How can I get better results photographing dry erase boards?

Question

As far as photography goes, I'm less than an amateur. I have a camera my friend (the head of the photography dept. at a local college) recommended to me that I really want to learn to use, but haven't had time (Nikon D90 - a gift from a relative). I used to do a little more work years ago with film, but I've forgotten more than I remember.

I'm a writer and when I'm working on a story, I use white dry erase boards of different sizes (from about 9x11 inches up to about 2'x3', but one or two are a little larger than that). This works fantastically well for me when I'm diagramming plots or doing scatter notes, before I sit down and do the writing. With the dry erase boards, it's easy to change things around by just wiping a section out and restarting.

I'd really like to be able to take pictures of these whiteboards and save the image when I'm done (and perhaps, later, print it out).

The problem is, with the larger boards, if I'm back far enough to get a photo that fits all of it into the frame, it's too hard to read what I've written on it. (Also, the surfaces are reflective.) I've been told there is software I can use so I could take a number of photos of sections of one board and have the software put them together in one big image. I don't know how well that works (and I don't know what that process is called), so I'm worried about the cost of the software as well as being able to keep the scale the same from shot to shot.

I don't mind building something to do this if it's not something huge, or if I can set it up quickly once I'm done. I just don't want to have to worry about lots of details when I'm in "work mode."

Is there a fairly simple way I can use my camera to take images of these boards that include the whole board and still let me see enough detail so I can read what I've written on them?

Answer 1

I think you want simple, so I'd recommend using Program mode, which gives you the greatest control without making you learn about exposure. Program mode (the 'P' on the Auto-P-S-A-M dial) gives you these advantages:

• it sets exposure correctly for the lighting conditions, so you won't get a too-dark or too-light image, and you don't have to think about shutter speeds or aperture values or what they mean.
• it won't try to raise the flash, which would reflect off the whiteboard
• you can set exposure compensation, which helps if the camera isn't guessing the exposure correctly.
• you can set the ISO.
• you can set the white balance.
• if you really want to, you can change the shutter speed / aperture combination that your camera chose. For your particular use case, you want to spin the dial all the way to the right (I think) to get the fastest shutter speed.

So, with all that, I'd follow this checklist:

• set your image quality to the highest possible. Don't use RAW.
• set into Program mode.
• unless you're using a very small whiteboard or can't get closer to it, zoom all the way out (to give the camera the widest range of apertures to choose from).
• set the ISO to 100.
• set exposure compensation to 0.
• set white balance to Auto.
• take a sample picture (aim the camera, fill the viewfinder with the whiteboard, half-press the button so it will auto-focus, then while calmly breathing out, slowly and steadily press the rest of the way down).

Now look at the results. Apply any of the following corrections, as needed, and take another sample picture:

• Zoom in to a sample of the text: if the picture is too blurry, raise the ISO and try to hold the camera steadier.
• If the picture is too dark, increase exposure compensation (+1). If the picture is too light, decrease exposure compensation (-1).
• If the colors don't look right, change the white balance. I know very little about white balance, so you'll have to get someone else to help with this.

When the "sample picture" doesn't have any problems, promote it to "finished picture" and you're done.

Answer 2

I've had to preserve whiteboard scribbles a few times. The problem is that you usually can't control the lighting and it's rarely good. The technique I've converged on is to take two pictures. With the camera on a tripod, take the first picture of the board as is. Then erase the board and take the second picture with exactly the same settings.

Now digitally subtract the two pictures and add offset and adjust gain to get what you want. The trick of subtracting the two pictures cancells out the inevitable uneven lighting accross the whiteboard.

For those of you thinking "yeah, right, that can't possibly work that well", here is a example I just dug up from over 10 years ago. These were all taken with the quick and dirty "office" camera, which was some Kodak point and shoot back then if I remember right. In any case, it had no special capabilities that any ordinary camera wouldn't have.

Whiteboard with scribbles:

Erased whiteboard:

Result:

Notice that the camera had nothing to focus on in the second shot so it was a little blurry. It still didn't matter since it's main purpose was to get the bacground "white" level for the first shot, which changed slowly enough to that a little blurriness didn't matter.

Answer 3

I regularly take photos of whiteboards sized 3' x 4' or larger with my cell phone camera to record meeting notes, and it produces passable results. The D90 should absolutely kick butt on this.

The two factors you want to avoid are glare and motion blur. As Guffa mentioned, you want to avoid glare from ambient (room) lighting, so get into a position as square to the board as possible where you don't see a lot of glare. Next, you want camera settings that disable the flash and keep the shutter speed high enough to hand-hold the camera. Stan mentioned a tripod, which would certainly eliminate camera shake, but that's sort of a pain just to capture a whiteboard. Unless you need a super-high-quality capture for something, I think you're probably better off just bumping up the ISO setting to something like 1600 - this will introduce a small amount of noise in your image, but it should be inconsequential for your purposes. There's a button to set ISO on the back of the camera.

Now, you want to select a camera setting that'll give you a shutter speed somewhere around 1/60. You could probably get away with something a little slower (1/50, 1/40), and anything faster is fine (1/80, 1/100, etc.). The camera can manage most of this for you as long as you're not on full-auto (the green camera on the dial). There's a "vari-program flash off" mode that looks like it would work pretty well for you (a crossed-off flash symbol right next to the green "auto" setting), but feel free to play around with some of the other modes, too. The camera should show you the shutter speed it's going to use to take the photo, but note that shutter speeds are shown in "camera shorthand" -- "125" really means 1/125, and so on.

A final note -- if you can figure out how to post an example photo here (with the settings used for the photo, if possible), that'll go a long way toward helping folks identify specific problems.

Answer 4

Your camera should definitely be able to capture the entire board without having to stitch images together, as long as you are using the highest resolution.

You should use lighting that falls at an angle on the board. Make sure that you don't have a light behind you, that would reflect in the board.

If you use the built-in flash, the reflection will of course be right in the board and ruin the image. If the light is dim, you might have to disable the automatic flash. (Consult the camera manual.)

Also, if the light is dim, the exposure time might be too long when you don't use flash, so that you get motion blur. Then you either need a tripod (or at least something to put the camera on), or simply add more lighting.

Answer 5

I don't want to skirt the question, but I take photos of white boards frequently but using a different method then you suggested. I use my iPhone to take the photo using one of three different applications:

• Genius Scan App
• Built in Camera App
• Microsoft Photosynth App

My favorite is the Genius scan app. It is designed for doing things like this, and has adjustment features built right in for perspective corrections. It also auto recognizes the white board usually and only selects that portion. What is great is that you don't have to really worry about perfectly aligning the camera to the white board, the app really takes care of that for you. It also has nice output functionality to output to PDF or JPG, and send to a variety of apps.

You certainly can use a DSLR for higher quality, but you will have to do post processing that can become tedious if all you are looking for is to capture the whiteboard and back up your memory. The phone applications work great for me and I always have my phone with me.

Answer 6

The technique you are looking for is called "panorama", which in the digital age normally consists of stitching together a number of image tiles into a single larger image. As long as you have the entire board covered with about a 20% overlap between the pictures, you should be able to get a single coherent image using any of the panorama software packages out there. (Photoshop includes a panorama function, but it's not so good for a two-dimensional set of tiles -- several shots high by several shots wide -- in versions later than CS3.)

For scenics, one usually shoots all of the pictures from a single fixed location, but for shooting a flat board, you'd probably want to move the camera between shots to keep the camera parallel to the board and at the same distance. Since the whiteboards are very reflective, you'll want to light them either from overhead or from opposing 45-degree angles. Since the text content and lines are what you're after, fall-off of the light shouldn't pose any major technical problems -- you just want to avoid having light coming from the direction of the camera so you don't get hot spot reflections that obscure the text.

There is another (non-photographic) alternative you might want to look at, though: Scrivener. The corkboard paradigm isn't too very far from what you're doing now. If you can make the transition (and I know a radical change in working method isn't easy), it can ease the process of going from rough-in to writing. (Happy customer, and it's just a thought, not an ad.)

Answer 7

Whiteboard Photo on a PC, or Whiteboard Capture Pro on iOS are very, very good at taking any picture of a whiteboard and turning it into a diagram like image.