Автор: ecobo
Дата: 30-04-09 00:22
Много често се ползва тоя израз за обективи. Но този тип визия идва от други неща, не от обектива.
Ето какво пише по въпроса Майкъл Райхман:
Beyond Resolution
Нямам нерви да го превеждам цялото...
Тортата на черешката:
"Много от нас снимаха на голям формат в миналото и са забелязали, че дори на А4 копие човек може винаги да различи големия от средния формат, и със сигурност - от 35 мм формат.
От техническа гледна точка това бе трудно обяснимо, защото резолюцията си я имаше и на по-малкия формат, обективите си бяха качествени. И все пак, малките принтове от големия формат винаги можеха да бъдат отличени.
Такъв е и случая с дигиталния среден формат. Въпреки, че 21-25Мп ДСЛР може да произведе изключителни принтове, човек може ясно да види разликата със средния формат, понякога дори на малки картинки за web."
Оригинала:
I ran into a friend at PMA in Las Vegas, and over a coffee he commented that he found that even on the web he thought that he could see a difference between my P65+ shots from Antarctica and those from the 25 Megapixel Sony A900.
I didn't disagree, and this raises an interesting point which a number of us who were testing the P65+ on the Antarctic trip in January had seen and discussed.
Many of us have shot large format film in the past, and had noted that even in an 8"X10" (A4) print one could always tell a large format image from one shot on medium format, and certainly from 35mm.
From a technical point of view this was hard to explain because the resolution was certainly there on the smaller format images, and their lenses were up to the job. Yet, small prints from large format could always be differentiated.
This is the case with medium format digital images today. Even though a 21-25MP DSLR can produce exceptional prints, one can clearly see the difference that medium format makes, sometimes even at the web's low resolution.
Even some very savvy technical types in the industry don't have a firm explanation for what it is we're seeing. The best explanation that I've been able to come up with is what I like to call micro-contrast. What we appear to be seeing in large format film and medium format digital (especially from 39MP and up) is the ability for the system to differentiate tiny differences in luminance values, tonality and colour.
Is this because MF backs are 16 bit rather than 14 or 12 bit which DSLRs use? Maybe. But there's something more than this because that wouldn't explain why large format film exhibits the same sense of clarity in small prints. This micro-contrast may simply be the cumulative effect of a number of factors which enable the viewer to discern what appears to be greater detail.
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