Will a 1-inch lens cover the Sony IMX267 1-inch sensor, and is using a larger-format lens OK?
Asked 3/23/2021
7 views
2 answers
0
I’m using a camera with a Sony IMX267LQR sensor, described as a 1-inch format sensor with a quoted diagonal of 16.1 mm and 4096×2160 output. I estimated the sensor’s width and height from the pixel aspect ratio and diagonal, and got roughly 14.25 × 7.5 mm. My lens is a Navitar NMV-8M1, specified for 1-inch format with a picture size of 12.8 × 9.6 mm.
Are my sensor-dimension calculations reasonable? More importantly, does a 1-inch lens actually cover this sensor, or do I need to step up to a 1.1-inch lens? If I use a lens designed for a larger sensor than mine, are there any downsides besides cost/size?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
5y ago
2 Answers
2
- Did I make a correct assumption regarding finding the sensor dimensions using similar triangles?
Yes. But you don't need to worry about them. All that matters is the sensor diagonal (16.1 mm in your case), because the lens projects a cone of light that lands on your sensor as an image circle. As long as the sensor diagonal fits within the lens's image circle, you're set.
In your case, it's very close. A 1" sensor is considered to have a 16.0 mm diagonal. So a lens that is intended for use with a 1" sensor would project that size of image circle, at a minimum. It probably projects just a little larger, to minimize the sharp vignetting at the corners of a standard 1" sensor.
- Did I buy the wrong lens then for my IMX267LQR sensor?
Personally, I don't think the extra 0.1 mm your sensor extends will be a problem. However, if you went with Navitar's 1.1" format 8mm lens, it states it projects an image circle of "⌀17.6", meaning the circle's diameter (⌀) is 17.6 mm. That would certainly cover your sensor, while also slightly reducing corner vignetting.
- If I do get a larger lens, would it have any negative impact on my image quality?
The 1.1" format lens states a resolution of 160 lp/mm (center) / 100 lp/mm (corner), whereas the 1" format lens states a resolution of 120 lp/mm / 80 lp/mm (center / corner, respectively). That means the 1.1" lens is a higher-resolving lens than the 1" format lens.
Generally speaking, there is no problem putting a smaller sensor behind a lens designed for a larger one. That is exactly what the whole "crop factor" discussion is about in the DSLR and mirrorless world. Lenses designed for so-called "full frame" (43.3 mm film/sensor diagonal) are mounted all the time on "crop" bodies with sensors that are 1.5–1.6 times smaller than the full frame sensor. Those crop bodies are just looking at a smaller portion of the image circle projected by the lens.
Originally by user11924. Source · Licensed CC BY-SA 4.0
user11924
5y ago
0
Generated from our catalog & community — verify before relying on it.
Yes, your geometry is reasonable, but for lens coverage the key spec is the sensor’s active area or diagonal, not just the labeled “1-inch” format. Sensor format names are categories, not exact dimensions.
Using the IMX267’s pixel pitch and active pixels gives an active area of about 14.13 × 7.45 mm, with a diagonal around 15.97 mm—essentially a true 1-inch sensor. That means a lens specified for 1-inch format should generally cover it.
Your lens’s stated picture size of 12.8 × 9.6 mm corresponds to a diagonal of 16.0 mm, which is extremely close to the sensor’s ~16.0–16.1 mm diagonal. So you likely did not buy the wrong lens; at worst, coverage is right at the limit and corner shading/vignetting would be the thing to watch for.
Using a lens designed for a larger sensor is normally fine. The main tradeoffs are usually higher cost, larger size, and weight. There is no inherent penalty simply because the lens covers more than your sensor needs; in some cases, using only the central portion of a larger image circle can even avoid edge falloff.
Recommended products
UniqueBot
AI5y ago
Your Answer
Related Questions
What does a webcam’s “1/4-inch sensor” mean, and can it be used to estimate pixel pitch?
How can I estimate pixels per degree from a phone image using EXIF focal length and digital zoom?
How can I estimate the minimum magnification needed to resolve a feature of a given size?
Why is a “1-inch” camera sensor only 13.2 × 8.8mm?
How do I calculate focal length for a 1 m × 1 m field of view at 10 m distance?