HTFC Forums

H.T.F.C.

How To Fix Computers





Go Back   HTFC Forums > Hardware Newsgroups > Digital Photo

Register FAQ Members List Calendar Search Today's Posts Mark Forums Read
  #11  
Old 11-05-2009, 01:51 PM
Bob Larter
Guest
 
Posts: n/a
Default Re: Moire in Canon A590

Alfred Molon wrote:
> In article <wBpIm.349$Wf2.15@newsfe23.iad>, Peabody says...
>> Today I tried to take a picture of the strings of a grand piano,
>> from the back end, and got a significant moire pattern in the area
>> where the bass strings lie above the treble strings, but are strung
>> in different directions. This criss-cross area looked pretty bad.
>>
>> Is there anything I can do to reduce or eliminate this effect? Any
>> camera setting that I could select?
>>
>> Would a better camera do better in this situation, or is it just
>> physics? Does the A590 not have any low-pass filter to reduce this
>> aliasing problem?

>
> Canon uses too weak antialiasing filters in their cameras, to maximise
> the perceived resolution in the images. Other manufacturers use stronger
> AA filters to avoid this problem.


You have that backwards. Canons have *strong* antialiasing filters, &
tend to benefit from a bit of sharpening when processing from RAW.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
Reply With Quote
Sponsored Links
  #12  
Old 11-05-2009, 03:42 PM
David J Taylor
Guest
 
Posts: n/a
Default Re: Moire in Canon A590

"bugbear" <bugbear@trim_papermule.co.uk_trim> wrote in message
news:vNWdnSfLzeu1Pm_XnZ2dnUVZ8tVi4p2d@brightview.c o.uk...
[]
> The A590 does indeed have those, but I've never used them.
>
> I assumed (wrongly) you meant something more
> like auto-adjust levels, or contrast-stretch
> as found in DeskTop packages.
>
>
> BugBear


I didn't "mean" anything, BugBear, I was just answering your question
about cameras with a contrast adjust facility. Some of the Nikon range do
have the ability for in-camera post-processing as well, but I've never
used it, so I'm unfamiliar with that's on offer. See:

http://www.kenrockwell.com/nikon/d50...us-retouch.htm

If that's correct, it doesn't include level adjustment.

Cheers,
David

Reply With Quote
  #13  
Old 11-05-2009, 06:21 PM
John Navas
Guest
 
Posts: n/a
Default Re: Moire in Canon A590

On Thu, 05 Nov 2009 10:04:23 +0000, bugbear
<bugbear@trim_papermule.co.uk_trim> wrote in
<vNWdnSfLzeu1Pm_XnZ2dnUVZ8tVi4p2d@brightview.co.uk >:

>David J Taylor wrote:
>>
>> "bugbear" <bugbear@trim_papermule.co.uk_trim> wrote in message
>> news:n7qdnQNnjerZBW_XnZ2dnUVZ7o5i4p2d@brightview.c o.uk...
>> []
>>> The A590 doesn't have a contrast adjust. Indeed, I'm not aware of a
>>> camera that does, or what it would (usefully) do.
>>>
>>> Could you help out?


>> Just two examples:
>>
>> Nikon D5000 - compare Vivid with Natural:
>> http://www.dpreview.com/reviews/nikond5000/page18.asp
>>
>> Nikon D700 compare Vivid with Neutral:
>> http://www.dpreview.com/reviews/NikonD700/page20.asp
>>
>> I think that other non-DSLR cameras I've had provide similar options
>> under a variety of names.

>
>Ah - "those" - thank you.
>
>The A590 does indeed have those, but I've never used them.
>
>I assumed (wrongly) you meant something more
>like auto-adjust levels, or contrast-stretch
>as found in DeskTop packages.


The better new compact digital cameras do have such functions.

--
Best regards,
John

Buying a dSLR doesn't make you a photographer,
it makes you a dSLR owner.
"The single most important component of a camera
is the twelve inches behind it." -Ansel Adams
Reply With Quote
  #14  
Old 11-05-2009, 06:33 PM
Alfred Molon
Guest
 
Posts: n/a
Default Re: Moire in Canon A590

In article <4af2ca62$1@dnews.tpgi.com.au>, Bob Larter says...

> You have that backwards. Canons have *strong* antialiasing filters, &
> tend to benefit from a bit of sharpening when processing from RAW.


Have a look at these test images shot with the Siemens star:
http://www.digitalkamera.de/Meldung/...t_sind_4_und_5
_Megapixel_Digitalkameras_wirklich_/1232.aspx

You'll notice that the Canon cameras extend the lines of the Siemens
star in the wrong way, producing artifacts. Other cameras do not suffer
from this problem.
--

Alfred Molon
------------------------------
Olympus 4040-8080, E-series DRLRs forum at
http://tech.groups.yahoo.com/group/MyOlympus/
http://myolympus.org/ photo sharing site
Reply With Quote
  #15  
Old 11-05-2009, 10:26 PM
Peabody
Guest
 
Posts: n/a
Default Re: Moire in Canon A590

bugbear says...

>> Turn down the in-camera sharpening to the lowest level.
>> Might help to turn down contrast to lowest level too.


> The A590 doesn't have a contrast adjust. Indeed, I'm not
> aware of a camera that does, or what it would (usefully)
> do.


Well, it has a contrast setting for taking the picture, but
not one for adjusting contrast after the fact.

So it lets you adjust contrast, sharpness and saturation. I
assume these are just settings for jpeg conversion, and
don't affect how the exposure itself is actually made.


Reply With Quote
  #16  
Old 11-05-2009, 11:33 PM
Info Man
Guest
 
Posts: n/a
Default Re: Moire in Canon A590

On Thu, 05 Nov 2009 09:17:56 +0000, bugbear
<bugbear@trim_papermule.co.uk_trim> wrote:

>Info Man wrote:
>> On Wed, 04 Nov 2009 19:09:52 -0600, Peabody <waybackNO784SPAM44@yahoo.com>
>> wrote:
>>
>>> Today I tried to take a picture of the strings of a grand piano,
>>>from the back end, and got a significant moire pattern in the area
>>> where the bass strings lie above the treble strings, but are strung
>>> in different directions. This criss-cross area looked pretty bad.
>>>
>>> Is there anything I can do to reduce or eliminate this effect? Any
>>> camera setting that I could select?
>>>
>>> Would a better camera do better in this situation, or is it just
>>> physics? Does the A590 not have any low-pass filter to reduce this
>>> aliasing problem?

>>
>> Turn down the in-camera sharpening to the lowest level. Might help to turn
>> down contrast to lowest level too.

>
>The A590 doesn't have a contrast adjust. Indeed, I'm not aware of a camera
>that does, or what it would (usefully) do.
>
>Could you help out?
>
> BugBear


I'm not personally familiar with the A590, but if it has the typical
Powershot "Custom Colors" setting, you can find it there. Turn down
sharpening, contrast, and the red channel to -2. That is the most accurate
sensor to JPG rendition I have found in the Powershot series, that which
matches the RAW data from that line of cameras. I use a different model of
Powershot with this "custom colors" feature and never take it off of those
aforementioned settings.

If your Powershot does not have that "custom colors" adjustment feature, I
guess it amounts to buying savvy. All the P&S cameras that I buy have both,
sharpening and contrast adjustment.

High contrast on the resulting JPG files in many consumer level cameras is
set inordinately high. The Nikon cameras being the absolute worst in this
regard. This is due to marketing where people expect an eye-popping image
right from the camera no matter the lighting conditions. I don't buy a P&S
camera unless it is renowned for its low contrast or has an option to turn
it as low as possible. The low-contrast cameras take full advantage of the
sensor's dynamic range to where there is rarely any need to obtain any RAW
data from the sensor. Sony cameras in the past used to be well known for
this lower contrast output (which I admired for their decision from a pure
photographer's standpoint), which sadly sharply cut into their sales due to
the vast inexperience of the snapshooting masses. The full dynamic range of
the sensor is reflected in those cameras' JPG output which innately have
low-contrast JPG output, or where it can be turned down.

Reply With Quote
  #17  
Old 11-05-2009, 11:35 PM
Bob Larter is Lionel Lauer - Look it up.
Guest
 
Posts: n/a
Default Re: Moire in Canon A590

On Thu, 05 Nov 2009 23:51:45 +1000, Bob Larter <bobbylarter@gmail.com>
wrote:

>Alfred Molon wrote:
>> In article <wBpIm.349$Wf2.15@newsfe23.iad>, Peabody says...
>>> Today I tried to take a picture of the strings of a grand piano,
>>> from the back end, and got a significant moire pattern in the area
>>> where the bass strings lie above the treble strings, but are strung
>>> in different directions. This criss-cross area looked pretty bad.
>>>
>>> Is there anything I can do to reduce or eliminate this effect? Any
>>> camera setting that I could select?
>>>
>>> Would a better camera do better in this situation, or is it just
>>> physics? Does the A590 not have any low-pass filter to reduce this
>>> aliasing problem?

>>
>> Canon uses too weak antialiasing filters in their cameras, to maximise
>> the perceived resolution in the images. Other manufacturers use stronger
>> AA filters to avoid this problem.

>
>You have that backwards. Canons have *strong* antialiasing filters, &
>tend to benefit from a bit of sharpening when processing from RAW.



Bob Larter's legal name: Lionel Lauer
Home news-group, an actual group in the "troll-tracker" hierarchy:
alt.kook.lionel-lauer (established on, or before, 2004)
Registered Description: "the 'owner of several troll domains' needs a group where he'll stay on topic."

<http://groups.google.com/groups/search?hl=en&num=10&as_ugroup=alt.kook.lionel-lauer>

"Results 1 - 10 of about 2,170 for group:alt.kook.lionel-lauer."
Reply With Quote
Sponsored Links
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Canon A590 - quality a disappointment - lemon, or typical? bugbear Digital Photo 11 05-20-2009 09:13 AM
Canon A590 IS - any owners can answer usage questions ? Ian Woodrow Digital Photo 4 06-05-2008 02:13 PM
moire on monitor - why? Mike S. Video 2 10-25-2007 10:26 AM
Time to dump moire filters? Rich Digital Photo 1 08-02-2007 05:02 AM
Why not do moire filtration in post-process? Rich Digital Photo 33 06-16-2007 06:16 PM


All times are GMT. The time now is 07:01 AM.


Powered by vBulletin® Copyright ©2000 - 2009, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.2.0
© 2004 - 2007 Web-S-Sense Pty. Ltd. Usenet and forums posts © their respective authors.
Ad Management by RedTyger