Digital BW, The Print

Don,

I think the technique is good, but I would recommend taking it a bit further and finding out: 

1) How many zones can you record in a single exposure.
2) At what zone does your camera overexpose and blow out the highlight detail.

You may find that your camera's exposure range only covers 5 zones or so.

Knowing your ISO to get midtones placed correctly is good, but I think knowing how to place highlights without blowing them out is much more useful for digital captures.

Of course with most digital cameras you can always check the histogram after the shot.  It would be nice if the built-in metering took into account all pixels and fit every scene into the dynamic range of the camera for each shot.  Maybe some day...

--Tom

On Wed, 10 Sep 2003, D. Hill wrote:

> 
> I've had a few responses about my method of
> determining effective ISO for the digital realm - so
> here goes:
> 
> This testing is very similar to that done with
> conventional photographic materials.  I use a
> hand-held meter, even toned card (white or grey), and
> a zone dial (the sticker from calumet that attaches to
> the pentax spotmeters).
> 
> To determine effective ISO of the camera, read your
> cameras manual for the default ISO setting, and set
> your camera as such.  Most digital cameras default at
> 100, but still check.
> 
> Use a tripod and fill the viewfinder with the white
> card - I typically will make sure that the light is
> even across the card, and the sun is at a 45 degree
> angle to the card itself.  At this point, set the
> focus at infinity.  
> 
> Meter the card, and do a series of Zone V exposures. 
> I shoot a series in 1/3 increments from 1 stop below
> to one stop over ASA 100.  This gives me a set of
> seven Zone V values from ASA 50 - 200.
> 
> At this point, I convert all images to 16 bit
> greyscale files in photoshop as stated in my previous
> post.  Using the eyedropper tool, I choose the image
> that is closest in value to 50% (zone V value).  
> 
> If you have taken notes, you should be able to line up
> what image is the correct ISO for your equipment.  My
> equipment sets my ISO as 80 - but most likely your
> results will vary from mine. 
> 
> This is a very simple and quick method in determining
> ISO - and is extremely helpful when you want to place
> a specific zone for imaging.  As I stated before, this
> does not allow for any processing functions of the
> zone system (such as n-1, n+2, etc.) but does allow
> specific placement of the important values.
> 
> Good luck,
> Don
>

On Wednesday, September 10, 2003, at 06:48  PM, Thomas Fors wrote:

>
> Don,
>
>
>
> I think the technique is good, but I would recommend taking it a bit  
> further and finding out:
>
>
>
> 1) How many zones can you record in a single exposure.

Don't confuse zones with f stops. zone 0 is always black and zone 10  
white. Even a 5 stop latitude will have 11 zones.
>
> 2) At what zone does your camera overexpose and blow out the highlight  
> detail.

Always zone 10
That is the definition of zone 10

>
>
>
> You may find that your camera's exposure range only covers 5 zones or  
> so.

You mean stops.
>
>
>
> Knowing your ISO to get midtones placed correctly is good, but I think  
> knowing how to place highlights without blowing them out is much more  
> useful for digital captures.

Absolutely

>
>
>
> Of course with most digital cameras you can always check the histogram  
> after the shot.  It would be nice if the built-in metering took into  
> account all pixels and fit every scene into the dynamic range of the  
> camera for each shot.  Maybe some day...
>

That would kill high key and low key photos.
Better that we should do the fitting (expansion at any rate) post  
capture.
>
>
> --Tom
>
>
>
> On Wed, 10 Sep 2003, D. Hill wrote:
>
>
>
>>
>
>> I've had a few responses about my method of
>
>> determining effective ISO for the digital realm - so
>
>> here goes:
>
>>
>
>> This testing is very similar to that done with
>
>> conventional photographic materials.  I use a
>
>> hand-held meter, even toned card (white or grey), and
>
>> a zone dial (the sticker from calumet that attaches to
>
>> the pentax spotmeters).
>
>>
>
>> To determine effective ISO of the camera, read your
>
>> cameras manual for the default ISO setting, and set
>
>> your camera as such.  Most digital cameras default at
>
>> 100, but still check.
>
>>
>
>> Use a tripod and fill the viewfinder with the white
>
>> card - I typically will make sure that the light is
>
>> even across the card, and the sun is at a 45 degree
>
>> angle to the card itself.  At this point, set the
>
>> focus at infinity.
>
>>
>
>> Meter the card, and do a series of Zone V exposures.
>
>> I shoot a series in 1/3 increments from 1 stop below
>
>> to one stop over ASA 100.  This gives me a set of
>
>> seven Zone V values from ASA 50 - 200.
>
>>
>
>> At this point, I convert all images to 16 bit
>
>> greyscale files in photoshop as stated in my previous
>
>> post.  Using the eyedropper tool, I choose the image
>
>> that is closest in value to 50% (zone V value).
>
>>
>
>> If you have taken notes, you should be able to line up
>
>> what image is the correct ISO for your equipment.  My
>
>> equipment sets my ISO as 80 - but most likely your
>
>> results will vary from mine.
>
>>
>
>> This is a very simple and quick method in determining
>
>> ISO - and is extremely helpful when you want to place
>
>> a specific zone for imaging.  As I stated before, this
>
>> does not allow for any processing functions of the
>
>> zone system (such as n-1, n+2, etc.) but does allow
>
>> specific placement of the important values.
>
>>
>
>> Good luck,
>
>> Don
>
>>
>
>
>
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Regards,

Loring Palleske
Creative Imaging
416.301.1711

Again, this is very rudimentary zone work - this is
not film based media, and it is difficult to actively
transfer all aspects of a proven methodology.

> I think the technique is good, 

Thanks, but its not mine.  Fred and Ansel did most of
the work.

> but I would recommend
> taking it a bit further and finding out: 
> 
> 1) How many zones can you record in a single
> exposure.

As my work is based upon the least amount of
manipulation (and time in photoshop eeking every
nuance of detail), as well as placing one specific
zone - it really does not matter how many zones I can
record - as long as the placed zone is correct. 

> 2) At what zone does your camera overexpose and blow
> out the highlight detail.

Without photoshop manipulation, useful detail range is
from zones 3 - 7.  Zone 8 shows some detail, and 9 is
pretty much paper white.  So, this is a standard scale
in traditonal zone work.  Additionally, it allows for
an exceptional "negative" if you wish to get the best
print possible. 

Kinda like cheer - keeps the white's white and, well,
you get the point. 

> 
> Of course with most digital cameras you can always
> check the histogram after the shot.  

That's why I use this system - you don't have to check
the histograms.  What is the fun word for those of us
always checking the little screen?  Ahh yes,
"chimping" - I've been known to do that all too much.

> It would be
> nice if the built-in metering took into account all
> pixels and fit every scene into the dynamic range of
> the camera for each shot.  Maybe some day...
> 
> --Tom

I agree - but wouldn't that strip the final remaining
joy out of photography?  They have to make it a little
difficult for us consumers.

Don



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On Wed, 10 Sep 2003, Loring Palleske wrote:

> 
> Don't confuse zones with f stops. zone 0 is always black and zone 10  
> white. Even a 5 stop latitude will have 11 zones.

Yes, you are correct.  I should have said stops instead of zones.  

The beauty of the zone system though is that it calibrates your film's dynamic range into zones which happen to be one stop apart.  If they weren't a stop apart, it would be very difficult to place items in a particular zone using a spot meter.  In fact, in The Negative, Adams defines the zones to be a stop apart.

> >
> > 2) At what zone does your camera overexpose and blow out the highlight  
> > detail.
> 
> Always zone 10
> That is the definition of zone 10
> 

That is true for film only once it has been calibrated to that by finding your standard development time.

With film, it's the toe of the curve (shadows) that determines your ISO.  My point was with digital, I think the highlights should determine your ISO.

For example, say you have a scene with both a white and gray object in it, and you meter the white object and placed it in zone 10 (paper white) which corresponds to a digital value of 255.  You meter the gray object at that exposure and it happens to fall exactly on zone 5, so you make an exposure.   I doubt that the gray and white objects in the digital file will have values of 128 and 255 respectively.  In fact, no matter what values they fall on, I doubt that their difference will be anywhere near 127.

So, by using an ISO based on zone 5, objects that fall into zone 7 (where you would expect full texture) may in fact turn out to be a value of 255 (paper white) in the digital file, and so will zone 8, 9, ...

--Tom

If you meter the gray object and the white is blown out - you will have 
a 127 difference.

There is no toe on digital (yet - I read Fuji is working on a new chip) 
it is linear - that is why highlights blow out so badly.


On Thursday, September 11, 2003, at 12:14  AM, Thomas Fors wrote:

> For example, say you have a scene with both a white and gray object in 
> it, and you meter the white object and placed it in zone 10 (paper 
> white) which corresponds to a digital value of 255.  You meter the 
> gray object at that exposure and it happens to fall exactly on zone 5, 
> so you make an exposure.   I doubt that the gray and white objects in 
> the digital file will have values of 128 and 255 respectively.  In 
> fact, no matter what values they fall on, I doubt that their 
> difference will be anywhere near 127.
>

If you meter the gray object and the white is blown out - you will have 
a 127 difference.

There is no toe on digital (yet - I read Fuji is working on a new chip) 
it is linear - that is why highlights blow out so badly.

>
>
> So, by using an ISO based on zone 5, objects that fall into zone 7 
> (where you would expect full texture) may in fact turn out to be a 
> value of 255 (paper white) in the digital file, and so will zone 8, 9, 
> ...

You are confusing zones and f stops again. While 1 stop steps work for 
B&W film, it does not for slide, colour neg or digital. You have to 
adapt to what you are using. Find out your latitude and remap. You may 
find on consumer cameras that zones are about 1/2 stop each. Some pro 
backs actually have a 12 stop latitude so again zones would have to be 
mapped.

I agree 100% about your exposure. Treat it like slide - meter for your 
important highlight (with detail) and let the rest fall where it may.


Regards,

Loring Palleske
Creative Imaging
416.301.1711