Lighting black backdrop to get grey results in horrible mottled effect

dubcat

dubcat

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Amir
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I have a black backdrop and a white backdrop. I want a grey backdrop without having to buy one just yet. So, I know I have two options.

  • using the white, ensure there is no spill on the backdrop and use distance to ensure the backdrop is exposed say -2ev relative to the subject
  • using the black, light the backdrop

I am forced to go with the second option since my shooting space is tight. However, when I do so I can see a mottled effect on the black backdrop. I guess this is because the light is coming in from an angle and of course the backdrop is not perfectly flat. Is there anything I can do to get rid of this without having to deal with it in post processing? My post processing skills are so poor I don't fancy having to deal with it there.

Here is an example (no post processing other than reducing exposure by 0.7)

StudioBackgroundGreyTest-3_zps2d7490d9.jpg
 
The problem is basically caused by light bouncing off of uneven surfaces at all sorts of angles, including straight towards the camera.

Getting rid of the creases is you best option. You should though be able to get the background out of focus by using a much wider aperture than the f/8 that you used here.
 
Thanks Garry. I feared you would say that. This is one of the popup photodeals backdrops. I don't really see how i can get rid of those creases.

I was hoping to not have to resort to a larger aperture as I intend shooting multiple people who can not be relied upon to sit on exactly the same plane as one another. For head shots, 3/4 length shots and a full body shots is there a minimum distance from the backdrop that you typically recommend?
 
dubcat said:
Thanks Garry. I feared you would say that. This is one of the popup photodeals backdrops. I don't really see how i can get rid of those creases.

I was hoping to not have to resort to a larger aperture as I intend shooting multiple people who can not be relied upon to sit on exactly the same plane as one another. For head shots, 3/4 length shots and a full body shots is there a minimum distance from the backdrop that you typically recommend?
Click to expand...

Hmm.
I see that the max aperture of your lens is f/4, so even if you can use a larger aperture, it probably wouldn't be a good idea with that lens.
DOF is a complex subject, just look at a chart to see for yourself how many different factors affect the final result - so I can't advise you on the distance needed.

If it's a cheap backdrop it's very possible that it may be a bit shiny, a lot of the cheap ones are.

So, your best bet (whether you like the answer or not) is probably to get a grey paper background.
 
OK thanks. I think the answer here is going to be to find more distance. Maybe move in to another room in the house. I do intend to get a backdrop holder and grey backdrop at some point. I was just hoping to hold off for now.
 
are you using flash direct at subject? If you bounce it off the ceiling it should be pretty black?
 
cambsno said:
are you using flash direct at subject? If you bounce it off the ceiling it should be pretty black?
Click to expand...

Hi Simon, I'm trying to make it grey by pointing a flash directly at the backdrop. I'm not looking for a black backdrop.
 
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