Category Archives: lessons

True HDR explained and examples

I thought I’d spend the 2nd day of 2015 talking about “True HDR” versus “HDR effects”.

One is actually HDR, the other isn’t.

A bit of background. HDR is unique to digital photography, because back in the olden days (Pre-Bush Jr) most photography was done via a chemical process. Exposing film in a camera caused a reaction with light sensitive silver nitrate compounds, which were then dunked in various chemical baths to be “developed”. It was during this time/temperature process that the real magic of photography occurred. You never got to see the results until after this process, and I can vividly recall my palpitating heart the first time I opened a processing tank to view my first ever developed roll of Tri-X. Almost beat out by my first ever solo landing in a Cessna… Almost.

Film had a small range of contrast it could handle before it either made shadows go completely black or the highlights went complete white. This range depended on the film you were using. Slide film has the lowest (narrowest) contrast range; certain negative films the widest range.

With black and white negative film one could adjust exposure and then development to compress the image, also called “Zone System”. The Zone System is best remembered as “expose for shadows, process for highlights”

This was best used by photographers utilizing large format cameras, where a single frame could be processed differently from the other frames.

With digital, there is really no processing. So HDR was developed as a way to compensate for the limited exposure range of digital sensors. This is accomplished by making several exposures of a scene, bracketing each exposure to get images with good shadow detail then images with good highlight detail.

Using Photoshop or another piece of software, you then could stack the images and merge them into one single image with shadow and highlight detail. There are various effects that happen, and a good HDR image is almost like what the human eye can see.

Everything else is artistic intent.

HDR effects are simply taking a single, evenly exposed image and getting the HDR look by compressing highlights and shadows and causing edge effects. It’s not really, truly HDR. It’s just an effect.

That effect certainly can’t bring out details in shadows in a scene with extreme range.

Let’s take an extreme example. I uploaded to my gallery a scene of a piece of gnarled tree trunk with the sun backlighting the wood and pine needles. This one I did a 7-EV bracket to allow of the extreme brightness of the direct sun peeking through the pine needles.

Here’s a collage of the 7 exposure range I used….

All 7 exposures. (Click to Loupeify)

All 7 exposures. (Click to Loupeify)

Looking at the contact sheet, you can see where my trusty Nikon thought the proper exposure should be, exposure #4.  Wow…  It’s losing the shadows badly…  and the better single exposure is #5, or plus 1 EV.

And that’s where True HDR comes in.

Using only photoshop, I did a Merge to HDR pro, and played with the settings to achieve a very nice HDR of the scene.

Vola!  Click to gigantisize

Vola! Click to gigantisize

Next post I’ll examine several of the Android apps for HDR photography….

Also posted in Advice, How-To, Photo Lessons, photography Tagged , , , , |

It ain’t the same!!!!

..dunno which is worse.

In the old days, it was the blank sheet of paper in the typewriter. A white piece of paper. A blank sheet of paper, usually the cheap paper so thin you can read through it, so thin toilet paper was thicker… But a sheet of paper, nevertheless, promising to give life to your thoughts, give textual reality to your ideas and dreams.

Now, it’s a uncaring white screen, daring me. It’s daring me to work, put words on the screen. Not *real* words, mind you. Little 1’s and 0’s.

REAL words came from a TYPEWRITER. It made noise. It was WORK to write. Your typing fingers would feel the impact of the keys… and ribbon rolling across, the “e” with the top filled in from endless hours of typing. Your fingers would vibrate from the typing….

With the paper, you could have the eager joy of ripping it out of the typewriter and stacking it up, the stack would grow and grow. If the page sucked, you have the visceral pleasure of ripping the offending piece of offal out of the infernal machine and crumpling it up, crushing the life out of it. Then tossing it to the wastebasket, already overflowing with crushed dreams, thoughts, ideas… shitty dreams, shitty thoughts and ideas not even worth the 5 cents for the paper.

Now… Now, when you dislike something, it’s CLICK. It’s deleted. The typing. Non-tactile clicks…

Not the same. Not at all.

Also posted in General raving and shit Tagged , , |

Photo Shooting Table

Photographing glass, bottles or anything semi-transparent is easy with the right set-up.

Home build rig designed to allow me to photograph a piece of glassware, a bottle, or even moldy bread with the option of lighting from below to highlight a bottle’s contents, with some added light from above to fill in the details of the item, with the option of placing a strobe head behind the paper and having it light up the bottle from behind.

It’s made from 1/2″ PVC pipe, and a lot of T’s and Elbows. I have a piece of glass as the top, and I use a roll of high end vellum as the sweep.

Here, I have one strobe head shooting upwards to light up the table with a soft box set as a fill.

The image below shows how this all comes together to make a beer bottle “glow” and create a decent gradient as the background. I added a piece of black cloth to avoid lens flare from the strobe aimed upwards.

The rig ran me about $25.00 in PVC parts and the glue. I’ll post some detailed photos of it, including dimensions for anyone wanting to make one for themselves. The key to this design is the rear cross support is well below the level of the glass top, to allow for some back-lit images without having a shadow appear in the images.

Also posted in lighting, Photo Lessons, photography, product
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