Ad
Ad
Ad
Pages: [1] 2 3 ... 10 »   Bottom of Page
Print
Author Topic: removing the AA filter  (Read 63259 times)
Tim Gray
Sr. Member
****
Offline Offline

Posts: 2002



WWW
« on: October 13, 2007, 08:06:38 AM »
ReplyReply

http://www.maxmax.com/nikon_d200hr.htm

Link from the Online Photographer

http://theonlinephotographer.com/the_onlin...blog_index.html  of Oct 12.

As Mike Johnston says "live dangerously".

I've seen it mentioned before that there are effective software options to remove/reduce the resulting increase in moire - what works best?
Logged
jing q
Sr. Member
****
Offline Offline

Posts: 594


WWW
« Reply #1 on: October 13, 2007, 10:55:11 AM »
ReplyReply

well I would do it.
the results I've seen from the samples are similar to what I get from a MFDB. It does make a difference in a print. Whether it's worth that amount of money to you is a different matter, that's all.
Treat it as a specialist mod like the IR or UV mods

personally if I had a 5D I would do it, but they don't seem to offer the mod for 1DsMkII
Logged
jing q
Sr. Member
****
Offline Offline

Posts: 594


WWW
« Reply #2 on: October 13, 2007, 02:51:55 PM »
ReplyReply

Quote
The results from the D200 mod do look worthwhile from what they have on their website. The results for the 5D less than impressive, when looking at the actual raw files in different raw apps that I use regularly. The cost is not a big deal, but if I see a nearly miniscule to no difference at 100%, then what in the world does a print comparison add. So maybe the price of the mod for the 5D isn't worth it. If I don't see much of a difference then comparing to a digital back is of little value.

The jpeg samples they show do look very different. But that is not the case looking at the raw files. And in the end they are trying to sell a service here. If someone is trying to squeeze one more percent of detail out of an image through some hardware mod, then maybe they are into the gear more than the art of photography.

And one bit of truth, color moire can be reduced through software, luminance moire patterns are hard as hell to get rid of. I would like to spend less time in front of the computer not more.
[a href=\"index.php?act=findpost&pid=145750\"][{POST_SNAPBACK}][/a]

actually you'll be surprised at the difference a print makes vs computer screen, even at 100%.
As we speak now I'm slowly uprezzing a file and sharpening it for 4ft x6ft to 240 dpi.
it took alot of trial and error of printing on the epson and comparing to the print to realise that what's on a screen can translate differently in print, in terms of what the human eye perceives as photographic or not (when is sharpening too much sharpening to the point of looking flatly digital?)

Talking about sharpening an AA-ed image, when I uprez my 1DsMkII file and I sharpen it I find that it's impossible to bring back minute detail that's soft through the obvious AA filtering in the first place.
You can sharpen an image to bring back local contrast but then when details are mushed in the first place,sharpening it later leaves pretty half-assed details. And using local contrast sharpening before uprezzing the image just leaves a degraded image.

When you look at images 100% on a computer screen you're seeing a rendering of square pixels forming an image, and when you print it out you're looking at dots. Too many people make comments based on looking at computer screen images, would you consider printing the pictures out to see if you can tell a difference?

I think at small print sizes you can't tell much difference but there was this image I shot on a H39 and I always thought it was unspectacular, until one day I had to blow it up to 5 ft and suddenly the picture seemed to pop out alot more compared to my 1DsMkII file, details rendered differently although on the computer screen you would be drawn to the 1DsMkII file instead

I'm weighing in on this topic because I personally feel that images do benefit from a lack of AA filter.
I shot with a Kodak Pro Back quite awhile back and even then I already felt that the images rendered at the optimal ISO was providing me images that had finer details and a more photographic, dimensional look than my MkII which, as much as I love it, does seem like its images have been shot through some soft cloth sometimes in terms of rendering details.

People are willing to pay alot of money to buy a zeiss lens simply for subtle gains in terms of rendering of an image, so I don't see why there's so much negativity regarding the service being offered.

once again it's abit of a specialist service, and not suited for everyone I'm sure.
Personally I would do it in a flash if only they offered it for my camera.

I'm sure that the company is willing to provide more samples should you email them
Plus there's a forum member who's had his 5D modded and he seems happy with it. Perhaps you can ask him for his opinion on it.
« Last Edit: October 13, 2007, 02:56:16 PM by jing q » Logged
jing q
Sr. Member
****
Offline Offline

Posts: 594


WWW
« Reply #3 on: October 13, 2007, 03:04:30 PM »
ReplyReply

also I wonder if removing the AA filter will help with the problem that occurs due to diffraction
Sometimes I have to shoot F16 and trust me your images ain't gonna look pretty at F16 on a full frame sensor...details are absolute mush.

but ahhh I'll just think hypothetically for now.
Logged
nma
Full Member
***
Offline Offline

Posts: 154


« Reply #4 on: October 13, 2007, 03:12:04 PM »
ReplyReply

Quote
http://www.maxmax.com/nikon_d200hr.htm

Link from the Online Photographer

http://theonlinephotographer.com/the_onlin...blog_index.html  of Oct 12.

As Mike Johnston says "live dangerously".

I've seen it mentioned before that there are effective software options to remove/reduce the resulting increase in moire - what works best?
[a href=\"index.php?act=findpost&pid=145701\"][{POST_SNAPBACK}][/a]

The democarcy of these forums is that everyone's opinion is equal. But not all of them are correct.  With digital imaging, we are not entiltled to infinite resolution; the attainable resolution is limited by the sampling frequency of the sensor, not the lens.  In fact, if you ignore this inconvenient truth, you get aliasing. Aliasing of periodic elements,such as fabrics, are called Moire patterns. The image is distorted, with high frequency details in the wrong location. There is no such thing as color Moire patterns. The  sampling problem for Bayer sensors is complicated by the different sampling frequencies of the red, blue and green detector elements. Once this distortion is observed in an image, there is no sure way to remove it unless you know what the image is supposed to look like. In other words there can sometimes be mitigation of the effect but there  is no general method to remove aliasing.  

The AA fiter is there to attenuate high frequency information beyond that which can be faithfully recorded by the sensor. It is digital imaging 101 to roll off the high frequency information above the Nyquist frequency of the sensor. This is THE standard approach in digital signal processing. No amount of voting or opinion is going to change this. One goes naked at their own peril. In digital photography, the roll off of the high frequency information is done by blurring the image before it reaches the detector with an AA filter. In paractice, AA filters may not be perfect. The goldilocks effect would be not too weak to allow aliasing and not too strong to remove any detail.  With the AA filter it is generally helpful to apply a small amount of sharpening during raw conversion.  

Arguing, for example, that the Leica M8 is better because it lacks an AA filter, is a hypothesis. There is no proof. It might be some other element in their proprietary development. To prove it is the lack of an AA filter one needs to make measurements with an M8, with and without an AA filter. Measurements, not pictures shot out your porch window that are later displayed as jpegs on a computer monitor.

Sorry fot the rant, but this same subject has just been explored in Cameras, Lenses and Shooting gear.
Logged
jing q
Sr. Member
****
Offline Offline

Posts: 594


WWW
« Reply #5 on: October 13, 2007, 03:24:10 PM »
ReplyReply

Quote
The democarcy of these forums is that everyone's opinion is equal. But not all of them are correct.  With digital imaging, we are not entiltled to infinite resolution; the attainable resolution is limited by the sampling frequency of the sensor, not the lens.  In fact, if you ignore this inconvenient truth, you get aliasing. Aliasing of periodic elements,such as fabrics, are called Moire patterns. The image is distorted, with high frequency details in the wrong location. There is no such thing as color Moire patterns. The  sampling problem for Bayer sensors is complicated by the different sampling frequencies of the red, blue and green detector elements. Once this distortion is observed in an image, there is no sure way to remove it unless you know what the image is supposed to look like. In other words there can sometimes be mitigation of the effect but there  is no general method to remove aliasing. 

The AA fiter is there to attenuate high frequency information beyond that which can be faithfully recorded by the sensor. It is digital imaging 101 to roll off the high frequency information above the Nyquist frequency of the sensor. This is THE standard approach in digital signal processing. No amount of voting or opinion is going to change this. One goes naked at their own peril. In digital photography, the roll off of the high frequency information is done by blurring the image before it reaches the detector with an AA filter. In paractice, AA filters may not be perfect. The goldilocks effect would be not too weak to allow aliasing and not too strong to remove any detail.  With the AA filter it is generally helpful to apply a small amount of sharpening during raw conversion. 

Arguing, for example, that the Leica M8 is better because it lacks an AA filter, is a hypothesis. There is no proof. It might be some other element in their proprietary development. To prove it is the lack of an AA filter one needs to make measurements with an M8, with and without an AA filter. Measurements, not pictures shot out your porch window that are later displayed as jpegs on a computer monitor.

Sorry fot the rant, but this same subject has just been explored in Cameras, Lenses and Shooting gear.
[a href=\"index.php?act=findpost&pid=145758\"][{POST_SNAPBACK}][/a]


the problem with applying sharpening during RAW conversion is that it leads to a degrading of the edges of objects in the image when the image is uprezzed.

I tried uprezzing from an image that was lightly sharpened during RAW conversion, and I tried uprezzing from an image that was unsharpened during RAW conversion,
and then did 10 percent bicubic increments (which btw does make a difference as opposed to uprezzing to full resolution directly, even with CS3), and then sharpening the final resolution images after that and the initially unsharpened images hold up to sharpening better in terms of smoothness and photographic quality, whereas the initially sharpened image tends to become chunky at the edges (pixellation and heavy contrast).

The difference to me is pretty big but I think to most people it won't make much of a difference and most people don't print too big anyway, but for all the talk about Nyquist and whatever technical issues...(sorry my mind blanks out at the mention of such words), at the end of the day the final product in front of me speaks for itself.
Logged
marcmccalmont
Sr. Member
****
Offline Offline

Posts: 1724



« Reply #6 on: October 13, 2007, 03:26:39 PM »
ReplyReply

I've had my modified 5D for 9 months now without a AA filter. I find very little moiré and the Image Quality after sharpening (prints) is improved to my eye. I have no regrets and the $450 was worth the improvement (for me). This is a subjective/empirical evaluation of course. Those of you with a AA filter can theorize all you want but there is a real world improvement and my conclusion is; in the current high megapixel sensors for landscapes and nature , the AA filter is not necessary it is a hindrance.  About 7500 frames to date w/o the AA filter.
Marc
Logged

Marc McCalmont
jing q
Sr. Member
****
Offline Offline

Posts: 594


WWW
« Reply #7 on: October 13, 2007, 03:27:22 PM »
ReplyReply

You may want to look at this thread for more discussion on this topic

http://luminous-landscape.com/forum/index....opic=20081&st=0

Would someone like to perhaps enlighten me on why most medium format backs seem to forgo the AA filter?
and medium format backs are held up as the holy grail of image quality
Logged
marcmccalmont
Sr. Member
****
Offline Offline

Posts: 1724



« Reply #8 on: October 13, 2007, 03:34:21 PM »
ReplyReply

Quote
You may want to look at this thread for more discussion on this topic

http://luminous-landscape.com/forum/index....opic=20081&st=0

Would someone like to perhaps enlighten me on why most medium format backs seem to forgo the AA filter?
and medium format backs are held up as the holy grail of image quality
[a href=\"index.php?act=findpost&pid=145765\"][{POST_SNAPBACK}][/a]


Only my opinion, MFDB have high megapixel sensors and IQ is paramount to their end users. MFDB are not general purpose cameras but specialized tools.
Marc
Logged

Marc McCalmont
nma
Full Member
***
Offline Offline

Posts: 154


« Reply #9 on: October 13, 2007, 09:21:56 PM »
ReplyReply

Quote
You may want to look at this thread for more discussion on this topic

http://luminous-landscape.com/forum/index....opic=20081&st=0

Would someone like to perhaps enlighten me on why most medium format backs seem to forgo the AA filter?
and medium format backs are held up as the holy grail of image quality
[a href=\"index.php?act=findpost&pid=145765\"][{POST_SNAPBACK}][/a]

Are you suggesting that the lack of an AA filter on medium format backs  proves something?  We don't know what a MF camera could do with a properly designed AA filter. Maybe it is left off to maximize profit  .  It's all speculation.  Is the emperor dressed or naked?  We do know from theory and practice, that distortions can be observed in cameras without an AA filte. We are just arguing about exactly where the line is to be drawn. Maybe if you get a sharper lens you will be less thrilled with your AA-less camera.
« Last Edit: October 13, 2007, 09:22:42 PM by nma » Logged
jing q
Sr. Member
****
Offline Offline

Posts: 594


WWW
« Reply #10 on: October 13, 2007, 11:26:23 PM »
ReplyReply

Quote
Are you suggesting that the lack of an AA filter on medium format backs  proves something?  We don't know what a MF camera could do with a properly designed AA filter. Maybe it is left off to maximize profit  .  It's all speculation.  Is the emperor dressed or naked?  We do know from theory and practice, that distortions can be observed in cameras without an AA filte. We are just arguing about exactly where the line is to be drawn. Maybe if you get a sharper lens you will be less thrilled with your AA-less camera.
[a href=\"index.php?act=findpost&pid=145804\"][{POST_SNAPBACK}][/a]

yes I am suggesting it proves something.  
You can't get sharper than a Rodenstock HR lens that people use for architectural purposes with their medium format digital backs.
I'm sure they come across lots of air conditioning vents too.

regarding theory and practise I don't know why no one is talking about experience with actual prints rather than 100% on a computer screen
looks like no one believes me when I say that it's different...
« Last Edit: October 13, 2007, 11:37:23 PM by jing q » Logged
spotmeter
Sr. Member
****
Offline Offline

Posts: 309


WWW
« Reply #11 on: October 13, 2007, 11:38:38 PM »
ReplyReply

I just got the November issue of Photo Techniques, in which Mark Dubovoy compares several up-rezzing software options.  It's a well-written article with many comparisons of final results.  

He ends his article with a discussion of capture devices (cameras) and notes that up-rezzing photos taken with the Leica M8 are better than those taken with the 1Ds MkII, in part because of the lack of an AA filter in the M8.
Logged

feppe
Sr. Member
****
Offline Offline

Posts: 2909

Oh this shows up in here!


WWW
« Reply #12 on: October 14, 2007, 03:35:39 AM »
ReplyReply

Quote
I just got the November issue of Photo Techniques, in which Mark Dubovoy compares several up-rezzing software options.  It's a well-written article with many comparisons of final results. 
[a href=\"index.php?act=findpost&pid=145825\"][{POST_SNAPBACK}][/a]

Off-topic, but could you provide a Cliff's Notes about the article? It's been a while since I've tested the different uprezzers.
Logged

marcmccalmont
Sr. Member
****
Offline Offline

Posts: 1724



« Reply #13 on: October 14, 2007, 01:03:26 PM »
ReplyReply

Quote
Marc,

I appreciate the first hand account. Any chance that you could provide me a raw that shows the uber sharpness and an appealing image to boot. I am genuinely interested. The samples on maxmax just uninspire. I'd be happy to give you my FTP info for it.
[a href=\"index.php?act=findpost&pid=145815\"][{POST_SNAPBACK}][/a]
Yes of course whats your email address?
Marc
Logged

Marc McCalmont
Tim Gray
Sr. Member
****
Offline Offline

Posts: 2002



WWW
« Reply #14 on: October 18, 2007, 05:30:19 PM »
ReplyReply

Well, certainly in Michael's first comments on the 1ds3 the existence of the AA filter features prominently.

I'm more curious than ever if it's even possible for an aftermarket removal of the filter (particularly given the anti dust functionality).
Logged
Graeme Nattress
Sr. Member
****
Offline Offline

Posts: 582



WWW
« Reply #15 on: October 18, 2007, 06:22:14 PM »
ReplyReply

I'd not recommend it.... It's there for a reason - do you think Canon would like to get sharper images and reduce their camera's cost by removing it if they thought they could get away with it. You can criticise Canon all you like for not having a mirror lock up button or whatever, but when it comes to engineering digital cameras, in terms of performance and image quality, they certainly know what they're doing.

As for the medium format companies, I'd reckon that a defect free AA filter of the size they'd need could be rather expensive :-)

Graeme

Quote
Well, certainly in Michael's first comments on the 1ds3 the existence of the AA filter features prominently.

I'm more curious than ever if it's even possible for an aftermarket removal of the filter (particularly given the anti dust functionality).
[a href=\"index.php?act=findpost&pid=147035\"][{POST_SNAPBACK}][/a]
Logged

www.nattress.com - Plugins for Final Cut Pro and Color
www.red.com - Digital Cinema Cameras
Leping
Jr. Member
**
Offline Offline

Posts: 87



WWW
« Reply #16 on: October 18, 2007, 06:57:52 PM »
ReplyReply

For years unbiased people know Nikon models, especially the D70/D70s, use very weak AA filters, thus generally the per pixel sharpness is higher out of Nikon bodies.  My D2x provides around 30% more true resolution than my 5D, both with AA filter, and with over 90% of my work still with 4x5 and 6x7 film I am sure I know what I am talking about.

Like every manufacture, Canon, or anybody else, does not know everything they are doing.  The 1DIII AF problem is an example.  I shoot and love my 5D more than the Nikon, mostly because I spent more on higher grade Canon lenses, but I am amazed ingorant people talking about the "surperior Canon technology" with their heads burried in the sand.  For example I see repeatedly people are saying Nikon D3 steal Canon's 1DIII/1DsIII battery, while in fact Nikon started using the same battery for 3 years by now and the fact is just other way around.

In my native country China they have created special words to describe Canon images for landscape works, "ROU", which means muddy looking which is mostly from the AA filter.  My 5D does not have such problem since the filter has been removed and I had never problems with it.  I am speaking to people with large format film experiences and understand what a 30x40 fine print would look like, not the MP3 generation.

Quote
You can criticise Canon all you like for not having a mirror lock up button or whatever, but when it comes to engineering digital cameras, in terms of performance and image quality, they certainly know what they're doing.

As for the medium format companies, I'd reckon that a defect free AA filter of the size they'd need could be rather expensive :-)

Graeme
[a href=\"index.php?act=findpost&pid=147050\"][{POST_SNAPBACK}][/a]
« Last Edit: October 18, 2007, 07:00:19 PM by LEPING » Logged

Graeme Nattress
Sr. Member
****
Offline Offline

Posts: 582



WWW
« Reply #17 on: October 18, 2007, 07:12:26 PM »
ReplyReply

Sure Canon don't know everything, but both Canon and Nikon know that an optical low pass filter is a required element. You can debate back and forth on who's implementation is better, but as other factors effect the appearance of aliasing, like photosite fill-factor and microlenses (as does the MTF of the actual lens used), you can't easily do a "like for like" comparison. What I'd do (and indeed, this is what I do do) is get a large, high resolution zone plate test chart and shoot that. It shows you pretty much exactly what you need to know in terms of resolution and aliasing.

Graeme
Logged

www.nattress.com - Plugins for Final Cut Pro and Color
www.red.com - Digital Cinema Cameras
Monito
Jr. Member
**
Offline Offline

Posts: 96



WWW
« Reply #18 on: October 18, 2007, 08:30:26 PM »
ReplyReply

Quote
I've seen it mentioned before that there are effective software options to remove/reduce the resulting increase in moire - what works best?[{POST_SNAPBACK}][/a]

No software can do a good job of removing this moire ([a href=\"http://en.wikipedia.org/wiki/Image:Moire_pattern_of_bricks_small.jpg]GNU Licensed Image, usage allowed[/url]):

Logged

MonitoPhoto (Landscape, Architecture, Portraits: Halifax, Nova Scotia)
Ray
Sr. Member
****
Offline Offline

Posts: 8847


« Reply #19 on: October 18, 2007, 08:30:36 PM »
ReplyReply

Quote
My D2x provides around 30% more true resolution than my 5D, both with AA filter, and with over 90% of my work still with 4x5 and 6x7 film I am sure I know what I am talking about.
[a href=\"index.php?act=findpost&pid=147054\"][{POST_SNAPBACK}][/a]

What do you mean by 30% more true resolution? 30% more lines per picture height or picture width?

According to dpreview tests of line charts, the D2X delivers around 20% more lines per picture height than the 8mp 20D.

Perhaps you are referring to typical resolution in the corners of the frame where cropped 35mm formats usually have an advantage.
Logged
Pages: [1] 2 3 ... 10 »   Top of Page
Print
Jump to:  

Ad
Ad
Ad