FZ1000 Preventing Blown Highlights with JPG capture

 

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.