Velocity Reviews - Computer Hardware Reviews

Velocity Reviews > Newsgroups > Computing > Digital Photography > Re: How to photograph an oil painting

Reply
Thread Tools

Re: How to photograph an oil painting

 
 
PeterN
Guest
Posts: n/a
 
      05-17-2013
On 5/17/2013 12:10 AM, Eric Stevens wrote:
> On Wed, 15 May 2013 20:07:58 +0200, Wolfgang Weisselberg
> <(E-Mail Removed)> wrote:
>
>> Eric Stevens <(E-Mail Removed)> wrote:
>>> On Tue, 7 May 2013 22:59:03 +0200, Wolfgang Weisselberg
>>>> Eric Stevens <(E-Mail Removed)> wrote:
>>>>> On Thu, 2 May 2013 23:21:45 +0200, Wolfgang Weisselberg
>>>>>> Eric Stevens <(E-Mail Removed)> wrote:
>>>>>>> On Mon, 15 Apr 2013 18:52:23 +0200, Wolfgang Weisselberg
>>>>>>>> Eric Stevens <(E-Mail Removed)> wrote:
>>>>>>>>> On Sat, 13 Apr 2013 00:41:28 +0200, Wolfgang Weisselberg

>>
>>>>>> You DO know even you can photograph a number of well defined
>>>>>> patches under well defined light conditions and evaluate the
>>>>>> results? You don't even need a light source tuned/filtered
>>>>>> to specific narrow banded frequencies, e.g. with a grating or
>>>>>> a prism?

>>
>>>>> You are rambling and I am sure you know that.

>>
>>>> Then you would accept a short "You don't have a clue.
>>>> They don't do anything special except for marketing for which
>>>> you fell."?

>>
>>> No, I wouldn't accept that. I would accept that you are trying to be
>>> difficult in defence of an indefensible position.

>>
>> I would accept that you are misled by (arguably clever)
>> marketing from DxO, or paid by DxO.
>>
>>
>>>>> If you know of any other
>>>>> software which specifically tests for colour sensitivity under a range
>>>>> of different circumstances and then applies it to image correction, I
>>>>> am sure you would have told us.

>>
>>>> Let's see: DPP. AfterShot Pro. Lightroom. ...
>>>> In fact any software that offers WB presets (different
>>>> circumstances) and manages to produce OK colours.

>>
>>> Please tell us how and where these various products go about testing
>>> the colour sensitivities of various cameras and how the results are
>>> embedded in their software.

>>
>> Please tell us *how* and *where* DxO goes about to testing the
>> colour sensitivities of various cameras and how the results
>> are embedded in their software.
>>
>> As to the others: They make test shots and embed the results
>> of the results of them in the conversion from RAW file data to
>> a proper TIFF or JPEG or similar with the correct colour space.

>
> So they make test shots. With how cameras and of what type?
>
> Assuming that is what they do, how does the software know which camera
> it is supposed to be emulating?
>>
>>
>>> It will not be sufficient for you to explain how these products
>>> provide knobs which the operator can twiddle until they obtain a
>>> result with which they are subjectively satisfied.

>>
>> It will not be sufficient for you to recite advertizing
>> claims, I want details from you.

>
> I'm not sure that you will read them. I don't think you have read
> those I have given you already. However, try these:
>
> Go to http://dxo.com/intl/photo/dxo_optics_pro/features and scroll
> down to:
>
> "Visit our lab
>
> Come take an exclusive tour and check out the different calibration
> process steps for cameras and lenses in our laboratory."
>
> Click on the adjacent video and watch:
>
> That DxO really does seem to believe they have the ability to adjust
> colour renditions to match different cameras is made clear in:
>
> http://www.dxo.com/en/photo/dxo_opti...raw_conversion
> "Each manufacturer, and often each camera model, is characterized by
> how it renders color. But what color range do you want for your
> images? DxO Labs has tested a wide range of digital cameras, giving
> you the choice of applying their different color renderings to your
> photos, regardless of the camera that you actually use."
>


Saw a live demo last night of the full DXO line. We put the presenter to
the proof, and he came through with flying colors. It was a two hour
demonstration, of which almost one hour was reserved for our skeptical
questioning.
DXO Viewpoint did perspective control with greater ease, and in less
time than the demo of that feature in Creative Cloud.

--
PeterN
 
Reply With Quote
 
 
 
 
PeterN
Guest
Posts: n/a
 
      05-18-2013
On 5/17/2013 6:01 PM, Eric Stevens wrote:
> On Fri, 17 May 2013 11:34:28 -0400, PeterN
> <(E-Mail Removed)> wrote:


<snip>

>> Saw a live demo last night of the full DXO line. We put the presenter to
>> the proof, and he came through with flying colors. It was a two hour
>> demonstration, of which almost one hour was reserved for our skeptical
>> questioning.
>> DXO Viewpoint did perspective control with greater ease, and in less
>> time than the demo of that feature in Creative Cloud.

>
> It's not perfect but it seems to do things that no other application
> that I know of does.
>
> I was particularly impressed with what even the old software can do
> with a fisheye lens.
> http://www.kenrockwell.com/tech/dxo/optics-pro.htm
> Not that I have got a fisheye lens.
>


No it's not. I was particularly impressed with it's noise reduction and
highlight recovery capabilities. Some stores here have a special
involving a significant price reduction. The elite verson is $200 in
stead of $300, with a more significant reduction in Viewpoint, and
filmpack. I see little use for
filmpack, but will be ordering Viewpoint.

--
PeterN
 
Reply With Quote
 
 
 
 
Wolfgang Weisselberg
Guest
Posts: n/a
 
      05-18-2013
Eric Stevens <(E-Mail Removed)> wrote:
> On Wed, 15 May 2013 20:07:58 +0200, Wolfgang Weisselberg
>>Eric Stevens <(E-Mail Removed)> wrote:
>>> On Tue, 7 May 2013 22:59:03 +0200, Wolfgang Weisselberg
>>>>Eric Stevens <(E-Mail Removed)> wrote:
>>>>> On Thu, 2 May 2013 23:21:45 +0200, Wolfgang Weisselberg
>>>>>>Eric Stevens <(E-Mail Removed)> wrote:
>>>>>>> On Mon, 15 Apr 2013 18:52:23 +0200, Wolfgang Weisselberg
>>>>>>>>Eric Stevens <(E-Mail Removed)> wrote:
>>>>>>>>> On Sat, 13 Apr 2013 00:41:28 +0200, Wolfgang Weisselberg


>>>>>>You DO know even you can photograph a number of well defined
>>>>>>patches under well defined light conditions and evaluate the
>>>>>>results? You don't even need a light source tuned/filtered
>>>>>>to specific narrow banded frequencies, e.g. with a grating or
>>>>>>a prism?


>>>>> You are rambling and I am sure you know that.


>>>>Then you would accept a short "You don't have a clue.
>>>>They don't do anything special except for marketing for which
>>>>you fell."?


>>> No, I wouldn't accept that. I would accept that you are trying to be
>>> difficult in defence of an indefensible position.


>>I would accept that you are misled by (arguably clever)
>>marketing from DxO, or paid by DxO.


>>>>> If you know of any other
>>>>> software which specifically tests for colour sensitivity under a range
>>>>> of different circumstances and then applies it to image correction, I
>>>>> am sure you would have told us.


>>>>Let's see: DPP. AfterShot Pro. Lightroom. ...
>>>>In fact any software that offers WB presets (different
>>>>circumstances) and manages to produce OK colours.


>>> Please tell us how and where these various products go about testing
>>> the colour sensitivities of various cameras and how the results are
>>> embedded in their software.


>>Please tell us *how* and *where* DxO goes about to testing the
>>colour sensitivities of various cameras and how the results
>>are embedded in their software.


>>As to the others: They make test shots and embed the results
>>of the results of them in the conversion from RAW file data to
>>a proper TIFF or JPEG or similar with the correct colour space.


> So they make test shots. With how cameras and of what type?


well, since you're the one asking, they probably use a
point'n'shoot from 2004 and from a completely different
manufacturer to find out what colours give what response
in a 2012/2013 DSLR. For added fun, they roll dice as to
what lighting conditions should be used (and don't note that
choice down). Lastly, I guess they let an ape mix and apply the
paint from different paint suppliers (with different pigments
and dye types) each time.

Only DxO has understood that you probably need to shoot the
test scenarios with the camera you're going to measure the
colour response for and that it might be a good idea to have
a well known lighting situation: even and of known spectral
composition, and that you might as well go ahead and use
colour targets of which the exact colour response is well
known and measured.

Then, of course, only DxO has figured out what colour spectrum
will actually be reflected when one has a well defined,
well behaved target (no flourescent whiteners, for example)
and a well defined light shining onto it. They probably have
patents on adding the numbers involved, too, not that anyone
else could come up with it. Then DxO does something
completely revolutionary that noone else in the world does:
Use RAW! They actually use RAW to find out how strong the
response is to each of that patches, given that they know how
much light entered the camera and how the response varies
from patch to patch of the same exposure.

Then DxO uses their proprietary, secret, patented knowledge
to compute the transmission spectrum of each of the R, G, G,
and B filters (yep, 2 different G filters in some cameras)
and use *that* to calculate that if the light source is of
spectrum X then the colour Y will be recorded as a
(A,B,C,D)-RGGB-quadrupel.

Maybe they even check that by tuning their light source to a
given spectrum, run their math and check if the patches come
out as calculated.


> Assuming that is what they do, how does the software know which camera
> it is supposed to be emulating?


Well, of course they can't know, because only DxO has the secret
sauce necessary to read the metadata in the RAW. You know,
where such stuff as exposure time or focal length or aperture
is also noted down.


>>> It will not be sufficient for you to explain how these products
>>> provide knobs which the operator can twiddle until they obtain a
>>> result with which they are subjectively satisfied.


>>It will not be sufficient for you to recite advertizing
>>claims, I want details from you.


> I'm not sure that you will read them. I don't think you have read
> those I have given you already. However, try these:


> Go to http://dxo.com/intl/photo/dxo_optics_pro/features and scroll
> down to:


> "Visit our lab


> Come take an exclusive tour and check out the different calibration
> process steps for cameras and lenses in our laboratory."


> Click on the adjacent video and watch:


As to colour correction, all they say is that they shoot a
colour target (with only 24 patches!) under differently
filtered lights. This is neither complicated nor unique and
way less powerful than what I wrote above.


> That DxO really does seem to believe they have the ability to adjust
> colour renditions to match different cameras is made clear in:


> http://www.dxo.com/en/photo/dxo_opti...raw_conversion
> "Each manufacturer, and often each camera model, is characterized by
> how it renders color. But what color range do you want for your
> images? DxO Labs has tested a wide range of digital cameras, giving
> you the choice of applying their different color renderings to your
> photos, regardless of the camera that you actually use."


You mean same as I do when I shoot a colour target, e.g. a
QPcard 201 under a given light and use some software or plugin
to correct the differences from the *known* patches of the
card to the *measured* RGB response of the sensor?

Except they don't do it under the light I am using, but only
under some presets, like "sunny", "open shade", "tungsten"
and "flourescent"? Hello --- how do you think these presets
work anyhow? How do you think the RGB values, which are
different from each camera to each other camera --- because
the filters are changed --- can be converted to reasonable
colour images otherwise?


> http://1.static.img-dpreview.com/fil...off.png?v=2169
> Shows the screen module by means of which the user can select the
> camera whose response the user wishes to emulate.


So basically they allow 'cross processing' with a menu
selection.

Well, in AfterShot Pro I can feed it any random icc or icm as
the camera profile --- and yes, of course does the image
change visibily.

As they say:
| Input profiles
|
| Input profiles are used as the starting point for color
| management. Every image file in Corel AfterShot Pro has an
| input profile. For supported RAW files, Corel performs
| detailed color calibration and profiling techniques to
| produce unique Color Profiles for the various supported
| cameras. [...]
http://product.corel.com/help/AfterS...Doc/index.html

Well, it seems they do what DxO does regarding to colour, they
just don't produce the same amount of drama and self-adulation
about it.

See also here:
http://product.corel.com/help/AfterS...lor_tools.html
(scroll to bottom, "Color Management")

-Wolfgang
 
Reply With Quote
 
 
 
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Re: How to photograph an oil painting RichA Digital Photography 36 04-05-2013 02:39 PM
Re: How to photograph an oil painting nospam Digital Photography 6 04-02-2013 11:12 PM
Re: How to photograph an oil painting Peabody Digital Photography 2 04-01-2013 09:02 PM
Re: How to photograph an oil painting nospam Digital Photography 19 03-31-2013 11:21 PM
Re: How to photograph an oil painting nick c Digital Photography 0 03-30-2013 06:01 AM



Advertisments