Some images crops ,moire and aliasing

crop from sved same size SPP

crop from saved double size in SPP

crop saved same size in spp

crop saved double size in spp

Interesting moire crop from saved double in spp

I gather this last shot was taken through a screen thus not really moire.

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I don't really understand the point of your post. Do you have one?

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Yes last one and second to last one were shot through screen . Second to last i focused on screen  and choose distance such that there only about 1 pixel between wires in the screen. Just for the heck of it original image no duble sizing no adjustments

Yes i have.

I was looking those over wondering if it was a screen or a double-size upsampling artifact!

Good to know, and glad to hear that was real...

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Screens can induce moire to the naked eye, so could be accurate depiction.

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Formerly posting as 'Blissfly'

I second that - what should i look for in the pictures?  I see a wonderful sharp chimney, here at 100%:



I normally don't take pictures through windows/curtains so i cannot comment the last to pictures.

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/Henrik - Denmark
(SD14 and SD15 ... and about 5 kg glass)

Question:

Is that diagonal cable made up of twisted strands like it looks or is that an artefact?

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I am glad that you have an intention with the post. Would you like to share it with us? (And, please, do not just answer: "Yes")
Because if you do not tell, I would be tempted to call your opening post very unuseful.

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Kind regards
Øyvind

I'm sure he's shaking in his boots:-P

... all I can make of your post is that you have a bent for pixel peeping but with some strange purpose, which does not in real terms relate to making pictures to view as such.

Sorry - but that's what this post appears to be in the real World as distinct from being of any practical use to those wanting to make pictures.  So, if you really did have a specific purpose for posting, why not explain it a bit better. 

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Ahhhh . . . the "Real World" card, haven't seen that played lately, lol.

Here's a real world scene showing the difference between LO res and HI res (SD10):

In glorious greyscale

Looks a bit better if view as original.

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Ted http://tcktek.blogspot.com
SD10/70mm macro

It is made of twisted strands of cable plus supporting steel cable. Point of this was to add my 2 cents worth yada yada to yada yada about aliasing :-). Not that it does not exists but you have to work  to get it

The shots tell me thatz SPPs double-size output is not worth it but that is not exactly news

If you examine image 4 carefully, you'll see a great deal of aliasing.

- the bushes in front of the house one in from the left

- the vertical cables attached to the left hand wall next to the porch

- The wires that dip down under the porch next to the window

- Just about all the wires going from the porch to the join the thicker wires

- the foliage in the background behind the house with two cars is just a mess of aliasing

There is nothing new in this at all: Foveon images always look like this because of the absence of an AA filter and the pixel level sharpness.

It appears that most people don't see it, don't care or actively like it (because it looks crunchy sharp). Leica images, the Fuji x-trans and some NEX cameras do similar things. To my eyes it isn't "natural, film like", it screams digital but it's a matter of taste, I guess.

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David,

The problem is that you look at the image on a device which uses square or rectangular pixels to create the image you see, and you look at it at great magnification.

When the image is printed, it's printed either with continuous tone or with tiny droplets of ink which are round and not rectangular. I've looked at literally hundreds of very large prints from Foveon captures and when properly processed it's nearly impossible to see any of these issues you bring up. All that I see are beautifully sharp and colorful prints which, when compared to the same captures from my CFA cameras are usually superior.

Perhaps printing is not something you particularly care about - some people never print, but I guarantee you that professionals who do look at very large Foveon prints alongside CFA prints of the same scenes by high resolution CFA cameras are nearly always impressed favorably by the Foveon results. This has been demonstrated time and again by reviewers and photographers, yet there are those who seem to either not understand this or can't get past their bias for blur filtering. Leica, Nikon, Kodak and other manufacturers other than Sigma are now realizing this and producing cameras which are not compromised by the decrease in resolution and softening of the images by the AA filter. Do you really believe that they produce these cameras in a vacuum? Do you believe that they do not do their marketing homework before they invest in the production of an instrument to avoid the use of the AA filter?

It's a choice David. It's a choice which many prefer over the aliasing left (and I do know the meaning of the term aliasing) when the AA filter creates "mush" of everything above Nyquist. Yes, the very "filter" which cuts the resolution at Nyquist leaves "nothingness" and that "nothingness" is quite recognizable in significant enlargements as smears of color and grey between visible detail objects. Some may prefer this to "false" detail or as you are more fond of saying "aliasing noise," but many of us don't. So pointing to aliasing and suggesting that you would like to see a Foveon image with an AA filter is counter to that very thing which many of us like about the Foveon sensor. Don't you think that if the image produced by the Foveon were improved by the addition of an AA filter that Foveon would have engineered the sensor that way? Do you really think that they have not tried an AA filter and found it to be detrimental to the image? Give them a little credit. Kodak produced cameras for many years which had removable AA filters which were sold as an expensive (around $2000.00) option. I had one. Most of the time I used the camera without it because the image quality was enhanced.

Please, accept the fact that Sigmas simply do not use AA filters and that the majority of us who use these instruments professionally and for pleasure like it that way and that we are "very" happy with the results we get. When we need or want an AA filter, we reach for our other cameras which have them in abundance.

Best regards,

Lin

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Of course there is most of those branches less than one pixel in thickness number 76 on the house the same thing but if you save it double size in SPP ( actually consensus in here that SPP does poor job in that regard i don't know) and print it is easy 30 inches wide printout i did print out dp1 files 20 inch wide with no problems. This why i provided crops from farther away where lots of details less than 1 pixel wide for sure. This why i did shots through the screen, to tell the truth last one i just like how it looks like. Especially in print, gives impression of canvas and cloud looks like flaking paint  but maybe it just me i am not a professional not even an amateur just dabbling for fun in a spare time.

Thanks for the lecture.

I don't seem to remember a post of mine on that subject in this thread beyond noting my observations on the posted images and a statement of my own preferences (and acknowledging my minority position on this forum in this respect).

Glad you brought up Kodak. I still own my 14n, the most expensive piece of photographic kit I've ever bought, and undoubtedly the worst digital SLR camera ever made. That camera is not an advertisement for the advantages of removing the AA filter....

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You can not get aliasing, nor can you get moire, with a single object like a twig. Neither can "jaggies" on a straight edge be called aliasing - although they are artifacts in their own special way.

So any object like a twig (or a star) that is in good contrast with it's surroundings will show up in the image, even it is less than one sensel at the image plane.

From the classic movie:

"What we have hyah is a failyah to communicate"

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Regards,
Ted http://tcktek.blogspot.com
SD10/70mm macro