No AA filter.

[Nikon 2]

Just found out the MD 262’s sensor doesn’t have an Anti-Aliasing filter.
What does that do to the final image…

 

[BrianShaw]

I'm not an expert in Leica or anti-aliasing filters by any stretch of the imagination, so do some homework to verify andything I write. From what little I understand: Aliasing is a very infrequent problem that can be resolved in post. I've read that Leica doesn't include anti-aliasing to improve the image quality in the 99% (or insert any big number you choose here) of the situations where aliasing isn't a problem. I recall that it has something to do with the newer sensors being better (more pixels per mm, perhaps) than the older sensors.

This might help you (or not):

What is an anti-aliasing filter? – Kolari Vision

An explanation of what the anti aliasing filter, or lowpass filter, does, and how removing the anti aliasing filter increases sharpness.

kolarivision.com

Anti-Aliasing Filter Primer | La Vida Leica!

When designing the digital M cameras, Leica made two very important decisions regarding the sensor in an effort to maximize the sharpness of the image. Borrowing a page from more pro-level, medium format digital backs and eliminating the anti-aliasing filter being one of them. This article looks...

lavidaleica.com

DO THE LEICA CMOS SENSORS HAVE ANY ADVANTAGES OVER THE COMPETITION?

gmpphoto.blogspot.com

 

[BrianShaw]

... but from the thread title as currently written, some might say that the camera will excel at zone system and pictures of landscapes. LOL

 

[Nikon 2]

I'm not an expert in Leica or anti-aliasing filters by any stretch of the imagination, so do some homework to verify andything I write. From what little I understand: Aliasing is a very infrequent problem that can be resolved in post. I've read that Leica doesn't include anti-aliasing to improve the image quality in the 99% (or insert any big number you choose here) of the situations where aliasing isn't a problem. I recall that it has something to do with the newer sensors being better (more pixels per mm, perhaps) than the older sensors.

This might help you (or not):

What is an anti-aliasing filter? – Kolari Vision

An explanation of what the anti aliasing filter, or lowpass filter, does, and how removing the anti aliasing filter increases sharpness.

kolarivision.com

Anti-Aliasing Filter Primer | La Vida Leica!

When designing the digital M cameras, Leica made two very important decisions regarding the sensor in an effort to maximize the sharpness of the image. Borrowing a page from more pro-level, medium format digital backs and eliminating the anti-aliasing filter being one of them. This article looks...

lavidaleica.com

DO THE LEICA CMOS SENSORS HAVE ANY ADVANTAGES OVER THE COMPETITION?

gmpphoto.blogspot.com

…

 

[Nikon 2]

... but from the thread title as currently written, some might say that the camera will excel at zone system and pictures of landscapes. LOL

Don’t get me started…

 

[sojournermike]

I'm not an expert in Leica or anti-aliasing filters by any stretch of the imagination, so do some homework to verify andything I write. From what little I understand: Aliasing is a very infrequent problem that can be resolved in post. I've read that Leica doesn't include anti-aliasing to improve the image quality in the 99% (or insert any big number you choose here) of the situations where aliasing isn't a problem. I recall that it has something to do with the newer sensors being better (more pixels per mm, perhaps) than the older sensors.

This might help you (or not):

What is an anti-aliasing filter? – Kolari Vision

An explanation of what the anti aliasing filter, or lowpass filter, does, and how removing the anti aliasing filter increases sharpness.

kolarivision.com

Anti-Aliasing Filter Primer | La Vida Leica!

When designing the digital M cameras, Leica made two very important decisions regarding the sensor in an effort to maximize the sharpness of the image. Borrowing a page from more pro-level, medium format digital backs and eliminating the anti-aliasing filter being one of them. This article looks...

lavidaleica.com

DO THE LEICA CMOS SENSORS HAVE ANY ADVANTAGES OVER THE COMPETITION?

gmpphoto.blogspot.com

Hopefully Brian won’t mind if I add a little bit of information to his response, and a small contradiction

Aliasing is a problem that occurs when using any form of (digital) sampling of an analogue signal. In photographic terms, the sensor samples the brightness of the image projected by the lens at each pixel location, plus there is a colour filter overlay in most cameras of course. If the image consists of large areas of smooth colour and gradients this is fine. However, the the detail gets fine, down towards the size of the pixel pitch, ‘funny’ things happen as the pixels can’t accurately sample/resolve the detail that’s there. Colour filters make this worse by reducing the effective pixel pitch and having different frequencies for green and red/blue channels. This is all well understood through sampling theory, which articulates that you need a sampling frequency of at least twice the detail frequency in order to resolve it.

There are two ways to deal with this:

- do nothing. The consequences of this are that if you have detail at or around the sampling frequency you get ‘aliasing’. This creates a range of artifacts in the image including false detail, colour moire, exaggerated grain in film scans etc. Although raw processors have algorithms to deal with this, it’s not easy and the process is destructive to real detail - you can’t recover what you lost.

- filter or (slightly) blur the projected image so that detail beyond the resolution limit is eliminated. This largely avoids the problems with the first approach, but gives an apparently softer image.

Back in the ‘dawn of digital history’, sensor resolutions were much lower and wars were fought between photographers who loved their super sharp images full of false detail and who considered moire a small price to pay for inaccurate but sharp recording and those who preferred a more accurate but softer and apparently less detailed image. The last point is important - the images produced with an AA filter were generally more accurate as they did not contain false detail. Anyway, because of the Internet, the sharper is better crowd won and the manufacturers have us cameras without AA filters (Leica had to anyway as any extra glass in front of the sensor messed up the image from short back focus rangefinder lenses).

Leaping forward to today, high resolution sensors quite often use the lens as the blur filter, although modern lenses at wider apertures (small apeetures lead to diffraction becoming sufficient to have an AA effect) are increasingly able to resolve sufficiently well to bring aliasing back! However, as sampling frequency increases, you tend to see less objectionable examples, simply due to there being fewer situations with very high frequency detail. This is one reason I like high resolution sensors.

Some of my practical experience with this:

- when I had the Leica M9 colour moire was actually quite a common problem. 18Mp and a Zeiss ZM 2/50 were sharp enough to cast over roofs and clothes on a fairly regular basis. It was basically impossible to deal with nicely.

- I see far less of it with the Panasonic S1r at 47Mp, but it can still happen and is still painful

- it’s worse with colour sensors than monochrome of the ‘same’ resolution. Partly this is because mono sensors don’t give false colour moire, but also because they can resolve more absolute detail (broadly, a 50Mp colour sensor sensor can resolve the same overall detail as a 25Mp monochrome - but it’s complicated)

- Ricoh Pentax cleverly use the IBIS system in (some of) their cameras to simulate an AA filter by ‘jiggling’ the sensor a bit during exposure. This really is clever as you can switch it on if you think the image is likely to cause problems - for static subjects you could try with and without.

- high resolution pixelshift techniques significantly improve outcomes with colour sensors (at least). This is because, as a minimum they give full colour information at each pixel location (effectively like a mono sensor). It’s less obvious that the interleaved samples add much in a world with closer to 100% pixel coverage, but they help to reduce aliasing. A good example is film scanning - as an example, scanning Foma 100 with an S1r, I get much tighter and better controlled grain rendition using pixelshift than single shot mode. Whether it’s worth the time and file size is questionable of course, but it’s there.

Hope this is helpful - I haven’t forgotten the wars!

Mike

 

[Nikon 2]

Hopefully Brian won’t mind if I add a little bit of information to his response, and a small contradiction

Aliasing is a problem that occurs when using any form of (digital) sampling of an analogue signal. In photographic terms, the sensor samples the brightness of the image projected by the lens at each pixel location, plus there is a colour filter overlay in most cameras of course. If the image consists of large areas of smooth colour and gradients this is fine. However, the the detail gets fine, down towards the size of the pixel pitch, ‘funny’ things happen as the pixels can’t accurately sample/resolve the detail that’s there. Colour filters make this worse by reducing the effective pixel pitch and having different frequencies for green and red/blue channels. This is all well understood through sampling theory, which articulates that you need a sampling frequency of at least twice the detail frequency in order to resolve it.

There are two ways to deal with this:

- do nothing. The consequences of this are that if you have detail at or around the sampling frequency you get ‘aliasing’. This creates a range of artifacts in the image including false detail, colour moire, exaggerated grain in film scans etc. Although raw processors have algorithms to deal with this, it’s not easy and the process is destructive to real detail - you can’t recover what you lost.

- filter or (slightly) blur the projected image so that detail beyond the resolution limit is eliminated. This largely avoids the problems with the first approach, but gives an apparently softer image.

Back in the ‘dawn of digital history’, sensor resolutions were much lower and wars were fought between photographers who loved their super sharp images full of false detail and who considered moire a small price to pay for inaccurate but sharp recording and those who preferred a more accurate but softer and apparently less detailed image. The last point is important - the images produced with an AA filter were generally more accurate as they did not contain false detail. Anyway, because of the Internet, the sharper is better crowd won and the manufacturers have us cameras without AA filters (Leica had to anyway as any extra glass in front of the sensor messed up the image from short back focus rangefinder lenses).

Leaping forward to today, high resolution sensors quite often use the lens as the blur filter, although modern lenses at wider apertures (small apeetures lead to diffraction becoming sufficient to have an AA effect) are increasingly able to resolve sufficiently well to bring aliasing back! However, as sampling frequency increases, you tend to see less objectionable examples, simply due to there being fewer situations with very high frequency detail. This is one reason I like high resolution sensors.

Some of my practical experience with this:

- when I had the Leica M9 colour moire was actually quite a common problem. 18Mp and a Zeiss ZM 2/50 were sharp enough to cast over roofs and clothes on a fairly regular basis. It was basically impossible to deal with nicely.

- I see far less of it with the Panasonic S1r at 47Mp, but it can still happen and is still painful

- it’s worse with colour sensors than monochrome of the ‘same’ resolution. Partly this is because mono sensors don’t give false colour moire, but also because they can resolve more absolute detail (broadly, a 50Mp colour sensor sensor can resolve the same overall detail as a 25Mp monochrome - but it’s complicated)

- Ricoh Pentax cleverly use the IBIS system in (some of) their cameras to simulate an AA filter by ‘jiggling’ the sensor a bit during exposure. This really is clever as you can switch it on if you think the image is likely to cause problems - for static subjects you could try with and without.

- high resolution pixelshift techniques significantly improve outcomes with colour sensors (at least). This is because, as a minimum they give full colour information at each pixel location (effectively like a mono sensor). It’s less obvious that the interleaved samples add much in a world with closer to 100% pixel coverage, but they help to reduce aliasing. A good example is film scanning - as an example, scanning Foma 100 with an S1r, I get much tighter and better controlled grain rendition using pixelshift than single shot mode. Whether it’s worth the time and file size is questionable of course, but it’s there.

Hope this is helpful - I haven’t forgotten the wars!

Mike

I don’t see anymore moire in those sharp landscapes I’ve taken…

 

[sojournermike]

No, not every scene creates problems. It’s about detail frequency and edge aero facts. Couloir moire requires regular high frequency detail, hence roof slates and fabric weave are classic examples.

Here are a couple of links where people discuss problems with colour aliasing in the Ricoh GR iii - also 24Mp with a sharp lens.

GR iii no AA filter issue

Simulated AA filter for star trails with GR iii


If you don’t have a problem and can’t see the artefacts you can just be happy

 

[Nikon 2]

No, not every scene creates problems. It’s about detail frequency and edge aero facts. Couloir moire requires regular high frequency detail, hence roof slates and fabric weave are classic examples.

Here are a couple of links where people discuss problems with colour aliasing in the Ricoh GR iii - also 24Mp with a sharp lens.

GR iii no AA filter issue

Simulated AA filter for star trails with GR iii


If you don’t have a problem and can’t see the artefacts you can just be happy

 

[Nikon 2]

That’s a moire!

When the moon hits your eye like a big pizza pie, that’s a moire…

 

[Nikon 2]

Would you believe…

 

[BrianShaw]

Why not call it ART and move on..?

 

[Nikon 2]

Why not call it ART and move on..?

ART=A Random Thing…

 

[Mal Paso]

With prosumer Nikon cameras the anti-aliasing filter ended with the D800E which was a popular astro camera. The D800 has an anti-aliasing filter.

 

[Nikon 2]

With prosumer Nikon cameras the anti-aliasing filter ended with the D800E which was a popular astro camera. The D800 has an anti-aliasing filter.

Yes, I think that’s correct…!