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Old June 16th 18, 12:39 AM posted to rec.photo.digital
Savageduck[_3_]
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Posts: 16,487
Default Meaning of ISO value in digital photography?

On Jun 15, 2018, Carlos E.R. wrote
(in article ):

On 2018-06-15 22:18, Jim-P wrote:
On Thu, 14 Jun 2018 19:47:36 -0700, Savageduck wrote:

On Jun 14, 2018, Ken Hart wrote
(in article ):

On 06/14/2018 08:05 PM, Savageduck wrote:
On Jun 14, 2018, Jim-P wrote
(in ):



In the film days, we used the "Sunny-16" rule: Set the shutter speed
equal to the ISO (then "ASA"). In bright sunshine, use f/16. Slightly
cloudy- use f/11, open shade- f/8, full shade- f/5.6. This technique
would usually give a good exposure.

Combine that with the "focal length equals shutter speed" rule: The
longer the focal length, the faster the shutter speed to give acceptable
hand-held images. For a 200mm lens, you use a shutter speed of 1/250
second.

Example: 100mm lens calls for 1/100 second minimum. Set the ISO also at
100, and use the "Sunny-16" rule. Then refer to SD's exposure triangle,
three paragraphs down...

Let us start by asking, what camera are you using?

It would still be good to know what camera the OP is using.


I am using a smartphone camera. Although it is not as high quality as a
DSLR the principles should be the same and I am interested in understanding
them before taking my photography further.

The smartphone model is a Moto G5 Plus with a Sony IMX362 Exmor RS camera
module which is also used in the Nokia 7 and Samsung S7 Edge

https://phoneproscons.com/794/moto-g...r-camera-same-
amazing-sensor-as-in-xplay-6-and-zenfone-3-zoom/

I recall that old Sunny 16 rule and the thing which strikes me most about
it now is how slow the shutter speeds were in the old days. 1/250 was one
of the faster speeds I would use for day to day photography years ago but
my current smartphone often uses speeds of 1/1000 or 1/2000 which is
fantastic because by hand steadiness is not what it used to be.


My old SLR had 1/2000

The mechanics had a trick that allowed high effective shutter speed
while the shutter in fact moved relatively slowly, at 1/60 or
thereabouts. And old trick, actually. It opened a slit on the rectangle,
and the slit travelled the length of the aperture. If the slit was 1/5,
the effective speed was the actual speed multiplied by 5.


That is the rolling shutter effect which has returned with the advent of the
electronic shutter found in smartphones, digital video cameras, and many
mirrorless cameras. With some of the advantages of the electronic shutter,
rolling shutter effect can produce some unwanted effects with high speed
shots of moving subjects. For example athletes can be given elongated and
spindlely legs, wheels can be made oval, not round, propellor and rotor
blades can be unrealistically distorted.

https://en.wikipedia.org/wiki/Rolling_shutter

--

Regards,
Savageduck