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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 ...
jarnbjo's user avatar
  • 3,330
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 ...
user82310's user avatar
  • 251
13 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 ...
Alan Marcus's user avatar
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9 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 ...
PhotoScientist's user avatar
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 ...
flolilo's user avatar
  • 6,478
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 ...
LuZel's user avatar
  • 699
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 ...
mattdm's user avatar
  • 143k
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 ...
Benjamin Cooper's user avatar
2 votes

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. ...
Edgar Bonet's user avatar
  • 3,445
2 votes

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 ...
Matthieu Moy's user avatar
  • 1,673
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.
Tetsujin's user avatar
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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 ...
mattdm's user avatar
  • 143k
1 vote

How can the focusing distance manually set on a lens influence the firing of a flash?

Another possibility may be that the pre-flash reveals to the TTL algorithm that even the minimum power the flash can be set to will be too bright. So it doesn't fire the flash at all. You can test ...
Michael C's user avatar
  • 176k
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 ...
Ross Millikan's user avatar
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 ...
scottbb's user avatar
  • 33.1k
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 ...
Toby Speight's user avatar
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" ...
ths's user avatar
  • 7,181
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 ...
xenoid's user avatar
  • 21.6k
1 vote

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

Take out your shiny smartphone and hold it at arm's length. Stare at the screen. Now allow your eyes to focus on your reflected image. Then focus back on the screen. Your eyes are performing the same ...
Declan Kenny's user avatar
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 ...
Alan Marcus's user avatar
  • 39.4k
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. ...
Alan Marcus's user avatar
  • 39.4k

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