jptonks

Hello all,

I noticed that a Nikon D750 has an anti aliasing filter and a Nikon D850 does not. How important is that filter to obtaining sharp images and why is the filter left out of the higher end cameras?

Thanks for your help.

John T.

tradio Loc: Oxford, Ohio

I believe the AA filter slightly blurs images to compensate for lens shortcomings.

rmorrison1116 Loc: Near Valley Forge, Pennsylvania

The filter eliminates a phenomenon called moire which may occur when photographing closely repeating geometric patterns. It's kind of like a mirage. Most often moire may be cleaned up in post processing. Having the filter results in a slight drop in overall sharpness that's usually only obvious at a pixel peeping level, but it is there none the less.
This problem is more an issue with older digital technology while the newer image processors are better at handling it. Some manufacturers have decided to leave the filter off and let what happens, happen. My Canon 5DSr has the filter but its effect is cancelled, as if there is no filter. Moire has not been a major issue for me. It all depends on what you are shooting and lighting.

rmorrison1116 Loc: Near Valley Forge, Pennsylvania

You got the slightly blurs part correct, but not the reason for doing so. Has nothing to do with quality of lenses.

Apaflo Loc: Anchorage, Alaska

True. It relates to the spatial frequency of pixels on the sensor. With a high enough frequency an AA filter is of less value and commonly is not used.

WadeH Loc: Texas

Great explanation on AA filters. https://www.youtube.com/watch?v=AcO0S1An_LY

CO

I was checking out the new 45 megapixel Nikon Z7 at a photography expo recently. I was surprised to see moire patterns in ceiling tiles. The room had ceiling tiles that have fine lines running across them. When that portion of the room was in the image, moire was visible there. Nikon eliminates the anti-aliasing filter in their high resolution cameras because moire is less likely to occur. It occurred this time. The moire looked similar to this.

Strodav Loc: Houston, Tx

The D800 (have one) and D800E were released in early 2012 about a month apart. The only difference between them is there is a moire filter (anti-aliasing) in the D800 which they removed in the D800E. Side by side comparisons at 1:1 show the E version is just a hair sharper. You really have to be looking for it to see it. Most say that it is easier to remove moire while composing a shot (different angles, etc.) than it is to do anything with it after the shot (there are tools out there to deal with it), so the need for the filter is questionable. The trick is to realize it can happen with certain kinds of subjects, like fine lines in fabrics. So professionals and enthusiasts probably don't need or want them. Every once in a while on TV, especially in full HD, you will see someone with a piece of clothing they should not have worn because of severe moire patterns shifting every time they move.

Architect1776 Loc: In my mind

The AA Filter is removed so pixel peepers have something to look at and can feel better spending more money for the removal. At real viewing distances and sizes there is absolutely no difference as the unaided eye cannot perceive any difference whatsoever. The morie though is a problem and does occur more than many will admit, at least while pixel peeping they have "sharp" morie.
BTW the Top and most expensive pro cameras DO have the AA filter.

Largobob

I shoot with both a D500 and a D810....neither having an AA filter. I have never noticed any sign of moire in an image.

CO

The top and most expensive pro cameras like the Nikon D5 and Canon 1DX Mk.II have an anti-aliasing filter because they only have 21 megapixels on a full frame sensor. They eliminate the AA filter on cameras that have higher pixel density.

camerapapi Loc: Miami, Fl.

In the first place, the D750 has an anti-aliasing filter. Modern cameras have a very thin AA filter, a totally different departure of the filters in the past. Moire could be an issue without the use of the filter but many photographers using cameras without the filter claim that moire has not been a problem.
All of my cameras come with the filter. When I place a RAW file in my editor I cannot tell that the file is not sharp. That tells me that either the editor is applying sharpness or that the effect of the filter on sharpness is minimal. The images look great when the editing has been completed.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

Not true, my D5 has the filter.
Look, it's this way, camera manufactures would not put a filter on a camera unless they feel you need it. The D750 is one of the best camera's out of the box. So is the D850. I shoot the D850 and the D5. I can't see a difference. BUT I AM SURE SOMEONE HERE WILL DISAGREE.

Architect1776 Loc: In my mind

A person again cannot tell the difference if it has it or not unless they pixel peep. At normal human distance of viewing there is NO difference especially when printed. The human eye does not see at a pixel level. And yes there is definitely moire.
Real world looking at photos by real world people do not see any difference. Only those wishing to brag and spend money on the brag obsess over the AA filter issue.

Nikon D850 review
21st November 2017 Written by Gordon Laing

"The other consequence of the smaller photo-sites might be a slightly stronger effect from diffraction. While the optimal aperture on the D810 (and D800) was f/7.1 it could now be f6.3. Stopping down beyond this could make images softer due to diffraction. But that is only when you’re pixel-peeping. The other thing that could have changed from the D810 is moire. Both cameras have no anti-aliasing filter so there’s certainly not the huge difference like between the D800 with AA-filter and the D810. But in my first tests with the ultra-sharp Sigma 135/1.8 Art and my standard test-target I thought that moire was reduced compared to the D810. This is not a final qualified observation but I’ll keep an eye on this topic because moire can easily be seen without pixel-peeping and is hard/impossible to remove in post-processing. Btw.: that for me was the biggest let-down of the D810 compared to the D800."

aflundi Loc: Albuquerque, NM

Having an AA filter is important. Any sub-sampling sensor such as the almost universal Bayer filtered sensors should have an AA filter to prevent aliasing artifacts -- moire being the most obvious. Many people shoot subjects without repetitive patterns at pixel-level detail so they don't see moire, or have enough camera shake or subject motion blur to provide an AA-filter equivalent, but assuming there are pixel-level details with contrast, aliasing artifacts will *always* be there when there isn't some type of pre-sensor blur. Without patterns in the frame there won't be moire, but the artifacts will manifest as increased color-noise proportional to the contrast of the details -- which can be of much higher intensity than the common photon "shot" noise. I would hazard a guess that most people look for moire but not aliasing color noise, and wouldn't be happy if they did.

BTW, moire is nothing more than the color noise organized in a way that you can see it at a coarser level, and thus more obvious.

There's a popular notion that cameras like the D500, D7100, D7200, D800E, D810, D850 and Z7 have a high enough spatial resolution that the lens can provide enough softness to act as an AA filter. My tests, and plenty of sample photos from proud owners, show that even notoriously soft lenses are still plenty sharp enough to produce moire and alias color noise.

There are people, some have responded in this thread already, that say they don't see moire or artifacts with these cameras, but they may want to look more closely and critically at their images, or work on their technique to reduce shakiness as it is very easy to produce with those cameras. Ironically, I've heard comments from other people wondering if moire has become a trendy thing over the last few years since it has been popping up even in advertising photos.