7D & 'Mazing' (serious question)

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Archive 2009 · 7D & 'Mazing' (serious question)

omarlyn
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p.1 #1 · 7D & 'Mazing' (serious question)

Before I get to my question, I want to make it clear that I am not trying to fan any flames here between those that have posted (sometimes contentiously) about the 7D's 'mazing issue'. Without turning this thread into a back-and-forth arguement, I genuinely want to understand how to 'see' the 'mazing' that's been discussed ad nauseum.

My question/observation is the following: I've had my 7D now for just a few days and I haven't seen any 'mazing' as has been described in multiple posts here. However, I did notice that when I view a RAW image beyond 100%, I can see the actual pixels of the image. I'm not saying that some people are not genuinely having a problem but I do want to fully understand what I should look for. At low ISO on an OOF area, all I see @ 100% (using DPP) is OOF (with maybe just a few sharpening artifacts). When I view @ 200%, I see alot of blocky pixels so I don't know what difference any 'mazing' would make at this point. Is the 'mazing' pattern larger, smaller, or the same size as the blocks of pixels?

Omar

Edited on Nov 17, 2009 at 04:14 PM · View previous versions

Nov 17, 2009 at 03:39 PM

Future Man
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p.1 #2 · 7D & 'Mazing' (serious question)

Well look at the 5DII. Lots of people go wild over the pattern noise. I think what to take away from this is that EVERY camera has it's little quirks and oddities and you have to learn to work around them. There are certain ways to push every camera to get the best possible images.

Sorry this didn't have to do specifically with the 7D, but I just wanted to put this out there.

Nov 17, 2009 at 03:44 PM

stevet
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p.1 #3 · 7D & 'Mazing' (serious question)

The way to differentiate between 'seeing the individual pixels' and the 'mazing' artefacts is to look at an area of evenly illuminated solid single colour. Where adjacent pixels are the same colour you should not be able to 'see' them - if you can, then there are artefacts...

Cheers,

Nov 17, 2009 at 04:02 PM

cameron12x
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p.1 #4 · 7D & 'Mazing' (serious question)

There are many posts about the "mazing effect" and the negative impact it may have on real-world shooting in the master 7D thread but (as others have suggested), it may be a good time to separate this single topic from the master thread and focus on it here?

One school of thought is that the mazing effect manifests itself differently among different copies of the 7D, leading some to believe that this is a Canon QA/QC issue (G1/G2 channel imbalance). Others believe it's a design flaw in the sensor itself. Still others believe it's a mechanism by which Canon is using to deliver lower noise at high ISO settings, at the expense of leaving more noise at lower ISO settings. Some folks with good 7D copies are not seeing it at all (or minimally). Different converters, as expected, provide different results. Your results may vary.

The bottom line is that in some 7D copies it does seem to negatively affect image quality (leading to "harsh" looking images), and also perhaps prevents the camera from reaching its full 18mp potential for those copies affected (sharpening in post may have limited usefulness, as it may exacerbate the maze artifacting, degrading the overall image even further).

This is a VERY hot topic, and the jury is still out on it in many dimensions.

Edited on Nov 17, 2009 at 10:39 PM · View previous versions

Nov 17, 2009 at 04:11 PM

garycoleman
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p.1 #5 · 7D & 'Mazing' (serious question)

i think they forgot to put the letter A on mazing

Nov 17, 2009 at 05:11 PM

skibum5
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p.1 #6 · 7D & 'Mazing' (serious question)

omarlyn wrote:
Before I get to my question, I want to make it clear that I am not trying to fan any flames here between those that have posted (sometimes contentiously) about the 7D's 'mazing issue'. Without turning this thread into a back-and-forth arguement, I genuinely want to understand how to 'see' the 'mazing' that's been discussed ad nauseum.

My question/observation is the following: I've had my 7D now for just a few days and I haven't seen any 'mazing' as has been described in multiple posts here. However, I did notice that when I view a RAW image beyond 100%, I can see the actual pixels of the image. I'm not saying that some people are not genuinely having a problem but I do want to fully understand what I should look for. At low ISO on an OOF area, all I see @ 100% (using DPP) is OOF (with maybe just a few sharpening artifacts). When I view @ 200%, I see alot of blocky pixels so I don't know what difference any 'mazing' would make at this point. Is the 'mazing' pattern larger, smaller, or the same size as the blocks of pixels?

Omar

now this image had a TON of shrpening applied just to make the differences clear, notice that the upper left has a realmazing look to it with spiralling extended straight lines looking nothing like random noise, the one on the top right is a better copy of the 7D where the mazing is starting to blend into a normal noise pattern, the bottom right is a 50D, at this insane level of sharpening it has artifacts but they are largely random looking without more than a tiny trace of mazing structure and bottom left is a 5D2 sample comparing that to the one above it makes it clear how the mazing noise has an enitrely different structure to regular noise.

This image is copyrighted by the owner

different converters reveal mazing to different degrees, DPP shows it less and tends to break it into dotted lines (it also is beginning to seem like DPP smooths over areas of low contrast); current versions of ACR (and a few other) show it the most

here is one copy of the 7D with very, very normal processing:

This image is copyrighted by the owner

and 20D:

and a typical 50D copy:

This image is copyrighted by the owner

when looking at raw data the 7D tends to show one of the green channels having less noise than the other and slightly higher avg values (on the same patch) than the other and many tend to have a repetitive pattern of varying gain column to column on the green channels. some have it low enough that it doesnt seem to mess too badly with raw converters, quite a few seem to have the variances enough to cause artifacts/more noise after demosaic. perhaps doing all sorts of tricky stuff will allow acr 5.6 to handle copies better.

Nov 17, 2009 at 07:12 PM

jorkata
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p.1 #7 · 7D & 'Mazing' (serious question)

omarlyn wrote:
I genuinely want to understand how to 'see' the 'mazing' that's been discussed ad nauseum.

If you view images @ 200%, the mazing effect is manifested as those little horizontal and vertical patterns in skibum’s orange patches above.

Notice that the 50D and 5DII do not have them and that even the good 7D copy has them.

In addition, you might see salt & pepper noise – the black and white specks scattered around in shadows and other underexposed areas.

Nov 17, 2009 at 08:26 PM

cameron12x
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p.1 #8 · 7D & 'Mazing' (serious question)

These "tests" definitely provide value, but what would make this all more understandable (and perhaps more germane and usable) to folks is to shoot "real-world" images side-by-side, comparing the output from each camera.

Nov 17, 2009 at 08:38 PM

deepbluejh
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p.1 #9 · 7D & 'Mazing' (serious question)

Honestly, I see a little bit of this in the 5DII files from time to time. It is minimal to say the least and I can honestly say that it doesn't effect any of my work to any practical degree.

Nov 17, 2009 at 08:43 PM

Sam N
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p.1 #10 · 7D & 'Mazing' (serious question)

deepbluejh wrote:
Honestly, I see a little bit of this in the 5DII files from time to time. It is minimal to say the least and I can honestly say that it doesn't effect any of my work to any practical degree.

Ditto. It's only been really noticeable in one shot, and that was directly into the sun. The RAW converter used also has an effect on it.

Basically, don't worry about it. Shoot pictures and enjoy your camera.

Nov 17, 2009 at 09:05 PM

Daniel Heineck
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p.1 #11 · 7D & 'Mazing' (serious question)

Curious: how does a shot which manifests mazing print at typical ppi? (180-300, lets say)

I would think the dithering patterns of a printer to actually frustrate the effect.

In web shots it'll never matter as the details get crushed away in the downrezzing.

D

Nov 17, 2009 at 09:23 PM

cameron12x
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p.1 #12 · 7D & 'Mazing' (serious question)

Daniel Heineck wrote:
Curious: how does a shot which manifests mazing print at typical ppi? (180-300, lets say)

I would think the dithering patterns of a printer to actually frustrate the effect.

In web shots it'll never matter as the details get crushed away in the downrezzing.

D

I believe that for the most part we won't see much of the effects of this unless we're displaying cropped images on the Internet, or making large prints (or prints of cropped images).

So, at the end of the day, for some applications (and for very discerning folks), it still may matter.

Nov 17, 2009 at 09:36 PM

abqnmusa
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p.1 #13 · 7D & 'Mazing' (serious question)

You can see this "mazing" or artifacts in any camera viewed at 200% plus. I saw it in the full frame 5D, 20D, 10D, 40D, 7D, D3, D300. But not at 100%

Looking at at image beyond 100% is just created artifacts that are not in the data. There is nothing beyond 100% in the image.

Edited on Nov 17, 2009 at 11:13 PM · View previous versions

Nov 17, 2009 at 09:45 PM

dswiger
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p.1 #14 · 7D & 'Mazing' (serious question)

Nov 17, 2009 at 09:53 PM

abqnmusa
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p.1 #15 · 7D & 'Mazing' (serious question)

My 7D processed RAW files are printing just fine. No mazing ruining the image.

Nov 17, 2009 at 09:55 PM

NCAndy
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p.1 #16 · 7D & 'Mazing' (serious question)

Is the mazing visible in jpegs straight from the camera? Or is this a RAW conversion issue?

Nov 17, 2009 at 10:02 PM

Tim Ashton
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p.1 #17 · 7D & 'Mazing' (serious question)

garycoleman wrote:
i think they forgot to put the letter A on mazing

OK. Here is yet another Nikon troll getting into the act

From what I have seen and heard from a couple of owners and a retailer I reckon Gary is very close to the truth

What I see on various FM sites only supports that. If I had Canon glass and were looking to / could afford to upgrade, I would be in there like a shot,

Tim

Nov 17, 2009 at 10:07 PM

NCAndy
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p.1 #18 · 7D & 'Mazing' (serious question)

Tim Ashton wrote:
garycoleman wrote:
i think they forgot to put the letter A on mazing

OK. Here is yet another Nikon troll getting into the act

From what I have seen and heard from a couple of owners and a retailer I reckon Gary is very close to the truth

What I see on various FM sites only supports that. If I had Canon glass and were looking to / could afford to upgrade, I would be in there like a shot,

Tim

I'm looking forward to getting my 7D tomorrow. But, sometimes I just don't know what to think about all these 7D complaint threads. Obviously they didn't prevent me from getting one and making up my own mind. Many of the images posted at FM have really been quite good.

Nov 17, 2009 at 10:15 PM

paulfeng
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p.1 #19 · 7D & 'Mazing' (serious question)

NCAndy wrote:
I'm looking forward to getting my 7D tomorrow. But, sometimes I just don't know what to think about all these 7D complaint threads. Obviously they didn't prevent me from getting one and making up my own mind. Many of the images posted at FM have really been quite good.

I don't know that it's fair to dismiss some of these discussions as "complaint" threads. I very much want my 7D to perform as best it can. US$1700 is a lot of money for me, and I think the camera should work up to its potential.

In comparison, when I spend $4 on a mail order iPod FM car transmitter, and it turns out to be nearly useless, I chalk it up as a lesson to myself and I don't start a thread on an iPod enthusiast website (nor do I bother returning it for a refund).

Nov 17, 2009 at 10:23 PM

Nick Nishizaka
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p.1 #20 · 7D & 'Mazing' (serious question)

I agree with the others in saying that this has not affected my shots at all and I never view my images at 200%. Not to say that the problem isn't there...but what I don't see won't hurt me!

Nov 17, 2009 at 10:28 PM

skibum5
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p.1 #21 · 7D & 'Mazing' (serious question)

cameron12x wrote:
These "tests" definitely provide value, but what would make this all more understandable (and perhaps more germane and usable) to folks is to shoot "real-world" images side-by-side, comparing the output from each camera.

yeah, I sold all my other APS-C bodies long ago though so all I have is the test chart that I can replicate.

Nov 17, 2009 at 10:34 PM

cameron12x
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p.1 #22 · 7D & 'Mazing' (serious question)

Nick Nishizaka wrote:
I agree with the others in saying that this has not affected my shots at all and I never view my images at 200%. Not to say that the problem isn't there...but what I don't see won't hurt me!

The OP used 200% as an example (I'm not sure why), but Skibum's test samples are actually shown at 100%.

Edited on Nov 17, 2009 at 10:40 PM · View previous versions

Nov 17, 2009 at 10:35 PM

skibum5
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p.1 #23 · 7D & 'Mazing' (serious question)

Sam N wrote:
deepbluejh wrote:
Honestly, I see a little bit of this in the 5DII files from time to time. It is minimal to say the least and I can honestly say that it doesn't effect any of my work to any practical degree.

Ditto. It's only been really noticeable in one shot, and that was directly into the sun. The RAW converter used also has an effect on it.

Basically, don't worry about it. Shoot pictures and enjoy your camera.

yeah, with lots, if maybe not all, 7Ds it shows up WAY way more than it did on almost any 10D,20D,30D,40D,50D,5D2,1D2's though.

Nov 17, 2009 at 10:36 PM

skibum5
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p.1 #24 · 7D & 'Mazing' (serious question)

abqnmusa wrote:
You can see this "mazing" in any camera viewed at 200% plus. I saw it in the full frame 5D, 20D, 10D, 40D, 7D, D3, D300. But not at 100%

Looking at at image beyond 100% is just created artifacts that are not in the data. There is nothing beyond 100% in the image.

that is ridiculous that would be like saying printing at different sizes of viewing on different monitors makes up RAW data

(note I didn't use interpolation, just 1 pixel to 4 pixels straight blow up)

and it just makes it clearer that the harshness is due to mazing and not just general noise or something else and prevent jpg compression from altering the patterns

and as for you can see it any camera, well I never noticed it in any images I processed from all those other cameras and I noticed it in the very first 7D image I ever procesed (the IR test shot) and even when i applied crazy amounts of processing I still could only make out the barest hints of it with the other cameras, if even.

some 7D do seem to resist it noticeably better than others and only marginally worse than the other canons so it might not matter with those copies

and yes i know at the end of the day, for many photos it's lighting that matters more than what camera or lens or anything

for my usage, since I do already have a 5D2, I would be doing lots of heavy crops since the 7D would mostly be my "reach" body and i'm not so sure that my old 50D didn't do better at that (although it did have worse AF, was slower, etc.) than my 7D copies (although some copies like pauls might do better)

and do we really want canon to go this way with future bodies where the exact raw converter is now suddenly a critical issue and unless you buy 4 bodies and cherry pick the best one, you need to mess around with trading off fine detail vs. artifacts when a little better QC might mean just tossing files around however you like as with the previous releases and not have some people ending up with copies with 80-100% worse noise at some ISOs than other copies (which is a huge, huge variation compared to any previous canon release)?

Edited on Nov 17, 2009 at 11:06 PM · View previous versions

Nov 17, 2009 at 10:38 PM

skibum5
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p.1 #25 · 7D & 'Mazing' (serious question)

NCAndy wrote:
Is the mazing visible in jpegs straight from the camera? Or is this a RAW conversion issue?

much less in jpgs since canon's algorithm tends to break it into dotted lines instead of solid lines to begin with and also doesnt try to extract as much detail for lower contrast areas and jpgs tend to sort of smear details away compared to whatever you do with RAW files

Nov 17, 2009 at 10:39 PM


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