Which Camera to Use with Photogrammetry and PhotoModeler

PhotoModeler accepts photographs from most cameras including digital still cameras, mobile phone cameras, video cameras, and film cameras. Each type of camera has its advantages and disadvantages, but they all have a place with PhotoModeler.

What is the Best Camera for Photogrammetry?

When choosing a camera, you should consider your project requirements and your budget. The most common choice is a digital SLR camera. Point-and-shoot consumer digital cameras are common as well. Even cameras on mobile phones can be used in many cases. PhotoModeler can also work with photos taken with unknown cameras, providing there is some known information about the scene.

Consumer Digital Cameras are a good match for PhotoModeler. A typical project might require 1 part in 2000 accuracy or less for 3D models. 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. We recommend that if possible you use a camera with a fixed or prime (non-zoom) lens for photogrammetry - they are more stable and less issues are caused with calibration. A zoom camera can be used though - esp. if you use it at its wide angle setting always and it is stable at that zoom setting.

Digital SLRs or Digital Mirrorless Cameras are an even better choice, if they are within your budget. 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 $800 to $8,000 for a good DSLR / mirrorless camera and lens.

Cameras on drones and UAS are lightweight so they can be carried aloft. Some cameras are built into the drone, some are sport cameras like the GoPro, some are small point and shoot, and some are full DSLRs. PhotoModeler can accept most drone camera imagery.

Video Cameras are also compatible with PhotoModeler. Analog video can be digitized with a frame buffer and used in PhotoModeler. Analog video cameras provide low resolution images and the resulting PhotoModeler projects are usually accurate to 1 part in 250 or less. HD digital video cameras are common - they improve on standard video with greater resolution, greater image stability frame-to-frame, and easier transfer to your PC (USB, firewire or SD Card). The resolution is not as high as a still camera.

Film Cameras can be used by PhotoModeler when the image (from negative, positive or print) is digitally scanned. A good quality scanner is needed. Film cameras are not commonly used as digital camera image quality is so high now. Film is used in PhotoModeler when that is all that is available such as in forensic cases.

What is the Best Digital Camera?

There are many digital cameras on the market. The most important characteristics to look for in a digital camera are:

High resolution: most high quality cameras support resolutions of 12 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 or Mirror-less cameras, on the other hand, let you choose your lens - we recommend a wide-angle non-zoom lens (called a prime lens). Do not use vibration reduction or image stabilization lenses.
Control over settings: if your camera has automatic features such as image stabilization or orientation detection ensure there are menu settings for turning these features off. Other good controls are for manual focus and sharpening (and in some cases aperture and shutter speed). When doing projects with high contrast targets we recommend using cameras with an anti-aliasing filter (most cameras have one) and the ability to turn off or reduce the sharpening setting.
Lastly, easy and fast image download to your PC: the best methods are through Flash SD card, a USB interface, or in some cases WIFI.

Can You Recommend a Camera?

We cannot easily recommend a camera as there are many good cameras available, and each user has a different budget. As well, some cameras are better suited to some applications and tasks than others. As the "What is the Best Digital Camera?" answer above outlines, picking a camera with good resolution, an good quality prime lens, easy photo downloads, and some control over settings, and then all within your budget, will get you a long way. Once you have chosen a camera (or thinking about options), you can email us at support@photomodeler.com, tell us about the camera choice and what type of work you do, and we can provide feedback.

What do I Look for in Picking a Camera?

Many digital cameras can be used with PhotoModeler. When looking to buy a camera or checking if your current camera will work, it can be good to know what to avoid. If you can avoid these camera 'features' you will get better processing and better accuracy.

Avoid low resolution cameras. Try for a camera with at least 18 MPixel resolution. 24 MPixel and higher is better.
Avoid zoom lenses. If possible avoid a zoom lens and pick a lens with a single focal length - sometimes called a 'prime' lens. This can be hard to avoid with point-and-shoot cameras at lower cost. Some point-and-shoot cameras with a zoom lens will work if the camera starts up each time at a stable focal length, and can be it can be fixed so the focal length does not change easily.
Avoid OIS / Optical Image Stabilization. Try to avoid cameras where the body or lens have optical image stabilization. Note most modern mobile phone cameras have OIS.
Avoid long focal lengths. For most applications of photogrammetry, a shorter and wider lens will be better. Not so wide that is a fish-eye lens. For a 35mm equivalent look for focal lengths between 15mm and 50mm - 18mm to 35mm (in 35mm equivalent) is a sweet range for many applications.

Can I Use the Camera in My Mobile Phone?

In most cases, a mobile phone camera can be used by PhotoModeler. There are a few caveats: a) the resolution and image quality can be lower than many other digital cameras, b) some modern mobile phone cameras use OIS (optical image stabilization) which can reduce accuracy and increase project residuals (e.g. any iPhone after the 7), c) some mobile phone cameras will do manipulations such as auto-rotation, or auto-lens choice and merging, that can cause issues with photogrammetry, and d) it can be more difficult to get photos off a mobile phone than a normal camera.

Even if you won't be using a mobile phone camera for your final / production work, they are great for evaluation of the software and a great way to get started - as most of us have one in our pocket!

Can I Use a Camera With a Zoom Lens?

We normally recommend fixed lenses with PhotoModeler (i.e., no zoom or 'prime') 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 (i.e. the focal length does not change as you handle the camera) - these cameras are preferred.

What are the Best Camera Settings?

See the article Recommended Camera Settings for Photogrammetry.

What is OIS / Optical Image Stabilization and Why it is Bad.

Some camera bodies and some lenses have a feature that stabilizes the images to help reduce motion blur. This can be done electronically or can be done by physically moving a lens element or the imaging chip.This is quite common in most modern mobile phone cameras - but many cameras have the feature.

Ideally, you would use a camera with PhotoModeler that does not have this feature (esp. the mechanical kind). Even if the feature can be turned off (recommended), the ability to shift the image chip or a lens element means the camera is already less stable. Cameras that do not have good internal stability do not make the best cameras for photogrammetry. They can be used, but are not recommended for high-accuracy work.

Some camera manufacturers put the OIS in the lens, and in which case try to buy lenses without the feature. Other cameras have the OIS is built into the camera body. This often means the imaging chip is mounted on a rubber or similar platform so it can be moved by actuators. Even when the OIS feature is turned off, the imaging chip is still unstable as you move the camera around. The relationship between the imaging chip and the lens is a key element in accurate photogrammetry. If this relationship can change, the photogrammetric solutions are less accurate (or sometimes fail).

Avoid buying cameras with OIS (esp mechanical vs digital)
If you can, avoid most modern mobile phone cameras that have OIS
If OIS is in the lens, try to buy non-OIS lenses
If you have have an OIS camera, at the very least, turn it off.

What is Camera Calibration?

Camera Calibration is the process of determining the internal values of a camera (called 'interior orientation' in photogrammetry). These values are focal length, format size, principle point, and lens distortion. There are a few different ways to get the internal values for a camera:

EXIF header data - digital cameras often write the basic values to the image headers. Sometimes this can be enough.
Independent Camera Calibration - PhotoModeler has a Calibration project type that allows accurate pre-calibration of a camera.
Field Calibration - PhotoModeler can calibrate (or fine tune a pre-calibration) a camera when solving certain project types. Often this requires quite a strong geometry of camera positions in the project.
Auto-Calibration - Auto-calibration is a variation of Field Calibration and is used in automated Coded Target and SmartMatch projects. The calibration is carried out without user intervention during processing.
Inverse Camera - often use in forensic cases where you know nothing about the photo. Requires control points.