Photography Thailand Forum

[David Procter]

some more studio tinkering a la Marc

[David Procter]

 I shot this using two light sources: A soft box lit the face in the foreground and the face in the background was lit by a honeycomb on the left (with a red filter) and shot through a plastic sheet. Does anyone know how I can get rid of that graduated affect in the creepy background face?

[agitlits]

David, I like this portrait a lot. The expression in her face is very dramatic!

Did you adjust power on the strone manually. Was it fairly low power setting or did you do exposure comp. in post processing?

Thanks
Alex

[David Procter]

The strobes were adjusted. manually. i have a flash meter to get the right exposure. I converted to monotone with channel mixer and cloned out some nonsense and that was it.

[Marc Schultz]

I am not sure I entirely understand what the lighting issue is you are referring to, but if I understand correctly one side of the face in the back is brighter than the other? If so, that is probably light fall off from the soft box in the front onto the subject in the back. If you spread the subjects further apart then the light source wont reach the back subject. You could also hang a black curtain behind the front subject to again scrim off the light from the front reaching the back subject.

I am also not sure what the purpose is of the honeycomb and red filter on the back subject, but if you want to use a honey comb as a light source for people in general, then better to put a piece of tracing paper over it to soften the light cast a bit. Also, if you increase the power on the head with the honeycomb, it should fill in enough on the other, darker side of the face to match the light spilling off onto the face from the softbox.

Hope this helps...

[David Procter]

Thanks for your input marc. I'm very new to studio lighting and very much appreciate your words. The lighting is actually exactly as i wanted it. i shot it with a red gel because I initailly wanted it in colour but it just didnt work with the foreground tones. When I converted it to black and white i was pleasantly surprised by the ethereal nature of the face. i actually used a black sheet as you said and there was very little overfolw from back to front.  My problem is with a kind of pixelation in the face in the background like contour lines on a map. I've tried using gaussian blur but dont seem to remedy it. Could you suggest anything?

[Marc Schultz]

Your welcome. From the picture you posted I can't actually physically see the issue you are referring to. But from what you describe it sounds like possibly either posterization or banding. You can read about that here on Wikipedia and see if it is the issue you are referring to:

http://en.wikipedia.org/wiki/Posterization

There are also sometimes other issues with digital photographs known as Chromatic Aberration and Purple Fringing. You can read about these issues here as well:

http://en.wikipedia.org/wiki/Chromatic_aberration
http://en.wikipedia.org/wiki/Purple_fringing

If it has something to do with the way the background is being blurred by the lens in the areas that are out of focus then this could have to do with the way a particular lens handles something known as "Bokeh". The word Bokeh is of Japanese origin and you can read about that here:

http://en.wikipedia.org/wiki/Bokeh

And if that is not enough for you, then there is another category of issues with digital photos known as "Artifacts", which you can read more about here:

http://www.dpreview.com/learn/?/Glossary/Digital_Imaging/Artifacts_01.htm

It might be a good idea to actually familiarize yourself with all of these issues so you know exactly what it is you are dealing with. If you do that then it would also be nice if you would post another note letting us know which one of the above issues you feel applies to your picture.

[David Procter]

Excellent. I'll look into it. Thanks Marc.

[bjorn slis]

that looks a lot like a jpg compression problem, did you shoot it RAW, and if so, do you have the same problem before saving it as a jpg

[David Procter]

I shot as a JPEG. I'm going to check through the links marc has given me but I suspect you could be right. Thanks for your input

[Marc Schultz]

If it is a JPG compression problem as Bjorn suggested then that would suggest an artifacts problem.

There is a problem I often encounter on backgrounds when converting digital photos to B&W. Attached is a photo taken in 2004 with an older Canon 10D. The issue on the background of banding often occurs when the there is a drastic change in light from one spot to the next on the background. The attached photo shows an extreme example of what I am referring to, which will help you to clearly see the issue. Even though I now shoot with the 1DS Mark II, I still have the same problem which I am still trying to find a good solution for.

Kurt had once suggested if I work in 16Bit mode it might help the problem, but so far unfortunately it hasn’t. 

[bjorn slis]

So if I understand it right this (marc's shot) is not a jpg problem ?
How do you convert to BW Marc ?

[Marc Schultz]

No, I don't think it is a JPG problem as it is visible on the hi-res PSD file as well before I downnsize to low-res.

I normally convert to B&W in Photoshop using a Channel Mixer adjustment layer.

[David Procter]

This is exactly the problem I'm experiencing. The example you have given shows this very prominantly in the background. Its almost as if the the gradient of tones from the dark to light happens in steps. I tried using the clone tool to 'mix up' the contours in my picture but it was rather painstaking and not a satisfying solution.

[Marc Schultz]

I saw something somewhere which talked about dithering as being a way of fixing an image problem like this, but I am not familiar with the technique myself.