phase versus hassleblad

[Sheldon N]

FWIW, I was curious just how much practical DR my 1Ds III has, so I did my own little test.

I shot out the window of my office using the outdoor clouds as my highlights and the indoor room setting as my base shadows. I used a Sekonic L-558 spot meter (1 degree spot) to determine the relative exposure differences between the different parts of the scene. I bracketed off a series of shots at 1/3 stop intervals to pick the shot that was closest to being overexposed without losing detail. The shot was chosen by pulling a -1 exposure compensation in LR to rescue any highlights buried the RAW data, then picking the ideal ETTR shot as my one to process. I then tried to pull up the shadows in LR using fill light and tone curves, with lots of NR and no sharpening, plus a second round of NR in Noise Ninja. The attached shot is a 50% pixel view. The masked area in the window is a -1 exposure compensation overlay, to show the highlight details in the RAW file.

Details - 1Ds III, 24-70L, f/11, 1/25, ISO 100

I would say that details are visible down to around 10 stops below the highlight, but my personal threshold would be about 7 or 7.5 stops for a quality print. I'd love to see the same sort of test from a D3X or MFDB if any of you folks have the time.

[attachment=20751:1Ds_III_DR_Test.jpg]

[BernardLanguillier]

I wasn't talking about "claims", I was talking about technical explanations. And no, the kind of figures being bandied around in this thread definitely DO NOT tell the whole story. And facts are no harder then the definitions and methodologies used to establish them, which in this case obviously vary.

OK, words again. How is a technical explanation proposed by one side of the chasm without neutral validaton not a claim. It only differs if you trust the source, which closes the loop of this beautiful example of circular argument, you basically trust the source because you trust the source.

For one, DxO has a very clear methodology published on their site and I garantee you that their results would have been proven wrong with similar facts if they were wrong. The fact that nobody doing similar measures has been able to show different results is a clear proof that, per the definition they use, their results are correct.

As discussed elsewhere in this thread, the relevance of their figures for actual photography is doubtful, but the same doubt applies to both the DSLR and MFDB figures, and there has been no explanation proposed as to why the gap between their figures and real world ones would have to be larger for DSLRs than for MFDB, and certainly not 6 stops larger.

Cheers,
Bernard

[Ray]

Ray,

While I could have much to tell you, for the moment I won't comment further on this post, except to make one point and to ask you a question. The point is that I'm not a wealthy person who can afford to spend this kind of money frivolously and I wasn't either an idiot or on drugs when I bought that system. The question is: have you personally had a recent opportunity to compare similar images, having high scene DR, as rendered by a high-end DSLR and a Phase-1 P40+ or P65+ back?

Mark

Mark,
That's a fair question and I'll attempt to give a fair answer. There are many, many different models of cameras on the market. It would be unreasonable to expect anyone to hire each model of camera with lenses and compare performance with what they already own (or hire two camera models at a time) before making a purchasing decision.

Fortunately, we have a number of organisations which specialise in performing such tests and which make the results freely available on the internet.

I'm very well aware that larger sensors collect more light, and as a result of that fact are able to produce subtle improvements in image quality which can be clearly seen when such images (or prints) are viewed from a close distance.

For the past 5 years or so, I have owned mainly two different formats of cameras which differ in size by a degree which is just as great (approximately) as the difference in sensor area between a P65+ and a full frame 35mm. (ie. various Canon cropped format cameras plus a 5D, the 5D sensor being 2.6x the area of the Canon cropped format DSLR).

I'm no stranger to the advantages of the larger sensor. Generally the larger sensor provides higher resolution, smoother tonality, greater color sensitivity, lower noise and shallower DoF at the same f stop. These are all good reasons to buy a large-sensor camera (with the possible exception of shallow DoF).

They are the reasons why I am hesitating in choosing between a 7D and a 5D2 for my next upgrade. The 7D has the clear advantages of longer reach, lower weight, faster frame rate, possibly better autofocussing, and the 5D2 has the other advantages mentioned above.

It's interesting that the DR of the 7D appears to be just as good as the DR of the 5D2, up to ISO 400. Beyond ISO 400 both the old 5D and the new 5D2 outshine the 7D, but not by a huge amount. At most by a full stop or slightly less. Nothing like the magnitude of the DR differences between 35mm and MFDB that Mark Dubovoy claims.

Another important point which is so often overlooked when comparing image/print quality is viewing distance.

Anyone who views a print from a closer distance than 1.5x its diagonal could be considered a pixel peeper. No harm in that   . But I really question the wisdom of spending huge amounts of money on equipment which produces superior image quality which is discernible only from a pixel-peeping distance, or a closer distance than is required to appreciate the composition as a whole.

[Mark D Segal]

OK, words again. How is a technical explanation proposed by one side of the chasm without neutral validaton not a claim. It only differs if you trust the source, which closes the loop of this beautiful example of circular argument, you basically trust the source because you trust the source.

For one, DxO has a very clear methodology published on their site and I garantee you that their results would have been proven wrong with similar facts if they were wrong. The fact that nobody doing similar measures has been able to show different results is a clear proof that, per the definition they use, their results are correct.

As discussed elsewhere in this thread, the relevance of their figures for actual photography is doubtful, but the same doubt applies to both the DSLR and MFDB figures, and there has been no explanation proposed as to why the gap between their figures and real world ones would have to be larger for DSLRs than for MFDB, and certainly not 6 stops larger.

Cheers,
Bernard

Bernard, there is no circularity, and it's not just words. There's a difference between advertising, where the advertiser simply tells you they have best sliced bread on earth and you take it or leave it, versus a technical seminar where a number of things are explained (to the extent they are prepared to reveal) about the kinds of factors which go into their sensor technology. What really stuck in my mind about this session is that truly a great deal of stuff goes into the design of the hardware and the software of this technology,  so as I pondered your comment about being able to rely on the numbers, it simply struck me that the very limited set of numbers being discussed in this threadd are not a sufficient basis to conclude on anything decisively. Like you, I too believe in relying on objective, quantifiable factors as much as I can, and when it comes to photography in particular, I also believe in my eyesight. But returning to the numbers, as you well know, there are numbers and there are numbers. Every aspect of the design of a sensor and its firmware can be described in terms of measurements and numbers, and there must be a great many of them that only sensor design technologists would know. I would speculate that when comparing sensors, numerical differences (or even the presence or absence) of some of these variables would have more critical impact on driving differences between results than others. And only the designers would know that too. In fact. most of us probably don't know what we don't know about this business. So we can be "scientific" and pretend that the few numbers we know and can relate to are a sufficient basis for drawing conclusions, or we can simply acknowledge that maybe we don't know enough about which numbers (in combination) matter most, so perhaps better trust our eyesight and rely on what impresses us as makers of images.

As for DxO, some of it may be more or less relevant to actual photography as the case may be. It's not clear in my mind what the gap is between "their figures" and "real world ones", because I don't know what you mean by "real world ones". If you are alluding to the issue that different ways of measuring things produces different results, and more so for one technology than the other, let me take a stab at what the situation may be. The firms who claim that their stuff produces 7 stops of DR are measuring it using their own definition and methods. DxO and MF firms which claim that their stuff produces 13 stops of DR may be using a different definition and approach. So what's missing are sets of measurements for both technologies using both sets of definitions and methods. That may be the gap which needs to be filled. When that's done, I suspect that differences of 6 f/stops will shrink radically. And even if it does, what my eyes tell me will still be what my eyes tell me!  

[Ray]

How to test dynamic range in a meaningful way has always been a contentious issue. From the perspective of the practical photographer, I would suggest that the usefulness of a high DR lies in the capacity to extract meaningful image quality from the darker shadows without the necessity of clipping the highlights with overexposure in order to do that.

Some years ago, Jonathan Wienke devised a Dynamic Range Chart for this very purpose. The principle is, the legibility of text or numbers is an excellent way to define 'meaningful image quality'. If anyone wants to compare the resolution of two lenses (using the same camera), the lens that produces legible text in circumstances where the other can't, is the sharper lens. What could be more meaningful than that?

I used Jonathan's chart to test the DR of my 5D, some years ago. From memory, it was about 11 stops. In other words, I was able to take 11 exposures, each exposure half of the previous one, yet was still able to discern some detail in the 11th, extremely underexposed shot.

Of course, with such a method, the initial exposure is critical to the accuracy of the results. One has to aim for a true ETTR with the first shot, with each camera tested.

Any argument about the significance in practical terms of the discernible detail in the lowest exposure, is irrelevant. The essential point is that the same methodology should be used with each camera tested.

Confusion about DR specs tends to arise only when different methodologies are used when testing different cameras. I tend to place more faith in DXO Mark results than verbal pronouncements from owners of MFDB systems who refuse to show their DR comparisons, because DXO employ a consistent methodology with all the cameras they test.

Here's a jpeg compression of a downsized chart created by Jonathan Wienke. It could no doubt be elaborated upon and improved by someone interested in such matters. I'm currently too busy building retaining walls at the back of my new house.

[attachment=20753:Test_target.jpg]

[Graeme Nattress]

One thing to remember is that there can be other factors than the sensor, not least the lens and the development software / algorithms and gamma curve design that can dramatically effect the perceived dynamic range of an image. That is why it's important to measure with a common methodology.

Even when that measurement is done, and say it's done in a way that produces a very large number, much larger than you feel is right for that camera, then that is most likely your personal noise tolerance at work, along with your own image development methodology. Once you can factor in a value for those, you can take the measured number and subtract your factor and use that for how you want to meter / light / expose.

Graeme

[Mark D Segal]

Anyone who views a print from a closer distance than 1.5x its diagonal could be considered a pixel peeper. No harm in that   . But I really question the wisdom of spending huge amounts of money on equipment which produces superior image quality which is discernible only from a pixel-peeping distance, or a closer distance than is required to appreciate the composition as a whole.

Ray, OK, let me confirm that if I had to pixel-peep to appreciate the IQ from a Phase-1 back I wouldn't have spent my precious dollars on it. There is a richness of tonality, shadow detail and resolution which comes through whether the print is 11*17 or 27*36 and in both cases viewed at distances appropriate for seeing the whole picture as it was meant to be seen. Much as I really like what I get from my Canon 1Ds3 and I shall continue to use it as well, the Phase produces a higher quality of image with the bonus of lots more potential for huge amounts of enlarging or cropping while still preserving great resolution and tonality. So I look upon it as a tool for growing with - moving into a different style and type of image making. One of the nice things about a good DSLR is that we can use it almost like a sophisticated point-and-shoot and obtain terrific results. That's much harder to do with an MF set-up because it's more demanding to get the maximum of the resolution it can deliver. So one uses different things in different ways for different purposes - as usual.

[Mark D Segal]

may we have just your raw files instead of your word ? please don't tell that you are not keeping them

You needn't tell me what not to tell you, because I'll tell what I have to say regardless, and the answer for now is NO. But in the fullness of time it may be YES.  

[K.C.]

One of the nice things about a good DSLR is that we can use it almost like a sophisticated point-and-shoot and obtain terrific results.

So true and without this you wouldn't see art directors and models stepping in and calling themselves professional photographers.

I'm really glad there is a tremendous difference between DSLRs and medium format digital backs. The best research is being done by companies like P1 and that will trickle down for the rest of us.

[BernardLanguillier]

I agree Bernard.
I read your posts carrefuly, and you certainly point some interesting details. But in another topic (about the pentax MFD), you assumed that the 645D could be a game changer. Maybe I did not understood in what way or context you pointed that fact, and how could it be a game changer in the current panorama.

Well, assuming that the current talk about MF sensors being that much superior DRwise is actually true, don't you think that such miracle technology available for 6500 US$ would be game changing?

Wait... it is actually already available in second hand P45 for no more than 9.000 US$. You got to wonder why both sellers and buyers have aligned their prices with high end DSLRs although they remain that superior...  

I simply think that in these kind of debates, there is fast much more writings and concepts that images, in a website dedicated to...image. So what happen is that we have an incredible amount of arguments but very little real life images in order to endorse the arguments. Yes, a lot of graphics.

Well, many of the people in this thread are known for their excellent photographs. They managed to take excellent photographs with slide film also, and don't appear to have changed their style that much... although they gained a huge 5 stops of DR.  

As far as my selfish self is concerned, you will find a few images here. http://www.flickr.com/photos/bernardlanguillier/

Most shot with a DSLR (SLR/n, D2x, D3 and D3x in the past 15 months), some shot with a Mamiya ZD in those days where I was still a believer in some form of MF black magic.  

Cheers,
Bernard

[Rory]

This is a fascinating discussion and I am eager to see the evidence that MF DR exceeds DSLR (in my case a D700) by 6 stops.  So far I have heard a lot of rhetoric from MF DR defenders but little else.

Mark says "The dynamic range of a typical high-end professional 35 mm DSLR is around 7 F/stops. Medium Format cameras are closer to 13 F/stops of dynamic range. You can see the difference from 30 feet away in a small print."

Michael says "Tests done by me in the past, as well as others more recently, show that DSLRs have a dynamic range of 6–7 stops while top medium format backs are in the 12-13 stop range. This is using the common definition of DR as mentioned above."

Mark Segal, playing coy, says about presenting files with evidence: "You needn't tell me what not to tell you, because I'll tell what I have to say regardless, and the answer for now is NO. But in the fullness of time it may be YES."

I must say that I always felt LL was the reliable source but it is a real test of credibility to make a claim of 6 stops, a huge difference, without presenting the evidence.  I hope it is forthcoming.  Two raw files, one from a top end DSLR, ideally a D3x and one from a MF of a indoor/outdoor scene, with huge DR, and measured EVs would convince me one way or the other.

[Mark D Segal]

Mark Segal, playing coy, says about presenting files with evidence: "You needn't tell me what not to tell you, because I'll tell what I have to say regardless, and the answer for now is NO. But in the fullness of time it may be YES."

No, I don't play coy - ever. What I tell you is where it's at and I have my reasons. Full stop.

[BFoto]

Interesting that there is no discussion of light intensity, contrast ratios or bit depth.


http://www.cambridgeincolour.com/tutorials/dynamic-range.htm

[tom b]

With all the talk of dynamic range haven't you missed the elephant in the room. Just look at the CA/blue fringing on the Hasselblad picture in figure 3.

[attachment=20755:blue_fringing.jpg]

Am I seeing something that you aren't?

Cheers,

[vandevanterSH]

With all the talk of dynamic range haven't you missed the elephant in the room. Just look at the CA/blue fringing on the Hasselblad picture in figure 3.

[attachment=20755:blue_fringing.jpg]

Am I seeing something that you aren't?

Cheers,

I see blue fringing with my Hasselblad back under similar conditions.   An example:

Steve[attachment=20757:__1_of_1__5.jpg]

[deejjjaaaa]

the development software / algorithms and gamma curve design that can dramatically effect the perceived dynamic range of an image.

well, we can use CaptureOne in both cases... but so many great photogs here, equipped w/ the state of the art everything and yet not capable to post a couple of raw files (dslr + mfdb) to back up the claims... what an ultimate shame   ... I posted the question @ PhaseOne forum - let us see if the manufacturer will backup the customers  

[Wayne Fox]

aren't they putting microlens (even in gapless design) on top of the surface to direct the light to those "actual light sensitive areas", are they ?

I will admit to little actual first hand knowledge of this, but from what I've been led to believe (and is supported by this article ), the micro lenses are not lenses in the sense of focusing light, but instead redirect light that would normally fall on the wasted area between sites in to a site.  As such I don't believe they have the ability to focus the light on the specific area of the site that is light sensitive.

[BernardLanguillier]

I see blue fringing with my Hasselblad back under similar conditions.   An example:

Steve[attachment=20757:__1_of_1__5.jpg]

The fringing reminds me of my Fuji F10, the painterly effect of the Kodak SLRn...

Cheers,
Bernard

[jenbenn]

Here's my take. So far I have not been able to identify a constant and ominpresent correlation of sensor measurments with the actual visual appearnce of a printed photograph.  (The stress is on constant and omnipresent) Using the the highly critized 50D for example, I do sometimes see superior noise perfomacne to other cameras in certain circumstances while I see inferiror results in others. Evaluation results depend to a large degree  on how and how much you process an image to reach the desired final result. They also depend on light conditions (The 50d outperforms many cameras when I use ISO 1600 in good light but is vastly inferior to them when i use such high isos in low light)

 Shooting alongside colleagues with middle format cameras, I have seen theses cameras to be vastly superior to a dslr in some circumstances and for some images and about equal in others. I concluded that any technical discussion about measurments doesnt  help in any way when you want to know whether your photography requires a particulr type of camera. You have to go out and shoot different subjects, and see whether any theortical advantage translates to practically relevant differences.
 
 All you need to know is that medium format digital may give superior results. This information is enough to include such cameras in ones own evalutaion. Measurments might just do the opposite, they may steer you away from a camera that might deliver the best image quality for your subjects even though it is not worse than others according to some measurments.  As micheal pointed out, measurments are never objective because the measuring conditions are determined and pre-set subjectivly. If the measuing conditions do not reassemble your shooting conditons they are almost worthless to an individual photographer. This is why even the scientificly best executed camera evaluation is in no way a replacment for individual real life tests. And even so being thoroughly executed by the most highly respected technician or scientist labortory measurments  might not even be a good guidance for your own use of the camera,  depending on how the tests where done.

[Ronny Nilsen]

Well, assuming that the current talk about MF sensors being that much superior DRwise is actually true, don't you think that such miracle technology available for 6500 US$ would be game changing?

Wait... it is actually already available in second hand P45 for no more than 9.000 US$. You got to wonder why both sellers and buyers have aligned their prices with high end DSLRs although they remain that superior...  


Well, many of the people in this thread are known for their excellent photographs. They managed to take excellent photographs with slide film also, and don't appear to have changed their style that much... although they gained a huge 5 stops of DR.  

I have no idea about the true difference of the DR between a DSLR and MF back, but when someone claims a 6 stop advantage to the latter without any hard evidence presented, I  begin to suspect cognitive dissonance.

Not saying that is the case here, but extraordinary claims normally demands extraordinary evidence. And some sort of evidence should be presented to support the claim in this case.

Ronny