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Come in! There are a few adventures I’ve written about, but most of the content offers classes in photography and mentoring for photographers, including photo theory, which, although a vital part in our profession, is largely an overlooked subject in all published media that profits from and feeds our gadget minded mindset today.

Perfect exposure everytime with histogram data in your camera’s display – A55

July 07 2010 - Photo Technical

Welcome aboard photo enthusiasts.  The digital age have given camera’s a new light meter – the histogram.  Before exploring this topic, I mentioned last time that I had a funny story to tell relating to environmental seals for cameras.  These seals are a nice feature to have by helping protect your equipment against inclement weather conditions, but situation had a different twist.

This is the story of a miscalculation I made and how I was able to rescue my equipment that had no environmental seal.

When I lived in Los Angeles, where I began my photography career, it was always a treat to leave the congested city by taking a drive.  As long as you had the time this State offers many beautiful direction to travel.  This story took me up along Pacific Coast Highway.  At the time I was still in-house photographer for Vivitar Corporation, and I had packed a company OM-2 Olympus to harness photographs along the way.

I reached Morro Bay late morning.  It was a (not unusual) sunny and pleasant California day.  The bay is marked by a prominent large rock, or as the Spanish explorers called it, a crown shaped hill.  I can’t really say how tall it is, but it’s projection catches your eye.

That day my eye also caught these immense waves rolling in against the stone jetty.  As I pulled in to park I saw this spectacle had attracted a crowd of onlookers.  Thinking this might make for a dramatic photograph, I began planning how best to position myself for a shot, taking into account how far the surf from the breaking waves were reaching onto the jetty.

After having that all figured out, I moved forward to take my position as a wave was rolling in.  And it was a beauty…it must have been a rogue wave…it drenched me, other people, and the company camera.  Yikes, nothing worse on equipment than salt water.

What to do?  O.K. I wasn’t too bright with my calculations, but fortunately smart enough to jump right into action to save the equipment – I quickly drove to a service station.

Back then gas stations still had (free) pressurized air to fill your tires.  I pulled into the first station on my path, jumped out with urgency, and started blowing the salty water from all the crevices, hoping for the best.  I worked the moving parts on this camera for a few days, and can report thankfully that camera and lens continued to perform superbly for me.

Had the camera an environmental seal and this had happened, I may have been more lackadaisical in my concern, which is never a good attitude when dealing with the corrosive powers of salt water.  You might ask then, what can I do if out on the ocean and this happens?  You can be sure there will not be a nearby service station, and even so you’re lucky today to find pressured air you pay for.  Right you are; I suggest always having a can of pressured air on hand.  It will not only be useful for a situation such as this, but find many other uses.

On to the new camera light meter of the digital age… the histogram.  The photograph below shows the LCD display as it appears on most pocket cameras before you take the photograph.  I took this photo of my Leica LCD display as it was focused on a rope to be photographed…

If you are an avid photographer you may want to archive this photo to go along with the others in the next article to complete the discussion of the histogram.


Do note the “display” button at the lower right of the camera.  Using this or a similar button on your camera you can cycle though the options (I have four options) to reach the one having the histogram, which I point to with the red arrow I added… it’s the yellow area in the dark rectangular box.

The horizontal position of the yellow indicates the exposure and the vertical height of the yellow indicates the number of pixels affected in portions of the exposure.

You can see nearly all the exposure and pixels fall to the center, and slightly right of center (towards, but not overexposing).  This represents a perfect light reading, and after pressing the shutter, a perfect exposure.  I will explain this perfection in the next article.

For now, let me point out that as the yellow area (that can show as white or possibly another solid color on your LCD screen)  moves to the left edge, it indicates you are moving to underexpose.  When it moves towards the right edge means you moving to overexposure.

Should there be a thin vertical line going all the way to the top on either the far left (black) or right (white) side, then you are clipping the blacks or whites, respectively, which in turn means there will be a complete loss of detail in the darkest or lightest areas, respectively.  You must avoid clipping at either end, so reset your exposure if you notice these spikes.  And at this point I’m clipping the page for space… to be continued, and taking permission to go ashore.