says nothing about a 1:1000 contrast USAF target. They used a USAF target, but the only special qualities mentioned in the test report is that it was large. Presumably it was more like 1:100 contrast, since I believe that is about what can be achieved with a reflective target, but I am prepared to be corrected on that point if wrong.

Fifth, I believe there are comparison scans on the web between Minolta (5400 pixels per inch sensor) and Nikon (4000 pixels per inch sensor) where the resolution of the Minolta was slightly better than the Nikon. Unfortunately, I can't prove this assertion right now because I don't have the links handy.

Sixth, I am not disputing that it is often (even usually) sufficient to scan at less than the maximum possible resolution. What I do dispute is your assertion that less than maximum possible resolution is virtually never useful.

Seventh, most of your discussion is based on an assumption that maximum technique is virtually never used. I think this is somewhat of an exaggeration.

Eighth, what kind of lenses do you use on your camera? Do you realize that almost all the arguments you have presented for less-than-maximum scanner specification are also arguments that there is almost no reason to buy the sharpest lenses available?

alan_rockwood · August 25, 2010

Correction, 4000 pixels per mm can theoretically resolve up to 78.74, not 78.4. I read my calculator wrong.

Dave Luttmann · August 25, 2010

Alan, for fine grained films, 4000 ppi scans are indeed the bottleneck. For 4x5 sheet film, it's pretty rare to achieve numbers much beyond 80 lp/mm. For some 35mm and MF, you can indeed go well beyond that. It doesn't need to be a high contrast copy film. I know when Roger Smith tested the Voigtlander Bessa R3a with Leica glass and Ilford Delta 100, he achieved 125 lp/mm. A 4000 ppi scan won't come near that.

It is also not necessary to photograph a test chart to achieve these resolutions....just take a landscape where trees cover the sky. Like I said, for 4x5 it's not really necessary. For 35mm and MF, I've done enough scans over the years to see that scanning higher than 3200 ppi is very often warranted.

kelly_flanigan1 · August 25, 2010

Alan;

FIRST; the lens test data I quoted were with formal USAF 1:1000 charts; you shoot a negative; you read the pairs and groups with a microscope. There is NO scanner in the loop. This type of lens testing has been done for decades. Since there is NO scanner in the loop; the scanner does not matter.

SECOND; The lens test you quoted are of 1:1000 test charts; nobody's facial features has a TEN F stop range between details. The actual contrast is little. One has a 2 or 4 or 8 ratio between details; instead of 1000.

THIRD; again these Kodachrome tests are not of real world subjects; but of a high contrast 1:1000 charts. Actual pictorial details do not have 1:1000 contrasts; thus pictorial data is not in this fairy tale region.

FOURTH; ALL these tests are with charts are 1:1000 contrast; unless otherwise noted. It is as fundamental as knowing baseball has 9 innings. Thus all this data of high numbers 100 line pairs per mm resolution is with this lab test super high contrasts; that NOBODY shoots at.

***This is the point I have been trying to get across; that those HIGH 85 to 105 line pair per mm test numbers are of super super high contrast test targets; like about all published tests are. The test is run to see the resolution one gets with these targets; which are not what pictorial stuff is. ***When one repeats the same type of test with a *grey* set of bars; the data drops like a stone/ rock. One does not get these high numbers anymore; and this is BEFORE one even has a scanner in the loop. ALL those high numbers get hammered when a typical details object is shot; ie the resolution numbers on film of the test chart are way way lower. As the contrast of the target drops; does the ultimate resolution.

FIFTH; if some Minoltas at 5400 dpi tested higher than a 4000 dpi Nikon ask yourself why was it a marketing dud? It is because on a practical basis it did not really matter. It is sort of like buying a faster dialup modem of 200k; up the phone system has it all capped at about 53K anyway

SIXTH; one can use above 4000 dpi sometimes in rare cases. If you want to you can have all your own stuff drum scanned at 12000 dpi; there really is no law against it. There really is no black and white answer. You may ponder why if super end 8400 to 12000 dpi scans have been around for a long time; why do very few use them? Why in heck do folks as you say "scan at less than the maximum possible resolution." Is it that a 11,000 dpi scan might be 250 bucks each?

Most all folks on the planet "Scan at less than the maximum possible resolution" it has been that way for decades. Some folks actually look at costs and weigh the tradeoffs. One could have stuff high end drummed scanned 5,10, 15 or evey 20 years ago.

You bring up an interesting point; why do not all photographers not use Summicrons at F4 on tripods and have all drum scanned at 11,000 dpi?

SEVENTH; I am saying that the average persons super great shot with great technique often makes images that do not tax a 4000 dpi film scanner. The stuff that is done well still gets boxed in by the the laws of optics; one has little contrast at all way out there with a high number of cycles; thus there is little if any benefit needed of a scanner beyond 4000 dpi.

There can be stuff out there beyond 4000 dpi; this well understood 20 years ago

The best of the best can be farmed out and then folks will be either impressed at that 200 bucks spent per frame; or they will cry due their stupidity; they flushed cash down the toilet.

There really is a growing group of lay folks; it is a darn good thing the economy is poor; it often wakes up folks with blinders on.

From a customer relations standpoint it is really about education. Morally one needs to say to folks that you probably will not notice. It is sort of like telling somebody they really do not need new tires if they have a lot of tread.

Formal lens tests in those old magazines are with USAF test charts with 1:1000 contrast. Nobody shoots objects like that in normal life.; unless it is for microfilming engineering drawings; that was done eons ago.

Modern Photography sold the same charts they used as a "KIT" for about 15 years. You used Panatomic-X, you had two lights 45 degrees to the charts on a wall. You expose by turning the lights on and off to quash all vibrations.

The 1:1000 is the contrast of the USAF charts; the white reflects 1000 times more than the black. In f stops; that is 10 f stops; ie 2 to the 10 th power is 1024.

The grave error is assuming that 1:1000 test data matches folks stuff shot with pictorial contrasts.

It is a grave gross error of assuming that those great HIGH test numbers done with 1:1000 test charts are what folks get with regular contrast subjects. An analogy is like assuming a cars best MPG test data for a steady 40MPH matches a persons normal commute with stop and go and varied speeds. One gets numbers one half or less.

Pictorial images are not of the same contrasts as those lens tests; they are of actual objects that only have a stop of two; or a fraction of stop difference.

The "Crime" is preaching using data where is does not apply. When Test data for one high contrast lens test is shot with lower contrast test targets; the test data drops like a rock. The same goes with car MPG tests; if one wants to be a con-artist; you quote data that is high over one speed of 40 MPH ; and let others assume it applies to their case with stop and go; picking up kids.

Thus the actual real life pictorial negatives when sharp are down in the 45 to 60 line pair per mm and never 100. At the limit of the lens tests 100 data; the resultant image on film at 100 line pairs per mm is not 1:1000 in contrast; more like about none. One is just barely resolving bars at the limit of performance. The transfer function is such that the 1:1000 test targets image on film is now with little contrast. When the same lens shoot grey scale USAF charts with a low pictorial contrast; one gets number no where near 100; more like 40 to 70's numbers. One gets numbers less than a 4000 dpi scanner. One really has a poor situation; the film/lens is down and one is near the scanners limit too

At some point the fibbing about getting 100 lines per mm in pictorial has to be pointed out. These are pure fibbing manure numbers. . This manure is spread around as gospel; when it really is just done to stack the deck; ie a con artists gambit.

Having worked in optical engineering; it is easy to spot BS numbers.

Most sharp pictorial shot are really in the 50 line pair per mm range in resolution; with stuff that was done with good technique and a lot of care. As a practical basis; nobody ever gets 100 line pair per mm on film with normal pictorial subjects. The ultimate great stuff might be 60 to 70; in rare few cases. If on has actual details on this range; a higher end drum scan at 8400 dpi can have a better transfer function than a 4000 dpi box. It just means that one might get some higher contrast at the higher resolutions; compared to a 4000 dpi box. As another said; "it often is just not worth it"

Saying one gets negatives in the 100 line per mm range with pictorial is really NUTS. In effect the dogma is like a used car salesmen that cons folks. The salesmens goal is to sell cars and use BS data. He has no morals and doe not care if his dogma is wrong or misleading. Thus he finds test data that that the used 3400 Lb Buick gets 45 MPG at 40 MPH and says the car gets 45 MPG to sell the car. The end user then finds out he actually gets about 18 MPG in the city and 26 MPG on highway trips. The end user drives 55 to 80 MPH on the highway; and not a steady 40 MPH. The used car guy cherry picks this single high number data point to be a devil; to purposely mislead folks. He implies that one gets 45 MPG with normal driving. The error is about the same as with lenses; just a TWO to one error

It is really not that the 100 number shot with 1:1000 test targets is wrong; it is just used by folks where the data is invalid; ie with murky grey objects.

The numbers I quoted for my formal USAF tests of lenses where with no scanner; you use a microscope and quote the lessor of the tangential and radial data for each zone.

You have to realize what the immoral thing is about preaching numbers that are not valid for other cases. It really is fraud in a legal sense

Tests with high contrast test targets go back 100 years now; the USAF chart is over 50 years old. High contrast test targets give one data point; and not the entire ball of wax.

By using the best case 1:1000 test data and assuming folks get this type of resolution numbers on a practical basis with pictorial shots; you are off base by about a factor of TWO.

It is as bad as the used car chap that misleads folks; legally it is a dis-service to the public to use data the wrong way.

It was well known that a 4000 dpi perfect scanner might resolve about 78 line pairs per mm with a perfect target 2 decades ago. I am not sure if you just learned this; or got a calculator or just think I did. All it is 4000/2/25.4= 78.74

The problem is that folks do not shoot 1:1000 shots of people; cars etc. There are not 10 f stops difference on eyelashes; glasses; hair etc. It is only a fraction of stop or two. Thus when one repeats the typical great best case lens tests of 80 to 100 line pairs per mm with 1:1000 targets; one is really only getting 35 to say 65 recorded on film.

Thus 4000 dpi film scanners are about never breached; since folks sharp stuff really is in the 35 to 65 line pair range.

By using the best case 1:1000 test data and assuming folks get this type of resolution numbers on a practical basis with pictorial shots; you are off base by about a factor of TWO.

Folks have always been able to drum scan 35mm stuff; one could do it in the 1980's.

When 4000 dpi film scanners became widely used; 35mm stuff farmed out for drum scans tanked/dropped; since little really warrants a higher end scan.

There really has been NO barriers for folks scanning a lot of there stuff above 4000 dpi except RAW CASH. Some folks do not have unlimited cash to waste. They just farm out the higher end stuff that needs it the blue moon cases.

Farming out stuff for scans above 4000 dpi for higher end drum scans is really about religion. One has customers that are often like brainwashed and have joined a cult; they believe that it matters a lot. On has to do handholding; they often go thru a detox; debrainwashed phase when they find out the farmed out stuff is about no better. Some will not want to pay; others want it sent back to be drum scanned again; a rare few will say you are right. There is this fallout phase for them; the sacred dogma got shattered.

Dave Luttmann · August 25, 2010

Hmmm,

I've seen the difference in prints....so the numbers aren't manure. I guess some of us print and scan better than others.

kelly_flanigan1 · August 25, 2010

All one has to do is farm out that rare stuff that needs a scan beyond 4000 dpi; if one runs 4000 dpi class scanners.

If one farms it out for another; one most often has to deal with their emotional crash; after the canned dogma cracks. For some it is a PITA; they do not want to pay. They want you to try another drum scan outfit. You are seeking holy grail scanner that will make their original have more info.

The folk who crash the worse look at the whole issue as a black and white one; they want a simpleton black and white answer to a complex issue. Their brains cannot handle any ratios; contrasts; MTF curves; reality . If one shows a Gaussian plot and says most pros only need this tiny tail of the Bell Curve scanned beyond 4000 dpi; they cannot understand it; or do not want to. It is more like trying to get across stuff to somebody who has been into Scientology too deep; and has been brain washed.

If one looks at each customers bell curve of slides; some could shoot 2 million and non need above a 4000 dpi scan; it is all low end stuff; most doed not even need a 2000 dpi scan.

Maybe M perfect might want 5 percent farmed out; and he is a 3 sigma customer that is rich; uses a tripod; shoots at F5.6; sweats the details. Another pro might have 1 out of a box of slides scanned above 400 dpi and he gets ticked off since the Nikon 4000 dpi film scan is like better.

farming out drumscan 35mm stuff is about managing the disappointed customer; they paid all this extra cash for the better Gizmo; and now they are disappointed.

alan_rockwood · August 25, 2010

Kelley,

The lens tests I referred to were in Modern Photography in 1978. Where do you get the information that they used a resolution target with a 1:1000 contrast ratio in that test? The only information I find in the article is that it was a large custom made USAF target. The contrast ratio is not mentioned in the article.

Maybe all 1951 USAF targets have a 1:1000 contrast ratio, but so far I can't find that specification anywhere.

If it really is a 1:1000 contrast ratio it would be interesting to know how they accomplished that challenging technical feat given the fact that it is not easy to get more than a 1:100 contrast ratio on an evenly illuminated reflective target. Perhaps you know how they did it.

kelly_flanigan1 · August 25, 2010

All; I have about at least FIVE of the Modern Photography test kits they sold over more than a decade. Herbert Keppler of then Modern Photography started the magazine selling them so one could do ones own tests. You got the test booklet; the charts; and a dinky Edmund magnifer to try to read ones negatives.

The USAF chart is described here in MIL standard 150A; ie MIL-STD-150A; it is about a 4.3 meg PDF

http://www.everyspec.com/MIL-STD/MIL-STD+%280100+-+0299%29/MIL-STD-150A_16197/

Page 21 (31 on the PDF file) has the description.

There are 3 types of charts; High, Medium and Low Contrast

High is has a density difference of at least 2.0

Medium has a density difference of 0.8

Low has a density difference of 0.20

High is the one that Modern Photography use to use and sell. They uses the same charts in house as the ones they sold in the kits

A density difference of at least 2.0 is a logarithmic scale. 10 to the 2 power is 100. It means the target has to have at least 100 times difference in reflectance between the white and black.

Since most of the time these are contact printed; the difference is closer to 1000 than 100; thus often called the 1:1000 target in slang.

When one does a test also with the medium and low USAF charts; the resolution drops. On gets poor numbers with the LOW contrast chart.

A density difference of 0.3 is a two to one difference in reflectance; actually 0.30103

If one had charts at exactly 1:100 versus 1:1000 it would not change test result numbers much; it would be less than variabilty of the tests

The working test charts themselves are just high quality glossy photos; contact prints; the ones I have are not RC prints but the old ferrotype stuff where one use a chrome plate.

One can get about 5 to maybe 8 stops range with photopapers. It varies by the paper; developer etc. Some papers have a reflection density of about 2.3; that means about a 200 to 1 range; this is pushing it. The eye is suppose to be able to see 100 to 200 different level of grey in a great photo/chemical based print. To get dark blacks one need fresh paper; leaving it in the developer long enough and not a bad safelight.

I hope some of this helps; regards.

DOWNFALL/shortcoming of just the high contrast Target:

The down fall of just using the high contrast charts was found out in the 1950's when TV video cameras emerged. TV engineers found out that lenses that had high numbers on those high contrast charts for the ultimate resolution sometimes were WORSE than lessor lenses; when used on LOW res TV taking tubes. The crafty Electrical engineers got involved and the MTF for lenses got started; it gives the entire ball of wax.

A test of a lens A versus lens B with all three types of charts can have both lenses giving high numbers with the high contrast charts; and B might be far better than A with the medium and low contrast chart.

Most folk never even know that there are three variants of the USA charts; i used the medium and low ones too with microfilm check sorters too.

alan_rockwood · August 25, 2010

Two orders of magnitude: 1:100 contrast ratio, just the figure I suggested in an earlier post.

By the way, I bought one of Modern's lens test kits back in 1971 for a class I was taking. I have no idea what happened to the kit.

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