Ray,
Thanks for good comments. I would almost expect you pointing out the viewing distance issue. I would add that it's working the way that we don't increase viewing distance proportionally to image size. Think of an IMAX or Omnimax theatre. One of the reasons to print big is that you can see the print at reasonable distance and still feel immersed in the picture.
Hi Erik,
I would put it another way. I'd claim that, more frequently, we do not
reduce viewing distance in proportion to the smaller image size of an A4 or A3 or A2 print that may hang on our wall. It's why I bought the 24" wide Epson 7600 a few years ago. It's my experience that, in the average house and sitting room, where there may hang a number of A4 or A3 photos, one does not appreciate the fine detail contained in such prints on most occasions when one happens to glance in the direction of one of those photos. One generally has to make a deliberate effort to get off one's chair and walk right up to the print to view it from a distance of about 1.5x its diagonal.
This is why I prefer to hang small prints in a hallway. I can view them from an appropriately close distance every time I pass them, and on occasions I may linger a few seconds to admire the texture of a rock or tree trunk in the foreground. I would never attempt to place a large panorama in a hallway unless it could withstand close scrutiny without appearing fuzzy.
I remember well the early days of the introduction of the HDTV standard. There were different groups lobbying for different resolution standards. In those early days, large HD screens were horrendously expensive and the group lobbying for the 720p standard had a good point. They would demonstrate that in order to see the difference between 720p and 1080p on a 'then' affordable but still expensive big screen TV of 32" or so, one would have sit no further than a metre away from the screen, which is far closer than most people would want to sit.
However, that point of view of the 720p lobby has proved to be rather short-sighted. Big HD screens are now affordable, which is why I recently bought a 12th generation 65" Panasonic plasma TV. It's better to be stuck on a 1080p standard for a few decades than a 720p standard.
Incidentally, when I sit about 2.5 metres from my 65" Panasonic I get a noticeably 'immersive' experience from a good quality 2mp image. If the image were significantly higher resolution than 2mp, then in order to appreciate that higher resolution, I would have to sit closer than 2.5 metres and would then have to turn my head from left to right to see the entire image clearly. I think the same principle applies in the cinema. Despite the screen being relatively huge, you still wouldn't want to sit closer than 1.5x the screen diagonal for an immersive experience.
Now to get back to the DR issue. Having more pixels on the same sensor does not help DR capability in any way, as I understand. In fact it probably hinders it slightly because the total read noise can be greater, unless there is some compensating technological development in other areas, and there usually is of course. I imagine if Phase One had produced an MF full frame 24mp back instead of the 60mp P65+ FF DB, the D3X might not have had a DR advantage.
I personally don't have any trouble determining which of my cameras has the higher dynamic range, unless the DR of the cameras I'm testing is very similar. If anyone makes a claim that camera 'A' has 4 to 6 stops greater DR than camera 'B', but is unable or unwilling to demonstrate such differences with visual examples, then I think such claims can be taken with a grain of salt.
A 4 to 6 stop difference in DR, or even half of that difference, should be very easy to demonstrate. One might disagree over a 1/4 stop, or a 1/3rd stop or even 1/2 a stop either way, but 2 stops or more?? No way!!
I can appreciate to a certain extent the objection of the busy professional who has done his research into his need for a particular DB, and who may already own lots of fine MF lenses. If DR is not an issue for him and he has lots of good reasons for using MF equipment, why should he take the time to demonstrate clearly and precisely the DR differences between his DB and any 35mm equipment he happens to own? What's in it for him? To do a thorough job requires care and patience. If one doesn't do a thorough and meticulous job, getting the ETTR exactly right with both cameras, the FoV and lens quality favouring neither one camera nor the other, the focussing and DoF the same, and the lighting and the scene exactly the same in both shots, then one's test will be criticised and considered flawed.
On the other hand, exhortations from such professionals directed at people like us, to persuade us to test the DBs for ourselves and get first-hand experience, are also not practical, unless one is fairly sure beforehand that one is in need of that additional performance and resolution of a DB regardless of the DR issue. Assuming there's a store available that hires out the latest DB's and 35mm gear with appropriate lenses, it would be an expensive exercise that could hardly be justified in order to settle just the DR issue.
If a 4 stop increase in DR (over FF 35mm) were sufficient reason to persuade me (and many others) to go the very expensive MF route, I'm sure the MFDB sales reps would be falling over themselves to demonstrate this DR difference. I wonder why they are not? My guess is because they can't.
Making claims of a 4-6 stop DR advantage then becomes merely a sales ploy to encourage people to visit their nearest MF dealer to check out these extraordinary claims for themselves. Having taken the trouble to do this, and after getting the opportunity to handle a Phase MFDB system and perhaps realise it's not as heavy and cumbersome as one imagined, and having seen close-up examples in the showroom of the marvelous detail that a larger format and high pixel-count camera is capable of, sheer material greed may take over, (I want it. Bugger the DR) and
then there's the possibility of a sale. Oops! Have I given the game away?
Wouldn't I look foolish if I were to spend the price of a new Canon 5D2 body in order to hire a P65+ back, MF camera body with lens, plus a D3X and lens in order to confirm that a bunch of guys with PhDs at DXO Labs were actually right. I'm not that silly, ya know!
