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Function of the FOVEON-microlenses

LUIS A GUEVARA

Well-Known Member
EDIT: These posts are copied from another thread, which ran a bit out of topic. :) Done, because this topic is worth to be discussed separately!

Klaus



Hi Luis,

I can absolutely underline all of your above findings.
I would never sell my good old SD9 for its high class pixel-sharpness which really might be due to its Foveon TypI-Sensor and its lack of microlenses.
...........

Klaus

Very nice images Klaus . Can you imagine what your dedication could do with a Leica lens in your SD9?

I have never offered a mount replacement kit for the SD9 , (The one for the SD14 will not fit the SD9 ) but I am considering making a few ones to explore the interest of the numerous SD9 owners that feel like you and me , that there was a loss of Image Quality with the introduction of microlenses.

What do you think ? What does everybody think about this . ?

Also , when the SD14 really go down in price I will attempt to remove the Microlenses and install the infrared filter right at the sensor , like the SD9 does.

I would like everybody that has an interest in these ideas to either post here or send me an email

Thanks .Luis
 

Guest .

Banned
Very nice images Klaus . Can you imagine what your dedication could do with a Leica lens in your SD9?

I have never offered a mount replacement kit for the SD9 , (The one for the SD14 will not fit the SD9 ) but I am considering making a few ones to explore the interest of the numerous SD9 owners that feel like you and me , that there was a loss of Image Quality with the introduction of microlenses.

What do you think ? What does everybody think about this . ?

Also , when the SD14 really go down in price I will attempt to remove the Microlenses and install the infrared filter right at the sensor , like the SD9 does.

I would like everybody that has an interest in these ideas to either post here or send me an email

Thanks .Luis

Hi Luis,

our posts overlapped ... :)

Well ... I use an awful lot of old manual lenses that either fit the old M42-screw-mount or the T-mount.

The unquestionable advantage of this procedure is, that fitting these lesnses is a non-destructive business.

The other point is, that I do not own NIKKOR or other highclass bajonett-mount lenses which I could use with a permanently converted SD9/10/14.

Due to "former :D " poverty I used to use cheap but well chosen and really good M42-stuff in the old days ... :D

But this could appear very different to those, who have their lenses in their shelves ... :)

Well ... to remove the SD14s microlenses .... sounds like an adventure to me!! Is that really possible?! You must be a magician!! :z02_respekt:

Doing without the microlenses would mean to increase the sensor's demand of light to an estimated 60%. You would have to recalibrate the camera's complete light-metering?!

Sounds fascinating!

See you with nice pictures

Klaus
 

LUIS A GUEVARA

Well-Known Member
... it's me again .... :)

Finally, even the frequently badmouthed POLAROID X530 can produce the SIGMA-effect employing a FOVEON-image sensor.

Be it, that A SIGMA is less modern, slower and much more difficult to handle ... it definately can do brilliant pictures with the most vivid colours I can imagine.



Klaus

You really have nice images ,Klaus . You seem ,like me, to like frontal or side lighting which tend to produce abundance of medium and high tones . Normal RAW processing compresses the upper tones , reducing detail and tone delicacy . Have you considered doing a LINEAR processing of those images that could benefit from expanded tonal pallette in the highlights , like this one ?:

-Seerosenteich3-.JPG

I am re posting an image that I posted in another thread (
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was processed Linearly:

8140473-md.jpg

Luis
 

LUIS A GUEVARA

Well-Known Member
Hi Luis,

our posts overlapped ... :) ................Doing without the microlenses would mean to increase the sensor's demand of light to an estimated 60%. You would have to recalibrate the camera's complete light-metering?!

Sounds fascinating!

See you with nice pictures

Klaus

The Microlenses are like Funnels sitting on top of each Photosite , what they do is to capture the light Photons that would , otherwise, fall between the Photosites . That certainly captures more Energy to excite the 3 Layers of each energy hungry photosite.



The problem is that is using photons that contain different information and mingling them together , degrading the purity of the capture . In essence the Microlenses increase the apparent size of the Photosite . That obviously reduces Resolving Power at the Pixel level, acting like a Softener filter .

Removing the Microlenses in some sensors is trivial since they are mechanically attached to the sensor ,and in others is not since they are epoxied to it. We will have to wait and see.
 

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Guest .

Banned
Hi Luis,

thanks for this information! ;)

The only problem, I now have is that this info does not really fit here ... I will sort it later and open a new thread to "store" it.

EDIT: Posting originally from another thread, where it went OT! Here it belongs!

Klaus


Well, doing without these micro lenses would mean a worse signal to noise ratio on the other hand.

Sigma themselves cannot afford to worsen picture noise with their cams. This is the obvious worst point with the Foveon technology.
Silly enough, Resolution ( ... they always confuse it with pixel counts!!!...) and noise performance seems to be everything that counts to the folks!:(


See you with nice pictures:z04_5769:

Klaus
 

LUIS A GUEVARA

Well-Known Member
Hi Luis,

although I am very much in X3F-raw-processing (extremely important to achieve considerable image quality) I have to admit, that I have no idea of NORMAL vs. LINEAR RAW-processing?! :)
Thus, although I launched a number of "image software threads" here and in our German-forum, I would not consider myself to be an expert in the issue!

Sorry ... could you explain that in more details?! I suspect, I should not be the only one here, who would like to be taught ....

Thanks a lot Luis!! :)

See you with nice pictures

Klaus

Sure Klaus. I had written a small tutorial in my website that you and others
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I had also created a Thread at photo.net called: Linear Processing of RAW Image Files .

And a video
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It will probably be best to see them in the order shown. I hope the links work.

If there is sufficient interest maybe we could start a dedicated Thread. Luis
 

LUIS A GUEVARA

Well-Known Member
Hi Luis,

Well, doing without these micro lenses would mean a worse signal to noise ratio on the other hand.

Klaus

Noise in digitall images exists at the lowest end of the sensors sensitivity range . Instead of using Microlenses ( Something that I believe none of the digital Leicas use ) manufacturers should concentrate on creating more efficient lenses that TRANSMIT MORE LIGHT.

Leica is the only designer that treats light as a FLOW OF ENERGY through the lens optical path and therefore tries to minimize changes of direction that create internal losses ,as well as minimizing the number of glass elements for the same reason.

The first thing that you will notice ,if you convert your camera to Leica , is the increase in luminosity in the Viewfinder and the rejection of Noise in your images that result from exciting the photoreceptors adequately.

Of course the photographer should do whatever he or she can, to keep those photoreceptors as close to saturation as possible , as up to 2 stops of overexposure can be easily handled by LINEAR processing of the RAW files.

My recomended setting for Contrasty Front or Side lighting is about 3/4 of a stop of overexposure . That could be easily compensated in Lightroom or Camera Raw without having to do a linear conversion.

Luis
 

foveonfan

Well-Known Member
Noise in digitall images exists at the lowest end of the sensors sensitivity range . Instead of using Microlenses ( Something that I believe none of the digital Leicas use ) manufacturers should concentrate on creating more efficient lenses that TRANSMIT MORE LIGHT.

Leica is the only designer that treats light as a FLOW OF ENERGY through the lens optical path and therefore tries to minimize changes of direction that create internal losses ,as well as minimizing the number of glass elements for the same reason.

The first thing that you will notice ,if you convert your camera to Leica , is the increase in luminosity in the Viewfinder and the rejection of Noise in your images that result from exciting the photoreceptors adequately.

Of course the photographer should do whatever he or she can, to keep those photoreceptors as close to saturation as possible , as up to 2 stops of overexposure can be easily handled by LINEAR processing of the RAW files.

My recomended setting for Contrasty Front or Side lighting is about 3/4 of a stop of overexposure . That could be easily compensated in Lightroom or Camera Raw without having to do a linear conversion.

Luis

Thanks for teaching me to see the light, Luis. ;)

Sincere regards, Jim R.
 

Guest .

Banned
Hi Luis,

I am trying to watch your VIDEO-link above .... unfortunately, it does not work?! The link runs dead?!

I tried Firefox and the IE ... same failure?!

Are the others more successful?

sample 6.JPG

Is there anything, I am getting wrong?! Qicktime streams are no problem normally.

See you with nice pictures

Klaus
 

foveonfan

Well-Known Member
Luis, sorry to puzzle you. Your simplified explanations regarding the characteristics of the Foveon sensor, it's optical filter etc. are what I was thanking you for.

I guess I am not knowledgeable in some of the areas that you are. :) Let me just say that I am extremely happy to have you here as a contributor to my knowledge.

Sincere regards, Jim R.
 

LUIS A GUEVARA

Well-Known Member
Luis, sorry to puzzle you. Your simplified explanations regarding the characteristics of the Foveon sensor, it's optical filter etc. are what I was thanking you for.

I guess I am not knowledgeable in some of the areas that you are. :) Let me just say that I am extremely happy to have you here as a contributor to my knowledge.

Sincere regards, Jim R.

Thanks Jim . I see . I just wanted to know which of my numerous postings you where referring to , "Seeing the Light" happens to be the underlying subject of Linear processing.

I intend to be a regular contributor to this forum but since I believe that this camera is the best Tool available for the Visual Artist and completely unsuited for the professional , my entries will always have an artistic slant.

Art is said to require Vision , Craft and Content , therefore I intend to contribute in all those areas and more. Luis

PLEASE CLICK ON IT TO SEE IT LARGER

IMG18235cropped1200.jpg
 

foveonfan

Well-Known Member
I'm looking forward to your continued contributions , Luis! I agree wholeheartedly with your descriptive "visual art tool" comment.

Sincere regards, Jim R.
 

Guest .

Banned
Hey Luis,

that is a picture after my fancy!! Very nicely done! :z02_respekt::z02_respekt::z02_respekt:

Luis, there is a thing I would like to ask you ....

Have you ever tried another DSLR brand to compare it with your SIGMA-findings?!
You find both chaps ... those who came from other brands, experience a SIGMA and stay ... and others who test the SD and go for a CANON.

To be honest ... I came to SIGMA when the SD10 was sold out for very little money. My first picture results were that disappointing that I first wanted to return it.
As soon as I then learned that my poor image results went on my own incompetence to cope with that difficult cam, I became more ambitious.
Now I would not consider a changeover at all.


See you with nice pictures

Klaus
 

LUIS A GUEVARA

Well-Known Member
Luis,

that is a picture after my fancy!! Very nicely done! :z02_respekt::z02_respekt::z02_respekt:

Luis, there is a thing I would like to ask you ....

Have you ever tried another DSLR brand to compare it with your SIGMA-findings?!
You find both chaps ... those who came from other brands, experience a SIGMA and stay ... and others who test the SD and go for a CANON.

To be honest ... I came to SIGMA when the SD10 was sold out for very little money. My first picture results were that disappointing that I first wanted to return it.
As soon as I then learned that my poor image results went on my own incompetence to cope with that difficult cam, I became more ambitious.
Now I would not consider a changeover at all.


See you with nice pictures

Klaus

There are several issues at play here:
  • The early Sigma dependance on user RAW processing clashed with the low imaging literacy of the early adopters , with bad results. Lots of people moved to other brands that offered in camera JPG with no user participation required.
  • Poor Quality control during manufacturing of early cameras. This factor has improved , but it has not gone away.
  • Lack of good lenses .This also has improved tremendously lately , but still cannot compare with the major players. Sigma is at best a follower and not a leader in lens design and manufacturing.
  • The slow evolution of the Foveon sensor and its difficult Scalability couldnt catch up with the lure of higher Pixel Count and Full Frame appeal of Canon and Nikon.Now whith the acquisition of Foveon things might change in unsuspected ways.
  • Sigma cameras are better suited to artistic sensibilities , which are a Minority, while the rest of the users are interested on making money with the camera. Let them go away . Artists do not know what money is.

My first Single Reflex camera , during the film era , was not one , was two, a Canon and a Nikon F2 . The Canon had better IQ than the Nikon that couldnt focus properly, but non of them could compare with the Leica M3 , so I swaped them for a used M3 , that went to Europe with me and even photographed Wetzlar , where she was born. When I came to the US from France , I moved up to View cameras and never considered a digital camera until the first Sigma SD9 , which I bought and is the one that takes all those images that you like. Now I have two of them.

Just like View cameras , Sigma cameras are not for every body, except for the most demanding people able to put up with its bad sides , in order to get the image quality they sought. Sigma cameras are clumsy and slow , just like View cameras , but just like View Cameras they are really at home in the Great Landscape , where their image quality is the only one that can make justice to Nature.

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Luisportrait.jpg
 

foveonfan

Well-Known Member
Another well thought out post, Luis. I'm in total aggreeance with your analysis. It is a fact that the vast majority of DSLR users have no ambition to activate their grey matter in order to take a picture by personally controlling the camera. ;)

Sincere regards, Jim R.
 
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