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Topic: photos (18 msgs / 588 lines)
1) From: Dan Bollinger
Exactly right.  A very good alternative is to use the palm of your hand
instead.  Letting the same light falling on your subject fall on your hand,
move the camera close until you only see your palm.  Don't worry if it is
out of focus.  Press the shutter button half-way to lock the setting (or do
whatever you camera requires) compose your shot and then press the shutter
button the rest of the way.  Dan
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true,
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trivial
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start
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certain
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The
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important
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2) From: Dan Bollinger
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NONE!  The whole idea of this exercise is to keep your camera's autoexposure
system from thinking the dark beans are actually a poorly lit 13% gray
average scene and then overcompensate by overexposing the shot.  Using a
gray card your whites will be white and your blacks will be black and your
beans will be juuuuust right.  :)
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3) From: Dan Bollinger
Kodak Schmodak!
You misread or I missaid.  Here's what I was REALLY trying to say.  Exposure
compensation using a gray card is intended to deal with reflectance light
meters (like the ones in cameras) which read the reflected light.  This
problem occurs because the reflected light will be less for dark subjects
and more for light subjects, hence throwing off your exposure. If your
subject is very light or very dark or varies from the 'normal' reflectance,
then you need to compensate in order to get a good exposure.   The color of
the subject (i.e. coffee) doesn't matter since what you are (temporarily)
measuring is the artificial subject called a gray card.  If you want to
adjust that a half-stop go ahead you probably won't see much difference in a
color print since they are adjusted again by the automatic print developers.
Also, digital cameras can adjust the image later using their software.
All this is moot if you do what I've been doing for the past 35 years.  Use
an incidence light meter which measures the light falling on the subject. No
compensation is required.
I hope this clears this up.  Dan
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opinion
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coffee
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4) From: C.M. Alpha
Does anyone with a drum roaster have a digital camera?  I have found out that it
is very difficult to get a digital photo that corresponds to what the eye sees. 
Yes the photos of coffee I have taken look very uneven, but the actual coffee
looks very even.  The camera seems to be raising the contrast and brightness,
probably an effect of the automatic white balancing.  Anyone with a digital
camera and a roaster if you could please, take a couple of shots and send them
to me privately. Having photos is helpful in understanding the process and the
results - so knowing how the photos correspond with the reality is important.
Regards, Cathy
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5) From: Ed Needham
You can see one of mine onhttp://www.homeroaster.comIt's in the BBQ grill
article at the bottom.  I took it with an Olympus C-3000 using a flash
outdoors.  It looks just like the roast in my opinion.  Maybe there are some
camera settings you can fiddle with to get a more accurate representation.
Use bounce flash if you can remove the flash from the camera.
Ed Needham
ed
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6) From: Ted Kostek
Cathy,
I don't have digital camera, but I am photo buff.
You are probably correct that the camera is adjusting the contrast and
brightness automatically, but every camera uses a slightly different
algorithm, but I don't know how different.  Color matching is not a trivial
thing.
Another option you have is to include about some white in the image; start
around 40%.  Your camera is trying to get the image to conform to certain
average characteristics, but your subject (beans) are all dark brown.  The
camera gets confused.  You might also trying getting the camera to
"underexpose" the shot, but you may not have exposure compensation.  I would
guess something like 1 stop underexpose might give a more accurate
rendition.
tmk
--
Ted Kostek
765 494 2146 (desk)
765 494 1489 (engine room)
765 494 0787 (fax)
"Always keep in mind that your own resolution to succeed is more important
than any other thing."  Abraham Lincoln
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7) From: Ed Needham
Prof photographers use a standard gray card to set their camera exposures.
They 'meter' from the gray card rather than surrounding colors to get a true,
balanced exposure.  Gray cards are available at photo stores, and most
digital cameras can 'lock in focus and exposure settings by slightly
depressing the shutter when making the test, then holding it until you
depress it fully and take the shot.
Ed Needham
ed
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8) From: Irene and Lubos Palounek
Ed wrote:
" ...prof photographers use a standard gray card to set their camera
exposures..."
Ed is correct, although not just professionals use the standard gray card;
many amateurs use it, too. I would suggest use the 18% gray card to set up
not only the exposure, but also the "white balance".  That is something
impossible with "film" cameras, but possible with many digital cameras.
Lubos
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9) From: Irene and Lubos Palounek
Dan's recommendation (see below) would not work with many cameras.
"...letting the same light falling on your subject fall on your hand, move
the camera close until you only see your palm.  Don't worry if it is out of
focus.  Press the shutter button half-way to lock the setting (or do
whatever you camera requires) compose your shot and then press the shutter
button the rest of the way..."
Well, many newer cameras use automatic focusing. The procedure described
above would work only if the camera-to-palm distance is the same as the
camera-to-beans distance.  Some cameras have a button to "freeze" only the
exposure, not the distance; that would possibly work.
Scientific studies now indicate that an average scene actually reflects 13
percent (not 18 percent) of the light that falls on it. For the sake of
consistency, the Gray cards continue to be 18 percent gray. Kodak recommends
that, when using any 18 percent card, it exposure should be increased by a
half stop (+0.5 compensation factors) for most subjects. I have no idea what
the correct compensation is for coffee beans.
Regards, Lubos
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10) From: Photogal1966
 I have no idea what
the correct compensation is for coffee beans.
Wouldn't that depend on the roast? LOL
Andrea
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11) From: Irene and Lubos Palounek
To my statement: "...I have no idea what the correct compensation is for
coffee beans...", Dan answers: "NONE!"
Dan, please, elaborate; explain, why coffee beans require no compensation
while most subjects do. For most subjects, Kodak recommends compensation
factor of +0.5 from the "Gray card reading". In other words, Kodak's opinion
is that with +0.5 compensation factor, in pictures of most subjects the
"whites will be white and blacks will be black." Why do you say that coffee
beans are different from "most subjects"?
Regards, Lubos
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12) From: Dan Bollinger
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Nope.  Didn't say that at all!  :)   Someone asked what the magic
compensation was for coffee beans after taking a gray card reading; not
should you use an added half-stop.  What I said was that calibrating your
meter reading using a gray card is done regardless of the subject's value.
Take a reading off the gray card, use that exposure or add a half-stop
whatever you like, but don't overcompensate by adjusting again for 'dark
beans'.
You know, a half-stop is no big deal folks.  All things considered, your
film varies a half-stop from its stated ISO, your shutter is off by a
half-stop and your meter is off by a half-stop and if you are shooting
outside, you lighting might change by a half-stop by the time you take the
picture.  Don't believe me?  Just point two cameras or meters at the same
wall and compare readings.  ;)    Dan
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13) From: Ed Needham
The thing about any auto exposure camera is that it 'tries' to make the scene
very average (gray tone) in exposure.  Take a picture of a black wall and you
won't get a true black wall.  Take a picture of a predominantly white scene
and you will likely get a grayish scene.  Imagine what it does to dark
brown/almost black  coffee beans.  If the digital camera can be 'fooled' by
locking in an average scene...a gray card, a hand at the same distance/ same
light, then the camera will arrive at the proper exposure for beans, black
coal or white Destin sand.
I set my flash to fire for every shot, unless I know I want only available
light.  It is a concept many have not considered... "Why the heck would you
want a flash on a bright sunny day???"  For outdoor portraits, it is
indispensable to fill in very dark shadows from very bright sunlight.  On
overcast days, it makes the subject pop out of the background.  Shooting with
a strobe also makes colors more accurate, since the light from a strobe is a
predictable, very white light.
I've been a 35mm camera nut most all my adult life, but just having a ball
with my digital camera and computer darkroom.  The camera usually takes great
shots without too much input from me, but I really miss the manual 35mm
settings. What they call manual settings on my digital would take a computer
programmer to set up for each shot...menu1-->menu2-->menu3-->set pseudo
aperture.  ...menu1-->menu2-->menu3-->set pseudo shutter speed.  OK...now,
set up for shot 2...repeat.  Oh, and ...menu1-->menu2-->menu3-->set fake ISO
film speed.  By that time, I think I missed 'The Decisive Moment'.
Ed Needham
ed
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14) From: Ryuji Suzuki -- JF7WEX
From: "Irene and Lubos Palounek" 
Subject: +photos
Date: Mon, 19 Aug 2002 16:56:52 -0500
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I think more serious people use incident light meter for that purpose...
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That's usually done with filter pack in enlarger... the creative place
for real control freaks.
The spectral sensitivity of films vary across emulsions and by
selectring films you could do a lot of tricks. Really a lot of things
are actually done with silver salt photography though for many people
digital sounds like the only way to do it.
--
Ryuji Suzuki
"I can't believe I'm here.
People always say that I'm a long way from normal."
(Bob Dylan, Normal, Illinois, 13 February 1999)
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15) From: Ryuji Suzuki -- JF7WEX
From: "Irene and Lubos Palounek" 
Subject: +photos 
Date: Mon, 19 Aug 2002 17:36:57 -0500
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It all depends on what you are metering. That's it.
--
Ryuji Suzuki
"I can't believe I'm here.
People always say that I'm a long way from normal."
(Bob Dylan, Normal, Illinois, 13 February 1999)
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16) From: Irene and Lubos Palounek
First, let me ask those readers who are NOT interested in roasted beans
photographs to skip this long message.
Second, let me say that I consider this subjects (of taking correctly
exposed and balanced pictures of coffee beans) VERY coffee-roasting related.
If we want to compare different roast levels by looking at pictures of
roasted beans, both the darkness (exposure) and color balance of the bean
pictures are MOST important. (Also, we should use color, not black and white
pictures.)
Third, let me introduce another aspect of the searchb for accurate
reproduction of the bean look and color, use of polarizing filters. When
trying to capture the "real color" of flowers and plants, many photographers
use polarizing filter. Without polarizer, the foliage often has blue cast
caused by the blue sky reflection - or red cast caused by nearby brick wall,
etc. The polarizer greatly reduces this cast, making the colors truer and
richer.  I think that a polarizer will help when taking pictures of coffee
beans, too. That would, of course, complicate the proper use of incident
light meter. (Yes, I know that the most popular use of polarizers is for sky
darkening and for taking pictures through reflective surface of a lake or
glass and that polarizers are used even in B&W photography.)
Fourth, let me say that I fully agree with Dan: an incident light meter is a
MUCH better way of determining the correct exposure as compared to using the
gray card. I would suggest to anyone seriously interested in taking good
close-up pictures of roasted beans (or anyone seriously interested in
photography) to get at least the Gossen Pilot 2 - Analog Incident and
Reflected Light Meter that can be bought new for $96.00 or used for much
less. Flash users could use the Wein WP-500B Standard - Incident Flash ONLY
Light Meter which costs $69.50 new. There are many other meters available,
of course, from the $100 inexpensive Shepherd FM990 basic flash and ambient
light meter to the excellent but expensive Sekonic L-608 "Super Zoom
Master" - Digital Incident, Spot and Flash Weatherproof Light Meter. Buy the
incident light meter and skip the Gray Card discussion below (and in
previous messages.)
Fifth, let me restate the "gray card compensation" argument of this thread:
Kodak recommends that, when using an 18 percent gray card to determine the
correct exposure, for most subjects the exposure should be increased by a
half stop (+0.5 compensation factors). Dan argues that such a half-stop
compensation should NOT be used for coffee bean pictures.
Let me quote the instructions that come with recent Kodak 18% cards:
"Meter readings of the gray card should be adjusted as follows:
 1) For subjects of normal reflectance increase the indicated exposure by
1/2 stop.
 2) For light subjects use the indicated exposure; for very light subjects
decrease exposure by 1/2 stop
 3) If the subject is dark to very dark increase the indicated exposure by 1
to 1.5 stops"
As I understand it, similar "compensation instructions" were included with
the Kodak gray cards prior to 1970. When the instruction sheet for the Kodak
gray card was revised back in '70s, someone inadvertently left off that part
about compensating. Now it's back.
Well, back to the argument. In the "+photos" thread here, I stated that "I
have no idea what the correct compensation is for coffee beans." To that
comment, Dan answers: "NONE!"
Dan "no compensation" recommendation is same as Kodak recommendation for
"light subjects."
I still doubt that the "no compensation" advice is correct.  When taking
pictures of roasted coffee beans (without an incident light meter) I would
stick with Kodak recommendation for "subjects of normal reflectance" and
increase the exposure indicated by measuring the 18% card by 1/2 stop, that
is +0.5 compensation factor.  However, I might be wrong; as I stated before,
"I have no idea what the correct compensation is for coffee beans." However,
I do NOT understand your reasons, Dan, why you state that "NONE"
compensation is required.
Yes, the roasted coffee beans perhaps are not "subjects of normal
reflectance". However, remember, we are not trying to make a "pleasing
picture", but a picture that accurately represents the real beans, as
accurately as possible.
I think that it is very important that people without an incidence light
meter do understand the correct use of the 18% gray card for taking pictures
of coffee beans. The gray card AND Kodak's recommendations seems to be a
good starting approach.
Remember, we are often dealing with differences of degree of roast caused by
"five more seconds of roasting." That is, in my opinion, a smaller
difference in the bean look than the difference caused by the recommended
+0.5 compensation from gray card reading.
Below are few more points to consider.
Dan, you wrote: "Kodak Schmodak!" -- and state that no compensation is
requited for coffee beans; in fact, you state that coffee beans should be
treated like "light objects" per Kodak's recommendation. That's where I
disagree with your opinion and I do not understand the reasons why you state
it.
I fully agree with you, Dan, that "...all this is moot if you do what I've
been doing for the past 35 years.  Use an incidence light meter which
measures the light falling on the subject...."
I got my our first incidence light meter around 1953, about the same time
you got yours, I guess. Yes, incidence light meter is the preferred way of
exposure measuring, but I doubt that many readers of this list have such a
meter. Slight exposure variations are important for me, because I am still
using transparency films, not negatives; as you know, slides require correct
exposure.  That's why I often bracket the exposure.  Perhaps the best
suggestion for taking pictures of coffee beans with digital cameras would
be: use the incident light meter AND bracket the exposure with your digital
camera; compare the resulting print with the actual beans; pick up the frame
that most closely represents the actual beans.
I have very little experience with digital cameras; I still use my trusty
Nikon F100 SLR. I have found that its built-in meter is quite accurate with
most subjects -- but I think it is quite useless for coffee beans close-ups;
it would try to show all beans as "18% gray" -- probably the same darkness,
just different hue.
BTW, for people who don't own an 18% gray card and don't want to buy an
incident light meter, I highly recommend the "National Geographic Field
Photography Field Guide" which has the 18% chart on its inside back cover.
It is an excellent guide to photography. In fact, I recommend that book even
to people who own the 18% card. Even experienced photographers and incident
light meter owners will find some interesing information in that book.
Gary correctly writes "...if you meter just the beans, and shoot, you'll get
18% gray beans, no matter how dark they really are.  If you stick 18% gray
card on the beans and meter for THAT, then remove the card, the meter will
tell you you are underexposing the beans.  Ignore it and shoot!  You want
the beans "underexposed" to get them to look darker than 18% gray, just as
they do in real life."
Yes, you want the roasted bean "underexposed". To do that, if you are using
the gray card method and follow Kodak recommendation for subjects of normal
reflectance, you should increase the indicated exposure by 1/2 stop.
Following the ""no compensation" advice, you would get beans half a stop
lighter than correct. (Let me repeat: I fully agree with those who in fact
recommend: forget the gray card and get an incident light meter.)
Finally, although I usually fully agree with Ryuji Suzuki's opinions, I
disagree with you, Ryuji, and the following statement about using "white
balance" of digital cameras:
"That's usually done with filter pack in enlarger... the creative place for
real control freaks.
The spectral sensitivity of films vary across emulsions and by selecting
films you could do a lot of tricks."
In this thread, we are NOT talking about creative control and doing tricks,
but about recording an accurate image of coffee beans. If you want to show
me a picture of degree of roast, you would not use a film balanced for
tungsten lights while shooting outside, would you? When shooting color
transparencies indoors with tungsten lights, you would most likely use
proper film such as Kodak 64T or Fuji 64T, not an outdoor "daylight" film,
correct? On the other hand, you would not use a Tungsten film for outdoor
pictures when you want accurate color reproduction, correct?  When using a
digital camera, you cannot "switch films". You tell the camera something
about the color temperature of the light using the camera's "white balance"
function.
Regards, Lubos
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17) From: Ed Needham
And some even use both....
Ed Needham
ed
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18) From: Ed Needham
With that much text, I thought for sure I'd find something I disagreed with,
but I didn't.
About the only thing I thought about adding concerned the polarizing filter.
It can reduce glare, but a 'sky' filter (pinkish/yellow tint) maybe in
addition to the polarizing filter, will filter out the blue light from the
sky.
I am a strong proponent of the 'Zone System' used by Ansel Adams, but
expanded upon by Minor White, Richard Zakia and Peter Lorenz in "The New Zone
System Manual", Morgan and Morgan, Inc. (1975).  Basically, it says to meter
the darkest part of a scene and the lightest part of the scene and set the
exposure accordingly, based on the tonal latitude of the film, and the
intended developing and printing process, and most importantly, the desired
outcome.  It approaches photography from sensitometry, calibration and
previsualization perspective and can get very technical.  Of course, that's
probably not applicable to the type of photography we really need to use for
shooting beans, but it's a pretty cool, and accurate system nonetheless when
a specific desired outcome is really important.  Don't expect to buy the book
and go out shooting.  It's more like learning the bible.
Digital photography has come a 'long' way, and has, in my opinion given me
more freedom to be creative.  I can shoot 305 shots on a 64mb Smartmedia
memory card at 1024x768 resolution, and I can shoot until my heart's content,
not worrying about how much it's going to cost to develop 36 pictures of a
pile of beans.  I can also load those puppies into my computer and with Corel
Photo Paint, doodle and play with them to work digital darkroom miracles.
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This is really the meat of the post
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Of practicality to shooting beans (with digital) is three things: 1) using a
white, balanced light like a flash/strobe, 2) detached from the camera (if
possible) for the best modeling of the contour and texture of the beans, and
3) bracketing exposures.   For the light, use flash/strobe, full, clear
sunlight or color balanced light bulbs in a regular lamp socket.  Do NOT use
fluorescent, incandescent or morning/evening sunlight.  For modeling, having
the light hit the beans from about a 45 degree angle over and up from the
camera will give a  textured appearance rather than a flat look (so that's
why those guys hold their strobe up at arms length...hmmm).  Bracketing just
means to take a series of shots at different settings.  In other words, take
about six shots (three higher, three lower), changing the exposure a half
step each time.  Choose the shot that displays the beans most accurately.
Taa daa!  Great beans.
I think we've gone too far with this thread, but I like photography almost as
much as I like coffee.  My last post on the topic.
Ed Needhamhttp://www.homeroaster.comed
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