Honeyeater. FZ1000 with I-Zoom at E800mm then cropped. Reasonable picture quality on the bird but the branch is blown out. I used I-Dynamic but not exposure compensation. |
Preventing blown
highlights with high subject brightness range
Exposure Compensation, i-Dynamic and Zebras
The previous post was about using RAW capture in situations
with high subject brightness range (SBR).
This post covers some strategies for shooting JPG in the same
conditions.
Until the FZ1000
arrived in my household I almost exclusively shot RAW, using a
succession of DSLRs then Panasonic and other MILCs.
However many useful features of the FZ1000 require JPG
capture. These include the extra zoom options, Intelligent Zoom (i-Zoom), Extra Optical Zoom, Digital Zoom and Macro Zoom.
I have recently been using i-Zoom to photograph birds with a
focal length of up to E800mm at f4. I
find this preferable to shooting RAW at E400mm and cropping later as focussing
and exposure appear more accurate with the i-Zoom. I am usually trying to
capture a bird which appears very small in the full E400mm frame.
I also use i-Zoom to photograph flowers with the camera at
1000mm or more from the subject. It's a novel new experience which I call
"standalongwayback" macro.
Many camera users prefer to use JPG for all their shots as
it is so much more convenient than RAW capture.
I live in Sydney Australia where bright clear sunny days are
the norm. Yes, it's tough but someone has to live here. The weather is great
but the photographic challenge consists of situations with high SBR.
With RAW capture this is no great problem but FZ1000 JPGs are frequently subject to blown out
highlights with unrecoverable detail
loss.
Setting i-Dynamic to Auto or High does not solve the
problem. Simply setting negative exposure compensation results in very
dark mid tones.
Scene with I-Dynamic High, no exposure compensation. |
Same scene with I-Dynamic high and negative 1.6 steps of exposure compensation. I progressively reduced exposure until the zebras on the clouds just disappeared. |
On the Digital
Photography Review website (dpreview.com) there is a review of the FZ1000
posted in July 2014. I refer the reader to Part 13 by Rishi Sanyal titled "JPEG Tone Curves/Dynamic
Range".
You will notice the JPG tone curve which is typical of
Panasonic cameras, almost straight at the highlight end with no roll off
towards the top. This allows good detail definition in light tones with
plenty of contrast at the upper end of the curve. The problem is that without roll off, slightly overexposed
highlights are lost completely, never to be recovered.
Among other things, this interesting analysis explores the
relationship between Exposure Compensation, i-Dynamic and highlight capture. Specifically Rishi discovered that a combination
of negative exposure compensation and
i-Dynamic High allows for a substantial increase in highlight capture with
normal mid tone lightness.
This discovery provides the JPG shooter with a way to manage
high subject brightness range.
It involves using Exposure Compensation, i-Dynamic and
Zebras simultaneously.
Zebras ? This feature has been available on video
cameras for some time but is now provided
for still capture on the FZ1000 and other cameras. It is like the preview version of
"blinkies", the black and white pulsing indication in playback images
that highlights have been overexposed with lost detail.
You can find Zebras in Tanzania or perhaps more conveniently
on page 5/8 of the FZ1000 Custom
Mode. Explanation can be found on Page
193 of the Operating Instructions.
There are two zebra patterns, I have no idea why, they serve
the same function. Zebra 1 leans to the right at the top, Zebra 2 leans to the
left. Take your pick.
When you click on the [Zebra Pattern] tab a submenu with 4
items appears, Z1, Z2, Off, Set. In the
Set tab there is another submenu Z1 and Z2.
In this last submenu you are invited to pick a number labelled as a
percentage, from 50% to 105%. You can
Google this to discover what the percentages mean but for the moment just
regard it as a number indicating a level.
Video practitioners use levels around 70% to judge correct exposure for
light toned faces. But I want a level
which helps to identify and control blown out highlights in still photos.
After some experiment I am currently using 105%.
i-Dynamic You find this in the Rec Menu, Page 3/7. Explanation is on Page 134 of the Operating
Instructions. There are 4 options, Auto,
High, Standard, Low and Off. For readers
living in places where high SBR is the
normal circumstance I recommend setting High. This
means whenever Quality is JPG then i-Dynamic is active. If you are not sure set
Auto, which I have found usually gives the same result as High with high SBR.
The concept behind i-Dynamic is that the camera underexposes
to protect the highlights then applies a tone curve correction to lift the mid
tones to a normal level. It only works
in JPG capture.
Putting it all
together
Setup
* Set Zebras to 105% (or a bit less if you prefer).
* Set i-Dynamic to High or Auto.
* Set Quality to JPG.
* Set the Zoom Lever (the
one around the shutter button) to [+/-], Page 7/8 of the Custom Menu.
Why ? You can achieve exposure compensation with the rear dial but this takes
three actions, Press to click, adjust EC, Press to return to normal
operation. Using the Zoom Lever only
takes one action if it is configured for [+/-]. It's faster and the lever only
has one job. When I use the rear dial for
[+/-] I constantly find myself changing the exposure when I really
wanted to change the aperture or shutter speed (depending on the Mode Dial
position).
* Set [Exposure Comp Reset] in Page 4/5 of the Setup Menu
(Page 54 in the Operating Instructions) to ON. This way any [+/-] is cancelled
if you switch the camera off, change the Mode on the main Mode Dial or the
camera is allowed to go to sleep.
Managing the exposure
* Preview the subject, see if zebras are blinking on
highlights.
* If so nudge down
the exposure until the zebras just stop blinking.
* Make the exposure. If you have time and opportunity try a
few slightly different exposures.
* Again if you have time press the Playback button to review
the last few shots. Adjust exposure if
necessary and try again.
* When the lens auto
retracts, curse the misguided
boffin at Panasonic who dreamed up that silly lens retract idea.
* Remember to cancel the [+/-] if the next exposure is in a
different location.
That's it folks enjoy better JPGs.
Thanks Andrew. I will give it a go as I have struggled with overblown highlights with my bird photography. Especially white birds.
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