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10-03-2014, 07:57 AM   #1
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Importance of low pass filter?

I see the K5IIs says "no low pass filter". What does this mean, say in comparison to the K50 that probably has this filter?

Thanks!

10-03-2014, 08:06 AM   #2
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The low pass filter blurs the image slightly to reduce moire'. Removing it provides for sharper photos, but with the chance that certain fine repeating patterns could generate artifact. Do a Web search for "moire" to see examples and a technical explanation.


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10-03-2014, 08:12 AM   #3
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Thanks Steve; I appreciate your help! In landscape/wildlife it appears the low pass filter would not be a factor.
10-03-2014, 08:17 AM   #4
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With thousands of shots with both k-5IIs and k-3 I have yet to see the elusive 'moire'. However, I shoot nature and food primarily and subject does matter. I have been told that in weddings or other shoots with patterned fabric it can be an issue. Certainly a complete non-issue for me. When the k-3 came out with the ability to use the SR to mimic the AA filter it was touted as a big deal, and perhaps it is. I turned it off and have never used it, so for me not an issue. YMMV.

10-03-2014, 08:26 AM   #5
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Thanks! I don't believe it would be a factor for me either, as I shoot primarily wildlife/landscapes. I think I'll still stick with buying the K50.
10-03-2014, 08:55 AM   #6
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I've had moire on some fences. Lightroom cleaned it up perfectly.

In theory you could get it on bird feathers. I've never seen it happen and if it did I'd just fix it in Lightroom.
10-03-2014, 09:06 AM   #7
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I was really concerned about the lack of low-pass/AA filter on the K-5 IIs when it first came out because I've been shooting digital for more than a decade and remember messing with an old 6MP Nikon DSLR that had the AA filter removed by a company that offered this service for photographers who wanted the best possible resolution from their cameras.

Back then, the moire for the 6MP sensor was TERRIBLE when the AA filter was removed. "Jaggies" were also a major problem (clearly visible in hair or diagonal lines of buildings) when the AA filter was removed from the old 6MP sensor.

With that experience under my belt, I was certain that the K-5 IIs would have similar problems ... but I was wrong. The K-5 IIs and K-3 deliver fantastic detail and you either have to photograph close-ups of colorful bird feathers or really have to go out of your way to create obvious moire or jaggies. While I still have some cameras with AA filters (Sony RX1) but I think I will always choose to purchase cameras without AA filters from now on.

I won't burden your bandwith with a full-res image here, but if I took the image below with my old Nikon D70 which was had its AA filter removed there would have been crazy moire in areas of the blue fabric that are in focus and the individual strands of hair and the angled lines of the sunglasses would have been nothing but jaggies. The K-5 IIs and K-3 can handle this stuff without any problems.

From K-5 IIs:


10-03-2014, 09:24 AM   #8
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QuoteOriginally posted by csa Quote
Thanks! I don't believe it would be a factor for me either, as I shoot primarily wildlife/landscapes. I think I'll still stick with buying the K50.
Just to be clear the k-50 has an AA filter which slightly blurs the image, the k-5IIs and the k-3 do not. So theoretically the k-5IIs and k-3 will produce sharper images than the k-50 at the possible risk of getting some moire patterns in certain things. As you note this is not normally an issue in landscapes, though repeating patterns such as fences or bird feathers can show it.
10-03-2014, 01:50 PM   #9
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Yes, get the K5IIs. I've only seen moire once with the AA filter off on my K3, but the added sharpness is very apparent.
10-03-2014, 01:57 PM   #10
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See our k5iis and k-3 reviews on the homepage. There are some nice comparisons in there.

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10-03-2014, 04:30 PM   #11
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QuoteOriginally posted by JJJPhoto Quote
Back then, the moire for the 6MP sensor was TERRIBLE when the AA filter was removed.
Moire happens when you have a pattern that is finer than the sensor can resolve. At 6 MP on APS-C, the pixels are rather large, so it would seem that most patterns would be finer than the sensor can resolve. Hence, that Nikon was like buying a one-way ticket to moirecity.

Moire will be rare on the K-5IIs with its much finer sensor. On the K-3, it should be exceptionally rare.
10-03-2014, 05:20 PM   #12
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QuoteOriginally posted by MadMathMind Quote
Moire will be rare on the K-5IIs with its much finer sensor. On the K-3, it should be exceptionally rare.
Because most lenses will act as effective low pass filters on these sensors
10-03-2014, 07:43 PM   #13
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Example of moire

Here's an example of moire on the K3 (DA 15 at f7.1, cropped). Notice the coloured pattern running laterally near the join between to two nearest "lilies". The deck is made up of a fine grid of metal ridges, that causes the aliasing with the sensor's pixel pattern.

10-03-2014, 07:46 PM   #14
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It should also be noted that moire is a function of the image/screen size. You may see moire at screen size only to have it vanish when you view at 100%. If you are cropping, it may disappear from your image upon the resize.
10-03-2014, 09:47 PM   #15
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With all the shots I've taken with my K-3 and K-5 IIs - birds, landscapes, flowers, granddaughter, etc - I've only seen moire once. That was in the rubberised fabric of a trampoline, but it was very difficult to remove in post. I've never had it in feathers or clothes fabric yet.
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