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Use your own camera, or buy pre-calibrated
PhotoModeler accepts photographs from most camera types including digital cameras, film cameras, and video cameras. Each type of camera has its advantages and disadvantages, but they all have a place with PhotoModeler.
If you don't have a camera yet, Eos Systems sells a pre-calibrated Nikon D90 digital SLR camera bundled with PhotoModeler software (available in North America only).
What Is The Best Camera For My Project?
When choosing a camera, you should consider your project requirements and your budget. The most common choice, among customers who are able to choose, is a digital SLR camera. Point-and-shoot consumer digital cameras are common as well. In some fields, such as forensics and accident reconstruction, film is the only choice because that is the evidence at hand. PhotoModeler can also work with photos taken with unknown cameras, providing there is some known information about the scene. See InverseCamera.
Consumer Digital Cameras are a great match for PhotoModeler. A typical project might require 1 part in 2000 accuracy or less or you may need a good 3D model with high-quality photo textures. Consumer-grade digital cameras are convenient, affordable and produce good results. You can expect to pay anywhere from $200-$600 US for a new consumer digital camera. See below on how to choose.
Digital SLRs are an even better choice if they are within your budget. With an DSLR you have more control over settings, get to choose the best lens (usually a fixed, non-zoom, wide angle), and often have higher resolution. You can expect to pay anywhere from $700 to $8,000 for a good DSLR and lens.
Film Cameras, along with a print scanning on a good flatbed scanner, can provide images suitable for medium accuracy projects. Negative scanners can also be used with film cameras for better results than using prints. You will want to ensure your negative scanner produces stable results. A quality flatbed scanner can be purchased for between $500 to $900 US. A suitable negative scanner will cost between $800 and $3,000.
Video Cameras are also compatible with PhotoModeler. Analog video can be digitized with a frame buffer and used in PhotoModeler. Video cameras provide low resolution images and the resulting PhotoModeler projects are usually accurate to 1 part in 500 or less. HD video cameras that capture digitally improve on standard video with greater resolution, greater image stability frame-to-frame, and easier transfer to your PC (USB, firewire or SD Card).
High-End Cameras, such as professional digital cameras or metric film cameras can be used with PhotoModeler when the highest possible accuracy is required. With a sub-pixel target marked project these cameras have shown accuracy in PhotoModeler of 1 part in 20,000 and better. High-speed and other specialty cameras can be used as well. Contact our sales department to discuss.
A good source of digital camera information can be found on these sites: Digital Camera Resource List, Steve's Digicams, and Digital Photography Review.
What Is The Best Digital Camera?
Digital cameras are a great match for PhotoModeler projects. There are so many digital cameras on the market, with new ones becoming available at such a rapid rate, that we cannot recommend a particular brand or model (unless we test it thoroughly in-house, as we have done with the Nikon D90, for example).
The most important items to look for in a digital camera are:
- High resolution: most high quality cameras support resolutions of 6 mega pixels or better.
- High quality non-zoom lenses: almost all digital consumer cameras will come with a zoom lens, so this is difficult to avoid. If using a zoom lens, you should set the optical zoom to one setting for all your PhotoModeler projects. Avoid using the digital zoom settings - digital zoom manipulates the photo without actually adjusting the focal length. DSLRs on the other hand let you choose your lens and we recommend a wide-angle non-zoom lens.
- Control over settings: if your camera has automatic features such as image stabilization or orientation detection ensure there are controls for turning these features off. Other good controls are for manual focus and sharpening (and in some cases aperture and shutter speed).
- Easy, fast image download to your PC: the best methods are through Flash card (SDCard with SDCard reader for the PC), or a USB interface cable.
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Can I Use A Camera With A Zoom Lens?
We normally recommend fixed lenses with PhotoModeler (i.e., no zoom) but zoom lenses can be used with PhotoModeler if extra care is taken. PhotoModeler needs to know the focal length of the lens for each picture taken. Some cameras do not store focal length information, so you will want to fix the zoom at a known focal length - such as the widest angle, the most telephoto or the power-on-default zoom - before you start shooting. Be careful not to change the zoom during the photo shoot or your accuracy will be affected. Some consumer cameras have a more stable zoom than others (ie. the focal length does not change as you handle the camera) - these cameras are preferred.
Will I Need To Modify My Camera?
For digital cameras, no. If you are using a film camera with a film scanner that crops the edges of the frames and you need high accuracy, you can optionally place an Eos Film Plane Insert in your camera. This insert is a small piece of transparent plastic film that attaches inside the back of the camera and extends a short distance into the image plane. The insert has two fiducial marks that appear on each photograph and allow PhotoModeler to orient itself to the lens and camera body in a consistent manner.
What Is Camera Calibration?
When you require the good accuracy, you can use PhotoModeler's Camera Calibration software to calibrate your camera. Eight to twelve photos are taken of a supplied grid pattern, imported into the Camera Calibrator software and processed automatically. The program calculates the camera's focal length, lens distortion, format aspect ratio, and principal point. The resulting calibration data file can be saved on disk for use in all PhotoModeler projects that involve photos taken by that camera, at the same settings. PhotoModeler also includes self-calibration and field calibration modes to improve camera parameters further when accuracy is your prime concern. Further information on calibration can be found in our Knowledge Base.
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