Does taking out the OLPF filter make your Canon EOS 5D Mark III sharper?

by planetmitch14 Comments

James Miller has done something on his own that we're not recommending, but the results look very interesting – he's removed the optical low pass filter (OLPF) (also sometimes called the AA or Anti Aliasing) from the front of his Canon EOS 5D Mark III sensor (which is what the Nikon D800E is like – remember there are two versions of the Nikon D800 – one with the filter and one without – but the Nikon D800 also has moire issues the Canon EOS 5D Mark III doesn't have).

We first posted this on the planet5D HDSLR scoop news page yesterday and James has posted this video as an update.

So, is it worth voiding your warranty on the Canon EOS 5D Mark III? You be the judge.

Liberation Begins – 5DMK3 OLPF Removal Day 2

[tentblogger-vimeo 39594898]

Update 3: Now back on line. The native files from the Canon seem to be getting flagged as interlaced for some reason have to watch the one.
Update 2: Messed up on the transcoding from the native files. Somehow I set the prores to interlaced! New edit coming later today. Sorry folks
Update. I plan a shoot along side another standard MK3
towards the end of the week. I should have shot local or something different to judge resolution. Very hard to judge with this video. I'll shoot on a nice prime for the next test.
Popped down to Brighton, on the UK's South coast today to shoot some footage with the 5DMK3. This camera has had one of the 2 OLPF removed.
Graded footage. The images & stills from today suffered from heat rising on the ground and gives a shimmer, this is not aliasing but does make some detail appear soft.
Shot using the Heliopan ND Vario. Causes some slight corner vignetting. I should have removed this and increased shutter really. The Vimeo download is at a much lower bitrate than the originals that looked so nice.
Need a hosting company or someone to donate some room so I can share some original native clips.
Soundtrack: Liberation Begins / A.R. Rahman

Here's the first video he posted: [tentblogger-vimeo 39541733]

(cover photo credit: snap from the video)


  1. My understanding is that James is just removing the antialiasing and NOT increasing the resolution. Am I wrong?

    1. Author

      Well, I think we’re picking nits here, but, the OLPF filter does reduce the resolving power of the sensor in order to solve some problems of moire and aliasing – so in effect, yes, you’re increasing the resolving power of the camera by removing it.

      99.999% of the people using the 5D3 will be happy with it as sent out by Canon

  2. I know this isn’t about color correction but I had to say something about it…. Not a fan of the color correction done on this video. For one, the sky appears green, but then there are scenes where there is a blue sky. A) It should be consistent B) The choice of color correction just isn’t good IMO. It makes me think, “Yuck”

  3. Basically, what he did is take apart his 5D MarkIII and removed the optical low pass filter, which by doing so, does increase the resolution. Pity, after spending $3,500 dollars you find out you need to take apart your camera to get the resolution you should have gotten to begin with. If this doesn’t solidify the point these are still photo cameras, first and foremost, nothing does. The video capability, although great, is not the priority in the making of any DSLR.

  4. bloody 5D has been out for 5 minutes and already you are stuffing around with it. Take Note: It is a still camera, with a vid facility, not a video camera, which has proper on board audio, among other things

    Forget it. You won’t make it into a vid camera, the companies will see to that

  5. i dont get it. doesnt the OLPF affect stills too?

    since, from what i have seen, there is no moire and aliasing without it, why is it there in the first place?

    removing it is good for both video and stills.

    1. Author

      Yes, the OLPF was actually designed for stills in the first place. I plan to ask Canon at NAB about the filter situation going forward

  6. Which is exactly why Nikon offers their new D800 in two different models, one with the OLPF and one without. Personally, moire can be worked around, having a cataract on your camera, can’t. Okay, relax, I’m not knocking the 5D MarkIII, but honestly, the examples provided by James Miller, there’s no denying that’s a significant video quality difference.
    Am I wrong?

  7. Crazy. I would obsess with the SCREENPLAY, not the resolution of a camera which takes amazing video and which a real audience, not pixel peepers, are ever going to notice. If you have a great story to tell, you can shoot it on an iPhone. But if you have nothing good to say with the medium, then you WILL start obsessing about image resolution, sharpness, etc. Now I am not saying technique is not important (I am quite the gearhead myself) but please, this is just going to much.

  8. I think people like myself are comparing the Mark 3 image to the Mark 2 (happy owner since 2009). And really questioning is it worth it to upgrade. And should a person spend $2200 for a Mark 2 vs $3500 for a Mark 3. I rented a Mark 3 and love the cameras new features (especially the low light) but It is not as detailed sharp as the Mark 2. And don’t want to apply sharpening in post as I don’t have to do that with Mark 2 footage. So waiting to see what Canon is announcing on April 15 or possibly buy a Canon 1DX?

  9. I contacted MaxMax inquiring about what they are doing in this arena and they will in fact remove the filter and replace it with a substitute. In fact, they just received the proper glass to filter out the I.R. The basic removal costs around $500 and a few hundred more if you want your auto sensor cleaning re-attached. However, in speaking with Dan General there…he was unable to confirm that the removal would actually have an effect on video. He’s hoping to to a test as soon as he gets a chance. He also invited me to post his thoughts upon viewing the blog posts about those that have done their own filter removal. Here are his thoughts:
    “For video (not stills), the 5D III may benefit for the focused position by removing the AA (OLPF) filter. However, they introduced two new problems:
    1. Because the AA was removed without adding another clear window of precisely the same thickness, they changed the focal plane so that now the camera front focuses. Since the camera is not focusing correctly, they actually added *more* blur, not less. Removing the AA adds sharpness but changing the sensor focal plane adds much, much more blur.
    2. The AA filter also has an IR Cut Filter (ICF) coating that helps block IR light. Now the camera is more sensitive to IR light.

    What they really did was not increase sharpness but the opposite. This has the perverse effect of helping out for video because the 5760 x 3840 needs to drastically downsample to get a 1080P video signal. This downsampling is a complicated business to do well. The easiest way is to simply throw 4 out of 5 rows out. This gives you bad aliasing. I would guess that Canon has a fairly basic downsampling algorithm.

    To use the 5D III for video, you either want a really good downsampling algorithm which would have to come from Canon or someone who has hacked the camera, or you add much, much more blur. If you add enough blur, then when the Canon software throws out 4 or 5 lines, the aliasing is reduced.

    Their solution is a partial solution, because, yes, it adds blur, but the camera aliasing will be even worse for objects in the foreground since those objects will be in correct focus and even sharper than before.

    While I don’t have time currently to do this experiment, here is what I would try:
    – Set camera on a tripod taking a video of something known to cause aliasing. Something sloping up or down with a sharp edge should work. Target should be about 5-10 feet away.
    – Set camera to manual focus. Take a short video clip.
    – Without moving camera, change focus slightly more in distance. Repeat 5 times making focus slightly further out.
    – Without moving camera reset focus and take 5 more pictures making focus slightly closer.
    Import all the videos in a computer, label each one and see how sharpness changes. My guess is that the one with the most aliasing will be the one in sharpest focus. You will find a spot where the camera stop aliasing and the video image looks the best. After that, the whole image will start going soft.”

  10. I removed the olpf filter by hand and adjusted the focus problem by turning the adjustment screws on the sensor 1/3rd of a turn at a time. It was tedious and nerve racking by the results are more than amazing! I can’t believe how great the images are as well as video. My mark iii is a whole new beast!!!

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