40 votes
Accepted

Can you tell from a blurry photo if focus was too close or too far?

It depends. In many cases, it may actually be possible without any further visual aids in the picture. Many lenses, if not most, will show different longitudinal chromatic aberration in front of and ...
  • 2,883
21 votes

Can you tell from a blurry photo if focus was too close or too far?

When the aperture is positioned to minimize vignetting, the bokeh shapes for objects that are too far is rotated by 180° compared with objects that are too near. (The aperture image is reflected ...
  • 251
16 votes
Accepted

Since it's not "focal length", what is the term for the distance at which things are in focus?

Focal length is the distance between the lens and the sensor when the subject is in focus, not the distance to the subject. The term for the distance to the subject in focus is the focus distance ...
11 votes
Accepted

Why doesn't the focus distance at which my lens has magnification 1 match the formula?

The equation assumes a simple single element lens that is bilaterally symmetrical. The camera lens, to mitigate the 7 major aberrations (shortcomings that degrade) is constructed using several ...
  • 37.2k
8 votes

Why doesn't the focus distance at which my lens has magnification 1 match the formula?

first of all, kudos on your effort to break a photography problem down to first principles. The discrepancy you've observed stems from a common oversimplification. Your 100mm Lens is actually what ...
7 votes

Can you tell from a blurry photo if focus was too close or too far?

My answer only deals with "human" ways in differentiation - that is: No software, only your eyes and hands. If I have no reference (as in: you blind me, you set the focus distance, and then I can ...
  • 6,437
6 votes

Can you tell from a blurry photo if focus was too close or too far?

If the plane is too far or to close is just from the blur hard to say. the easiest way is to have objects in front and behind and see which one is sharp and so you could determine if it is too far or ...
  • 699
6 votes

Do the out of focus elements in this photo look normal?

There's nothing obviously wrong with the image. You've got a very narrow depth of field, so the grass in the foreground and background is out of focus, but that's not surprising if you were shooting ...
  • 31.4k
4 votes
Accepted

50mm and 100mm macro lenses difference at the minimum focus distance?

When a macro lens has a reproduction ratio of 1:1 an object with a given size will be reproduced at the image plane at the same size. This is irrespective of the focal length. The only difference is ...
  • 530
3 votes
Accepted

Does focusing at infinity mean the sensor is at F?

Does focusing at infinity mean the sensor is at F? Yes. The definition of focal length is that it's the distance from the optical center of the lens to the image plane when the lens is focused at ...
  • 31.4k
3 votes

Sharp focus photography with APS-C

There is absolutely nothing about this photo that requires a camera more advanced than your Canon 60D and a $100 lens. The basics are: Good lighting — a whole topic to itself Stop down the aperture ...
  • 142k
3 votes

Do the out of focus elements in this photo look normal?

I think you are seeing strong chromatic aberrations. Those come from different colors of light getting refracted slightly differently, so the focus points for the different colors are in different ...
  • 2,011
3 votes

Why is the focus distance for a mirror image further than the surface of the mirror itself?

Yes, you either get the lake (or mirror, with its beautiful carved wood frame !)) in focus, or the reflected clouds at infinity. If you want the ducks on the lake and the beautiful reflection of the ...
2 votes

Do the out of focus elements in this photo look normal?

What you're seeing is know as bad bokeh. What's bokeh? It's a term that describes the quality of the out of focus areas in an image. What is good bokeh and what is bad bokeh? Umm... if you like the ...
  • 2,351
2 votes

Do the out of focus elements in this photo look normal?

I had the same problem with the EF 75-300 lens. I found out that the optics in the glass is made poorly and has a really bad drop off around the edges and when its out of focus the poor contrast on ...
  • 1,130
2 votes

Is there any way to know the distance between the camera and the focused subject

It's saved in the exif data when the photograph is taken, as Focus Distance, but I know of no way to access it directly from the camera, either before or after taking the shot.
  • 21.4k
2 votes
Accepted

What units are used for zoom and focus distance for the varifocal Dahua camera?

From the specs, the lens's zoom is from 4.1mm (wide) to 16.4mm (zoomed in). Focal length is the only standard measurement of this, and that's almost universally in millimeters. (You can find it ...
  • 142k
1 vote

disappearing off to infinity

As scottbb said, getting closer was the ticket. It was a journey that had me abandon the panorama approach. One image I like is below. The 15-45 lens for my Canon M6 focuses rather close. I ...
1 vote
Accepted

disappearing off to infinity

Sounds like you're basically trying to create a 'bokehrama', i.e., the Brenizer method, where you stitch together several shots to simulate otherwise impossible shallow depth of field, such apparent ...
  • 31.4k
1 vote

Can you tell from a blurry photo if focus was too close or too far?

Yes, if the content includes edges at different distances. If you can tell that a further object is more blurred than a nearer one, then it's further from the plane of focus. That means that the ...
1 vote

Can you tell from a blurry photo if focus was too close or too far?

No it is technically not possible to detect from the blur alone how far or in which direction the image is out of focus. This is the reason why contrast-detection autofocus systems have to "hunt" ...
  • 6,919
1 vote

Why doesn't the focus distance at which my lens has magnification 1 match the formula?

There are two reasons why the subject-to-image distance is not 40 cm at unit magnification: the focal length of the lens may not be 100 mm the distance between the principal planes may not be zero. ...
  • 3,385
1 vote

Why doesn't the focus distance at which my lens has magnification 1 match the formula?

Most fixed focal length lens focus by changing their focal length in addition to moving the lens's nodal point(s). To focus on an object close to the camera, the lens reduces its focal length. A lens ...
  • 1,663
1 vote

Sharp focus photography with APS-C

The short answer is, bigger is better! The image sensors of the various digital camera types vary in size. The so called full frame image sensor is a copycat of the image size yield of the esteemed ...
  • 37.2k
1 vote

What is the depth of field if the the focus distance is set to infinity?

With the camera focus set to infinity (as far as the eye can see) the hyperlocal distance is the near subject distance that will render an object with acceptable focus. The far distance is infinity. ...
  • 37.2k
1 vote

Since it's not "focal length", what is the term for the distance at which things are in focus?

The specific answer to the core of your Title Question, "the term for the distance", is: Infinity. Infinity is the (imagined) subject distance in front of the optical center of the lens that ...
1 vote

Is it possible to make your own focus distance scale?

Focus distance is measured to the focal plane mark, a circle with a line through it, on body, near rear edge of the top LCD. This marks the location of the digital sensor or film. I have to say, "...
  • 12.7k
1 vote

50mm and 100mm macro lenses difference at the minimum focus distance?

As agf1997 says, minimum focus distance for macro lenses varies somewhat with lens design, however as a rule of thumb you can expect the minimum focus distance (i.e. minimum working distance) to be ...
  • 669
1 vote

Why is the focus distance for a mirror image further than the surface of the mirror itself?

Your camera doesn't know there is a mirror(*), it focuses on the "virtual image" created by the reflection. And for nearby objects this virtual image is at a significantly greater distance than the ...
  • 18k

Only top scored, non community-wiki answers of a minimum length are eligible