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Author Topic: Interesting comparison of IQ180 and 8x10" film  (Read 50840 times)

lenny_eiger

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #40 on: September 23, 2011, 08:14:39 pm »

Hi Lenny,
That interesting! Is this the lens?  http://www.bhphotovideo.com/c/product/43853-USA/Rodenstock_160702_150mm_f_5_6_Apo_Sironar_S_Lens.html
It does mention in the overview that the ideal Working Aperture Range is f/11 -22.
What's this lens like at F11?

Yes, this is the lens. But I wouldn't have any idea what it does at f11. I wouldn't ever consider so wide open. Unless I was shooting something quite 2 dimensional. I am a lover of depth of field. However, I did shoot it at f22, 32, 45 and 64 just yesterday and 22 was not better than 45. 64 did start to get a little soft. Like all of these things, the manufacturer's recommendations don't always work out in real life...
The essential problem with all such comparisons involving different formats of cameras, using different lenses which may also have different performance characteristics even at the same aperture, is reconciling the test methodology with the principle of "best tool for the job".

I have an Ebony, its on a tripod and it was in the garage with the door open, natural light and no wind. No movements were used, simple straight ahead shot of some chisels, etc. I used Delta 100, at 100. I also souped in a Jobo using Xtol at 1:1. Then scanned on the Premier at 10 microns. i created one profile for the first neg and used it for all of them...

Now it seems very clear to me, if the 8x10 format used at F32 cannot even closely match the resolution of the IQ180 used at F16, there's not much point in equalising DoF by using the 8x10 at F64. The differences would be even wider.

I think the results of this test are very clear, that in situations where a reasonably long DoF is desired, the IQ180 without a shadow of a doubt produces better image quality than 8x10 film (at least the film types in the test).

I think the results are quite unclear. An 8x10 in my world would blow the 80 megapixel away on a variety of fronts, both resolution, but more importantly in tonal separation and reproduction.. What you have here is an incompetent setup by unknowledgeable people. Everyone will tell you that the operator is a key factor in a scan. This operator did not know what he was doing. (With all due respect.) Clearly hadn't gone past 745 in the past. He is using an old scanner that is not the top of the line and comparing it to the top of the line... These kinds of tests should be done with a Premier, with an experienced operator. Otherwise, its just bogus.

I'm not the only experienced operator, there are plenty, but choose someone who has some idea how to use the tools, please...


What is missing from this test is a comparison at the shallow end of DoF. For example the IQ180 at F2.8 versus the 8x10 format at F11 or F13. Would this situation favour the 8x10? Somehow, I doubt it, but it would be good to see a comparison, perhaps of a still-life taken in the studio.

I notice that Markus has rescanned the results at a higher resolution which has had the effect of narrowing the differences slightly, but not changing the over all conclusion.

Its nice that he is attempting to be accommodating. What he needs to do, however, is to pass the film to someone who can do it justice....

I'm rushing off, sorry if this sounds rushed.... more later.

Lenny
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Jack Flesher

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #41 on: September 23, 2011, 08:23:10 pm »

Re scanning film and resolution. I have no dog in this fight, but back in the day I used an Imacon LF scanner. No, the Imacon was not an Aztek drum scanner, but it was pretty darn good. Anyway, I (and others who shot a lot of LF film) found that in most cases, 1800 DPI was around the maximum point you could extract detail off film -- the best low ISO slide films, neg films went a little higher -- anything higher usually just enlarged grain and gave no real additional usable image detail. And I would probably not argue with somebody claiming they see a wee bit more at 2400, but beyond that, you're chasing windmills.  

Point 2: Regardless, 745 is not everything a perfect 8x10 has to offer.  However, let's keep in mind that if it already looks soft at 745, it 'aint going to be any better at 8000...

Point 3: Lens resolution really depends on how you test. *SOME* LF lenses with 300mm or larger IC's are capable of making 60 line pairs, most are not -- I know this, because I tested a bunch back in the day. (The 150 APO Sironar S will NOT cover 8x10 -- the uber rare 150 APO Sironar W fall just shy of covering fully, but it was close enough and is a cult status optic -- and note it's a BEAST by comparison to the 150S, like 4 times as big.)  Seriously, 30 to 40 line pairs was really good for an 8x10 lens.  Note however we're not talking center-field here, we looked at 1/3 out from center to have a usable average number.  So yes, if you are only talking center field, 60 is probably doable with a few of the best.  

Cheers,

  
« Last Edit: September 23, 2011, 08:27:17 pm by Jack Flesher »
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lenny_eiger

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #42 on: September 23, 2011, 11:49:03 pm »

Re scanning film and resolution. I have no dog in this fight, but back in the day I used an Imacon LF scanner. No, the Imacon was not an Aztek drum scanner, but it was pretty darn good. Anyway, I (and others who shot a lot of LF film) found that in most cases, 1800 DPI was around the maximum point you could extract detail off film -- the best low ISO slide films, neg films went a little higher -- anything higher usually just enlarged grain and gave no real additional usable image detail. And I would probably not argue with somebody claiming they see a wee bit more at 2400, but beyond that, you're chasing windmills.  

See, this is exactly what I was saying... people make judgements about what is possible based on their equipment. Imacon's are ok. I'd say a little higher, likely somewhere in the 2,000-2,300 range. The earlier ones might have been 1800.... don't know. However, that's a CCD scanner. To assume what an entirely different technology could do (or could not do) does not make a lot of sense...

Point 2: Regardless, 745 is not everything a perfect 8x10 has to offer.  However, let's keep in mind that if it already looks soft at 745, it 'aint going to be any better at 8000...

I'd give that a possible. So the fellow was either bad at focusing his camera, has a mediocre lens, regardless of brand. Or maybe he was just bad at scanning. Maybe he was manually focussing the scanner? Or running it at a much higher micron setting. I haven't looked at the film so I can't say either way...

Point 3: Lens resolution really depends on how you test. *SOME* LF lenses with 300mm or larger IC's are capable of making 60 line pairs, most are not -- I know this, because I tested a bunch back in the day. (The 150 APO Sironar S will NOT cover 8x10 -- the uber rare 150 APO Sironar W fall just shy of covering fully, but it was close enough and is a cult status optic -- and note it's a BEAST by comparison to the 150S, like 4 times as big.)  Seriously, 30 to 40 line pairs was really good for an 8x10 lens.  Note however we're not talking center-field here, we looked at 1/3 out from center to have a usable average number.  So yes, if you are only talking center field, 60 is probably doable with a few of the best.  

I use the 150 for my little Ebony 4x5. Sweet little camera. I have a Canham Lightweight 8x10 and I use a 12 inch Sironar S for that one. It's an amazing piece of glass. It's also very big, as you say....

Best,

Lenny
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qwz

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #43 on: September 23, 2011, 11:55:50 pm »

Quote
I think the results of this test are very clear,
Ray, very clear that test is incorrect, if you ever see technically good 8x10 shot.
Of course IQ180 has clear advantage in easiness in photographic process, not in image quality.

For example, i can take digitalback, shot hanheld on iso 800 (convert from RAW to quickproof JPEG in C1) and compare it with Sony NEX with stabilized kit lens and get better result from small sensor too, not because NEX camera has better IQ, but because test is incorrect.
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Wayne Fox

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #44 on: September 24, 2011, 01:42:46 am »

I know this, because I tested a bunch back in the day.
I enjoy Pawnstars, and they use this expression all the time ... which they normally mean at least 40 years or further back.  Not quite the same as in our business (since back in the day can mean less than a decade when speaking of photographic technology) but despite that when I refer to things I've done "back in the day", I feel kinda old :)
« Last Edit: September 24, 2011, 01:44:56 am by Wayne Fox »
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ErikKaffehr

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #45 on: September 24, 2011, 02:03:37 am »

Hi,

My guess is that the 8x10" images have a focus problem. Poor luck! It is also possible that scanning was bad, but he tried to verify the image with a 20x loupe and found no better detail.

I'd say that scanning at 750PPI was not a that bad idea. That would give the same kind of resolution as the digital back, for easy comparison. That would not show resolution advantage of the 8x10" film on the other hand. I'd certainly would scan at higher PPI. The comparisons I made between film and sensor were generally at 3200 and 4800 PPI. The impression I have is that we start to get into diminishing returns past 1600 PPI. There will be some gains increasing resolution but not proportionally.

Sensor pixels are generally very good quality, but film scans seem to me to be soft and noisy. Sharpening and noise reduction may matter a lot.

Best regards
Erik


See, this is exactly what I was saying... people make judgements about what is possible based on their equipment. Imacon's are ok. I'd say a little higher, likely somewhere in the 2,000-2,300 range. The earlier ones might have been 1800.... don't know. However, that's a CCD scanner. To assume what an entirely different technology could do (or could not do) does not make a lot of sense...

I'd give that a possible. So the fellow was either bad at focusing his camera, has a mediocre lens, regardless of brand. Or maybe he was just bad at scanning. Maybe he was manually focussing the scanner? Or running it at a much higher micron setting. I haven't looked at the film so I can't say either way...

I use the 150 for my little Ebony 4x5. Sweet little camera. I have a Canham Lightweight 8x10 and I use a 12 inch Sironar S for that one. It's an amazing piece of glass. It's also very big, as you say....

Best,

Lenny
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luong

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #46 on: September 24, 2011, 04:12:14 am »

The fact that the author finds that scanning at a higher resolution did not change much is actually the most telling sign that his procedure did not produce the levels of resolution that 8x10 should.  

I  have worked with well over a thousand 5x7 drum scans at 1800dpi. For most of those cans, I have used the "guide file" workflow described by Rich Seiling of WCI, which consists of doing adjustments on a 750dpi file, and then transferring layers to the full size file. This means that I have seen both 750dpi and 1800dpi versions of the file. I have almost always found the 1800dpi version to contain significantly more detail. This is in real world, uncontrolled, vastly varying situations, with all sorts of depths and f-stops: my National Parks project.

Based on that observation, that the author finds no significant resolution gain beyond 750dpi would indicate that the transparency was technically flawed.

By the way, since I mentioned him, I had a short twitter correspondence with Rich Seiling (@richseiling) and here is his conclusion in 140 characters:  "Bottom line is that the test methodology does not show the true potential of 8x10. 8x10 is far better than what is shown."
« Last Edit: September 24, 2011, 04:16:45 am by luong »
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j-land

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #47 on: September 24, 2011, 05:18:09 am »

Just to add another example... 8x10 Foma 400 (thick base, grainy) shot with a 240mm lens at f45, scanned at 1800 dpi on an Epson 4990, sharpening applied post-scan. Reduce the 100% crops to a third the linear size you see on screen (assuming your screen is approx 100dpi) and you have a 43"x56" print at 300 dpi.
(edit - you may need to enlarge the window of the 1:1 crops to get them to actual pixel size)
« Last Edit: September 24, 2011, 05:22:47 am by j-land »
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MHMG

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #48 on: September 24, 2011, 02:12:39 pm »

The results of this study can be explained almost completely in terms of depth of field. Choose a scene that requires extreme depth of field, and even a consumer digicam can best that 80 megapixel IQ180 back in terms of overall image sharpness. The scene that was photographed in this study, from truck license plate in foreground, to car at mid range, to building details in far background, although not extreme, would still tax the depth of field on a lens of normal focal length for an 8x10 view camera, and a photographer would be better off moving to 4x5 or medium format camera for this scene (which is what happened in choosing the IQ180 back). We are not talking about optical resolution limits here. We're talking about depth of field issues. If a flat plane like a mountain range at infinity (think Ansel Adams "Winter Sunrise, The Sierra Nevada, from Lone Pine, California") had been selected where you have little depth of field issues to contend with, then the scan resolution would have to be cranked up to at least 4000 ppi to capture what the 8x10 negative can record, and the study would have rendered a vastly different result.

A contact silver gelatin print from and 8x10 negative can render over 30 lp/mm even though a young viewer with very sharp eyes will only resolve 6-10 lp/mm at normal viewing distances. If you've ever had a course in Fourier transform analysis, you will remember that those high frequencies contribute directly to the perceived sharpness in mid frequency square wave response. In other words, even the high frequency details that we can't resolve directly still contribute to the wonderfully diffuse tonality and sharpness that we observe when looking at contact silver gelatin prints made from large format film. Digital print resolution still has a way to go. Ditto for digital image capture. Film still holds the advantage on high frequency details. That said, digital capture has now largely beaten film in terms of low and mid-frequency response. Although low and mid frequency response dominates in terms of our perception of acutance or "sharpness" in an image, whenever you hear photographers talking about "plasticky" looking skin or "smeared" background details, for example, it's often those pesky high frequency details being stomped on by anti-aliasing filters and/or noise reduction algorithms that cause the perceived visual effect.

cheers,
Mark
http://www.aardenburg-imaging.com
« Last Edit: September 24, 2011, 02:22:37 pm by MHMG »
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Stefan.Steib

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #49 on: September 24, 2011, 03:07:49 pm »

This remembers me a lot to the discussion about my thread about "the End of tolerances reached"over in getDPI.
Although I have stopped shooting 8/10" about 12 years ago now, before that I was destroying boxes and boxes of it in my studio every day,
mostly Velvia , my standard lens for that was either the 480 ApoRonar or the 600 ApoRonar, sometimes when needing something shorter I was using a 360 Apo Sironar S.
I was using an 8x loupe for focusing, stuck my sheets into the film holders with double sided tape to keep it flat and blew up to 16000 Ws onto the subject to mostly get around with either 45 or maybe 64, nicely hold by my fat Cambo or Plaubel tripods. This gave stunning results  - BUT - back then most of the time people did not make use of much more of maybe max 200-400 MB scans of these shots (I was working for print stuff nearly exclusively). Even then I can remember that I had a substantial amount of shots where I needed to repeat some shots when the focus was not 100 % right (we had Munich largest lab around the corner so we did  not much polaroids- instead we were waiting for the 1 hour to see if everything came out right .

This I suppose was the maximum that could be done to get Res. sharp and DOF wise sharp images at the time. And still if I look at the images today I know we have gone further with digital now.
The lenses have become better, the sensitivity is so much better and even worse for legend building: today anybody can take a look on their results at 400 % on a 30" Eizo or NEC if needed.
This leaves not much uncertainty about good or bad - you just see it. Under that same conditions  most films hanging around in archives being remembered as legendary sharp, fade by taking the facts to the harsh light of a todays scanner, which are dramatically good and uncover about anything that we did never see 30 years ago.

I have also done scanning services for the Bavarian State library for historical glass negatives, over 100 year old treasures made by finest craftsmanship of the 19th century, photographed with hand made lenses that did cost a fortune back then. There are amazing results, black and white worlds uncovering the finest details. But to the one which makes me speachless there are 50 others which were just barely sharp, defocused, poorly fixed and having staines and so on. We forget that the amount of material that has been used to get a real masterpiece was immense, thus a truly outstanding photo was something very valuable.

This has nearly completely changed today. With a medium format system with 80Mpix you will do nearly 100 % good shots (technically) if you know what you are doing and your equipment is
up to the task. I admit that some of my 8/10" Velvias still today make me stand still and remember what a great Time this was, but I would never go back - for no money on the world.

Greetings from Munich
Stefan Steib - hcam.de
« Last Edit: September 24, 2011, 03:13:20 pm by Stefan.Steib »
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Schwarzzeit

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #50 on: September 24, 2011, 04:15:14 pm »

The results of this study can be explained almost completely in terms of depth of field. Choose a scene that requires extreme depth of field, and even a consumer digicam can best that 80 megapixel IQ180 back in terms of overall image sharpness. The scene that was photographed in this study, from truck license plate in foreground, to car at mid range, to building details in far background, although not extreme, would still tax the depth of field on a lens of normal focal length for an 8x10 view camera, and a photographer would be better off moving to 4x5 or medium format camera for this scene (which is what happened in choosing the IQ180 back). We are not talking about optical resolution limits here. We're talking about depth of field issues. If a flat plane like a mountain range at infinity (think Ansel Adams "Winter Sunrise, The Sierra Nevada, from Lone Pine, California") had been selected where you have little depth of field issues to contend with, then the scan resolution would have to be cranked up to at least 4000 ppi to capture what the 8x10 negative can record, and the study would have rendered a vastly different result.

Mark,

I agree on the depth of field issue. However, it is possible to get exactly the same overall diffraction limited detail level by stopping down the larger format appropriately. Stopping down the 8x10" for this test to f/64 would have almost equalized the DOF with the 645 sensor at f/16. In film photography the larger format still gains from a better film MTF due to the lower enlargement ratio for an equally sized print. On the other hand smaller formats allow faster shutter speeds or need less flash power. If this is critical than there could be a real advantage for the smaller format.

A contact silver gelatin print from and 8x10 negative can render over 30 lp/mm even though a young viewer with very sharp eyes will only resolve 6-10 lp/mm at normal viewing distances. If you've ever had a course in Fourier transform analysis, you will remember that those high frequencies contribute directly to the perceived sharpness in mid frequency square wave response. In other words, even the high frequency details that we can't resolve directly still contribute to the wonderfully diffuse tonality and sharpness that we observe when looking at contact silver gelatin prints made from large format film. Digital print resolution still has a way to go. Ditto for digital image capture. Film still holds the advantage on high frequency details. That said, digital capture has now largely beaten film in terms of low and mid-frequency response. Although low and mid frequency response dominates in terms of our perception of acutance or "sharpness" in an image, whenever you hear photographers talking about "plasticky" looking skin or "smeared" background details, for example, it's often those pesky high frequency details being stomped on by anti-aliasing filters and/or noise reduction algorithms that cause the perceived visual effect.

cheers,
Mark
http://www.aardenburg-imaging.com
Thanks for the explanation, but are you sure that the highest frequencies contribute to the perceived sharpness? Isn't is just a matter of a higher MTF in the visible frequencies that boosts the perceived sharpness?

-Dominique

hjulenissen

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #51 on: September 24, 2011, 04:16:15 pm »

If you've ever had a course in Fourier transform analysis, you will remember that those high frequencies contribute directly to the perceived sharpness in mid frequency square wave response. In other words, even the high frequency details that we can't resolve directly still contribute to the wonderfully diffuse tonality and sharpness that we observe when looking at contact silver gelatin prints made from large format film.
I did have such courses, and what you are saying makes no sense to me.

-h
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ErikKaffehr

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #52 on: September 24, 2011, 04:28:34 pm »

Hi,

Thanks for sharing your experience!

Best regards
Erik


This remembers me a lot to the discussion about my thread about "the End of tolerances reached"over in getDPI.
Although I have stopped shooting 8/10" about 12 years ago now, before that I was destroying boxes and boxes of it in my studio every day,
mostly Velvia , my standard lens for that was either the 480 ApoRonar or the 600 ApoRonar, sometimes when needing something shorter I was using a 360 Apo Sironar S.
I was using an 8x loupe for focusing, stuck my sheets into the film holders with double sided tape to keep it flat and blew up to 16000 Ws onto the subject to mostly get around with either 45 or maybe 64, nicely hold by my fat Cambo or Plaubel tripods. This gave stunning results  - BUT - back then most of the time people did not make use of much more of maybe max 200-400 MB scans of these shots (I was working for print stuff nearly exclusively). Even then I can remember that I had a substantial amount of shots where I needed to repeat some shots when the focus was not 100 % right (we had Munich largest lab around the corner so we did  not much polaroids- instead we were waiting for the 1 hour to see if everything came out right .

This I suppose was the maximum that could be done to get Res. sharp and DOF wise sharp images at the time. And still if I look at the images today I know we have gone further with digital now.
The lenses have become better, the sensitivity is so much better and even worse for legend building: today anybody can take a look on their results at 400 % on a 30" Eizo or NEC if needed.
This leaves not much uncertainty about good or bad - you just see it. Under that same conditions  most films hanging around in archives being remembered as legendary sharp, fade by taking the facts to the harsh light of a todays scanner, which are dramatically good and uncover about anything that we did never see 30 years ago.

I have also done scanning services for the Bavarian State library for historical glass negatives, over 100 year old treasures made by finest craftsmanship of the 19th century, photographed with hand made lenses that did cost a fortune back then. There are amazing results, black and white worlds uncovering the finest details. But to the one which makes me speachless there are 50 others which were just barely sharp, defocused, poorly fixed and having staines and so on. We forget that the amount of material that has been used to get a real masterpiece was immense, thus a truly outstanding photo was something very valuable.

This has nearly completely changed today. With a medium format system with 80Mpix you will do nearly 100 % good shots (technically) if you know what you are doing and your equipment is
up to the task. I admit that some of my 8/10" Velvias still today make me stand still and remember what a great Time this was, but I would never go back - for no money on the world.

Greetings from Munich
Stefan Steib - hcam.de
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BernardLanguillier

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #53 on: September 24, 2011, 05:07:50 pm »

Predictably, my question would be... why not stitch with the IQ180 if high image quality really matters?

Stitching is fully applicable for many of the scenes where a 8x10 camera would be used. Stitching will be much faster and will deliver out of this work resolutions by actually re-creating a virtual sensor area similar to that of the 8x10 film.

Cheers,
Bernard

MHMG

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #54 on: September 24, 2011, 06:04:20 pm »

Predictably, my question would be... why not stitch with the IQ180 if high image quality really matters?

Stitching is fully applicable for many of the scenes where a 8x10 camera would be used. Stitching will be much faster and will deliver out of this work resolutions by actually re-creating a virtual sensor area similar to that of the 8x10 film.

Cheers,
Bernard


Equally predictable response would be to save a ton of money and stitch with an FF or DX dSLR, notwithstanding the limitations of stitching versus single capture.  And if you are willing to shoot film, the price of entry into 8x10 kit is about an order of magnitude less than the IQ180.  Or for about the same price of owning a decent 8x10 kit, one can rent and IQ180 for a week or two  ::).

At the risk of sounding like sour grapes, I would love to own many of the products that MR and his colleagues at LL have routine access to and/or have purchased for their personal use. No doubt on both technical and artistic merits, this stuff rocks. Yet, in my over forty years of serious amateur photography, I doubt I've spent in totality the amount of money I'd have to drop on an IQ180 back, let alone the camera body and lenses it sits on.  Interesting times we live in.  I will stick to film for a little while longer when I want to shoot a detailed landscape.  For everything else, the newest cell phone cameras and digicams are starting to blur the lines between amateur and pro output!
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Jack Flesher

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #55 on: September 24, 2011, 08:09:30 pm »

I enjoy Pawnstars, and they use this expression all the time

Crap. The *OLD MAN* uses it all the time, and I aint anywhere near as old as him!
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ErikKaffehr

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #56 on: September 24, 2011, 10:27:26 pm »

Hi,

When diffraction limited, MTF is essentially inversely proportional to f-number, pretty sure about that. So if you stop down two stops you loose half of the MTF. The other, more important, factor is that it is more probable that perfection is achieved on a camera without movements  and having live view for focusing, or exactly calibrated helical focusing and laser rangefinder.

I don't really buy into the significance of high frequency detail, this figure shows sensitivity of human eye: [img "http://www.imatest.com/docs/images/csf.gif" /img] . We can certainly see fine detail, but I have not seen any evidence that large format analogue would have more high frequency detail.

One issue, that I have not seen discussed here is that an MFDB with high resolution lenses will produce fake detail due to aliasing. Aliasing arises when the lens has high MTF beyond the Nyquist limit of the sensor. Stopping down to f/16 would eliminate that advantage. It has been said that stopping down to /f11 on the Leica S2 by and large eliminates visible aliasing.

Best regards
Erik

Mark,

I agree on the depth of field issue. However, it is possible to get exactly the same overall diffraction limited detail level by stopping down the larger format appropriately. Stopping down the 8x10" for this test to f/64 would have almost equalized the DOF with the 645 sensor at f/16. In film photography the larger format still gains from a better film MTF due to the lower enlargement ratio for an equally sized print. On the other hand smaller formats allow faster shutter speeds or need less flash power. If this is critical than there could be a real advantage for the smaller format.
Thanks for the explanation, but are you sure that the highest frequencies contribute to the perceived sharpness? Isn't is just a matter of a higher MTF in the visible frequencies that boosts the perceived sharpness?

-Dominique
« Last Edit: September 25, 2011, 01:46:31 am by ErikKaffehr »
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Nick Rains

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #57 on: September 25, 2011, 12:01:56 am »

Seems to me there is a curious mishmash of comparisons going on here. The worst one is comparing a film scan at 100% on the screen to a digital capture at 100%. How the film looks will depend to a great extent on the spi used by the scanner operator.

The easiest way by far to do these types of tests is to make prints. At what increasing size does one format start to look better or worse than the other? This is subjective I know, but the print has to be the final arbiter, not the theory IMO. That leads me to one problem I have with this article, 745spi is just plain silly. If you want to make a 60 inch print you will end up printing at about 120ppi, hardly ideal, and I know prints of that size from 10x8 cameras are capable of results better than that - Lough, Fatali etc.

I have worked with 4x5 film and roll film for many years, I have recently been working with some guys shooting the IQ180 and I personally shoot the S2. I have also been in the business of fine print making for the past 15 years and I know a bit about how all those formats look. For instance, roll film was always sharper (over any given film area) than sheet film, that's why I shot 6x12 roll film in preference to 4x5. In a 1.5m print the roll film image looked sharper.

And having seen what the IQ180 can do in the right hands I am positive it would be a winner in a 1.5m print
shootout, at least from a pure resolution point of view. Tonally, well that might be a matter of preference or style.
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Australian Photographer Leica

ErikKaffehr

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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #58 on: September 25, 2011, 12:24:22 am »

Hi!

I my view comparing at actual pixels is very much valid. Pixels are pixels and they are what go into the print. Now, if pixels are properly scaled for printing the image on the screen will be far to much magnified. I have seen this in my tests. If I scale two different images for printout at 200 PPI or 360PPI there can be a very large difference on the screen but much less difference in prints.

Prints cannot be distributed over the net, and looking at small crops would essentially like pixelpeeping at the computer.

I guess I could fly to Brisbane (?) Australia to check out your prints, but I need my SEKs for sensors and lenses so I prefer to pixel peep.

The comparison was intended to find out if IQ180 could replace 8x10". With the test methodology of the authors the result was a resounding yes. It may be argued that the authors should been more competent using the 8x10", and I certainly would scan film at higher resolution. The results may also simply indicate that achieving perfection with 8x10" is not easy.

Best regards
Erik
Seems to me there is a curious mishmash of comparisons going on here. The worst one is comparing a film scan at 100% on the screen to a digital capture at 100%. How the film looks will depend to a great extent on the spi used by the scanner operator.

The easiest way by far to do these types of tests is to make prints. At what increasing size does one format start to look better or worse than the other? This is subjective I know, but the print has to be the final arbiter, not the theory IMO. That leads me to one problem I have with this article, 745spi is just plain silly. If you want to make a 60 inch print you will end up printing at about 120ppi, hardly ideal, and I know prints of that size from 10x8 cameras are capable of results better than that - Lough, Fatali etc.

I have worked with 4x5 film and roll film for many years, I have recently been working with some guys shooting the IQ180 and I personally shoot the S2. I have also been in the business of fine print making for the past 15 years and I know a bit about how all those formats look. For instance, roll film was always sharper (over any given film area) than sheet film, that's why I shot 6x12 roll film in preference to 4x5. In a 1.5m print the roll film image looked sharper.

And having seen what the IQ180 can do in the right hands I am positive it would be a winner in a 1.5m print
shootout, at least from a pure resolution point of view. Tonally, well that might be a matter of preference or style.
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Re: Interesting comparison of IQ180 and 8x10" film
« Reply #59 on: September 25, 2011, 01:17:30 am »

Predictably, my question would be... why not stitch with the IQ180 if high image quality really matters?

Stitching is commonly practiced by owners if such backs, and tech cameras are becoming even more popular partially because they allow perfect stitching by moving the back.

Of course, you can't always stitch, and most of the time you don't need to.  I find I tend to stitch when I have a really wide pano I'm trying to capture, because I know I'll get sharper corners than if I throw on my 28mm.

I also have seen images that were stitched 8x10 film ... totally amazing :)
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