phase versus hassleblad

[Mark D Segal]

Thanks Fred, very interesting indeed. And for sure much more relevant than the assumed DR advantage of these magical backs.  

Cheers,
Bernard

OT, but just to underline - that website is an excellent resource in general on MF-LF photography for those who read French. I just wish they would use larger font size and lighter background.

Mark

[Mark D Segal]

Michael,

Nobody discusses the value of MF nor of MFDB, the only point discussed here is the gap in DR. Taking a bit of distance, I am really wondering what triggered the resurgence of this whole DR discussion in March 2010.

In this context, I am looking forward to trying out the Pentax 645D when it is released, that should enable us to clearly separate the topics of vendors, price and format for the sake of a healthy discussion.

Cheers,
Bernard

Bernard, I was really intrigued by your mention of this camera some posts further back. IF they really do release this product anywhere within a reasonable range of the price point you suggest, it COULD INDEED be a game changer depending on a number of factors of course, not the least of which would be the quality of Pentax service backing it up. The one experience I had with them here in Canada has soured me on anything to do with Pentax, much as I have always respected the high quality of their optics and the practical design and pricing of their equipment going back many decades. Anyhow, on the technical side, if and when it does hit the market, it will deserve, and of course get, a very serious looking over in terms of value for money. Depending on the outcome of those analyses, it could either change games or it won't. No point speculating now - all that remains to be eagerly anticipated. There's nothing like competition and brand-agnosticism to keep life interesting for us consumers.

[imagico]

Absolutely correct. That would be exactly what is needed. However, Stouffer tops out a just over 4 OD, and I'm now using an over 5 OD chart so as to fully ensure I'm not missing anything in the noise floor. So on a Stouffer, I shoot a bracket of exposures to ensure I can see the full range.

Graeme

As i understand neither Mark Dubovoy nor Michael claim the DXO results and other measurements are incorrect - the idea is that they are irrelevant from the photographers and printers perspective.

But since there is the claim of 13 vs. 7 stops of MFDB vs. DSLR it is reasonable to ask for the basis of these numbers.  Mark Dubovoy says the 7 stops are based on the 'universal consensus' of DSLR makers when comparing to film.  The 13 stops are from sensor specs.

IMO it is safe to assume the 13 stops refer to the engineering definition of DR and considering this could be lower under practical circumstances (sensor built into a back and used in non-lab conditions) the DXO measurements are close enough to support this.  That leaves us with the 7 stops claim - a value which since given in context with film DR could well refer to a kind of 'practically usable DR' kind of understanding of DR as it has been mentioned in this thread.  So if we assume (just wildly guessing here) that this definition difference makes up for 2 stops and that Mark Dubovoy's poll was made some time ago when DSLR capabilities were still about 2 stops lower in DR than today we are already much closer to the DXO results.

Greeings,

Christoph

[image66]

"Anecdotal Evidence" is no evidence at all.

Whether we want to agree with it or not, "Relative Log Exposure" is a fixed way of measuring a capture medium's (film or digital) ability to respond to different levels of light. In otherwords, dynamic range. The following information is from the published datasheets for the listed films.

In the case of Fujichrome Velvia 100 (RVP 100), the straight-line section is just over four stops, with a couple stops either way in the toe and shoulder.

In the case of Fujicolor Pro 160S, the Relative Log Exposure shows about 9 stops--depending on how you interpret the curves.

In the case of Ilford Delta 3200, there really is no straight-line section, but the Relative Log Exposure range is around 12 stops.

What DXO attempts to do is shot Relative Log Exposure curves for digital cameras. Doesn't anybody else find it interesting that not only do the manufacturers of digital cameras NOT give us published specifications of the sensors, but we photographers aren't demanding them? Shame on us. If the camera companies insist on being the new "film manufacturers", then we must demand the same information from them that we got from the real film companies.

Frankly, I get pretty bored about the subject of dynamic range and digital sensors. Arguments over that are frequently the signs of little minds at work. While we argue over dynamic range, and resolution, we ignore issues like color accuracy and fidelity as well as the ability to capture certain colors like lavender and violet.

Michael, I know you and your friends are "top industry experts" but you've got to do better than this. I don't care how many credentials you guys have--you can't dumb stuff down to "Ken Rockwell" like claims. We expect more from you. We already have one Ken Rockwell and he's just fine at what he does. We just don't want you to copy him.

And PLEASE, it's "lose" not "loose".

[ErikKaffehr]

Hi,

Something I noted that when the Swedish periodicals write something about successful photographers they almost invariably use a digital Hasselblad, among other stuff. I don't know if that's because they need DR, Megapixels or what. Probably many reasons.

Being an engineer by training I have a strong preference for things that can be explained by common sense and physics. The DR advantage MFDBs are stated to have is not obvious to me from that standpoint.

I guess that Sweden is a Hasselblad country, it was invented here...

Best regards
Erik

I'm not going to fan the flames any more than needed, but I can't resist making one more comment in support of Fred's.

The world-wide market for medium format backs is approximately 7-8,000 units. That's all manufacturers combined.

These devices (with camera body and a couple of lenses) are priced in the $30–$50,000 range U.S. As Mark pointed out in his essay, that's the cost of a current luxury car.

One more factoid: About 70% of MF systems are bought by working professional photographers, the rest by fine art photographers and wealthy amateurs.

Here's the point. For the pros an MF system is a tool for earning their livelihood. It is purchased with the intention of helping them make money. No person would spend a good chunk of a year's income on a tool that did not offer an advantage. In my experience every pro that I know (and I know quite a few around the world) has done their own exhaustive comparisons and test, not relying on web site chatter, magazine reviews and online tests.

The fine art photographers are in a similar boat. They too make their livelihood (or a good part of it) from exhibiting and selling their prints. If a $1,000 to $6,000 DLSR gave them what they needed, why on earth would spend $30-$40,000 on a back?

As for the wealthy amateurs, I'll just say that it my experience (having taught and worked with several thousand folks like this over the years on my workshops and tours) I have yet to meet one who wasn't a savvy business person who understands the value of a dollar. Like the pros and the fine art guys, they spend that kind of money for an MF back because they believe that it will provide them with a tool that allows them to produce superior quality images. And if you speak to the people at major VARs who sell this gear, you'll learn that the amateurs are often even more demanding as customers than pros.

So, where does that leave us? Are all, or even most of the people that buy medium format equipment fools, willing to spend their hard-earned money chasing a chimera, or simply looking to boost their egos regardless of cost? I don't think so, and it seems to me that anyone that does, simply hasn't taken the time to do a simple side-by-side comparison for themselves.

Frankly, there is no argument, only lack of knowledge and experience, or living in denial.

Michael

[Graeme Nattress]

As i understand neither Mark Dubovoy nor Michael claim the DXO results and other measurements are incorrect - the idea is that they are irrelevant from the photographers and printers perspective.

But since there is the claim of 13 vs. 7 stops of MFDB vs. DSLR it is reasonable to ask for the basis of these numbers.  Mark Dubovoy says the 7 stops are based on the 'universal consensus' of DSLR makers when comparing to film.  The 13 stops are from sensor specs.

IMO it is safe to assume the 13 stops refer to the engineering definition of DR and considering this could be lower under practical circumstances (sensor built into a back and used in non-lab conditions) the DXO measurements are close enough to support this.  That leaves us with the 7 stops claim - a value which since given in context with film DR could well refer to a kind of 'practically usable DR' kind of understanding of DR as it has been mentioned in this thread.  So if we assume (just wildly guessing here) that this definition difference makes up for 2 stops and that Mark Dubovoy's poll was made some time ago when DSLR capabilities were still about 2 stops lower in DR than today we are already much closer to the DXO results.

Greeings,

Christoph

Sensor spec for DR would be full well / read noise, which is not what DXO do - they point a real camera system at a target and measure the resulting image. Yes, it does give a measure of "engineering" DR, but it's objective and repeatable. Practical DR is = Engineering DR - personal noise tolerance. Given many will measure engineering DR very similar, but personal noise tolerance differs wildly upon people, use of photo and scene, the only reasonable number to report is the engineering one and let the individual subtract their number based on their experience.

Graeme

[DaFu]

I have a bad cold this morning so useful work is out of the question. Mark D’s mention in the article of being able to tell the difference between Medium Format dynamic range and DSLR range at 30’ caught my attention. Now, I don’t have a medium format back but I do have a gorgeous print of one of Michael Reichmann’s pictures that, as I recall, he took with a medium format back. I don’t have a new DSLR either but I thought I’d make it even easier to see the difference if I used a print from a Nikon 990 from 10 or so years ago. That should be really obvious shouldn’t it?

My experimental methodology is rather rough (not having much energy): the pictures are different sizes, the subject is different, one has UV glass the other doesn’t, there’s a light fog this morning, this picture is just taken with the paltry range of a Canon G10, and my attempts at holding the camera steady were lackluster because I kept having these occasional shaking fits. The one thing for sure is that you are looking at the two pictures from about 30 feet away.

The other thing I’m sure about is that the photo on the right is of a duck.

Dave

[cunim]

This has probably been pointed out already, but specifications for chip family packages are readily available.  I suspect one could also get specs for the custom variants.  For eg. Dalsa:

http://www.dalsa.com/sensors/products/sens...Number=FTF6080C

On the whole, an interesting balance of compromises that yields a surprising DR given the very fast readout, high temperatures and low cost.  To put it in context, a scientific grade CCD can easily exceed $30K on its own and the support package is more than that.

[JeffKohn]

So, where does that leave us? Are all, or even most of the people that buy medium format equipment fools, willing to spend their hard-earned money chasing a chimera, or simply looking to boost their egos regardless of cost? I don't think so, and it seems to me that anyone that does, simply hasn't taken the time to do a simple side-by-side comparison for themselves.

Frankly, there is no argument, only lack of knowledge and experience, or living in denial.

Cynnical translation: you know what you know, facts and explanations from the hoi polloi be damned.

You might have a valid point with this post, if you were responding to yet another "35mm DSLR is just as good as MFD" thread, but that is not the case here. This thread was started specifically about the unsubstantiated claim that MFD has a 6-stop advantage in DR over 35mm digital, which you repeated and agreed with in your Editor's Note.

I have to agree with image66, this site's editorial content has lost credibility on technical matters of late...

[Dave Millier]

I have absolutely no doubt that you are completely correct: the medium format backs justify their premium price.

Now, having got that out of the way and returning the the question of this 6 stop advantage over 35mm sensors....

Frankly, on the face of it that sounds absurd. If the claim had been that there was a 1 stop or perhaps 2 stop advantage I might believe it without cast iron evidence as it sounds plausible given what we have seen with the short life of digital. But 6 stops would represent something like the largest difference in a critical measured parameter of imaging technology there has ever been. It's a ridiculous chasm in capability! Think about the huge amount of work fuji had to do, inventing a completely new way of doing things to get an extra 2 stops.  I don't think any more discussion is worthwhile without some hard evidence.  To quote Richard Dawkins (on his own forum, interupting a debate) "I don't care what your opinion is, it's worthless; I don't care what my opinion is, it's worthless, too. Show me the evidence. "  In this case the purported difference is so huge that even the often invoked blind man ought to be able to judge it in about 1/10th sec...

regards

Dave

I'm not going to fan the flames any more than needed, but I can't resist making one more comment in support of Fred's.

The world-wide market for medium format backs is approximately 7-8,000 units. That's all manufacturers combined.

These devices (with camera body and a couple of lenses) are priced in the $30–$50,000 range U.S. As Mark pointed out in his essay, that's the cost of a current luxury car.

One more factoid: About 70% of MF systems are bought by working professional photographers, the rest by fine art photographers and wealthy amateurs.

Here's the point. For the pros an MF system is a tool for earning their livelihood. It is purchased with the intention of helping them make money. No person would spend a good chunk of a year's income on a tool that did not offer an advantage. In my experience every pro that I know (and I know quite a few around the world) has done their own exhaustive comparisons and test, not relying on web site chatter, magazine reviews and online tests.

The fine art photographers are in a similar boat. They too make their livelihood (or a good part of it) from exhibiting and selling their prints. If a $1,000 to $6,000 DLSR gave them what they needed, why on earth would spend $30-$40,000 on a back?

As for the wealthy amateurs, I'll just say that it my experience (having taught and worked with several thousand folks like this over the years on my workshops and tours) I have yet to meet one who wasn't a savvy business person who understands the value of a dollar. Like the pros and the fine art guys, they spend that kind of money for an MF back because they believe that it will provide them with a tool that allows them to produce superior quality images. And if you speak to the people at major VARs who sell this gear, you'll learn that the amateurs are often even more demanding as customers than pros.

So, where does that leave us? Are all, or even most of the people that buy medium format equipment fools, willing to spend their hard-earned money chasing a chimera, or simply looking to boost their egos regardless of cost? I don't think so, and it seems to me that anyone that does, simply hasn't taken the time to do a simple side-by-side comparison for themselves.

Frankly, there is no argument, only lack of knowledge and experience, or living in denial.

Michael

[fredjeang]

Hi jeff,

Well I do not think LU-LA has lost credibility, maybe at the contrary.
Again, I have to agree with Michael's post about ambiguity. I do not agree for agreeing, if I did not I would say it clearly, so let me explains my thoughts.
When I hear talking about scientific rigor (that rigor that was supposed to missed here in that topic), as if science was able to put a definitive and absolute answer with graphics, and when I turn towards real scientits like Ed Witten, these guys always talk about the ambiguous part of laws and nature as a full component of the ecuation. Ambiguity is part of reality and the 5 o 6 stops may be true in some cases, in other case not. But if it CAN be true in some cases, then it is not a wrong information.

About this famous comparaison with the G10, of course that it is true...BUT, now...lets take the G10 file in severe post production like in fashion, art or advertising. Everybody would agree that there is no room for that. The file simply does not contain enough information to handle such a treatment, and that kind of treatment is the standar in professional photography. (without talking about the enlargement of course). So, yes, Michael is right. He is just saying that "you can do that with the G10 file", but he was not saying "both files had the same capacities". So it became a kind of ambiguous argument, some have seen contradictions but in my understanding there was absolutely no contradiction.

About the display on the web, I put a post in the past talking about that, but I did not know that it was such a sensitive topic. Well, yes, it is possible to see the differences in low resolution on the web. It is not scientific but perceptual. I do see it and for sure many of you.
One day, a member send a link in a topic about LF, a site with contact prints. You can tell the difference right on the web. There is something very special, an overall sensation of quality and clean that simply does not exists with smaller sensors. And one of the sensation resides between the transitions in the tones.
I can see it on the web, why not on a print so?

MF users are talking about the differences they see between the back brands. For example Leaf has a fame to be closer to film etc...it seems that in MF users, there is a general consensus about these differences that are clearly visible. What Mark post about the Hasselblad style ( for reproduction etc...) is known and visible. Would it be measurable? Maybe not.

Also, many of the MF detractors would die to have an MFD to work with. This is a major contradiction, much more than the G10 one don't you think?. The only one who post clearly a coherence about that, was Bernard when he said he would not buy an MF back even if they were cheaper than Dslr. But many of us would love to have one and work daily with it.   Is it not true?

Sorry gentlemen, I respect your views and opinions but I still trust Michael, even more after his last post about ambiguity.

Now I'm going away from the flames because it is hot hot  

Best regards,

Fred.

[thierrylegros396]

2 facts.

1. In most websites you can read that S90 has a better dynamic range (about 1 f-stop) than the G10.
After a lot of tests I can say that at ISO80, for RAW files developped with LR2.6, the G10 is better in terms of dynamic range and color accuracy !
At ISO200 they are equals, and above S90 is better.
It is strange, because I cannot give any scientific explanation for that fact !
But it's like that.

2. Up to 8-9 f-stop it is easy to show differences in terms of dynamic range and color accuracy.
Above, it's often very difficult for a lot of reasons: very limited DR of paper, shadows areas purity, color shift in very bright zones,...

So we need a more rigorous definition of dynamic range, and a use of the same protocol.


Another strange thing, I've re-discovered old scanned film photos saved in jpeg.
I was able to recover far more highlights than with my Fuji pocket camera jpegs.

So yes, it's possible that MF have a 2 or 3 f-stop advantage, but 7 seems unbelievable.

Have a Nice Day !

Thierry

[tho_mas]

What Mark post about the Hasselblad style ( for reproduction etc...) is known and visible

unlikely. It rather shows that he couldn't even manage to run the software correctly: http://luminous-landscape.com/forum/index....st&p=351480

[Jeremy Payne]

Sorry gentlemen, I respect your views and opinions but I still trust Michael, even more after his last post about ambiguity.

Sorry, Fred ... but not one thing you've said has been on point in this entire thread.

It ain't about trusting anyone ... it's about backing down from a preposterous claim everyone knows is completely nonsensical.

[JohnKoerner]

Jack - let me correct this - there are two Mark's active in this discussion - the writer of the article who is Mark Dubovoy with a PhD, and then a member of the discussion audience - me - Mark Segal, who does not sport a PhD. I did not make any statement to the effect that ANYONE should be able to see the difference between MF and high-end DSLR images (but I did say that I could in respect of a bit of my own work), nor did I say anything about seeing such differences from 30 feet away. That was the other Mark. Let us keep our Marks de-confused   .

My apologies good sir!

I was having enough trouble discussing Mike and Michael on the thread below this one, that dealing with Mark and Mark got me turned around on this one  

I will enter an edit correction immediately  

Jack



.

[feppe]

Well I do not think LU-LA has lost credibility, maybe at the contrary.
...

As has been repeated ad nauseum, the main point of contention is the claim of massive difference in dSLR and MFDB dynamic range. I and apparently some others believe this is due to comparing apples to oranges which yields invalid results. Most likely this is empirical tests for dSLRs vs. published manufacturer figures for MFDBs.

This even when there is a perfectly adequate objective source of data in DXOmark. While one can argue about the validity of their data, they do have a consistent and published methodology. Therefore comparing their figures between dSLRs and MFDBs would show if there was such a massive difference in DR, although the absolute numbers might be different than what the "real-world" DR is.

Nevertheless, the author of the article nor Michael have been forthcoming with any data to support the claim. I've only seen peripheral anecdotes, "expert" "consensus" unsupported by evidence, and plenty of smoke and mirrors. This certainly doesn't fair well for credibility.

[fredjeang]

Sorry, Fred ... but not one thing you've said has been on point in this entire thread.

It ain't about trusting anyone ... it's about backing down from a preposterous claim everyone knows is completely nonsensical.

Correct Jeremy. Some of the things I said yes indirectly have something to do.
But I got your point and agree, specialy about the use of language. Trusting was not the correct word.
Well, when I wrote "trusting" I mean that I think Michael is right about DR.
Now as someone said we would need a standar because it seems that it is not that clear at all.

Regards,

Fred.

[deejjjaaaa]

Nevertheless, the author of the article nor Michael have been forthcoming with any data to support the claim. I've only seen peripheral anecdotes, "expert" "consensus" unsupported by evidence, and plenty of smoke and mirrors. This certainly doesn't fair well for credibility.

WMD in Iraq... and LuLa like Fox News w/ Michael being O'Reilly then.

[fredjeang]

unlikely. It rather shows that he couldn't even manage to run the software correctly: http://luminous-landscape.com/forum/index....st&p=351480

Aaaaarrrggg...  
But Hasselblad is known in the world for that. Museums, intitutions etc...Maybe Mark did it not so bad with the software.

You convinced me, and I'm going to study these fantastic japanese paper with Bernard.

I will never enter any more on a technical topic about 35mm and MFD. Too hot without fireman jacket.


Cheers to all, and sorry for my sometimes clumsy english. Hope I was not too much.

Fred.

edit: Maybe what I tried to manifest is that point in form of a question: Michael Reichmann or Mark Dubovoy are not specialy known for their lack of rigor and knowledge in the photography community, right? So, why would Mark put a completely non-sense information on a web that is visited worldwide? Then, Michael would have post an editor's note rectifying this point, don't you think? But he confirmed more or less Mark's information. My question is why? They might have good enough reasons for that I guess. Knowing that Michael uses daily MFD as 35mm, why would he put a completely false information? That does not make sense. I think this question is not that silly and maybe before these bombing of criticisms we might also think that they maybe right. That was my point.

[tho_mas]

But Hasselblad is known in the world for that. Museums, intitutions etc...Maybe Mark did it not so bad with the software.

known for a contrasty oversaturated look by default? Not that I know of ...