Luminous Landscape Forum
Equipment & Techniques => Cameras, Lenses and Shooting gear => Topic started by: MarkSe on January 10, 2012, 08:39:47 am
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i bought a 24mm ts-e II today and made some test photos with my 5d I
check out the images, is this normal? (100% crop without editing)
the artifacts at the thin lines/ trees have nothing to do with uploading the images,
it does look the same in photoshop. ???
(http://up.picr.de/9219044jpq.jpg)
(http://up.picr.de/9219053lwx.jpg)
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What artifacts?
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i bought a 24mm ts-e II today and made some test photos with my 5d I
check out the images, is this normal? (100% crop without editing)
the artifacts at the thin lines/ trees have nothing to do with uploading the images,
it does look the same in photoshop. ???
What kind of artifacts do you refer to? Is this center crops or to the side? The very slight chromatic abberation is normal (probably demosaicing artifacts in this case though, 5D I pixels are too large to show the CA which is unusually small for a wide angle EF lens).
If you're referring to the JPEG comrpession artifacts, that's because it is JPEG not uncompressed RAW :-).
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If you're referring to the JPEG comrpession artifacts, that's because it is JPEG not uncompressed RAW :-).
i don`t think that this are jpeg compression artifacts, check out the raw file, it looks pretty much the same!
http://www.megaupload.com/?d=A344IFG7 (standarddownload)
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i bought a 24mm ts-e II today and made some test photos with my 5d I
check out the images, is this normal? (100% crop without editing)
the artifacts at the thin lines/ trees have nothing to do with uploading the images,
it does look the same in photoshop. ???
Hi Mark,
I'm also a bit puzzled about what we're looking at and what you are questioning. Maybe you can explain further, and/or have a look at some full size samples (http://www.openphotographyforums.com/forums/showthread.php?t=9350) I took with my 1Ds3, which has much smaller sensels and is therefore more prone to picking up lens aberrations.
Cheers,
Bart
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i don`t think that this are jpeg compression artifacts...
"this" being what? What we are saying is that we do not see the artifacts you are talking about. How about using arrows to point them out?
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i don`t think that this are jpeg compression artifacts, check out the raw file, it looks pretty much the same!
http://www.megaupload.com/?d=A344IFG7 (standarddownload)
I've looked at the CR2 and I see no artifacts. The jaggies in your screenshot is probably from too much sharpening applied, try disable sharpening alltogether and work from there. My raw converter's default sharpening expect softer pictures (smaller pixels more diffraction) so default sharpening is too much for your picture.
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i uploaded a 100% crop (tif file, not jpeg!):
http://www.flickr.com/photos/_marks/?saved=1
look at the fine details of tree! i think it shows a lot of aliasing artifacts ( http://upload.wikimedia.org/wikipedia/commons/8/88/Aliasing_a.png )
here is the raw file: http://www.megaupload.com/?d=A344IFG7 (standarddownload)
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i uploaded a 100% crop (tif file, not jpeg!):
http://www.flickr.com/photos/_marks/?saved=1
look at the fine details of tree! i think it shows a lot of aliasing artifacts ( http://upload.wikimedia.org/wikipedia/commons/8/88/Aliasing_a.png )
here is the raw file: http://www.megaupload.com/?d=A344IFG7 (standarddownload)
That may be because of the sharpening settings in the raw converter, which may be too aggressive. With sharpening disabled, there's no aliasing in the picture for me. Another problem may be if your software has a bad demosaicing algorithm. The artifacts look similar to the result you get if your raw converter use an AHD demosaicer. Which raw converter do you use? Those older lower res cameras with weak antialias filters are more sensitive to which type of demosaicing algorithm you use.
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I do not want to waste my time downloading and then embarking on a wild-goose chase, looking for something apparently only you see, while you do not even want to bother showing what you mean.
Besides, thanks for the educational link, but aliasing is software-related, has nothing to do with lens quality. Your post was titled: "24mm ts-e II / bad quality?"
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strange, i always used raw converter's default sharpening with all my lenses and never had problems with jaggies or artifacts.
my 17mm ts-e doesnt show any jaggies with the same default sharpening.
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look at the fine details of tree! i think it shows a lot of aliasing artifacts ( http://upload.wikimedia.org/wikipedia/commons/8/88/Aliasing_a.png )
Hi Mark,
Lenses don't produce aliasing, camera sensors and sharpening can create jaggies when the lens is sharp enough. I didn't check the aperture of your shot, but remember that the lens seems to be sharpest in the center of the image circle at approx. f/4, and that corners keep improving until, say, f/11 where the image center has dropped a bit of resolution due to diffracton.
Do note that that's on a sensor with a sensel pitch of 6.4 micron such as a 5DMark2 or a 1DsMark3. Other cameras can have different behavior due to AA-filter and sensel pitch + microlens design.
Converting your shot with Canon's DPP software converter with sharpening set to 3 or 4 produces sharp branches, but I'm not sure if that's what you focused on or on the background. The actual focus plane is usually sharper than the rest of the DOF zone (wherever you place that limit).
Cheers,
Bart
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I think this is actually evidence of your 24 TS-E II being really good (i.e., sharp) rather than bad. But you'll probably need to reduce your sharpening amount and maybe radius slightly.
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I think this is actually evidence of your 24 TS-E II being really good (i.e., sharp) rather than bad. But you'll probably need to reduce your sharpening amount and maybe radius slightly.
i think you are right. I also helps shooting at f13 or f16. The image gets a tiny bit softer and the aliasing disapears.
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Correct. Softer lenses (or softness introduced by diffraction, etc.) will effectively act as a stronger optical low-pass filter.
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i think you are right. I also helps shooting at f13 or f16. The image gets a tiny bit softer and the aliasing disapears.
I'm not seeing the problem you reported, however IMO f13 (much less f16) defeats the IQ of the 24mmTS-E II. Diffraction softening is noticeable on my 24mmTS-E II/5D2 at f11; by f13 it is pronounced. I get the cleanest corner-to-corner results with that lens by capturing at f8, and addressing sharpening issues at the appropriate software stage.
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Got this lens two days ago and I am very impressed by its IQ and blown away by the sharpness produced by the lens, insane :)
Usually I am not a pixel peeper but as I am working in Lightroom always do noise reduction and sharpening at 100% (1:1 ratio) so I could not avoid seeing this artifact looking like zig-zag or jagged lines often shown in periodic pattern with high frequency. See attached photos for example. On first example there is no sharpening applied at all in Lightroom (set to 0, and I am not sure if the raw-conversion use some kind of "hidden" sharpening algorithms) and also no output sharpening in jpeg export. In second example the sharpening is overdone and set to 50 to exaggerate the pattern.
I am not worried at all about this issue and it will never show up in prints made(largest print I do is A3+) but I am interested in a theoretical explanation why this phenomenon appears. I have never seen this with other Canon lenses I have used.
Edit: aperture used was f/5,6. Tilt applied but I did not wrote down its value as I was just playing around.
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I am not worried at all about this issue and it will never show up in prints made(largest print I do is A3+) but I am interested in a theoretical explanation why this phenomenon appears. I have never seen this with other Canon lenses I have used.
Hi,
The phenomenon is aliasing artifacts. They are a result of recording finer detail than the sensor can resolve, and it's more prominent on cameras without an Optical Low-Pass Filter (OLPF or anti-aliasing filter). In addition, some Raw converters use a demosaicing algorithm that's not the best at reducing the negative side-effects of aliasing. For example, Raw Therapee's Amaze algorithm, and Capture One's algorithms are better at extracting high resolution detail, while at the same time reducing the artifacts as much as possible (it will never be fully avoidable).
Because the TS-E lens has higher contrast near the resolution limits, the aliasing will be more visible, just like the detail is more visible. The effect will be strongest with your lens at apertures around f/4 to f/5.6, and narrower apertures will produce a more even sharpness from center to corner, but also be a bit lower contrast and less susceptible to aliasing due to diffraction blur.
As the resolution of sensors gets higher (smaller sensel pitch), the aliasing will reduce, but it would probably take a bit less than 1 micron sensel pitch to practically get rid of the aliasing, so we're not there yet, and these artifacts are unavoidable without reducing image contrast, especially with good lenses and good technique (tripod etc.).
Cheers,
Bart
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Thank you for the informative answer :)
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Is this artifact reduced by going from a Canon 6D(my current camera body) to a more higher density pixel sensor like the Canon 5Ds and by how much?
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Is this artifact reduced by going from a Canon 6D(my current camera body) to a more higher density pixel sensor like the Canon 5Ds and by how much?
Hi,
If we're talking about Aliasing artifacts, and the same focal length is used, then yes the artifacts are less likely to occur.
The sensel pitch of the 6D is approx. 6.58 µm, and the sensel pitch of the 5Ds is approx. 4.14 µm. So the detail that is too small to be reliably resolved by the 6D, might be resolvable by the finer pitch of the 5Ds, which would avoid aliasing.
For aliasing to occur, the aperture must be wide enough to avoid diffraction blur, the focus must be perfect, and spatial frequency of the image detail must be equal or smaller than the so-called Nyquist frequency of the sensor. Camera or subject motion can also create enough blur during the exposure time to prevent too small detail from reaching the sensor.
So it's hard to predict how much less the risk is, but it is less likely to occur on the 5Ds under the otherwise same circumstances.
Cheers,
Bart
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Hi,
If we're talking about Aliasing artifacts, and the same focal length is used, then yes the artifacts are less likely to occur.
The sensel pitch of the 6D is approx. 6.58 µm, and the sensel pitch of the 5Ds is approx. 4.14 µm. So the detail that is too small to be reliably resolved by the 6D, might be resolvable by the finer pitch of the 5Ds, which would avoid aliasing.
For aliasing to occur, the aperture must be wide enough to avoid diffraction blur, the focus must be perfect, and spatial frequency of the image detail must be equal or smaller than the so-called Nyquist frequency of the sensor. Camera or subject motion can also create enough blur during the exposure time to prevent too small detail from reaching the sensor.
So it's hard to predict how much less the risk is, but it is less likely to occur on the 5Ds under the otherwise same circumstances.
Cheers,
Bart
I would mildly disagree. If the subject has texture in every frequency - which would be often the case eg. a feather or a skyscraper with lots of detail, then you are just pushing the aliasing further into the details by using a finer resolving sensor - until your lens contrast at the fine frequencies runs out. There is a reason why Mandelbrot called his book "The Fractal Geometry of Nature", and although he was a horror to deal with his maths are beautiful.
Edmund