Camera Specifications computing focal length and f/#

[thiirane]

So I have come across a specification of a narrow field of view camera. The specification states
IFOV=30 microrad
FOV=2x2
resolution=<.1m at 1 km

If I assume a 1K sensor at 9micron pitch and an aperture = 3.7cm

I have resolution at .013 m

Chip size = 9.2mm

Focal length is 6.167E5mm?? can this be right? Also f/#=1.6E4

Do I have the formulas correct

f/#=Focal Length/Aperture

Focal Length=Aperture/2*tan(IFOV)

 

[Andy Resnick]

Can you provide additional information- for example, the field of view = 2x2 what- radians, degrees, other? Any specific information on the lens?

Alternatively, do you have a product ID/name?

 

[thiirane]

Hi Andy,

Actually the only thing specified is the IFOV, FOV and resolution at 1Km I think it is up to the supplier to design the rest. FOV is degrees. I assumed a sensor 1K sensor at 9 microns.

 

[Andy Resnick]

It's still not entirely clear- are you specifying a sensor, a lens, or an integrated sensor+lens? The IFOV and FOV specs define the sensor array size (I also got a 1k x 1k array), but the resolution spec involves a lens (which will operate at f/15 at a magnification of 1*10^-6, according the spec and assuming you are using visible light), and combining everything indicates a 400mm focal length lens, if the pixel size is 9um.

Note- imaging over 1 km distance is complicated by atmospheric distortion, you are unlikely to meet your resolution spec unless your application is able to avoid this. Some friendly advice- providing the OP specs to a supplier will result in an irritated supplier.

 

[pmacias]

I would like to clarify that the focal length and f/# are important parameters in determining the performance of a camera. The focal length is the distance between the lens and the camera's image sensor, while the f/# is the ratio of the focal length to the diameter of the lens aperture. These parameters play a crucial role in determining the field of view, resolution, and image quality of the camera.

Based on the given specifications, it seems that the camera has a narrow field of view of 2x2 degrees, with a resolution of less than 0.1m at a distance of 1km. The IFOV (instantaneous field of view) of the camera is 30 microrad, which is the angular size of the smallest detail that the camera can resolve. The chip size of the sensor is 9.2mm, and the pitch is 9 microns, which means that the sensor has a total of 1000 pixels.

Using the formula for f/#, we can calculate the focal length of the camera to be 6.167E5mm, which seems to be a very large number. However, this calculation assumes a perfect lens with no aberrations and a point light source. In reality, the actual focal length may be slightly different due to the limitations of the lens. The f/# calculated is also very high at 1.6E4, indicating a narrow aperture. This means that the camera has a small depth of field, which can be useful for capturing highly detailed images at a specific distance.

In conclusion, the formulas used to calculate the focal length and f/# seem to be correct based on the given specifications. However, it is important to note that the actual performance of the camera may vary due to other factors such as lens quality, sensor sensitivity, and environmental conditions. As a scientist, it is essential to consider all these factors when analyzing camera specifications and their potential applications.