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03-30-2015, 12:12 PM   #1
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Dark edge / outline in photos

Hi folks... Firstly, apologies if I'm posting this in the wrong area of the forum (this is my first post in a long time - might even be my first ever post, actually).

So... I was playing around with a new lens (well, new to me!) yesterday and on a number of shots I noticed a troublesome "edge artefact" in certain areas. See the attached 100% crop... technique-related issues aside (focus, exposure, etc. etc. !!), you can see that, along the left-hand / underside edges of some of the flower buds and the stem, there's a fairly pronounced grey/black line. Is this something to do with CA and / or the sharpening algorithm I've selected in-camera? Both the RAW and JPEG images show the same phenomena, and I haven't carried out any post processing except for gamma correct. Lighting was obviously coming from the right.

Any opinions or thoughts on what's causing this would be much appreciated. I'm using a K3 with current firmware, and have the camera set to standard sharpness 2. The lens I used was an old Vivitar 28mm. Many thanks in advance!

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03-30-2015, 12:23 PM - 1 Like   #2
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I would try less sharpening and see if it's still there. This looks a lot like the effect of over sharpening.

Last edited by Parallax; 03-30-2015 at 12:33 PM.
03-30-2015, 12:25 PM   #3
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QuoteOriginally posted by BigMackCam Quote
Hi folks... Firstly, apologies if I'm posting this in the wrong area of the forum (this is my first post in a long time - might even be my first ever post, actually).

So... I was playing around with a new lens (well, new to me!) yesterday and on a number of shots I noticed a troublesome "edge artefact" in certain areas. See the attached 100% crop... technique-related issues aside (focus, exposure, etc. etc. !!), you can see that, along the left-hand / underside edges of some of the flower buds and the stem, there's a fairly pronounced grey/black line. Is this something to do with CA and / or the sharpening algorithm I've selected in-camera? Both the RAW and JPEG images show the same phenomena, and I haven't carried out any post processing except for gamma correct. Lighting was obviously coming from the right.

Any opinions or thoughts on what's causing this would be much appreciated. I'm using a K3 with current firmware, and have the camera set to standard sharpness 2. The lens I used was an old Vivitar 28mm. Many thanks in advance!
Looks like motion blur from the plant blowing in the wind.
03-30-2015, 12:31 PM   #4
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Thanks for the quick responses!

I'll try different sharpening settings next time and see how that affects things.

Very interesting comment re motion blur. In fact, it *was* windy, and I was shooting with a relatively slow shutter speed (about 1/200 as I recall). I guess I'd have expected more of a blur than a hard edge from that, but again I'll experiment and see what results I get...

03-30-2015, 12:32 PM   #5
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http://www.photos4u2c.net/2009/08/08/get-control-of-your-sharpening-halos-sh...ion-to-istock/
03-30-2015, 12:45 PM   #6
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Could also be caused by in-camera aberration corrections, but that would only apply to the JPEG unless you've manually done corrections in the RAW. In this case it looks more like sharpening.

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03-30-2015, 02:05 PM   #7
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Going along with Adam's comment... what software are you using to evaluate the RAW file. My guess is that if you are using the Pentax utility, then you will likely see the same thing, initially. You could dial back the sharpening, however, and perhaps it would go away.

Otherwise, if you are using a different software, you might want to undo as much automatic fixes as possible and work through the sharpening and lens corrections independently to see if anything presents itself as a solution.
03-30-2015, 02:42 PM   #8
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Not an expert, but I think that may be CA accentuated by oversharpening.

03-31-2015, 09:49 AM   #9
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It looks oversharpened to me.
03-31-2015, 10:18 AM   #10
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QuoteOriginally posted by sadatoni Quote
It looks oversharpened to me.
Agreed, though there is a ton of additional artifact probably caused by PP.


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03-31-2015, 10:34 AM   #11
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Thanks for all of the responses. Just to be clear, I carried out no post-processing on the file other than a little gamma correction. The crop I provided is from the JPEG, but the RAW file shows the same effect, and most importantly, in-camera (I can zoom into the RAW image on the lcd screen and clearly see the dark edge). As for sharpening, I only applied standard sharpening in-camera, set to 2.

Looking at other photos I've taken with this lens, it does appear to be quite prone to green CA in certain conditions.

The weather has been terrible here today (strong wind, rain and sleet!) so I haven't had a chance to experiment further, but will hopefully manage to do so tomorrow. I'm keen to take some pics with different in-camera sharpening settings to see if that affects it.

Out of interest, is there a preferred in-camera sharpening setting?

@Parallax - that article on sharpening halos was fascinating. Thanks for the link!
03-31-2015, 10:46 AM   #12
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Looks like chromatic aberration which is more pronounced with older lenses
You can do a search on You Tube for ways to correct this, depending on your post processing software.
03-31-2015, 11:11 AM - 1 Like   #13
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Just re-read my original post. I was having a "senior moment" re the lens. It's a Tokina RMC 28mm F2.8 - *not* Vivitar
03-31-2015, 06:49 PM   #14
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Well, really, the Vivitar 28 and the Tokina RMC 28 are probably the same lens. But trust me, the Tokina 28mm RMC (not the better spec SL) is a really crappy, low contrast lens. I used to sell them by the boat load in the early 1980s - and they were, ah, economy lenses then. The temptation always will be to over-sharpen the image on any digital RAW, and add too much contrast.

The output sharpening looks like Silkypix to me. Pretty sure you couldn't get there with Capture One, or even Lightroom.

Bottom line: bad lens, bad, over-processed RAW conversion (marginal RAW program?) - makes a good sensor look really bad.
04-01-2015, 04:53 AM   #15
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QuoteOriginally posted by ScooterMaxi Jim Quote
Well, really, the Vivitar 28 and the Tokina RMC 28 are probably the same lens. But trust me, the Tokina 28mm RMC (not the better spec SL) is a really crappy, low contrast lens. I used to sell them by the boat load in the early 1980s - and they were, ah, economy lenses then. The temptation always will be to over-sharpen the image on any digital RAW, and add too much contrast.

The output sharpening looks like Silkypix to me. Pretty sure you couldn't get there with Capture One, or even Lightroom.

Bottom line: bad lens, bad, over-processed RAW conversion (marginal RAW program?) - makes a good sensor look really bad.
Thanks for that. Yeah, I figured the lens wasn't great generally after various tests, although centre sharpness is decent enough... Oh well, it was cheap!!

Re processing: the crop I posted was the camera JPEG (highest quality setting) loaded into Photofiltre, just a little gamma correct, and then cropped and saved with fairly heavy compression to keep the file size low for posting here. That probably accounts for the overall quality of the image - BUT, the RAW file, viewed in-camera, clearly has these dark edges visible...
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