technical issue?

[sarah_19_nz]

Not looking for critique on this shot BUT I want to know what is causing the 'posterized' look on my grey background when you zoom in really close??? Can you see what I mean? Am I over sharpening in Lightroom? Perhaps bringing up the exposure too much causing degradation of the image? Its like 'pixel'y' What IS it and how do I fix it? It isn't as bad or even there at all on the JPG version. Cheers!

 

[lambertpix]

Could it be compression artifacts on the exported JPG? What's your quality set at when you export?

 

[sarah_19_nz]

i have NO idea! where do I look for this? I have lightroom 5 (and still learning the ropes)

 

[Derrel]

It's such a small image it's difficult to see much...I think I see what you mean in the gray background, but...again, a 1,000-pixel image compressed that much and converted to sRGB is not going to look all that good. Just looking at the lighting setup, and the brightness of her face, my guess is that yes, you've "lifted" the exposure too much, and are seeing some mottling in the gray background. Noise tends to show up most severely and noticeably in large areas of smooth texture, and if one "lifts" the exposure in post, noise can be exacerbated.

Also...the background is being lighted by light that's coming in from off to one side. A portion of the problem is the angle at which the light is actually grazing across the background paper itself; the side-lighting angle of the main light is also hitting the background paper, and is showing some very subtle shadows and subtle texture clues. Dues to the small sensor camera, and the short focal length, and her closeness to the background paper AND the f/7.1 lens aperture, the background paper is "almost" in the depth of field band...and that's why the texture is showing up a bit.

In other words, a small-sensor camera with a short lens at f/7.1 has what many would call "too much depth of field" to throw the background paper totally out of focus.

 

[sarah_19_nz]

absolutely Derrel. I have such a fear of using a wide aperture (scared I won't get everything in focus) I need to relax the 7.1 a little. And yes this photo was actually a 'screw up' that I needed lifting the exposure a ton!

 

[sarah_19_nz]

it happened badly in areas of her hair in other photos too. I'll see if I can zoom in and post one

 

[sarah_19_nz]

can you see it here in the darkest part of her hair, above her ear. If not ill screenshot exactly what I can see on my screen.

 

[sarah_19_nz]

here you go...

 

[Derrel]

Well, you needed more actual "lighting" in the dark areas. The dark areas are quite under-exposed compared against the light-struck parts of her face...the shadow side of the exposure is not all that clean...on a subject like a standing woman, your light source was too small and too far behind the line of her nose, so the whole,entire left hand side of frame #1 was in shadow...to avoid loss of image quality in the final image, you need to keep that AS SHADOW, or risk showing the sensor's rendering of the darks with some chroma noise...the color speckling is not "all that bad", but it is there. The issue is that if the shadows are kept DARK, then the image looks fine; the problem arises when a severely under-exposued, dark toned area, like her hair, needs to be "lifted" in post...

If you would have moved the light around and aimed at her from a more frontal angle, then there would have been more light in the shadowed parts of her, and her dark hair would have been moved "upward" in the exposure.

The other option would have been to have exposed MORE-generously, like f/5.6, and then pulling the highlights "back". That would have been preferable to under-exposing and then "lifting" the exposure in post-processing.

You ask if this is a technical error. Well...I suppose it could be considered simply under-exposing. Or shooting with inadequate fill lighting. Or less-than-optimal placement of the main lighting. Or not having a flash meter to guide you as to the proper exposure. In a single-light shot like this, the proper placement of the main light is critical. I suspect this is a softbox; a different modifier might have bailed you out a bit more. Technical error or technique error? I dunno....just words...

 

[MK3Brent]

What bit are you editing in? (8 bit color, 16 bit color?)

 

[sarah_19_nz]

I get what your saying Derrel, honestly it was a total muck up shot that I tried to recover. The jpg version is pretty normal looking but my lightroom adjusted file sucks! Hubby checked my bit and apparently that's "all good" he said it's on the highest. I just checked lightroom settings and it says 16 bit

 

[sarah_19_nz]

Could it be compression artifacts on the exported JPG? What's your quality set at when you export?

Found what you were talking about. Quality was set to 60. I bumped it up to 75 to see what will happen. It is also set to sRGB is this correct? what happens if I choose AdobeRGB? (I use photoshop to edit)

 

[KmH]

Yep. I see posterization in the lower corners.
Image Posterization
Bit Depth
Understanding Digital Camera Histograms: Tones and Contrast
Understanding Digital Camera Histograms: Luminosity and Color

I am also seeing quite a bit of color noise on the rest of the background.
Digital Camera Image Noise: Concept and Types

It is also set to sRGB is this correct? what happens if I choose AdobeRGB? (I use photoshop to edit)

Tutorials on Color Management & Printing
Using the Photoshop Levels Tool
Using the Photoshop Curves Tool

 

[sarah_19_nz]

Yep. I see posterization in the lower corners.
Image Posterization
Bit Depth
Understanding Digital Camera Histograms: Tones and Contrast
Understanding Digital Camera Histograms: Luminosity and Color

I am also seeing quite a bit of color noise on the rest of the background.
Digital Camera Image Noise: Concept and Types

Off to do some reading. Thanks.