# Tagged Questions

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68 views

### Calculation for getting dimension of object in image not working

I am trying to calculate the dimensions of an object in an image. This is a sample image I took to get height of blue shirt: I am following the math from this page with sastanin's answer. How do I ...
65 views

### How to determine film size from smartphone image exif data?

I took an image from my phone and got its exif data below. It was a samsung note 4, which uses a 35mm film size (24x36) with a 43.27 diagonal. But what I am trying to figure out is the sensor diagonal ...
77k views

### How do I calculate the distance of an object in a photo?

If I took a picture of a windmill on the horizon — given that I know the sensor size and the focal length of the lens and other factors to do with the shot — could I calculate how far away an object ...
68 views

### Converting FOV to Distance?

I have a camera with CS mount and I am now trying to figure out the best fixed-lens to buy so that my camera can see the object at a distance of 5" without the object looking like a tiny dot, it is ...
148 views

### What lens will let me take a photo of a bird high up in a tree?

What lens would work for a canon 6D to take up close photos of birds far away in the trees? My Canon 100mm-400mm lens just doesn't get that close.
3k views

### Is there a difference between taking a far shot on a 50mm lens and a close shot on a 35mm lens?

I am looking for a prime lens to pick up, and I'm wondering if there is any difference between 35mm and 50mm in terms of the end product if I just stand back more with the 50mm. I use the Sony a6000 ...
150 views

### Setup for taking photos of large flat surfaces (maps/plans/textiles) at limited distance

My Problem ist actually simple: I am trying to take photos of flat surface items (large flags, large maps, antique rugs and so on) in a room that does not offer enough height. I have been "...
87 views

### How to Decide Furthest Distance for Detecting Small Object with Camera? [closed]

Assume you have a 4K or 10K camera without zoom (1x). Case 1. Object width 2 cm and height 2 cm. It is 50 meter from the lens. The angle becomes << 1 so making the object invisible in the ...
323 views

### Is it possible to calculate the distance to an object using two pictures taken a few cm apart?

Is it possible to calculate the distance of an object to the camera with two pictures which are taken a few cm apart? We are able to estimate the distance with our eyes. But is it possible to do it ...
9k views

### What is the relationship between size of object with distance?

How does the size/length of an object vary with distance? Is it a logarithmic relationship? exponential? linear? I plotted a curve of the size/length of an object for different distances from the ...
77 views

### How can I determine the distance to a subject in a old photo with little other information?

My question is similar to this one, but I don't know how accurate the formula will work with old photos. If I assume that the runners would be 1m80 (5'11"), would it possible to estimate how far ...
215 views

### What kind of lens to use to get sharp images of people from a distance?

I am looking to buy a new lens and want something that will produce sharp images of people from a distance. I currently have a 50mm prime lens and my close-up portraits are great - crisp and clear - ...
188 views

### I have camera specifications but don't know the actual focal length

I'm trying to figure out the focal length of my camera. I'm trying to figure out the distance from my camera to an object using the equation listed here (How do I calculate the distance of an object ...
6k views

### What is ideal distance to subject for head and shoulder portraits?

Perspective is a matter of distance and has an effect on facial features and the observed three-dimensional feeling in a two-dimensional photograph. Proper lighting is a big part of this, but that's ...
2k views

### How do I convert focal length to maximum distance?

I would like to know whether there is any relation between focal length and distance. For example, what is the max distance I can shoot from a 55mm-300mm lens?
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### How do I measure the distance from an object to fit it in the screen? [duplicate]

I'm curious if there is any math formula for this. Let's take a close-up of a human face for instance, given the human face is about 20cm/8 inches, how do I choose the right focal length and from ...
632 views

### What factors determine the size of focus step done with remote shooting?

When a DSLR camera is used for remote shooting, corresponding software usually provides very simple way to change focus position: small, medium and large steps forward or backward. This is how it ...
404 views

### Can a telephoto lens have a wide field of view?

85mm-135mm lenses are great for portraits because of compression perspective distortion, meaning they flatten facial features. However at those focal lengths, you have to step back a few meters from ...
586 views

### Why does getting closer or zooming in decrease depth of field?

I know that aperture changes the depth of field (DOF), but why is it that by making the image appear larger (by getting closer to the camera or zooming in) there is less DOF?
271 views

### Is the distance scale on a lens linear?

I have Nikon lenses with distance scales on them so I can set the lenses to the hyperfocal distance when I need. Say now the focal length is 28mm and the aperture is f/16. The corresponding ...
612 views

### How do I calculate what the working distance will be with a macro reversed lens setup?

Once I got hooked up on macro photography and bought a 105mm 1:1 macro lens. I really like the lens and it also gives me a decent working distance. However, I started being obsessed with getting ...
473 views

### At what distance from the lens will the image be in focus given a subject distance and focal length? [closed]

I've been trying to figure this one out for more than an hour now and I have no idea how to calculate this... You capture a picture of a tree which is standing 3m away from the camera. The focal ...
914 views

### Image size of the Sun / Moon from a telephoto lens

I'm interested in taking a picture of the Sun / Moon using a telephoto lens. For example like this. It would be very helpful for me to know what the approximate image size of the sun / moon would ...
165 views

### How to take a moving object(far distance) in outdoor low light situation?

It's always been tricky to me how to take a far distance picture(moving) in a low light situation. I don't think flashlight would help in this case since it can't reach to the moving object. For ...
86 views

### Finding the point corresponding to a known height in an image

I have an image of a wall taken from a phone camera from a known height h from the ground. Assume that the camera was held perfectly parallel to the wall and that the bottom of the image is perfectly ...
411 views

### Finding the distance of object from camera to the point of autofocus

Is it possible to find the distance to which the camera is auto focussing ? Camera auto focuses itself to view a particular plane in the real world in front of it. Is it possible to estimate the ...
323 views

### How can the height of a subject in picture be calculated? [duplicate]

Maybe is not the perfect stackexchange site to ask this but I try. Feel free to move or close my question, but, if you can, suggest me where I can ask this one: I took a photo with a compact digital ...
163 views

### Using gray/white card to determine white balance, does it matter where I stand when I take reading photo?

If I want to use a white card to determine the white balance, and I'm taking a picture of something that is a short distance away from me, does it matter if I don't walk back to where I'm going to ...
297 views

### How to calculate distance from a subject to get the same field of view with different lenses? [duplicate]

Possible Duplicate: How much distance should one move so that a shot that can be framed at xx mm be framed at yy mm? I think the question is clear but I will provide an example. To fill the ...
1k views

### How much distance should one move so that a shot that can be framed at xx mm be framed at yy mm?

Is there a website / app that will tell you approximately how much distance a person should move so that they are able to frame the same shot at different focal lengths? Say for example, I'm ...
1k views

### Why does calculated distance of an object in an image vary when zooming?

I would like to calculate the distance of an object from my camera, so i used the formula given in this question and I got a very good answer, but I've found that when I zoom and take the picture and ...
6k views

### What does it really mean that telephoto lenses “flatten” scenes?

This is another perspective distortion question. I understand that perspective distortion is primarily a function of capture and viewing distance, but I am still working on fully understanding the ...
2k views

### How to measure distance to subject in Depth of Field calculator?

I used Depth of field calculator here. I should specify subject distance. How to measure distance to subject? In theory this is a distance to front principal plane or point. What is in practice? I ...
632 views

### How to calculate object size dependent on distance?

I shot some images for use in a blog post. With the closeups, I ran into the problem of too low depth of field. Because I only need them for the web, I think that the easiest way to solve it would be ...
1k views

### When a camera auto-focuses, is the current focus distance reported from the lens to the camera?

The question says it all -- does the camera "know" how far the subject is from the lens, i.e. what is the current exact focus distance set at the lens?