- #1
walter1998
- 11
- 0
Hello guys, I was wondering if you could guess or even calculate the diameter of a camera lens with a picture of a ruler.
Calculating Camera Lens Diameter with a Ruler
In summary, the conversation revolves around calculating the diameter of a camera lens based on a picture of a ruler. The participants discuss the limitations of realistically estimating the diameter without additional information and assumptions, such as the size of the image on the film or sensor. They also suggest making educated guesses based on the clarity and focus of the ruler and other elements in the picture. Ultimately, it is noted that an accurate estimate is not possible, but an educated guess can be made to avoid giving a completely wrong estimate.
- #2
mfb
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Not in any realistic way. An ideal camera will make the same picture independent of the size of the lens, and real cameras are quite close to that (and for the tiny deviations, you have no idea which part of the camera lead to them).
- #3
walter1998
- 11
- 0
This question is asked in a famous competition in my country: "Approximately calculate the diameter of the lens which this picture is taken with.(for measurements consider lens as a flat object)mfb said:
- #4
mfb
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Ah well, you also have some background here that can be useful. And I think you still need some additional assumptions (like no additional elements that block light).
- #5
sophiecentaur
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I think this is to do with probable f number and focal length. There are some clues to help you but the main bit of information that is totally missing would be the size of that image on the film / sensor assume it is an APS sensor?? perhaps.. Firstly, the ruler looks pretty straight, unless the lens is very expensive, we are not dealing with a very short focal length. The window frame is probably not far from the ruler and is badly out of focus so the aperture must be fairly wide (poor depth of focus).
The left side of the ruler is a bit soft so that could suggest either a poor lens or a wide aperture. You can make assumptions about the probable width of the window frame and then guess how far it is behind the ruler. That would give a clue about how far the camera is away from the ruler (draw some sketches).
I could suggest you take a camera of your own and try to reconstruct a similar picture (with buildings in the distant background - or is it a fence, only a few metres away?) and note the focal length and f setting. That will give you the width of the internal aperture but it cannot tell you the diameter of the lens without a lot more information.
There is no way you can get an accurate estimate but, like estimating the number of sweets in a jar, you can avoid giving really wrong estimate.
The left side of the ruler is a bit soft so that could suggest either a poor lens or a wide aperture. You can make assumptions about the probable width of the window frame and then guess how far it is behind the ruler. That would give a clue about how far the camera is away from the ruler (draw some sketches).
I could suggest you take a camera of your own and try to reconstruct a similar picture (with buildings in the distant background - or is it a fence, only a few metres away?) and note the focal length and f setting. That will give you the width of the internal aperture but it cannot tell you the diameter of the lens without a lot more information.
There is no way you can get an accurate estimate but, like estimating the number of sweets in a jar, you can avoid giving really wrong estimate.
1. How do I calculate the camera lens diameter using a ruler?
To calculate the camera lens diameter using a ruler, you will need to measure the distance between the center of the lens and the edge of the lens using a ruler. Then, divide this measurement by the magnification of the lens. The result is the diameter of the lens in millimeters.
2. What is the magnification of a camera lens?
The magnification of a camera lens refers to how much the lens can zoom in or out. It is typically measured in terms of a ratio, such as 1:2, which means that the lens can zoom in twice as much as it can zoom out.
3. Can I use any ruler to measure the lens diameter?
Yes, you can use any ruler as long as it has accurate markings and is long enough to measure the distance between the center and edge of the lens. A ruler with millimeter markings is recommended for more precise measurements.
4. Why is it important to know the lens diameter?
Knowing the lens diameter is important for various reasons. It can help you determine the compatibility of lenses with different cameras, make accurate calculations for magnification and field of view, and ensure proper fitting of lens filters and accessories.
5. Are there any online tools available to calculate lens diameter?
Yes, there are many online tools available that can help you calculate the lens diameter using a ruler. Simply input the measurements and magnification, and the tool will provide you with the diameter in millimeters. However, it is always recommended to double-check the calculations for accuracy.
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