Film versus DSLR dynamic range

Started Jul 24, 2007 | Discussions thread
uk102 Senior Member • Posts: 1,286
Re: And...

These are very pretty graphs that show DSLR’s as having huge DR. What is puzzling me is the following.

On my film (not slide) camera I can take a photo and the sky looks lovely and I can have sky in my all photo’s without thinking. I meter for the foreground and the foreground looks lovely so does the sky.

On my DSLR doing the same with .jpg and yes the sky nearly always blows out if the foreground is correctly exposed. Therefore I use RAW and thing are better but not perfect.

On this basis I know my slide film has 5 stops of DR when working with the camera meter. Yes the sky burners out just like shooting jpg. I can therefore conclude that slide and .jpg have about the same DR (5 stops).

I work with RAW images and can gain some sky detail, but not all, so theRAW files has a great DR than jpg. I can get the sky detail back if I use HDR, and the standard method is to Bracket the shots -2, 0, +2 . Comp. I can therefore compare the RAW files and what this appear to tell me is that a RAW files has around 7-8 stops of detail.

I think we can all test this for ourselves, but I spent my years in the dark room developing film and using an enlarge which as anyone who develop film means you get to understand of the exact DR of films & print papers. From what I have found slide film is about 5 stop, colour film 11 stop (depend on brand) and some B&W up to 19 stops.

...I DID NOT ask for Stouffer wedges (I already got them, , long time ago

We are working under Dave's "REAL WORLD" images principle, and I have
asked him to step-up to the plate and send me FILM IMAGES, so I can
scan them and process them, using my skills and tools, and post the
results, here.

The problem with "real world images" is that they have to be metered
carefully beforehand if they are going to be used to prove a certain
level of DR. That's the problem with your candle image. We have no
idea what the brightness values were. So we don't know what dynamic
range was captured. And I really don't care what you think "we" are
working under. And I'm working under any reasonable approach that
can demonstrate actual dynamic range. That can be a "real world"
image or any number of reasonable test images or exposure sequences.

Anyway, the image below demonstrates my point. It is a pair of nice
boring pictures of a Stouffers step wedge. For those who don't know,
each step represents a 1/3 stop exposure difference. Two strips are
shown. Each is from the same raw file. The bottom one is a a
"normal" developement that shows slightly more than 8 stops worth of
steps and hence slightly mroe than 8 stops of DR. The darker tones
don't show much visible noise. This is the 8 stops or so of DR that
I say is comfortably achieved by most DSLRs.

The wedge above that one has been processed to bring the values
beyond 8 stops into a useful range. On this image, you can make out
steps that go as far as the 11th stop. But there is a lot of noise
present in these last two stops. So the range of 11 stops is there,
but the question that each photographer has to answer for themself is
how useful those last extra stops of DR are? For me, they aren't
usually very useful. I'm pretty comfortable pushing into 9 stops,
and maybe even 10 in an pinch. - depending on final enlargement size
and subject matter. I have no hesitation saying that this camera
(E-330) easily has 8 stops of DR. But even though I can measure
more, those extra stops don't represent a lot of useful image detail.

Now a camera with a larger pixel pitch and and hence typically
greater well capacity will go into the the last three stops of DR
more comfortably. But that isn't true of the vast majority of DSLRS.
And further, Roger Clark says that even a 7Mp 1/1.8" sensor has 11
stops of DR. And while that that may be true technically, it isn't a
good practical preditor of what you can expect when you take
pictures. The usable DR is a few stops less. And the typical 6-10Mp
sensor on an APS-C or 4/3" camera has a similar problem, just to a
lesser degree.

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