No Blur Filter?

[pozz]

I was reading an article on moiré patterns and ran across the following: https://photographylife.com/what-is-moire

Despite the potential issues with moiré, the increased level of details in images was welcomed by the photography community. As a result, manufacturers completely omitted the blur filter from the optical low-pass filter stack in subsequent releases of high-resolution cameras. Today, most modern high-resolution APS-C (24 MP and higher) and full-frame cameras (36 MP and higher) have no blur filters in them.

While on one hand it is nice to be able to get as much detail as possible fro high-resolution cameras, many photographers are coming across moiré patterns when shooting in the field and don’t know how to deal with them.

So is this a manufacturer standard now? Is it possible to add blur filters?

I don't know much about cameras. Just asking out of curiosity.

 

[JeffS7444]

You probably know more than you think: It's other names include low-pass or antialiasing filter.

https://www.imatest.com/support/docs/2020-2/nyquist-aliasing/

In theory, you could add it: It's just another optical element sitting in front of the camera's sensor, and there are DIY kits and tutorials for removing them.

I for one will be most curious to find out whether aliasing ceases to be a practical concern at say 61 or 240 megapixels, as those happen to be the resolutions of Sony's A7R IV, and it's currently discounted.

 

[Ron Texas]

It's not necessary to have anti-aliasing filters with modern high resolution filters because the lens does that job.

 

[pozz]

It's not necessary to have anti-aliasing filters with modern high resolution filters because the lens does that job.

Do you mind explaining how that works?

 

[Soniclife]

It's quite a few years now drive they started disappearing from cameras, it does not seem to be a big issue, and if it is you can fix it in post.

 

[Ron Texas]

Do you mind explaining how that works?

I don't have the technical skills to explain it, but it was written about widely when Nikon introduced the D810, their first camera without an AA filter. The prior D800E was built with a canceling AA filter which produced the same rendering, but probably wasted a bit of light.

 

[pozz]

I don't have the technical skills to explain it, but it was written about widely when Nikon introduced the D810, their first camera without an AA filter. The prior D800E was built with a canceling AA filter which produced the same rendering, but probably wasted a bit of light.

Thanks. I'll try to look into it.

 

[StevenEleven]

If I read correctly the new (and exciting!) Canon full-frame R5 and it’s little but nimbler little brother the R6 are the first Canon larger sensor cameras to not have antI-aliasing filters. Honestly even with bargain basement Canons dating back to 2009 I can literally see the texture and pores and hairs and goosebumps on people’s skin and enlarge to 20 x 30 inches, I am not sure what the use of the extra scintilla of or now ultra-resolved sharpness is or what it is worth, but Canon is now keeping up with the Jones’s (and Nikons). I do not quite understand the technology, either, but I guess an anti-aliasing filter keeps some weird patterns from showing up in some photographs with certain repetitive patterns or fabrics. I’ve never experienced this because my cameras have anti-aliasing filters.

More on moire patterns (including in photography): https://en.wikipedia.org/wiki/Moiré_pattern (which is what an antI-aliasing filter is there to prevent, but which limits the resolution of the system slightly, if I understand correctly):

​

Moiré patterns appear in many different situations. In printing, the printed pattern of dots can interfere with the image. In television and digital photography, a pattern on an object being photographed can interfere with the shape of the light sensors to generate unwanted artifacts. They are also sometimes created deliberately – in micrometers they are used to amplify the effects of very small movements.​

​

In physics, its manifestation is the beat phenomenon that occurs in many wave interference conditions.​

In addition to dropping the anti-aliasing filter, the new Canons (R5 and R6) also have advanced auto-focus, in-body image stabilization and superior sensors to prior Canons. Now those improvemenuts can help you get some low light or long exposure or high contrast or motion-oriented shots off that you might not otherwise get, so that’s the real deal.

I am currently trying to figure out how I could ever possibly live with my current gear now that these new Canons have come out. Well I know how, the biggest factor in photography is the person behind the camera. I can (and should) continue to upgrade my in-house neural network (the one between my ears).

 

[Blumlein 88]

Do you mind explaining how that works?

Imagine running DSD1024. The sample rate and frequency is so high even without an explicit anti-alias filter some other part of the chain will limit frequency response and act as a filter.

Refracting lens are not of infinite resolution. So with a high enough pixel count the limited resolution of the lens becomes the resolution bottleneck and effectively is the blur filter.

 

[Ron Texas]

I am currently trying to figure out how I could ever possibly live with my current gear now that these new Canons have come out. Well I know how, the biggest factor in photography is the person behind the camera. I can (and should) continue to upgrade my in-house neural network (the one between my ears).

That's it in a nutshell. I have seen lens reviews where newer Nikon Z lenses with better measured sharpness were not preferred over older AF-S designs due to subjective factors such as rendition. Keep working on your skills and reap the rewards. Don't worry about the gear. If it is recent, it is already great. Unless you drop your camera in the ocean, it's good to go.

 

[Tks]

You probably know more than you think: It's other names include low-pass or antialiasing filter.

https://www.imatest.com/support/docs/2020-2/nyquist-aliasing/

In theory, you could add it: It's just another optical element sitting in front of the camera's sensor, and there are DIY kits and tutorials for removing them.

I for one will be most curious to find out whether aliasing ceases to be a practical concern at say 61 or 240 megapixels, as those happen to be the resolutions of Sony's A7R IV, and it's currently discounted.

PixelShift/Stacking mitigates moire?

 

[restorer-john]

I don't need no stinkin' blur filter, I just turn off the image stabilization and get lots of blur for free!

 

[mansr]

First off, Moiré patterns (in phographs) are caused by undersampling. The filters discussed are (spatial) low-pass filters analogous to those used in front of audio ADCs.

As the pixel density increases (sample rate in audio), the need for anti-aliasing decreases. Every lens has its resolution limited by diffraction (if nothing else), and if the sensor resolution exceeds this, there is no need for a filter, just like an audio ADC surpassing the bandwidth of the microphone doesn't.