chromatic aberration and moirè

[l.ceva]

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Dear all,

 

this is my first message.

 

I am an italian photographer an I have been using an M6 for years until 1999 date in wich I passed to digital.

A few days a go I got ma new M8 and a new 24mm elmarit M ASPH.

 

In theese days I took a lot of picture in DNG and processed them in C1 everything is fine expet for moirè and aberration in a few pictures.

 

For the moirè effect I read that the internal software of the camera shuld elliminate it automaticly but in some picture the effect is still present, is there something wrong in what I am doing in C1 or is this normal?

 

And about chromatic aberration what can You tell me?

 

all the pictures were taken with the new lens 6 bit coded and not with my ol lenses and the lens detection was activeted.

 

Thankyou in advance to every one and forgive me for my terrible English.

 

Lorenzo

[chrism]

Hi Lorenzo, moiré is a problem as there is no anti-alias filter on the sensor of the M8. On the hand, though, this does allow very high resolution images. I don't believe there is any in-camera processing to reduce moiré, but it can be reduced in post-processing. Phase One make a DeMoirise plug-in, that I use on the Mac.

Your English is far better than my Italian, which I have picked up over the years from a severe opera addiction (so I'm good at hearts, eyes, tears, love and death, but useless at all else!)

 

Chris

[Riley]

yes its the lack of AA, or low bypass filter

thats responsible for those colours in the first frame too

 

given the frequency of it, I would sooner have a fixable moire issue than less sharpness

[l.ceva]

Thankyou for your quik answer!!

 

I use several methods to elliminate moirè in PS !

 

The problem is that as I read on a lot of pubblication that the M8 don't use any antialis filter but the internal software should elliminate it in advance, This is what is written but not wat I experimented.

 

And can You tell me something about chromatic aberration? I am a also a Nikon user (d2X) and I shoot only in RAW format wich i convert in NIKON CAPTURE, in that software there is a function to elliminate aberration that works perfectly, I looked in C1 but I did not find something similar.

This function in NIKON CAPTURE is specific for camera/lens combination and works much better then any other method I experimented that's why I am asking if there is a simila function on C1.

 

best regards

 

Lorenzo

 

LORENZO CEVA VALLA - fotografia digitale

[AlanG]

there is a function to elliminate aberration that works perfectly, I looked in C1 but I did not find something similar.

 

Your English is excellent. I've been trying to learn to communicate a little in Italian because I'm heading off on a ski trip to Cortina next week. But don't test me. Do you know if there is any snow there yet?

 

There is talk that the next version of C1 (version 4) will have correction for chromatic aberation (CA) along with other new features. I think version 4 is scheduled to be releases within the next few months. Other raw software has CA correction. DxO software does not support the M8 at this time, but it uses the camera's EXIF information to look up each lens and camera from pre tested modules to automatically correct for C/A, vignetting, distortion, variation in lens sharpness and more. So these tools are becoming more common and will ultimately give us the equivalent of havaing nearly perfectly corrected lenses.

[ho_co]

Welcome to the forum, Lorenzo!

 

First, the other posters are correct: The M8 has no anti-aliasing capability. (Its sister the Digital-Modul-R does use firmware anti-aliasing which can be turned on or off, but apparently very few DMR users ever turn the feature on.)

 

Second: I don't think the second image you posted shows chromatic aberration. CA normally shows one color on one side of an object and a different color on the opposite side. There's a name for the effect demonstrated in your picture, but I don't remember what it is. The image here has to do rather with the way a lens sees a darker element (like tree limbs) against a brighter background. CA filters will not help that kind of color error, and if I'm not mistaken, no other simple solution will either.

 

Perhaps someone with a better memory for this kind of defect could say more about it.

 

--HC

[mike prevette]

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Lorenzo,

 

Your second image is not Chromatic aberration, as Howard has pointed out. It's an effect that plagues sensors, called electron spill. The extreme contrast of the edge causes the high voltage (bright side) of one pixel to effect the low voltage of the other pixels (darker).

 

_mike

[l.ceva]

ThankYou!

 

OK You are wright it is not Chromatic aberration but I still would like to find a solution with out considering to do so in PS, but anyway this is not a grat problem as it happens on a very few immages.

 

About the moirè effect I don't know if I am particularly unluky but taking pictures around my city I find it in a big number of images, Ok I can remove it in PS but is a borring opertion as it can't be done on the entire picture but only working in every specific zone of the picture.

 

Obviously the pictures I sent was made just to see how the camera manages moirè but in other pictures (normal) the effect is visibile too!

 

I repaet I know perfectly that M8 dont'use any antialsianig filter but as I said already on the leica site is written that this effect is corrected by the internal software and that is the reason of my question.

 

For Alan,

 

In Cortina up to now there is not a lot of snow, only artificial and I have been told that You can only ski in the mornig... but You might have luck as the forecast says the winter should came this week!

 

best regards

 

Lorenzo

 

http://www.lorenzocevavalla.it