Camera Matching Toolkit

I'd like to share a few notes on a photography class geared for 3D artist I attended a little while ago...I found it very informative and hope you will too!


Assembling your toolkit

A good crafsperson uses good tools to ply his or her trade. Having a toolkit makes your work not only easier, but it also helps to ensure accuracy. The first part of your toolkit is one of the most important pieces; your camera.

Lets face it, you cannot skimp on the quality here. There are a multitude of factors that dictate what makes a camera acceptable for simulations. Take in consideration the following factors:

1. Cameras

a. Film or Digital - This is a no brainer. While there may be many film purist/evangelicals out there who will tout the virtues of film, digital is here and it works very well. Many of the best photographers out there use digital cameras to capture their vision so if it is good for them, it is certainly good for you. Having the ability to see the end result immediately is well worth the price of admission!

b. Point-and-shoot-or DSLR - This is a tougher decision to make because this is often a financial one. My recommendation is to spend the extra cash to purchase a base model DSLR such as Canon's Rebel XTi or Nikon's D40. There are several manufactures out there that make dynamite cameras for a very respectable price and I will refer you to one of my favorite sites, Digital Photography Review or http://www.dpreview.com to further research the various models. SLR cameras have several advantages over a fixed system including two very important features, interchangeable lenses and RAW digital files.

c. My megapixel is bigger than yours - While a very large megapixel camera can be very advantageous in certain circumstances, I would recommend that you invest in a camera with the best optics and imager that you can purchase based on your budget. As the saying goes, "Bigger is not necessarily better", and this is true of most imagers. Most models these days start in the six megapixel range and climb to some insanely large sizes.

2. Hard Case - You need a good case to haul around your camera and other tools. A good Pelican case http://www.pelican.com/ can be employed for this very purpose, neatly and snugly containing your measurement tools. This makes for easy hauling, and is especially helpful when flying to a location.

Here is a list and description of the tools you should have in your case:

3. Cloth Tape 500' Measure - Acquiring an accurate distance from your camera to various elements in your shoot can be very helpful in creating an accurate simulation. Cloth is best as it is a bit more manageable over long distances.

4. Laser measuring device - For those tough-to-reach areas, a laser range finder can be most helpful.

5. GPS System - Though not absolutely necessary, a good GPS system can be helpful when working on a simulation covering a larger area. Knowing exactly where you are shooting from can be very helpful. There are several options in this field ranging from the mid $100s to the mid $1000s. If you can, try to locate a device that can establish sub-meter accuracy. There are several manufactures who offer a USB device that works in conjunction with software on a laptop affording you sub-meter accuracy that won't break the bank.

6. Inclinometer - This tool is truly a neat little device. It measures angles, usually relative to the ground.

7. Compass - This is used in conjuction with your inclinometer to measure heading. Both these devices will help to establish accurate bearing and tilt measurements for your camera.

8. Marking stickers - This is probably one of the least expensive elements of your kit. You can find these at your local office supply store. All they really are, are florescent colored stickers which you can use as markers within your scene to call out distances, heights, widths, and lengths and to help you track information in the captured photo.

9. Shot Cards - These serve two purposes; one to establish accurate color measurements and two, to provide a measurement grid that provides accurate metrics for scale and camera lens distortion. The first card is really just a color chart with simple grey and color swatches that can be used to establish an accurate color curve relative to the lighting in the scene.
This will be used along with a mirror ball to aquire accurate environmental conditions.

10. Mirror Ball - This is a newer high-tech/low-tech tool for measuring light and acquiring an environmental map for reflections/refractions in your simulation. You can find these at your local gardening store. Along with this, you will need some sort of stand. I recommend a tripod microphone stand which can be purchased at any local music store.

11. Fisheye Lens- An alternative to a mirror ball is to purchase a quality fisheye lens for your DSLR camera. While more expensive than the mirror ball method, a fisheye can provide you with a quick panoramic image using just two shots. Combined with a good stitching application, you can create panoramic HDR images quickly and efficiently.

Case, camera and tripod in hand, you are ready to shoot your location. Just like any successful production shoot, good planning is key to ensure that you won’t need to go back and reshoot, and it will ensure that matching your simulation proceeds smoothly and quickly. Scout your location well. Take several good pictures of the surrounding context. This will be helpful later when setting up your simulation. Once you have established your camera locations, set up your tripod and take a few measurements.

First you want to measure both the height and angle of your camera. I highly recommend that you shoot using a tripod if possible. This will make measuring easier. One additional advantage is the tripod will ensure a stable camera and a sharp image. Mark down all your measurements on a shot sheet. I created a shot sheet using illustrator complete with camera location measurements, landmark measurements, a sketch area for both a plan and elevation view and information about the location. You also want to get measurements of any landmarks for reference, specifically elements that are easy to recreate in 3ds max such as a box, cylinder, or sphere. These will be used later to establish proper camera alignment.

Next you want to shoot your mirror and grey balls to establish proper lighting reference. Both balls provide locations of light sources with the confines of the location, i.e. position of the sun or additional illumination sources such as street lights or highly reflective surfaces such as reflective glass on a building. Another method for capturing or measuring the lighting conditions of a location is to create a High Dynamic Range Image of the surrounding environment.

One of the problems attaining an accurate camera match is resolving the optical distortion associated with the curvature of a camera lens. This is particularly troublesome with a wide angle lens or from lower quality, smaller point-and-shoot cameras. Luckily for us, there is a relatively easy method for measuring and correcting this distortion you must create a simple grid which you then hold up in front of the camera and shoot. The ideal result is that all the horizontal and vertical lines are perfectly straight, but this is not always the case. Because most lenses are round, you might experience what is called barrel distortion. A camera with an excessive amount of barrel distortion will create an image where the horizontal and vertical lines will be straight at the center of the image, but slightly bowed at the edges of the image. Using the lense blur function in Photoshop will allow you to correct this distortion before you load the image into 3ds max for matching.

Measurements in hand and your shot sheet nearly complete, you should be set to shoot your image. I would recommend a few shots to ensure the best possible image. You might also shoot multiple exposures or bracket your shot to ensure you have more exposure latitude when assembling the image. Photoshop CS2 and later has the ability to combine multiple exposures into an HDR image. Having this exposure data will allow you to tweak areas of your image that are either under or overexposed for later compositing.

ang cool naman nito AJ. Thanks for sharing bro. This will really come handy.

I just finished camera matching 7 Bridge Options, with 7 different Pier designs and locations to 4 different camera views that had to be stitched and cleaned up....what a long week. It would've helped if I some descent shots to begin with. Nextime I have to get the PM to send me to take the photos!

thanks sa pagshare mo nito bro. gandang checklist.

Thanks for sharing....so helpful tips!