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Author Topic: How much correction do you do because of no AA filter  (Read 4354 times)

docmaas

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How much correction do you do because of no AA filter
« on: January 23, 2009, 12:09:38 am »

I'm curious how much trouble shooting without the AA filter is for you?  I don't understand why none of the current SLR makers other than Sigma and Leica have not offered models either without the AA filter or with one that can be easily removed and replaced.

I know of one Kodak shooter who said he had to work on almost every image due to moire and other artifacting but I'm not sure this wasn't partially due to some of the other problems with that sensor.

I had a canon 5D on which one of the two AA filters was removed and when switching from portrait to landscape I saw an 8-10% difference in resolution using mtf testing.  I occasionally saw traces of moire in the raw conversion but none in the final image.  One Leica DMR shooter also reported he sometimes sees moire in very fine bird feathers but doesn't consider it a big problem.

Thanks for any comments on how much of a problem it is for you.

Best,

Mike
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shutay

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How much correction do you do because of no AA filter
« Reply #1 on: January 23, 2009, 12:55:06 am »

I don't shoot alot of fabric but I did have a whole catalog of fabric handbags to shoot once which I did with an Ixpress V96C and the moire only manifested in a small number of cases. Recently I shot a still life scene and there was some moire on fine dust detail on the scene which made it look like I had multi-coloured dust, but it was easily controlled. Conclusion - moire is a rare problem for me and even if it does show, it's easily corrected.
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jing q

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How much correction do you do because of no AA filter
« Reply #2 on: January 23, 2009, 02:24:16 am »

got moire issues twice shooting people in officewear against a white backdrop...those grey pencil skirts are a big culprit
I sweep over them with a clone stamp in Colour setting so that it removes the colour effect from the moire...only that it leaves abit of the wavy pattern of the moire behind still
not a big problem but something worth considering if you shoot people in office wear against backdrops all day  
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Dustbak

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How much correction do you do because of no AA filter
« Reply #3 on: January 23, 2009, 02:55:40 am »

I shoot lots of fabric and use moire to check whether the fabric is in focus. Maybe that says something about how much moire you can get with fabric   It is all gone after having done the multishot BTW.

My experience is you can run into moire quite easily and you have several tools to minimize (or even get totally rid of it) that if you pay attention. I don't find moire a real hassle any longer. It isn't a dealbreaker so to speak, or it least it doesn't have to be.
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docmaas

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How much correction do you do because of no AA filter
« Reply #4 on: January 24, 2009, 08:04:12 pm »

Thanks for all of the replies thus far.  

Are there any landscape shooters who would like to contribute?

thanks,

Mike
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tashley

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How much correction do you do because of no AA filter
« Reply #5 on: January 25, 2009, 06:23:23 am »

Quote from: docmaas
Thanks for all of the replies thus far.  

Are there any landscape shooters who would like to contribute?

thanks,

Mike


Yup, I use an M8 with no AA filter and have almost never had moire. So infrequently as to be effectively never.

The main impact on PP is that I don't have to sharpen and in fact have got into the habit of removing all sharpening on most files as I process RAW. Lovin' it.
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feppe

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How much correction do you do because of no AA filter
« Reply #6 on: January 25, 2009, 07:14:37 am »

Quote from: docmaas
I had a canon 5D on which one of the two AA filters was removed and when switching from portrait to landscape I saw an 8-10% difference in resolution using mtf testing.  I occasionally saw traces of moire in the raw conversion but none in the final image.  One Leica DMR shooter also reported he sometimes sees moire in very fine bird feathers but doesn't consider it a big problem.

Is that the Hot Rod conversion? Waiting for my 5D MkII and have always wondered if it delivers as impressively as they claim.

docmaas

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How much correction do you do because of no AA filter
« Reply #7 on: January 25, 2009, 11:10:01 am »

Quote from: feppe
Is that the Hot Rod conversion? Waiting for my 5D MkII and have always wondered if it delivers as impressively as they claim.

Yes it is the hotrod conversion.  Unfortunately one of the aa filters serves as the cover glass on the sensor and cannot be easily removed.  I didn't find this out until after having the work done and the guy who converted it is still not convinced.  I wrote to Canon but they would not confirm  either way.  However since the mtf for the same lens differs by 8-10% when the camera is rotated from portrait to landscape I think it is indeed the case.  I suspect that the 5Dii is the same since the sensor illustration is the same.  I don't know if it was the case with the 1d/1ds cameras or not.

I did some test shots with Jack Flesher that I still have on my pbase site along with the mtf tests.   http://www.pbase.com/masimo/5d_hotrod

I've purchased an A900 and had an M42 Adapter machined to serve as a permanent mount adapter on my Contax 35-70 f4.  The camera has not yet arrived though so I have not tested the adapter for infinity focus.  It will be close and I'm confident it will work but still waiting to confirm.  I may eventually have the AA filter removed from the A900 as well.

Mike
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JohnBrew

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How much correction do you do because of no AA filter
« Reply #8 on: January 25, 2009, 08:54:32 pm »

Quote from: tashley
Yup, I use an M8 with no AA filter and have almost never had moire. So infrequently as to be effectively never.

The main impact on PP is that I don't have to sharpen and in fact have got into the habit of removing all sharpening on most files as I process RAW. Lovin' it.

I'm with Tim 100% on this!

Martin Kristiansen

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How much correction do you do because of no AA filter
« Reply #9 on: January 26, 2009, 12:27:19 am »

I shoot landscape with a Leaf AFI7S. Never had moire with it. Never had in a studio shooting fabric either. Get lots of moire with an old 1DS though.
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docmaas

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How much correction do you do because of no AA filter
« Reply #10 on: January 26, 2009, 01:16:17 am »

Quote from: Martin Kristiansen
I shoot landscape with a Leaf AFI7S. Never had moire with it. Never had in a studio shooting fabric either. Get lots of moire with an old 1DS though.

I've been assuming that all other things are equal on the two types of systems.  The 1DS is 76 square microns per pixel and by my calculations the Leaf Aptus 17 is about 91 square microns/pixel.  Smaller pixels should result in less moire for all other variables being held equal yet you are saying you see more moire with the smaller pixels.  

Obviously this make my assumptions questionable.  I just yesterday saw a shot of a building in NZ or SA I think with a lattice exterior that showed moire on a 1DS3 and then showed a capture 1 tool that removed the colors but the banding was still there.  

Maybe there is something the MF back do other than aa filters that remove the moire or maybe the aa filter itself causes moire that might otherwise not be there?  

I've never seen moire on my sigma and the leica shooters report not seeing it either.  The sigma is different of course in not having a Bayer filter but the leicas and all the MF backs do and they still don't have moire problems.  The sigma does show aliasing when the target objects get below 1 pixel but the aliasing even though it is false data often fits well into the image and doesn't look bad at all.

Mike
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bcooter

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How much correction do you do because of no AA filter
« Reply #11 on: January 31, 2009, 12:33:44 pm »

Quote from: docmaas
I've been assuming that all other things are equal on the two types of systems.  The 1DS is 76 square microns per pixel and by my calculations the Leaf Aptus 17 is about 91 square microns/pixel.  Smaller pixels should result in less moire for all other variables being held equal yet you are saying you see more moire with the smaller pixels.  

Obviously this make my assumptions questionable.  I just yesterday saw a shot of a building in NZ or SA I think with a lattice exterior that showed moire on a 1DS3 and then showed a capture 1 tool that removed the colors but the banding was still there.  

Maybe there is something the MF back do other than aa filters that remove the moire or maybe the aa filter itself causes moire that might otherwise not be there?  

I've never seen moire on my sigma and the leica shooters report not seeing it either.  The sigma is different of course in not having a Bayer filter but the leicas and all the MF backs do and they still don't have moire problems.  The sigma does show aliasing when the target objects get below 1 pixel but the aliasing even though it is false data often fits well into the image and doesn't look bad at all.

Mike


For a scientific standpoint I'm sure all this talk of microns and pixel size makes a difference, but moire is just something that happens to all cameras if you walk into the perfect storm.

Color moire can be fixed fairly easily, pattern moire is a nightmare.  

Now whether a mfdb moires more than a dslr is more dependent on what you shoot, how you shoot,  the lighting you use rather than any scientific standards.

I have a friend that swears he sees pattern moire on jeans, though I have shot a billion pair of jeans in all shapes, sizes with cameras ranging from all the Canons, Leaf Aptus, Phase and rarely if ever (I think ever) have seen pattern moire on jeans.  

It's easy to think that a digital back sans aa filter has a tendency to  moire more than a dslr, but usually a digital back is used in a locked down position with tripod, and/or with a large quantity of light, usually strobe, which just adds shaprness and more chances of the perfect storm.  With dslrs, they are usually hand held and more or less shot with continuous or available light so though moire can happen, there is a lot less chance of it happening in every frame.

The only way to be sure that you don't have moire is to tether the camera on a large screen with clear previews and this holds true with any digital camera.  

Given this, I find moire to be less of a problem than ever, as cameras have improved.  Also going to continuous light seems to limit it, though probably limits pin point sharpness also.

The only time I saw moire that was almost impossible to control was when I shot with a 22mpx back, though the project that had moire was men's suits with pronounced patterns and probably any camera in those conditions would be difficult to control moire.  

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BJNY

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How much correction do you do because of no AA filter
« Reply #12 on: January 31, 2009, 01:15:50 pm »

Hey Big,
I noticed a Smallcooter signed on earlier.
Any relation?
Billy
« Last Edit: January 31, 2009, 01:51:05 pm by BJNY »
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Guillermo

eleanorbrown

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How much correction do you do because of no AA filter
« Reply #13 on: January 31, 2009, 02:14:14 pm »

I've used Phase One backs for years---P25, 45 and 45+  with no AA filter on landscape and never ever had any problems.  Would love to have a dslr w/o an AA filter!  Eleanor

Quote from: docmaas
Thanks for all of the replies thus far.  

Are there any landscape shooters who would like to contribute?

thanks,

Mike
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Eleanor Brown
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bcooter

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How much correction do you do because of no AA filter
« Reply #14 on: February 01, 2009, 12:57:54 am »

Quote from: BJNY
Hey Big,
I noticed a Smallcooter signed on earlier.
Any relation?
Billy

Gee Billy, I don't know.  There are a lot of Cooters out there.

I think Small may be from the New York Cooter side of the family.  I check with my aunt Lisa and get back to you on that.


BC
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Bernd B.

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How much correction do you do because of no AA filter
« Reply #15 on: February 01, 2009, 11:48:24 am »

I shoot People with an H3D39 and I have to remove moiré on fabrics on about 70 percent of the images. This means processing in Phocus one version with the moiré filter off, another one with the filter on and then then some layer work. I need a minimum of 60 minutes per picture.

Of course the sharpness of these filkes is something completely different from those shot with a 5D or a D700.

Bernd
« Last Edit: February 01, 2009, 11:48:57 am by Bernd B. »
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