High-End Digital Vs. 4x5 Film

[David Luttmann]

FTR, the 4x5 film scan was done at 2500 PPI on a Tango and had to be downsampled slightly to match the BL file size.

Jack,

My understanding, and I may be mistaken here, is that the 4x5 was scanned at 1600dpi. I thought I saw that on the site, but can't locate it now. I can't find reference to the 2500dpi drum scan, so this part is vague.....although, in the end, it still shows the Betterlight as the best, which we know is the case through other testing.

Regards,

[Jack Flesher]

David, it's possible but... When I was there visiting, Charlie scanned the 4x5 and I am pretty sure he scanned it at 2500. I remember Bill downsizing it to match the BL file. However, this was a few months ago and it is entirely possible they re-scanned the 4x5 at a lower resolution to more closely match the BL.

[Gregory Gomez]

While I am no scientist nor am I a professional photographer, I do have some observations I would like to make about the comparison test of the Phase One P45 digital back with 4x5 film:

1. The individuals involved in the comparison test all purchased the Phase One P45. Quite possibly there could be unintended experimenter bias. These individuals may have a strong desire, conscious or otherwise, to justify their purchase. It would have been far better if an independent laboratory had conducted the experiment and had showed the results, in a double blind fashion, to a panel of photographic experts, art critics, painters, and professional photographers.

2. Because different digital systems were used, different optics were employed, and different cameras pressed into service for this test, there are too many variables to control in order to reach any valid conclusion about the Phase One back compared to 4x5 film. If only one camera system were used along with only one camera optic, then the only difference, or variable, would have been the method of image capture, Phase One digital circuitry versus 4x5 film. Then there is the issue of which film should be used. Since resolution was the parameter measured, a series of tests should have been done to select the very highest resolving film currently available for the 4x5 format. (I wonder if that had been done beforehand?) But after reading the title of the article one more time, the testing was not just about 4x5 film versus digital; a number of items were being tested against each other, including cameras, lenses, and digital backs. That's a lot to test in such a short article.

3. The fact that all of the testers were middle-aged, suggests that their eyesight may not have been up to the task of discerning minute differences in resolution among the various alternatives tested. (Mine certainly were not.)

4. While it's convenient to show the results to the world over the Internet, doing so will tend to mask the differences among the results because computer monitors have varying levels of resolution, etc. Honestly, I found myself having to study the pictures carefully to see any differences at all.

5. Personally, I am a little bothered that there is a charge for this DVD of $9.95, plus shipping and handling. Now ten to twenty bucks is no big deal. But I get the feeling that a commercial undercurrent is present in this test. That's what I object to; I don't object to The Luminous Landscape trying to cover the cost of the DVD, so no flames please.

6. Another thing that bothers me is the 30-day, free trial of the Capture One software. How nice. Here's that commercial element again. I'm sure Capture One is the very best on the market, right?

7. I found very interesting the fact that the testers did encounter some difficulties while photographing the test subject:

" We didn't manage to get exactly the same crop or angle on all shots.* Several of the shots had to be redone due to focusing, cropping or exposure errors.* One error that we did not have time to correct, is that the Velvia 645 shot was composed to fit the slightly smaller rectangle of the P45 sensor, instead of using the full 645 film area.* This will make the Velvia 645 look a little worse than it could be."

This difficulty will of course affect the outcome, but I am glad that they mentioned it up-front.

8. Notwithstanding my previous comment about the DVD, it's nice that the raw data is being made available for others to examine.

9. "All captures were made such that the 15.5 inches wide 'goal posts' in the test scene approximately filled the width of the frame, but to make comparisons I still had to compensate for differences in image size and offset." I realize that image size and offset are going to affect the final results to some degree, but once again, these "compensations" could affect the outcome. It's a question of trying to remove all the variables to derive one, pure result untainted by the differences in the equipment used, which may be an impossible task.

10. "Each different digital or film back or lens resulted in images with somewhat different contrast and color. Because it is very difficult to visually distinguish between contrast and actual resolution, I needed to normalize differences in contrast and color." This "normalizing" bothers me. I realize that it may be difficult to distinguish visually between contrast and resolution in color images, but making changes to the raw images does taint the final result.

11. "In order to clearly see the differences between the captures, it was important to sharpen the developed images. I made various attempts to sharpen each image 'to taste,' but found the process entirely too subjective." This admission alone is enough to invalidate the entire test. Why sharpen at all? If the testers had to sharpen to "see the differences among the captures," then these differences may very well be insignificant. And "sharping to taste" is almost an admission of making subjective what should have been objective. The testers could sharper the Phase One back results to a "better level of taste" over the results produced by the competition simply because they all purchased this back and were determined, at least at an unconscious level, to justify their purchase decision.

12. "At first I tried to rank order the nine digital and film backs according to their image quality but I ran into a number of stumbling blocks. The whole area of sharpening is quite subjective with no clearly correct method, and different sharpening will change the outcome of any ranking. Contrast plays such an important role in perceived resolution that normalizing the six ColorChecker grays was necessary, but that normalization impacts any comparisons of color and tonal gradation. There are many different variables to consider in image quality, including resolution, grain or noise, color fidelity, and smooth tonal transitions." The conclusion I can draw from this quoted passage is that the differences among the items tested was quite small and subjective at best.

13. When looking at the results between the scanned 4x5 image and the one produced by the P45 back and Capture One, it does appear, at very high magnification, that the P45 is slightly sharper. Maybe. I really don't know. But if contrast and overall color could somehow be corrected between the two samples, it would be a real tossup. The 4x5 image, for example, seems to have a slight yellow cast compared to the P45 image. I am also surprised how well the Canon images did; the same applies to the image produced by the Mamiya 645 using Velvia film.

14. Like the testers suggested, if one were to stare at the samples too long, one would get punchy. Well, that happened to me, I must admit.

15. "I see the resolution differences between the 4X5" drum scan and the P45 as quite minor, but with a slight edge still going to the drum scanned film. But when you consider the time and cost of shooting film, processing it, and then scanning, the advantages of a 39MP back like the P45 are compelling...So if we have a close race between a 39MP back's files and a 4X5" drum scan, where does that leave us? A traditional enlarger made print can't hope to compare...with top-tier medium format digital close to equaling 4x5" large format. And to my eyes images from the 16Mp Canon 1Ds MKII are awfully close to those from drum scanned 645 format Velvia." As critical as I have been over the testing methods used, and my criticism stands, I am going to have to agree, tentatively, with this conclusion, no matter how it was reached. If I were a top-tier, professional photographer with a large clientele and the money to buy something like the P45, I might consider it. But for an armature like myself, it's good to know that 4x5 images perform well, and when I make a "real keeper," that I can have it drum scanned in order to make a really awesome print of huge proportions. The problem is, however, I don't react well to prints much larger than 11x14 inches, so it would be a moot point, right?

16. One last thing: I don't understand how some of the respondents on this b-board could get so, well, worked up over this article. Maybe someone could explain that one to me?

[David Luttmann]

Michael Reichman mentions "another online forum"....at least he didn't spell out the Large Format Forum.....in a personal note as per attached below:

http://luminous-landscape.com/new/index.shtml

It's sad to see the unjustified comments of doctoring have made such a negative impression. OF course, this can always have negative repercussions back to the author. Maybe an apology is warranted. Just a suggestion.

[Ralph Barker]

In all fairness, there are always two sides to a coin, and multiple interpretations of most words, "doctored" included.

[Don Miller]

So how many people worldwide have attacked the reviewers - questioning their motives or ability? No more than a few. Critical analysis of the results and conclusions is certainly valid, however.
Do you feel Michael is upset by a few responses, or rather enjoys the "controversy"? I ordered the DVD to get some P45 files to print. I'm kinda bored with the detailed analysis. IMO all four camera types reviewed have been shown to have their place.

[Jack Flesher]

This is precisely why I no longer publish my own test results...

You go through enormous effort to control all the variables actually in your control, then admit to those you couldn't control, then post your results AND offer to share your raw files publicly and what do you get? You get idiots picking at every aspect of your test including alluding to your commercial intentions for charging an outrageous $9.95 for a DVD! A DVD that cost you $1 for the blank, takes several minutes of your time to burn and more time to ship. MR is probably netting what, $25 per hour for that effort? I can assure you he makes far more than that when billing at his normal hourly rates -- folks he is providing that DVD as a SERVICE so that all the naysayers could view and process these files on their own specifically to avoid these kind of accusations!

I personally applaud them for taking on the task in the first place -- they already knew how good the P45 was before they embarked on this comparison test and did not have to go through what they did to get the data to you. Given the response, it is unlikely they will ever bother sharing similar tests in the future...

[Jorge Gasteazoro]

You get idiots picking at every aspect of your test including alluding to your commercial intentions for charging an outrageous $9.95 for a DVD! A DVD that cost you $1 for the blank, takes several minutes of your time to burn and more time to ship.

As opposed to the idiot who thinks you should take his word and accept the parameters and results as the word of the oracle? I think Gregory's comments are very valid.

[tim atherton]

Whoa - hey - Jorge's back - hopefully a good sign that you are well enough to jump right into the digital fray...?

Good to see you

[Ralph Barker]

Jack - I understand your frustrations regarding testing, but it's probably not helpful to to the discussion to refer to those who may have criticisms as being idiots. Some of them may be, but the fact that they have criticisms may also be telling.

The underlying problem, it seems to me, is that there are no widely-accepted standards for these tests. As such, the methodology is always subject to criticism - some valid, some not. I'm not sure that trying to compare digital capture to film is valid in the first place. Both technologies produce good results, but by substantially different means. Thus, isn't it rather like comparing a violin to a guitar? Both have strings, and (can) produce music, but it's likely they will be used in different circumstances and for different reasons.

To compare digital to film, for example, the film obviously needs to be scanned. That introduces an additional variable that is not equally applied to both technologies under test. And, if the film is still to be scanned, why choose 1600 or 2500 PPI as the scan resolution? Why not scan at the highest resolution beyond which no additional detail can be extractd from the film? Then, what adjustment should be made for the optics of the scanner? Alternatively, why not examine the film directly under high magnification, and the digital capture at full magnification, to see which resolves better detail? Oops, that introduces different analysis isues on both sides of the comparison, too. Then, there's the question of why interpolate/up-rez one side, but not the other?

Personally, I think we'd be better served if everyone could admit that digital capture can be darned good now, even though it may not be as convenient in all circumstances, or as affordable, as everyone would like.