Where is Focus Distance in EXIF data: I'm thinking that the focus distance should be recorded somewhere in the image EXIF data as long as the lens and body are communicating. In this...

Alphabravo2020

I'm thinking that the focus distance should be recorded somewhere in the image EXIF data as long as the lens and body are communicating. In this case I used a Sony A7iv and a Sony 50mm GM f1.2.

Shouldn't the camera be able to figure out the focus distance from the information it gets from the lens? Anyway I don't see it there or maybe I don't recognize what it is called.

Gratuitous example image supplied upon request.

Longshadow Loc: Audubon, PA, United States

"Subject Distance" parameter?

Not all cameras save all EXIF data.

SX2002 Loc: Adelaide, South Australia

I sometimes use Opanda Exix, it tells you everything, even stuff you didn't need to know but there is no focus distance info...your camera has no way of recording the focus distance that I'm aware of...
My editing programme, FastStone gives you most of the basic Exif info which is enough for me...

(Download)

User ID

Alphabravo2020 wrote:

I'm thinking that the focus distance should be recorded somewhere in the image EXIF data as long as the lens and body are communicating. In this case I used a Sony A7iv and a Sony 50mm GM f1.2.

Shouldn't the camera be able to figure out the focus distance from the information it gets from the lens? Anyway I don't see it there or maybe I don't recognize what it is called.

Gratuitous example image supplied upon request.

Im wondering what use the focus distance would serve as a recorded parameter. Never needed to check on it so Ive never especially noticed its absence in the exif.

The position of the focusable moving optics doesnt seem like a source of really accurate distance info anywho.

I realize there were the Nikon D-type lenses which somehow related to use of flash, but were not at all a form of GN linkage so that "D" info could have just been a gross "near-mid-far" three steps of distance info.

selmslie Loc: Fernandina Beach, FL, USA

Alphabravo2020 wrote:

I'm thinking that the focus distance should be recorded somewhere in the image EXIF data as long as the lens and body are communicating. ...

It depends on the camera and the lens.

It can be useful if you are doing research but otherwise it's not as important as some of the other recorded information.

Here is an example from a Z7 with a Tamron 150-600.

Architect1776 Loc: In my mind

Alphabravo2020 wrote:

I'm thinking that the focus distance should be recorded somewhere in the image EXIF data as long as the lens and body are communicating. In this case I used a Sony A7iv and a Sony 50mm GM f1.2.

Shouldn't the camera be able to figure out the focus distance from the information it gets from the lens? Anyway I don't see it there or maybe I don't recognize what it is called.

Gratuitous example image supplied upon request.

Are you looking at the JPEG or raw photo.
I notice after going through PSE that most of the EXIF data seems to be stripped out.
But in the raw file it is all there with tons of other data that a JPEG is missing including distance information.
Open your raw file and see if distance is located there. I would imagine that is where you will find it.

selmslie Loc: Fernandina Beach, FL, USA

Architect1776 wrote:

Are you looking at the JPEG or raw photo.
I notice after going through PSE that most of the EXIF data seems to be stripped out.

Some editors default to stripping much of the EXIF data but it might be optional.

gvarner Loc: Central Oregon Coast

Camera focus is not based on distance. There is no feedback signal from the target to the sensor. It’s not like a laser distance finder. There are laser distance measuring devices you can use if you have a need to know the distance. Someone on UHH might know how focus is rendered in the sensor.

Longshadow Loc: Audubon, PA, United States

gvarner wrote:

Camera focus is not based on distance. There is no feedback signal from the target to the sensor. It’s not like a laser distance finder. There are laser distance measuring devices you can use if you have a need to know the distance. Someone on UHH might know how focus is rendered in the sensor.

"Smart Lens"? SOME cameras know the reference point of the focus based on the position of the focusing collar or the results of an algorithm based on such.

In Other Words: magic.

gvarner Loc: Central Oregon Coast

Longshadow wrote:

"Smart Lens"? SOME cameras know the reference point of the focus based on the position of the focusing collar or the results of an algorithm based on such.

In Other Words: magic.

Good one. It’s also why we can see a star without knowing how far away it is. Focus pokus. 😉😉

Longshadow Loc: Audubon, PA, United States

gvarner wrote:

Good one. It’s also why we can see a star without knowing how far away it is. Focus pokus. 😉😉

BebuLamar

gvarner wrote:

Camera focus is not based on distance. There is no feedback signal from the target to the sensor. It’s not like a laser distance finder. There are laser distance measuring devices you can use if you have a need to know the distance. Someone on UHH might know how focus is rendered in the sensor.

The distance is derived from the position of the focusing mechanism. I don't know about other brands but with Nikon the focus distance is available to the camera since they introduced the D lenses.

Architect1776 Loc: In my mind

gvarner wrote:

Camera focus is not based on distance. There is no feedback signal from the target to the sensor. It’s not like a laser distance finder. There are laser distance measuring devices you can use if you have a need to know the distance. Someone on UHH might know how focus is rendered in the sensor.

Then why do my cameras provide distance in the EXIF?

selmslie Loc: Fernandina Beach, FL, USA

gvarner wrote:

Good one. It’s also why we can see a star without knowing how far away it is. Focus pokus. 😉😉

You haven't given this much thought, have you?

The further from the camera the less precise the measurement. When focused at infinity it will report either "infinity" or a very big number.

selmslie Loc: Fernandina Beach, FL, USA

BebuLamar wrote:

The distance is derived from the position of the focusing mechanism. I don't know about other brands but with Nikon the focus distance is available to the camera since they introduced the D lenses.

I can see it in the raw EXIF for my Sony A7 II and III, my Nikon Df and even my Fuji X100T.

When I convert to JPEG and save for internet display (not at full resolution) most of the EXIF information disappears to save space.