What is going on here ?

XO-Studios · September 20, 2005

I have seen a phenomena, of which I am not sure where it stems from, maybe someone here has a clue, I am not sure if they are:
1) sharpening artifacts
2) JPEG artifacts
3) camera by-product
4) something optical
5) SM resizing/re-compressing
6) Something with my laptop screen

Anyway, look at this thread: http://www.dgrin.com/showpost.php?p=165943&postcount=1 (Thanks GSGary)

Notice immediate above the rider, especially the helmet where it transition to the grass, on my system I see somewhat of a halo, approximately 3-5 pixels (guess) away.

Now different thread, different photographer (DavidTO): http://www.dgrin.com/showpost.php?p=165315&postcount=1

Look immediately above the black hood, similar distance away 3-5 pixels.

What causes this ?

I have not looked at any other pictures yet, but I am wondering if anyone here has a clue where this is coming from?

Inquiringly,

XO,

XO-Studios · September 20, 2005

Both to bump this, and to give my best guess.

It looks that in transitions from in focus to OOF areas, either the in camera, or in software sharpening creates a sharpened edge. The halo is merely the start of teh area where you can see the transition from random blur/OOF pixels to wher the sharpening algorythm started to do 'its-thing' to get to the sharpely defined edge. Now this is siimply my best guess, I am still very curious to answers from some of the others here.

XO,

erich6 · September 21, 2005

I think it's a compression artifact. I see it in a lot of my pictures after I post them to smugmug. Usually more noticeable in the medium to small thumbnails but I see them in large ones as well.

Erich

XO-Studios · September 21, 2005

erich6 wrote:

I think it's a compression artifact. I see it in a lot of my pictures after I post them to smugmug. Usually more noticeable in the medium to small thumbnails but I see them in large ones as well.

Erich

Erich,

Since you see it in your pictures, before and after, could you post a 100% (or 200% crop here and a picture showing the phenomena. I am very curious as to what causes this, more specifically, I seek to understand, so I can circumvent or prevent this.

XO,

erich6 · September 22, 2005

OK. Here's Smugmug's "large" version of one of my images:

If you look closely you'll see the artifact around the edges of the lighthouse and the edges of the trees with the sky background.

Here's the 100% crop of this shot around the lighthouse. I made this crop from a downloaded version of Smugmug's "large" file and upsampled it to the same resolution as the 100% crop of the original JPEG I made on my computer.

And here's a 100% crop of the JPEG I made in Photoshop. No artifacts.

Erich

Khaos · September 22, 2005

Bottom line though is that the prints don't have the artifacts since they use the original right?

I don't think pixel peepers buy prints from others. They either print their own or pay someone to print their own.

People who purchase aren't looking for that and probably will never notice it without being told what to look for.

It also make me happy to know that if some jerk wants to print from his temp file the large image he got from my gallery, it won't be the quality he was expecting. People will steal, and I know how to expect acceptable losses.

If a photo is a good one it will still look good even with some artifacts. That's just my 2 pennies worth of opinion.

XO-Studios · September 22, 2005

My main thing is that it has become pretty clear that for some techniques to be properly reflected and discussed here, they need the full picture in large/800 pixel width as that is a limit for the forum, but also some areas at 100% crop to properly reflect upon techniques such as sharpening or other artifact creating techniques.

This to properly judge which artifacts are introduced by SM and which are introduced by the technique.

Interesting discussion so far.

XO,

erich6 · September 22, 2005

I never see artifacts in the prints I get from Smugmug. They're pretty good quality and good color match to my calibrated monitor. I can't say the same for many labs. They are obviously using the originals for printing.

I can see XO's point though. We need to be cognizant of what the compression does to the image so when we critique somebody's photograph we know what they had control over and what is just an artifact of posting.

Erich

digismile · September 23, 2005

When working on a challenge photo last year, I came to a similar conclusion as XO. The resampling that was taking place to create a small/medium/large-sized smugmug file introduced some unwanted artifacts. Some photos were much more evident than others (and some hardly noticable at all), so since then, I have made it a habit to resize my photos (that I want to display only in a forum) to 800 x 600 in Photoshop.

This is really a similar issue when sharpening. The sharpening needs to be tailored to the final size and output desired. I think it's a great feature of smugmug that we can display our photos at a variety of sizes and we only need to upload one file. I don't expect each resolution to be optimal to my original upload size.

But for whatever reason, I often don't notice these imperfections in other people's photos. Or maybe it's not that I don't notice, but my mind is prepared to accept a little "noise" and smooth things out, because it's the overall photo that is grabbing my attention. It's kind of like music. I can accept little mistakes from a favorite musician if the performance is still magic.

Good topic XO.

Brad

gsgary · September 23, 2005

They looked ok before i uploaded them

What is going on here ?

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