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How to measure ISO



 
 
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  #91  
Old November 7th 15, 01:43 AM posted to rec.photo.digital
Floyd L. Davidson
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Posts: 5,138
Default How to measure ISO

Eric Stevens wrote:
On Fri, 06 Nov 2015 22:46:38 +0000, sid wrote:

Eric Stevens wrote:


As I have already described I have been
exposing to the left by deliberately underexposing by 1/2 stop as they
advised.

But if you are really serious/religious about avoiding clipped
highlights, you should underexpose by 2 or three stops. 1/2 a stop only
will usually leave you with lots of clipped pixels.

See https://dl.dropboxusercontent.com/u/...-7500601-2.jpg
and
https://dl.dropboxusercontent.com/u/...R--7500957.jpg

Both of these were taken hand-held with the D750 set on -1/2 EV.


Without stating what your are metering from and what type of metering your
are using neither of your posts have any real meaning. Pointing your camera
at different parts of the scene you want to photograph will indicate
different exposure values as will different metering methods for example
spot metering as opposed to centre weighted or evaluative etc.


I can't say for certain but I was probably using matrix metering.
Irrespective of the mode of metering I would have been checking both
the captured image and the histogram as I went.


I downloaded the second of the two. Not bad on a
technical basis.

There are lots of "blown highlights" in the stained
glass area, but the significance is that it doesn't
matter! Who cares if there is visible detail or not,
the whole point is to have bright colors. That is
exactly what you got!

The shot was made using center weighted metering, with
EC set to -1. And Aperture Priority, so the shutter
speed of 1/15 was set automatically.

The only complaint I would have is the use of ISO 1250
and a wide open lens that isn't that good wide open.
ISO 1600 or even as high as 3200 would have been
virtually the same, and would have allowed stopping that
lens down to a sharper aperture. That is almost knit
picking though, and is only important if you are going
to make a large print. Of course if a large print is
the objective, then it is overexposed a bit too much too,
as that lost detail would be visible in a large print.

--
Floyd L. Davidson http://www.apaflo.com/
Ukpeagvik (Barrow, Alaska)
  #92  
Old November 7th 15, 02:32 AM posted to rec.photo.digital
Eric Stevens
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Posts: 13,611
Default How to measure ISO

On Fri, 06 Nov 2015 15:43:28 -0900, (Floyd L.
Davidson) wrote:

Eric Stevens wrote:
On Fri, 06 Nov 2015 22:46:38 +0000, sid wrote:

Eric Stevens wrote:


As I have already described I have been
exposing to the left by deliberately underexposing by 1/2 stop as they
advised.

But if you are really serious/religious about avoiding clipped
highlights, you should underexpose by 2 or three stops. 1/2 a stop only
will usually leave you with lots of clipped pixels.

See
https://dl.dropboxusercontent.com/u/...-7500601-2.jpg
and
https://dl.dropboxusercontent.com/u/...R--7500957.jpg

Both of these were taken hand-held with the D750 set on -1/2 EV.

Without stating what your are metering from and what type of metering your
are using neither of your posts have any real meaning. Pointing your camera
at different parts of the scene you want to photograph will indicate
different exposure values as will different metering methods for example
spot metering as opposed to centre weighted or evaluative etc.


I can't say for certain but I was probably using matrix metering.
Irrespective of the mode of metering I would have been checking both
the captured image and the histogram as I went.


I downloaded the second of the two. Not bad on a
technical basis.

There are lots of "blown highlights" in the stained
glass area, but the significance is that it doesn't
matter! Who cares if there is visible detail or not,
the whole point is to have bright colors. That is
exactly what you got!

The shot was made using center weighted metering, with
EC set to -1. And Aperture Priority, so the shutter
speed of 1/15 was set automatically.

The only complaint I would have is the use of ISO 1250
and a wide open lens that isn't that good wide open.
ISO 1600 or even as high as 3200 would have been
virtually the same, and would have allowed stopping that
lens down to a sharper aperture. That is almost knit
picking though, and is only important if you are going
to make a large print. Of course if a large print is
the objective, then it is overexposed a bit too much too,
as that lost detail would be visible in a large print.


Yes - I only thought to check the EXIF after I had posted. When you
have bright lights which are vastly overblown, such as interior
lighting, the sun, bright clouds or (in this case) clear glass
admitting light from the outside, it doesn't matter if they are over
exposed. They will print as white anyway. The colors were what I was
after.

I might have done things slightly differently if I had had more time.
At the time of this photograph I had not long had the camera and I
found myself part of a tour party rushing madly from one scene to
another. There was almost no time to think or fiddle with camera
settings. Accordingly I had configured two alternative program
settings. U1 was for outside. U2 was for inside. For U2 I selected an
ISO of 1250. As far as the aperturewas concerned, from what I had
read, the lens is sharpest at f/2.8. As with all zoom lenses you can
qualify that but it definitely works best when nearly wide open.
--

Regards,

Eric Stevens
  #93  
Old November 7th 15, 02:58 AM posted to rec.photo.digital
PeterN[_6_]
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Posts: 4,254
Default How to measure ISO

On 11/6/2015 3:03 PM, Savageduck wrote:
On 2015-11-06 18:59:47 +0000, PeterN said:

On 11/5/2015 6:52 PM, Alan Browne wrote:

snip


For things like stained glass inside buildings I'd suggest a tripod and
HDR methods. 3 images is probably enough in most cases. Same for
outdoor if the subject permits.


That depends on your camera. IIRC for the best HDR each exposure
should be two stops apart. While some Canons will do that auto
bracketing, my Nikon will only bracket one stop. Therefore, five
exposures are required, unless I do a manual exposure compensation.


When shooting exposure brackets for HDR anywhere from 3 to 9 bracket
shots with 1 stop intervals will work for most Nikon DSLRs. What has to
be taken into account is the scene & subject matter, and the camera
being used, as the buffer can play role in mking that cpture succesful,
particulrly if you are working hand held. Using a tripod and manually
adjusting for each frame is something else altogether.
With my D300S a 5 or 7 - 1 stop - shot bracket works best for NIK HDR
Efex processing. My X-E2 only gives me 3 shot brackets up to 1EV.
However, Fujifilm has a few DR stretching tricks in their firmware,
those I have yet to become fully familiar with.

Then there is what Lightroom gives you for photo Merge to HDR. With LR
and RAW/DNG you can work an HDR without the intermediate shots. If you
have a 5 shot exposure bracket you can take your +2EV and your -2EV and
merge those to HDR which will return a DNG with a dynamic exposure range
of -10 to +10 rather than the standard -5 to +5.

Then using LR you have another option. You can forego capturing the
exposure bracket altogether and gain that same HDR exposure adjustment
range much better than with any of the single exposure pseudo-HDR
methods found in NIK or Photomatix.


I can agree as to NIK. I have no experience with Photomatrix.

Take your original imported RAW/DNG create a "Virtual Copy"(VC).
With either the VC or the original in the LR Develop module, move the
Exposure slider to +2, or +3.
Then with the other VC/original, move the Exposure slider to -2, or -3.
Select both of these and right-click - Photo Merge - HDR. Your result
is a DNG with all the benefits of an HDR without the nastiness of
overcooked glowing HDRs.

https://dl.dropboxusercontent.com/u/1295663/FileChute/screenshot_380.jpg

This also gives me a way to stretch my 3 shot 1EV Fuji X-E2 brackets, by
adjusting the -1EV shot to -3, and the +1EV to +3, then Merging all
three. That also works very well.


There are indeed many ways of achieving an HDR effect. I just use the
one that's most comfortable for me at the time. e.g. If I was shooting a
moving critter I would use a different method that for a still object
with the camera on a tripod.

--
PeterN
  #94  
Old November 7th 15, 03:01 AM posted to rec.photo.digital
PeterN[_6_]
external usenet poster
 
Posts: 4,254
Default How to measure ISO

On 11/6/2015 5:35 PM, sid wrote:
nospam wrote:

In article , Alfred
Molon wrote:

As I have already described I have been
exposing to the left by deliberately underexposing by 1/2 stop as they
advised.

But if you are really serious/religious about avoiding clipped
highlights, you should underexpose by 2 or three stops.


definitely not.


Well that would be the case if one was metering on the highlights

1/2 a stop only
will usually leave you with lots of clipped pixels.


no.


Again, it depends on what your are metering from.


Did you expect a helpful answer, given in a non-confrontational manner.


--
PeterN
  #95  
Old November 7th 15, 08:19 AM posted to rec.photo.digital
Savageduck[_3_]
external usenet poster
 
Posts: 16,487
Default How to measure ISO

On 2015-11-07 01:58:41 +0000, PeterN said:

On 11/6/2015 3:03 PM, Savageduck wrote:
On 2015-11-06 18:59:47 +0000, PeterN said:
On 11/5/2015 6:52 PM, Alan Browne wrote:

snip

For things like stained glass inside buildings I'd suggest a tripod and
HDR methods. 3 images is probably enough in most cases. Same for
outdoor if the subject permits.


That depends on your camera. IIRC for the best HDR each exposure
should be two stops apart. While some Canons will do that auto
bracketing, my Nikon will only bracket one stop. Therefore, five
exposures are required, unless I do a manual exposure compensation.


When shooting exposure brackets for HDR anywhere from 3 to 9 bracket
shots with 1 stop intervals will work for most Nikon DSLRs. What has to
be taken into account is the scene & subject matter, and the camera
being used, as the buffer can play role in mking that cpture succesful,
particulrly if you are working hand held. Using a tripod and manually
adjusting for each frame is something else altogether.
With my D300S a 5 or 7 - 1 stop - shot bracket works best for NIK HDR
Efex processing. My X-E2 only gives me 3 shot brackets up to 1EV.
However, Fujifilm has a few DR stretching tricks in their firmware,
those I have yet to become fully familiar with.

Then there is what Lightroom gives you for photo Merge to HDR. With LR
and RAW/DNG you can work an HDR without the intermediate shots. If you
have a 5 shot exposure bracket you can take your +2EV and your -2EV and
merge those to HDR which will return a DNG with a dynamic exposure range
of -10 to +10 rather than the standard -5 to +5.

Then using LR you have another option. You can forego capturing the
exposure bracket altogether and gain that same HDR exposure adjustment
range much better than with any of the single exposure pseudo-HDR
methods found in NIK or Photomatix.


I can agree as to NIK. I have no experience with Photomatrix.


P-h-o-t-o-m-a-t-i-x, not matrix.

Take your original imported RAW/DNG create a "Virtual Copy"(VC).
With either the VC or the original in the LR Develop module, move the
Exposure slider to +2, or +3.
Then with the other VC/original, move the Exposure slider to -2, or -3.
Select both of these and right-click - Photo Merge - HDR. Your result
is a DNG with all the benefits of an HDR without the nastiness of
overcooked glowing HDRs.

https://dl.dropboxusercontent.com/u/1295663/FileChute/screenshot_380.jpg

This also gives me a way to stretch my 3 shot 1EV Fuji X-E2 brackets, by
adjusting the -1EV shot to -3, and the +1EV to +3, then Merging all
three. That also works very well.


There are indeed many ways of achieving an HDR effect. I just use the
one that's most comfortable for me at the time. e.g. If I was shooting
a moving critter I would use a different method that for a still object
with the camera on a tripod.


It is not so much as seeking an HDR "effect" as extending the exposure
dynamic range (DR) to lift detail from shadows and protect the
highlights. Most importantly, is gaining that boost in DR without
suffering the inclusion of tonemapping artificiality, haloes, unreal
glow, and unnatural saturation, the typical HDR signature of old. Today
it is possible to get natural, realistic HDR images.

When it comes to moving targets/subjects traditional exposure bracket
HDR is just not possible. Now with what LR has to offer the door is
open to shoot a single RAW exposure of a moving subject and process it
to convert it to a natural HDR image. This is something I would have
thought you would exlore. You can always take the new clean HDR into
NIK ColorEfex Pro and apply Tonal Contrast to provide some of that
tonemapping effect.


--
Regards,

Savageduck

  #96  
Old November 7th 15, 10:35 AM posted to rec.photo.digital
Sandman
external usenet poster
 
Posts: 5,467
Default How to measure ISO

In article , Eric Stevens wrote:

Eric Stevens:
As a general rule, I would also expose to the left. The D750
gives me little trouble with noise and I tend to have more
trouble with burned out highs than I do with loss of detail
in the shadows.

nospam:
ideally, it's best to expose to the right without clipping any
highlights.

Eric Stevens:
Why?


What do you do if, as I said, your problem *is* clipping
highlights?


nospam:
then reduce the exposure. if you clip the highlights, they're
gone. you don't want to clip highlights.


Which is more or less what I said in the paragraph at the top of
this article. Thank you for leaving it in.


But the topic was over or underexposure, where the general rule is to overexpose
(expose to the right) and you replied and said you'd rather underexpose (expose
to the left) in order to not clip highlight, but the general rule of overexposure
doesn't say "expose to the right, clip highlights", just expose to the right, so
your reply didn't make any sense in the context.

You are free to underexpose as much as you like, of course. In fact, I myself
tend to underexpose rather than overexpose. But that's not because the "expose to
the right" rule of thumb means clipped highlights. It doesn't.

--
Sandman
  #97  
Old November 7th 15, 12:06 PM posted to rec.photo.digital
sid[_2_]
external usenet poster
 
Posts: 385
Default How to measure ISO

Eric Stevens wrote:

On Fri, 06 Nov 2015 22:46:38 +0000, sid wrote:

Eric Stevens wrote:


As I have already described I have been
exposing to the left by deliberately underexposing by 1/2 stop as they
advised.

But if you are really serious/religious about avoiding clipped
highlights, you should underexpose by 2 or three stops. 1/2 a stop only
will usually leave you with lots of clipped pixels.

See https://dl.dropboxusercontent.com/u/...-7500601-2.jpg
and
https://dl.dropboxusercontent.com/u/...R--7500957.jpg

Both of these were taken hand-held with the D750 set on -1/2 EV.


Without stating what your are metering from and what type of metering your
are using neither of your posts have any real meaning. Pointing your
camera at different parts of the scene you want to photograph will
indicate different exposure values as will different metering methods for
example spot metering as opposed to centre weighted or evaluative etc.


I can't say for certain but I was probably using matrix metering.
Irrespective of the mode of metering I would have been checking both
the captured image and the histogram as I went.


Well that's the beauty of digital, the ability to instantly check your
results.

All I'm trying to point out is that your -1 ev could result in exactly the
same exposure value as Alfreds -3 ev depending on how and where you metered
the same scene.

--
sid
  #98  
Old November 7th 15, 12:07 PM posted to rec.photo.digital
sid[_2_]
external usenet poster
 
Posts: 385
Default How to measure ISO

PeterN wrote:

On 11/6/2015 5:35 PM, sid wrote:
nospam wrote:

In article , Alfred
Molon wrote:

As I have already described I have been
exposing to the left by deliberately underexposing by 1/2 stop as they
advised.

But if you are really serious/religious about avoiding clipped
highlights, you should underexpose by 2 or three stops.

definitely not.


Well that would be the case if one was metering on the highlights

1/2 a stop only
will usually leave you with lots of clipped pixels.

no.


Again, it depends on what your are metering from.


Did you expect a helpful answer, given in a non-confrontational manner.


Does the pope wear a silly hat?

--
sid
  #99  
Old November 7th 15, 02:56 PM posted to rec.photo.digital
Alan Browne
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Posts: 12,640
Default How to measure ISO

On 2015-11-06 13:31, PeterN wrote:
On 11/5/2015 10:09 AM, nospam wrote:
In article , Eric Stevens
wrote:

How on
earth do you set the diaphragm on your lens?

same as usual, with the front control wheel.

however, that has nothing to do with an exposure meter.

That will be news to many.


learning is a good thing.


Try it sometime.


You really are a **** Peter.

  #100  
Old November 7th 15, 02:57 PM posted to rec.photo.digital
Alan Browne
external usenet poster
 
Posts: 12,640
Default How to measure ISO

On 2015-11-06 13:30, PeterN wrote:


Most good photographers expose for the subject matter.


No, they expose for the light and the medium. Since digital cameras
behave very much like slide film, one generally exposed for the highlights.

Did ya learn anything from that?
 




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