IQ180 Vs. 8X10 film article

[theguywitha645d]

You are clearly wrong on all of the above, l/mm of a lens are measured on a certain FP distance, if FP distance is increased (and thus image circle magnifies) resolution drops. This simply means that if two lenses with the same glass resolving power are used to record the same AOV at different formats, the lens that records on the smaller image area will appear to have more resolution. Nobody said anything about same technology or scanners adding resolution, I think you (and others) are confusing resolution with analysis! Please re-read the post and make sure you understand it, don't quote in irrelevant matters.  Cheers, Theodoros. www.fotometria.gr

Actually, I am right about everything in my post. If you read carefully you would see everything is based on the angular size of the aperture from the image plane. A very basic concept actually.

I obviously have problems understanding what you write.

Cheers.

[Fine_Art]

Hi,

My impression is that we get diminishing returns on high PPI scans. The samples you referred to look quite soft at actual pixels. I downloaded the 6000 PPI sample and did the following experiment:

1) Sharpened it to taste
2) Duplicated the image
3) Resized the duplicated image to 50% using bicubic
4) upsized the duplicated image to 200% using bicubic (so I downrezzed and than uprezzed by the same amount)
5) Pasted the downsized/upsized image above the original image
6) Added a layer mask over about 1/3 of the image

It is very hard to see any difference between the two images. I added a screen dump with the top layer in subtract mode. The mask is clearly visible, and the black area is the difference between the two images.

My conclusion is that there is very little excess information in the 6000 PPI file compared to the same file downscaled to 3000 PPI.

Best regards
Erik

Here is a 750dpi vs that 3000dpi screen capture. I ran NN on the original, then downscaled to 3000dpi. I duplicated it, downscaled to 1/4 (750dpi) then set to 400% view side by side.

Of course people will say they can see spots on the 750 dpi so it must be all the information.

[fotometria gr]

Actually, I am right about everything in my post. If you read carefully you would see everything is based on the angular size of the aperture from the image plane. A very basic concept actually.

I obviously have problems understanding what you write.

Cheers.

Obviously......  Thanks for quoting,  please avoid to reply...  Regards, Theodoros www.fotometria.gr

[ErikKaffehr]

Hi,

You are absolutely right. I actually repeated my experiment downsizing to 25% and resizing by 400%, in that case the loss of information was obvious. It is interesting that the downsampled/upsamled image displays grain which looks like real grain.

Best regards
Erik

Here is a 750dpi vs that 3000dpi screen capture. I ran NN on the original, then downscaled to 3000dpi. I duplicated it, downscaled to 1/4 (750dpi) then set to 400% view side by side.

Of course people will say they can see spots on the 750 dpi so it must be all the information.

[fotometria gr]

Hi,

You are absolutely right. I actually repeated my experiment downsizing to 25% and resizing by 400%, in that case the loss of information was obvious. It is interesting that the downsampled/upsamled image displays grain which looks like real grain.

Best regards
Erik

Hi Erik, let me put things from a different POV. Imagine an enlarger... the more the enlargement, the worst the quality right? Now imagine a LF camera to record the same scene on each version of both 4x5 and 8x10 capability with the same AOV, ...the 8X10 image would be further apart and would have THE SAME RESOLUTION for the whole image ...wouldn't it(?), ie lower resolution per square inch! This of course assumes that film quality exceeds lens analysis, now... the same would apply if on that hypothetical camera we would use 120/220 film, ...wouldn't it? The recorded resolution would have been the same even on MF film because it would be even nearer to the lens. But nobody would dare to scan MF film on 750dpi and then compare it with an IQ 180!!! All the above wouldn't apply on 1940s or 50s where film was poor... but it would apply with modern films and of course cannot be extended to compare 35mm as well because film quality didn't advance as much...  , but given the shortcomings of scanning LF and the lesser quality of LF lenses, it proves that scanning should have been done at the higher possible scanning resolution, because its irrelevant of film size and IMO at as much multiscanning as possible to avoid scanning errors. Regards, Theodoros. www.fotometria.gr

[theguywitha645d]

I think it might be worth noting a few things. The diameter of an Airy disk given perfect aberration-free optics is this:

D=2.44 lambda N

Where N is the f-number and lamba is the wavelength of light.

And the Rayleigh criterion for resolving power (RP) is this:

RP= 1/1.22 lambda N

Note: focal length and magnification are irrelevant. N would be the effective f-number taking into account lens to image plane distance if working with a system not focused at or near infinity.

[fotometria gr]

I think it might be worth noting a few things. The diameter of an Airy disk given perfect aberration-free optics is this:

D=2.44 lambda N

Where N is the f-number and lamba is the wavelength of light.

And the Rayleigh criterion for resolving power (RP) is this:

RP= 1/1.22 lambda N

Note: focal length and magnification are irrelevant. N would be the effective f-number taking into account lens to image plane distance if working with a system not focused at or near infinity.

"Given perfect aberration free optics".....   is one, quoting on irrelevant matters is another... Jesus! Read before you quote, what you correctly state is true (physics) theory and are different and irrelevant than the problem we discuss that has to do with why scanning should have been done at 4000 dpi or more and also perhaps on different format! I mean this physics approach doesn't take into consideration "glass resolving power" does it? And it also doesn't consider the light sensitive erea recording/resolving ability! It assumes that are both INFINITE.... have you got it now? According to the way you make it appear an enlargement should be as sharp per square inch as a smaller print, what is you can not understand? Regards, Theodoros www.fotometria.gr
 P.S. Mind you that in "fotometria" we are now converting our P2 to work with lower circle lenses like the Mamiya RZ (with "Just Together" German kits) and that we don't use sheet film anymore but only plan to use (after we finish the conversion) the MFDB and 120/220 film! This is after observing that there was no difference with sheet film performance to MF film. Also consider that in our lab we test anything by printing it (digitally only from either HiRes files or from scanned files) and that these prints are enormous (110cm at the small side to ...whatever in the long side) and this is everyday job!

[UlfKrentz]

Obviously......  Thanks for quoting,  please avoid to reply...  Regards, Theodoros www.fotometria.gr

...lula used to be a nice place, just my 2ct...

[theguywitha645d]

"Given perfect aberration free optics".....  is one, quoting on irrelevant matters is another... Jesus! Read before you quote, what you correctly state is true (physics) theory and are different and irrelevant than the problem we discuss that has to do with why scanning should have been done at 4000 dpi or more and also perhaps on different format! I mean this physics approach doesn't take into consideration "glass resolving power" does it? It assumes that its INFINITE have you got it now? According to the way you make it appear an enlargement should be as sharp per square inch as a smaller print, what is you can not understand? Regards, Theodoros www.fotometria.gr
 P.S. Mind you that in "fotometria" we are now converting our P2 to work with lower circle lenses like the Mamiya RZ (with "Just Together" German kits) and that we don't use sheet film anymore but only plan to use (after we finish the conversion) the MFDB and 120/220 film! This is after observing that there was no difference with sheet film performance to MF film. Also consider that in our lab we test anything by printing it (digitally only from either HiRes files or from scanned files) and that these prints are enormous (110cm at the small side to ...whatever in the long side) and this is everyday job!

I did not quote your post, so please do not quote my posts. Not at least until you know a little more, or maybe a lot more, about optics. And how is your continued offensive behavior helping to make LuLa a nice place?

[fotometria gr]

...lula used to be a nice place, just my 2ct...

You may be right, I should have let this one go...., but would this make it a better place? I guess ...history will tell. ....Sorry, Theodoros. www.fotometria.gr

[fotometria gr]

I did not quote your post, so please do not quote my posts. Not at least until you know a little more, or maybe a lot more, about optics. And how is your continued offensive behavior helping to make LuLa a nice place?

Yes but you did quote ON MY POST! Which I have no objection of you doing anymore..., but just consider that are other people reading and we are both on their judgement, I have nothing personal or intentional against you, its just that I feel you "jump in" by twisting the subject projecting irrelevant knowledge (which you have) and thus you mislead the conversation AND project people with similar or better knowledge as ignorants. Don't forget your (much) earlier quote on me a couple or three days ago in this very thread, that you "jumped in" by "making up" phrases that didn't even exist and then, after I quoted back exposing your mistake (intentional or not) ...you just disappeared, .....you didn't even apologize... which I'm prepared to do for you, if I have said anything offensive against you (which I haven't), ....I only protested for you posting irrelevant as relevant, .....nothing more, nothing less....  Regards, Theodoros. www.fotometria.gr

[theguywitha645d]

Yes but you did quote ON MY POST! Which I have no objection of you doing anymore..., but just consider that are other people reading and we are both on their judgement, I have nothing personal or intentional against you, its just that I feel you "jump in" by twisting the subject projecting irrelevant knowledge (which you have) and thus you mislead the conversation AND project people with similar or better knowledge as ignorants. Don't forget your (much) earlier quote on me a couple or three days ago in this very thread, that you "jumped in" by "making up" phrases that didn't even exist and then, after I quoted back exposing your mistake (intentional or not) ...you just disappeared, .....you didn't even apologize... which I'm prepared to do for you, if I have said anything offensive against you (which I haven't), ....I only protested for you posting irrelevant as relevant, .....nothing more, nothing less....   Regards, Theodoros. www.fotometria.gr

Like I said, when you learn more about optics, come back and we can talk, otherwise keep to yourself.

Actually, you are deeply offensive, even if you do learn something, avoid me. I am happy to avoid you.

[fotometria gr]

Like I said, when you learn more about optics, come back and we can talk, otherwise keep to yourself.

Actually, you are deeply offensive, even if you do learn something, avoid me. I am happy to avoid you.

I'll say it once more "Don't project others as ignorants" but its your decision.... after all people can judge by reading....  Regards, Theodoros. www.fotometria.gr

[harlemshooter]

This site is clearly biased towards DSLR and MF digital image capture... Resolution is only one factor, of many, which informs "quality" images (and most differ on the subjectivity of quality).

Mr. Roversi seems to think the allure of LF film is not in its sharpness, but in its overall smoothness and softness. I agree. Perfect square pixels can't match what unique grain clumps offer in terms of how the entire image/print gels - and vice versa.

So let's stop this conversation please and just go take some pictures. Do what works for you.

[feppe]

This site is clearly biased towards high-end digital image capture...so it cracks me up how often these discussions about film vs digital come up. Resolution is only one factor, of many, which inform "quality" images.

Mr. Roversi seems to think the allure of LF film is not in its sharpness, but in its overall smoothness and softness. I agree. Perfect square pixels can't match what unique grain clumps offer in terms of how the entire image/print gels - and vice versa.

So let's stop this conversation please and just go take some pictures.

There's a peculiar need for the digital crowd to justify their gear and their price. In my experience us (partly) analog guys have mostly dropped that conversation years ago, and use it for various reasons rarely to do with resolving power, DR, or other narrow definition of IQ - if IQ has even any weight in the equation.

For the record I'm not saying there's no place or justification for an MFDB kit costing more than two-three good new cars - there is in many cases, and in many cases there's no need for justification (mostly affluent amateurs who don't get paid to photograph). Just like often there is a place and justification in spending low four figures in an LF kit, and five figures per year on film, developing and scanning.

Cameras are tools, and should be treated as such: right tool for the right application.

[fotometria gr]

There's a peculiar need for the digital crowd to justify their gear and their price. In my experience us (partly) analog guys have mostly dropped that conversation years ago, and use it for various reasons rarely to do with resolving power, DR, or other narrow definition of IQ - if IQ has even any weight in the equation.

For the record I'm not saying there's no place or justification for an MFDB kit costing more than two-three good new cars - there is in many cases, and in many cases there's no need for justification (mostly affluent amateurs who don't get paid to photograph). Just like often there is a place and justification in spending low four figures in an LF kit, and five figures per year on film, developing and scanning.

Cameras are tools, and should be treated as such: right tool for the right application.

Perhaps it should be added to the well stated above, that adding a 22mpx back to the same comparison and using an "open system" with an alternative film back for the rare case that higher resolution would be needed and purchase an old Jobo CPE2 developing device along with a 9000ED scanner to avoid the cost of the lab, could save the cost of 2 out of 3 cars and do the same thing more efficiently. Even if there is some insignificant loss in resolution that bothers some now, but didn't bother them 3 years ago. Even more so..., what if the above back was a multi-shot one? Regards, Theodoros. www.fotometria.gr

[heinrichvoelkel]

...lula used to be a nice place, just my 2ct...

+1

[TH_Alpa]

Yes, the famous "system news", very good information in it. I have worked myself on a few of it.

And I did actually write one of my earlier posts in this thread based on the information from one of this publication, the difference in sharpness when the film is not absolutely flat.

But still, Sinar did not make any research in resolution power of film or lenses, and all such information was based on available data from the lens and film manufacturers.

Thierry

Sinar used to produce very good brochures (system news) were they showed which improvements are possible if you do it the right way. These infos actually contained valuable informations. Some examples: demonstration which will be the difference of an optimal placed film and a film that is 0.3 mm  (I even remember that number) off at max f-stop. Difference if you expose a chrome with different exposure latitude and you give this into the offset print chain. And you could actually reproduce exactly this results. I remember especially the one with the adhesive film holder and one about lenses. All Sinar staff was always very helpful. Even at the time when I was a poor student who only owned a used f1, one lens and 3 film holders. I never experienced that with anything in the digital world.

Best,
Johannes