FoV instead of mm

Instead of reporting meaningless focal lengths in mm,
for this phone of Xiaomi (the Redmi K20), the actual
field of view is declared for the three camera modules:

- an ultrawide angle module with a FoV of 124.8 degrees
and 13 MP
- the main camera with a FoV of 79.4 degrees
- a tele module with a FoV of 44.6 degrees and 8MP

The article (German only) is at
https://www.golem.de/news/redmi-k20-pro-xiaomi-
praesentiert-top-smartphone-ab-320-euro-1905-141564.html

This could be done also for standard camera lenses. For
sure at least for ultrawide angle lenses the FoV is a
more relevant number than the focal length in mm.
--
Alfred Molon

Olympus E-series DSLRs and micro 4/3 forum at
https://tech.groups.yahoo.com/group/MyOlympus/
https://myolympus.org/ photo sharing site

In article , Alfred
Molon wrote:

Instead of reporting meaningless focal lengths in mm,
for this phone of Xiaomi (the Redmi K20), the actual
field of view is declared for the three camera modules:

- an ultrawide angle module with a FoV of 124.8 degrees
and 13 MP
- the main camera with a FoV of 79.4 degrees
- a tele module with a FoV of 44.6 degrees and 8MP

The article (German only) is at
https://www.golem.de/news/redmi-k20-pro-xiaomi-
praesentiert-top-smartphone-ab-320-euro-1905-141564.html

This could be done also for standard camera lenses. For
sure at least for ultrawide angle lenses the FoV is a
more relevant number than the focal length in mm.

no, it cannot be done, because the same lens can be used on different
cameras with different sensor sizes, and in many cases, on the *same*
camera, resulting in a different field of view in each case, all with
exactly the same lens.

nikon full frame cameras can be set to dx mode, instantly changing the
field of view of the attached lens.

the *only* thing that remains constant is the focal length.

On 30/05/2019 14.58, Whisky-dave wrote:
On Thursday, 30 May 2019 10:45:43 UTC+1, Alfred Molon wrote:
Instead of reporting meaningless focal lengths in mm,
for this phone of Xiaomi (the Redmi K20), the actual
field of view is declared for the three camera modules:

- an ultrawide angle module with a FoV of 124.8 degrees
and 13 MP
- the main camera with a FoV of 79.4 degrees
- a tele module with a FoV of 44.6 degrees and 8MP

The article (German only) is at
https://www.golem.de/news/redmi-k20-pro-xiaomi-
praesentiert-top-smartphone-ab-320-euro-1905-141564.html

This could be done also for standard camera lenses.

True and in this digital age why do we still use 1/x for exposure times why say 1/250th second when you can say 4 milliseconds or 4ms ?

This has a meaning: one speed step is double or half. It is easy for a
photographer to memorize the steps from frequent use.

The same goes for the apertu double or half "hole" area produce those
strange diaphragm numbers we are familiar with :-)


For
sure at least for ultrawide

Where the cut-off from calling a lens wide and ultrawide ;-)

angle lenses the FoV is a
more relevant number than the focal length in mm.

I'm guessing it's all down to tradition and what people are used to and difficult to change quickly.
like MPH rather than KPH of lbs rather than KG.

focal length has a meaning knowing the sensor size. At a time when
"everybody" was using 35 mm we memorized what angle the lenses would
have. But now that the sensors are different sizes we should perhaps use
angles instead.


--
Cheers, Carlos.

In article , Carlos E.R.
wrote:

focal length has a meaning knowing the sensor size. At a time when
"everybody" was using 35 mm we memorized what angle the lenses would
have. But now that the sensors are different sizes we should perhaps use
angles instead.

nope. when everyone was using 35mm, the focal length was used because
the frame size was always the same.

with digital, the same lens can be used with different size sensors,
even in the same camera (crop mode), thus changing the angle of view
with exactly the same lens.

the only thing that remains constant is the focal length, because it's
a physical property of the lens.

the field of view can vary.

On 2019-05-30 08:58, Whisky-dave wrote:

True and in this digital age why do we still use 1/x for exposure times why say 1/250th second when you can say 4 milliseconds or 4ms ?

Reciprocity.

--
"Even with the brain dead, the pig's heart keeps on beating...
sort of like ... pick a Kardashian."
-Anthony Bourdain, Parts Unknown

In article ,
lid says...
This has a meaning: one speed step is double or half. It is easy for a
photographer to memorize the steps from frequent use.

Well, 4ms or 2ms is also easy to understand.
--
Alfred Molon

Olympus E-series DSLRs and micro 4/3 forum at
https://tech.groups.yahoo.com/group/MyOlympus/
https://myolympus.org/ photo sharing site

In article , Alfred
Molon wrote:

This has a meaning: one speed step is double or half. It is easy for a
photographer to memorize the steps from frequent use.

Well, 4ms or 2ms is also easy to understand.

except that photographers have been using 1/250, 1/500, etc., for
*years* and it's not going to change any time soon, if ever.

On 30/05/2019 21.47, nospam wrote:
In article , Alfred
Molon wrote:

This has a meaning: one speed step is double or half. It is easy for a
photographer to memorize the steps from frequent use.

Well, 4ms or 2ms is also easy to understand.

except that photographers have been using 1/250, 1/500, etc., for
*years* and it's not going to change any time soon, if ever.

I could change, I see no issue.


--
Cheers, Carlos.

In article , Carlos E.R.
wrote:

This has a meaning: one speed step is double or half. It is easy for a
photographer to memorize the steps from frequent use.

Well, 4ms or 2ms is also easy to understand.

except that photographers have been using 1/250, 1/500, etc., for
*years* and it's not going to change any time soon, if ever.

I could change, I see no issue.

you might, but billions of others would have to agree to switch and
that's something that is not going to happen any time soon.

On 30/05/2019 23.59, nospam wrote:
In article , Carlos E.R.
wrote:

This has a meaning: one speed step is double or half. It is easy for a
photographer to memorize the steps from frequent use.

Well, 4ms or 2ms is also easy to understand.

except that photographers have been using 1/250, 1/500, etc., for
*years* and it's not going to change any time soon, if ever.

I could change, I see no issue.

you might, but billions of others would have to agree to switch and
that's something that is not going to happen any time soon.

I still see no issue. Modern cameras are computers, and most people are
used to configure software. trivial to add such a config.
Inches/centimetres, similar thing.

--
Cheers, Carlos.