Digital backdrops

fredjclaus · August 31, 2009

Has anyone used a digital backdrop? My camera club is doing a demonstration on doing portraits with this sort of thing and the demonstrator is going to be selling digital backdrop packs for only $40.00 each that night. I'm trying to get some insight before hand on how they work and if I have the required materials to use them. Is it something as simple as shooting on a green or blue backdrop and then putting the backdrop we want into the photograph via digital editing?

mtbparker · August 31, 2009

I've never actually played with a digital backdrop. But I have one of those green backdrops that I picked up a few years ago with my video editing program. The idea, of course, was that you could use its chromakey feature to overlay a person talking in front of some running video.

I'll play around with it tonight using still shots and try a quick hack in PS tonight to see how it goes.

Tom

marikris · August 31, 2009

I go to a photoshop meet-up here in houston, and one of the first things the organizer taught us is how to paint a backdrop. I'm sure there are tutorials online, so try that first before you buy that pack. The organizer also said she uses a green backdrop, though I have yet to try this.

mtbparker · August 31, 2009

Well, I did a quick experiment to check the viability of digital backdrops. (It was a simple experiment, but enough of one for me to make a $40 decision.) From what I could tell, I see two main problems

1) A green or blue back drop is a must. I can see digital backdrops being incredibly tedious over time if you're constantly having to select the edges of a subject with a fine tooth comb.

Related to that, I had a small problem with some of the green reflection bleeding back over onto the edges of me. I had to crank the magic wand tolerance up pretty high to get most of it. Unfortunately, I got caught in a pickle -- any higher I start losing body parts, any lower I get a very obvious green line. There's probably ways to control that through lighting, spacing, etc. But I don't know.

2) Getting the lighting to match the backdrop. Both the digital backdrops I experimented with show very different lighting that the actual portrait of me. There'd probably need to be work there to get the lighting to blend nicely with the back drop. To me, it's way too obvious that I've been overlaid in there.

At this point, if it were me, I'd have enough info to determine if I'd spend $40. Heck yeah. Why not?

Here are some of the results -- mind you, I spent all of 30 minutes on this. Most of it was rearranging my living room.

Here's the setup. I have a Nikon D40 with an SB800 and SB600. I tried to use the 600 for the backlight. Why? I'm not sure.

Here's the resulting green screen of me

Here's a retro 80's backdrop. Very obvious that it's a digital hack.

Here's a better looking one. Still obvious, but much less so.

[edit]And, if you don't like how it looks with your subject, you have the freedom to change it. (Didn't think of that until just now.) Interestingly enough, the green reflections on my face become much more apparent now that there's less green in my backdrop.[/edit]

And if you look closely here, you should be able to see me at the top of Mt. Everest. It was pretty cold, but a nice day hike nonetheless.

I don't know if this helps or not. But it was fun trying to play around.

Tom

Gary752 · August 31, 2009

I had started a thread in Technique on this. There is a program out that is great for this type of photography. It's called PhotoKey, and is available at http://www.tubetape.net/servlet/the-53/green-screen-software-chromakey/Detail There is a mini video about the program on the page. This program works with green & blue screens, and has some editing features built in as well. They even sell chromakey paint if you just want to paint a wall, but I personally think it is cheaper to go with the backdrop.

GaryB

Anarchyjim · August 31, 2009

Primatte

mtbparker wrote:

Well, I did a quick experiment to check the viability of digital backdrops. (It was a simple experiment, but enough of one for me to make a $40 decision.) From what I could tell, I see two main problems

Well... it's not really a $40 decision. It's $40 + the greenscreen and software necessary to do create the masks.

There are a few ways to approach digital backdrops, but the main issue is removing the original background while keeping details like flyaway hair and translucent objects (fabrics, glass, etc.).

1- Shoot against gray or white and do a mask by hand in Photoshop or similar program. This is going to be the most tedious option. You would think Photoshop would have great masking tools by now, but it really doesn't. Advanced PS users can use a combination of the tools + channel operations to pull off a good mask, but the caveat is that you really need to know PS backwards and forwards.

2- Shoot against gray or white and use a third party filter like MaskPro from OnOne Software. These make the job of masking much easier but still require manual input. Meaning that you have to apply the filter to each image and make adjustments. Great for small batches of photos, but it gets time consuming if you have many photos. However, it's considerably less time intensive than option #1 and will produce better results.

The advantage of 1 & 2 is you don't need anything special. Just get a medium gray background.

3- Shoot against green and use a Photoshop filter like Primatte Chromakey or a standalone greenscreen program. The advantage of greenscreen is that it's easier to do a large amount of photos. The software should be able to automatically identify the background and create the mask without you doing anything. This doesn't always work, but if the photos are shot correctly you should get a 50-80% success rate.

The downside, of course, is that you have to have a green background and shoot the photos properly. Green is not very forgiving, so you do need to experiment and learn how to shoot greenscreen. But if you're shooting 300 little leagers and putting them in Yankee stadium it's worth the effort.

So, before you plunk down $40 for a bunch of backgrounds, make sure you know how you're going to get them into your photos.

And, as mentioned, lighting is critical. If the lighting on your subject doesn't match the lighting in your background, no amount of software is going to help you make a realistic composition. Of course, if you're just putting yourself at the top of Mt. Everest... ;-)

Hope that helps...

cheers,
Jim Tierney
Digital Anarchy
www.digitalanarchy.com

Nikolai · September 1, 2009

mtbparker wrote:

Well, I did a quick experiment to check the viability of digital backdrops. (It was a simple experiment, but enough of one for me to make a $40 decision.) From what I could tell, I see two main problems

Tom,
How far were you from your green screen? The rule of thumb says "at least 4 ft" specificallly to avoid the screen casting the color shadow on you...
And yes, lighting is critical.

mtbparker · September 1, 2009

Jim,

You're right. Being that I said a green screen is critical, that would definitely be part of the cost. On the flip side, I did some google searches and there were examples where people used white or grey walls. But you've already talked about the pros/cons. As far as digital editing, I made an assumption. Based on the way Fred said it ("simple as ... digital editing"), I assumed he already has the ability to do that. I could have been wrong.

Nikolai.. I was closer than four feet. Thanks for the tip. I was wondering if that wasn't part of my problem.

While I was shooting portraits of my wife the other day, she mentioned the green screen. It piqued my curiosity. Then when Fred asked, I figured I'd give it a shot to see what could be done. My thinking was that if I could come up with something reasonable in a short amount to time, someone else with more experience and perhaps with more/better equipment could make it work really well.

Tom

Teromal · September 1, 2009

I have played around with a green chromakey a little before and had the same problem with a green tint around the subject. I was told this was due to the background not being bright enough, I was told it should be one stop brighter then the subject to help avoid this. I just dont have the lights to do it the way i was told which was light your subject the way you want and then bounce to two lights off a white ceiling to make the backdrop 1 stop brighter. Once thats done if the green tint is removed then extracting the person from the backdrop should only take a couple of minutes in photoshop.

Gary752 · September 2, 2009

Teromal wrote:

I have played around with a green chromakey a little before and had the same problem with a green tint around the subject. I was told this was due to the background not being bright enough, I was told it should be one stop brighter then the subject to help avoid this. I just dont have the lights to do it the way i was told which was light your subject the way you want and then bounce to two lights off a white ceiling to make the backdrop 1 stop brighter. Once thats done if the green tint is removed then extracting the person from the backdrop should only take a couple of minutes in photoshop.

Lighting the backdrop is rather simple! Just use 2 of those halogen work lights that have 2 seperate lights on a stand. One on each side, down low, slightly behind the subject, and angled to get even lighting across the background. Nik was correct that the subject needs to be at least 4 to 6 ft in front of the backdrop. I know what your going to say next, "But the color temp of the halogen lights is different from my studio lights!" Well, to be serious, it doesn't matter, because you are going to remove the background from the image. The main concern is to get the background evenly lit, and no wrinkles. If you go to the Technique forum, and look for the thread "Anyone try Greenscreen or something like that. I posted an example of an image that I manually colored the background green inn MickeySoft Paint, and then imported it into PhotoKey2, and added a couple digital backgrounds. Trust me, chromakey is not all that hard!

GaryB

takeflightphoto · September 4, 2009

another avenue
http://www.GreenScreenWizard.com

A fairly automated program for doing this. Even a look around their site will help you understand the ins and outs. The one thing I like about this over doing it in PS is that you can run batches of backdrops behind your image and see what works and what doesnt.

Take a look.

jon

ziggy53 · September 4, 2009

This is the discussion thread that BroPhoto mentioned:

http://www.dgrin.com/showthread.php?t=140047

fredjclaus · September 4, 2009

Watching the Green Screen Wizard promo video now and that looks great.

takeflightphoto wrote:

http://www.GreenScreenWizard.com

A fairly automated program for doing this. Even a look around their site will help you understand the ins and outs. The one thing I like about this over doing it in PS is that you can run batches of backdrops behind your image and see what works and what doesnt.

Take a look.

jon

Digital backdrops

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