Thursday, May 10, 2007

Anatomy of a Photo: eBay Part II

For many of you, getting a good photo of an eBay item using a DIY Macro Studio should be old news. I know I've talked about it before. So why do I have a Part II? Because I found a lighting scheme that seems to work pretty well (and only requires one flash or lamp) and also wanted to put in more details about the post processing. Don't worry though, this post will have less words and more pictures than the last few.

So, the task: to get some good pictures of my Nikon SB-20 for an upcoming post. Since I was already taking some eBay pictures of a video card, I used the same set up, but the first picture came out dark and I was momentarily confused. Then I realized that by taking a picture of my SB-20, I couldn't use the SB-20. Duh.

Lets start with the flash scheme. As usual, I can't take claim for coming up with the idea (darn that David Hobby guy). The basic idea is this: use a single source of light (in this case, a flash) but position the light box to provide a light source on both sides of the object. (Click to make the pic larger to see details)

In fact, the way I set it up, there is a ring light effect: the flash hits the near copy paper (diffusing through it), hits the far box flap (covered in copy paper, see at trend yet?), and also spills onto both the top and bottom of the box entrance. The result is pretty even lighting from all around the entrance of the box. The balance between the two sides is controlled by moving the flash closer or farther from the box (light intensity drops with distance, but the distance between the two sides will stay the same).

Total Cost: $0 (since I have plenty of copy paper, old boxes, and scotch tape)

And remember, I used a flash, but you can use any old light source (flashlight, desk lamp, etc). If you don't use a flash, use a tripod because your exposure time will probably be pretty long. I can't remember the exact settings (and they don't matter that much) but I think it was something like F/11 and 1/4 power on my Sunpak 383 for 1/200s (flash sync speed). Really I just kept shooting (in manual mode) until my histogram was nice and spread out and I liked the balance of lighting on the flash. FYI, I used an eBay trigger for synchronization.

So, now I have the photo at left. Not great, to be brutally honest.

You know, the more digital photos I take, the more I realize that post processing can take an mediocre photo and elevate it to a good or sometimes even a great photo. But, if you have to start with something, after all, garbage in, garbage out.

The first step is obvious. Crop it to get rid of the distracting stuff.

Then, time to fix the crappy color balance. I'll be devoting a future Quick Tip to color balance, so I'll just give a quick description here. When I took the photo, I set the 350D to the "Flash" white balance. For some reason, I got a redish tint (maybe some of the box wasn't covered in paper so it polluted my white light?). It also may have been the ambient, but I doubt it. The good news is that fixing the white balance afterwards is easy. The bad news is you lose a little color detail unless you shoot in RAW mode, but for this image, it doesn't hurt the quality much.

In this case, I adjusted the color balance in Paint Shop Pro XI as shown to the right. Photoshop has something similar, I am sure. Just click the Smart Select button and then put the target onto something that should be white in the original image (left image). The resulting color balance will be shown in the right image. There are other options too, but I find I rarely need them. Just make sure you select something that is supposed to be white.

Next, adjust the contrast and force the background to white; I usually use curves, but anything where you can see a histogram is useful works well. In the image at left you can see the PSP XI curves view with histogram. To be quick and dirty, I'll just bring in the left-hand curve to start at the first black pixels, and bring the right hand curve into a position inside the final peak (this is the white of the background). After all, you want to push the background to a pure white. Don't go too far or you'll start losing highlight detail.

Even after that one side of your image will still not have a pure white background because of variations in lighting. Of course, that wouldn't be a problem if you had a separate background light, but sometimes you don't have the time and money for that. But the solution is simple -- dodge (lighten) the background of the image as shown in the picture at right. Usually you want to use a small opacity (maybe 10% or so), soft edges, and set it to only modify highlights. This makes the dodge brush very forgiving if you accidentally touch the object edge. While it will take a few passes to bring the background up to pure white, it is worth it to protect the integrety of your subject. The end result is the image that started this entry.

So, that's it. The main thing I wanted to demonstrate was how easy it is to use a single light source to make a quality eBay picture with a white background to make the product jump out of the page. Once you've practiced the technique a bit, it really only takes 10 minutes total to set up, take the picture, and process it.

[If you missed it, read Part I.]


Tally said...

Thanks for this useful tutorial. Finally I've got some direction where to head to.

Sean said...

You're welcome. Glad I could help!