Sunday, September 16, 2007

Norman P1250D: Watt-Sec to GN Calculations

I recently had a stroke of good fortune - a retired photographer living in my parents' subdivision in Florida was selling a Norman strobe kit for $500 and through them offered it to me. Thinking this would be a great way to earn of few easy dollars, I did a little auction tracking on eBay to determine if a resale would make any money - not really. I told him so and suggested that he sell it himself - getting $500 should be a cinch. Another week goes by and my Dad calls to ask if I'd take the kit for $300 plus $70 in shipping. Say what!? The rest is history...

I now own an awesome 4-head Norman strobe kit, which includes:
Norman P1250D watt-second power pack
(4) LH2000 2500 w-sec lampheads with 150W halogen modeling lights
(1) 8.5" high output reflector
(1) 5" high output reflector
(1) 5" rotating barndoor ass'y
(2) 16" soft light reflectors
(2) 16" rotating barndoor/diffuser assemblies
(1) R9110 Rapid Cool blower fan
(2) 42" shoot-through white umbrellas
(1) 42" Westcott Halo umbrella softbox
(1) metal Norman snoot
(1) 42" collapsible fabric gobo
(2) heavy duty steel light stands

"So what's a 1250 watt-second power pack gonna make for light?", I ask myself as I clean and set up the new gear. Watt seconds is a "fools errand" as they say on Pirates of the Carribean - it doesn't apply itself readily to flash photography. No iTTL or automation - just lots of metering to create main/fill/key ratios based on personal experience.

Besides, strobe photogs are more interested in the apertures they can shoot at - DOF and bokeh are what really matter - and creating beautiful light, of course. So to make the GN conversions for a flash power reference, I put the following lighting reflectors, diffusers and umbrellas through a "watt-seconds @ 10-foot X ?? aperture" benchmark test to determine the range of GN's produced with the various power setting/modifier configurations.

250 watt-seconds @ 10 feet
8.5" high output reflector: f13 = GN 130
16" soft surface reflector: f13 = GN 130
16" soft surface reflector w/ diffuser: f9 = GN 90
Halo 42" umbrella softbox: 7.1 = GN 71
24" silver umbrella: f5.6 = GN 56
24" 'deep' silver umbrella: f5.6 = GN 56

750 watt-seconds @ 10 feet
8.5" high output reflector: f22 = GN 220
16" soft surface reflector: f20 = GN 200
16"soft surface reflector w/ diffuser: f16 = GN 160
Halo 42" umbrella softbox: 14 = GN 140
24" silver umbrella: f11 = GN 110
24" 'deep' silver umbrella: f9 = GN 90

1250 watt-seconds @ 10 feet
8.5" high output reflector: f29 = GN 290
Halo 42" umbrella softbox: 18 = GN 180

The Norman P1250D power pack has a maximum of 1250 watt-seconds (really?) with switchable 250, 500 and 750 watt-second settings. Each LH2000 lamp head uses a 150-watt halogen modeling light which can be set to correspond to the lighting ratio between lamp heads for a consistent preview. At the power pack, I can plug in as many as four lamp heads in the following combinations: 1@1250, 2@750/500, 3@750/250/250, 3@500/500/250, 4@500/250/250/250 or 4@250/250/250/250.

Got the owners instructions from Holly Enterprises in North Hills, CA - many thanks Brent for your help! I have a much better appreciation for the Norman brand now...

Needless to say, this just scratches the surface, but I am loving every minute of this gear and have a whole new skill to learn!


Tuesday, September 11, 2007

Nikon DSLR Intervalometer 101

Time lapse photography is very cool when you can actually see it all happening at one time. Apple's QuickTime Pro ($30) makes that possible by taking hundreds or thousands of individual images and sequence them together into a 'movie' of sorts. To do this, go to your Nikon's built-in intervalometer - Nikon calls it Interval Timer Photography (its menu is under the Camera icon on your Nikon DSLR body).

(D200 Users: On page 89 of the D200 manual, you get a simple directions and tips on camera positioning, using Manual vs. other modes, etc. that are likely to be the same or similar on other models.)

First, you set the Start to either Now or Start Time. 'Now' is immediate with a 3-second delay before the sequence begins. 'Start Time' can be set for hours and/or minutes according to the clock settings you have in place.

Second, you navigate to the Interval screen and set the time BETWEEN frames in hours/minutes/seconds. (see Step 4 calculation)

Third, you set the Select Intvl* Shots menu to record the number of shots X the quantity of each frame (for bracketing) = Total Number of Shots recorded. (see Step 4 calculation)

The Start Menu will let you initiate the sequence by selecting On and pressing the Enter button on your D200 body. Upon completion, copy files to your computer and use QuickTime Pro or another popular video editor to combine your images into a streaming presentation. Then upload to your web host for distribution. That's it!

Intervalometer Setup
Let's use a sample scenario that will last about two hours - a mountain scene, ball game, or similar situation. Here are the basic steps to determine the intervalometer settigs you will use.

1) Convert hours into minutes: 2 hours = 120 minutes
2) Determine total number of seconds: 120 X 60 = 7200 seconds
3) Determine time length of finished sequence: 300 seconds(at 30 fps)= 10 seconds of playback.
Use these fps rates to calculate:
U.S. TV Video: 30 fps
European Video: 24 fps
High Definition Video: 24 fps
4) Interval Rate: 7200 seconds of sequence divided by 300 final sequence frames = 24-second intervals for a 2-hour recording

Calculate a few scenarios ahead of time and you'll be ready to setup and shoot with no delays.

- For unattended sessions, use a tripod. If outdoors, secure your tripod well to prevent wind from knocking it over, protect from rain, etc.
- Prefocus to avoid inaccurate or random AF operation
- Use WB Preset and shoot in Manual Mode to maintain a consistent exposure - or leave in P, S or A for continuous metering during changing light conditions
- Use a fresh battery and a blank CF card to avoid running out or power or memory
- Have fun!

I'll report on the postprocessing and QuickTime conversion portion of this process when I receive the latest QT version from Apple...


Saturday, September 8, 2007

LR Grayscale Conversion Primer

I am fascinated with Lightroom's Grayscale Mix palette - it is far more comprehensive than Photoshop's few controls for accomplishing this essential photographic effect.

The following images serve as a primer for graycale conversion in Lightroom. Colors and their temperature are key ingredients along with the color shifts you can introduce to 'create' a grayscale to your liking. Emphasis can be place wherever you feel it is needed to define sky, subjects, shadows and highlights at values you desire - it's rather amazing what Adobe has programmed into Lightroom for us, so start experimenting on a full scale image to learn what it can do for you.

Follow the sequence of images and the 'builds' I have created to accomplish the final image...

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Straight Grayscale Conversion (no corrections)

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+100 Red

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+100 Red +100 Orange

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+100 Red +100 Orange +100 Yellow

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+100 Red +100 Orange +100 Yellow -70 Blue

As you study the progression, you can see how different areas react to the 'color change' we invoke on a grayscaled RGB RAW image - from shadow area to midrange to sky, etc. Keep in mind that we have not left the RGB color space, so these images can be printed in color - especially if you do on to use Split Toning - or converted to an 8-bit, single channel grayscale.


Thursday, September 6, 2007

Getting Creative with Lightroom 1.1

Grayscale Conversions and Split Toning go hand in hand, as these sample files well demonstrate. Start with a well made grayscale conversion using LR 1.1's new Grayscale mix controls - and move right into the Split Toning pallette for endless fun in colorizing your black and white compositions.

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Color Original

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Optimized Grayscale Conversion

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Split Tone 1

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Split Tone 2

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Split Tone 3

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Split Tone 4

As you can see, the iterations are infinite - moving the highlight, shadow and saturation sliders in Split Toning produces many variations that will affect different areas of the original - all based on the original colors. Temperature and Tint also play a part in the Grayscale Conversion process. We have a lot to work with in LR 1.1 - so let's get creative!


Wednesday, September 5, 2007

RGB: The Universal Color Space

RGB is really the only legitimate color space. We see in RGB. Cameras record in RGB. All other color spaces come out of it - LAB, CMYK, etc. But as photographers, all we care about initially is RGB - and which one to shoot in and process in.

RGB comes in several flavors too. On your DSLR, you can choose between sRGB and Adobe RGB for JPG shooting - RAW is a different story. For RAW there's another color space just waiting to be discovered. Here's the short list:

sRGB is the smallest color space and designed for use on the web, for thrifty prints at White House Custom Color, JPG's sent your Mom and clients, slide shows and web galleries - in other words, monitor viewing and small photo prints. sRGB's narrower color space compresses wider color gamuts to print/view most acceptably on low end devices - again, monitors and small prints. Opening files in this color space will always result in clipping of some colors - don't shoot in sRGB unless you don't have anything else - view it as an output space.

Adobe RGB is a wider color space that translates well into high end print media. While bigger than sRGB - and the preferred color space to shoot high quality JPG's - there is still clipping of some portions of color . It's most useful as an output color space for commercial printing and custom enlargements after conversion from RAW postprocessing in the ProPhoto color spaces. Therefore, Adobe RGB is also not the best starting point for original image files. What! Why? Because it does not contain all the colors your sensor can capture - read on...

ProPhoto RGB is the largest color space RAW images can be converted to after they are captured off the camera sensor. Read that again. ProPhoto RGB is actually a wider gamut than the human eye can see, which is perfect for our purposes. Postprocessing and editing RAW files in ProPhoto RGB can be performed in an 8-bit or 16-bit color depth and will retain all the sensor's pixel information until you convert to either a Adobe RGB or sRGB color space for monitor viewing and prints.

Unlike Photoshop, Lightroom does not burden much color management on us and has removed most if not all the color space concerns for us - it uses ProPhoto RGB as a RAW conversion default and allows us to convert to Adobe RGB and sRGB at the time of output. I like that - even if I can't see it on my display. Keep your monitor well tuned - or buy a decent one to start with - and you will spend more time working on your images and less time worrying about color spaces.


Grayscale Conversions: the Science Behind the Art

I always review the science behind photography to better understand - or just figure out - whatever I'm attempting to do. To condense the specifics behind grayscale conversions, first we need a little background about conversion to Grayscale from RGB...

What is RGB? What is Grayscale?
RGB is nothing more than three separate channels of 256-step, 8-bit grayscale images taken through a Red, Green and Blue filter overlaying the sensor in your DSLR. Each one records a different luminance range depending on the subject colors as they pass through the RGB filtration. Look at an RGB image in the Channels pallette in Photoshop and you'll see what I mean. None make an ideal grayscale...

Grayscale, in the purest sense, is a 256-step, 8-bit image - that's all. Those of us in the graphic design field refer to these as halftones when printed in black ink only. They have real limitations in representing all the tones of an original image and that has fomented the development of duotones, tritones and quadtones in the traditional history of lithography (printing). But I digress...

Downsampling a three-channel RGB image into a 256-step single channel image renders a pure black-and-white image - the trick is getting a pleasing or accurate representation of the scene. Traditionally, we have seen folks (1) simply desaturate an RGB image and yank Contrast, Brightness and Exposure controls with abandon to achieve their desired effects. Then, an 'educated' way to render a grayscale emerged by moving the image into LAB space and singling out the L channel for a clean, neutral grayscale image. That's true, it is, but now you have 1/3 of the data and a significantly smaller printing file to work with. You can see why we hear so much talk about this subject...

RGB to Grayscale Advantages
Keep an image in RGB makes sense in two ways - image control and file size. You want to keep both, right? Modern output devices are so handy that downsampling to a single channel of information is practically foolish - alright, it is - really. Software can create a superb grayscale rendition in so many ways that an RGB image shouldn't be viewed as a color file exclusively. It's application in grayscale conversions is practically unlimited - and its color data is the secret ingredient.

Photoshop vs. Lightroom
Photoshop's Channel Mixer allows for varying the levels of each RGB channel to maximize the potential of the original color image. When converting to a grayscale, this tool can individually alter the luminance of each channel, significantly altering its appearance to meet your personal criteria. But, being a little long in the tooth these days, it's limited controls are becoming apparent.

Lightroom 1.1's 'conversion' tools actually exceed Photoshop's with eight color sliders versus PS's three. Unique to LR is its ability to affect temperature and provide an Auto-Adjust after each adjustment - providing a much wider range of control. Warming and cooling the color areas produces big differences in grayscale rendering and will help you achieve a pleasing conversion with practice. Split Toning allows for highlight and shadow colorations for even greater nuances. With Lightroom, you have serious grayscale conversion software at your command.

Today, it is commonplace to leave your grayscale conversion in the RGB color space at the output stage - this gives greater depth and richness to the tones and allows for 'colorizing' in sepia and other tones. Or mixing color areas with grayscale areas - common in wedding images.

Any way you look at it, grayscale conversions are being made better with the new tools in Lightroom 1.1!


Tuesday, September 4, 2007

Lightroom: Color Spaces & Workflow

I've been reading Martin Evening's LR book and am learning a ton about it. For example, when you see your images the first time around in LR they may appear dark but still have a full histogram representation. This is due to a 1.0 linear gamma as the file comes directly from digital camera RAW files. (Explains why the LCD review on the camera is never the same too!) What this means is that if displayed as-is, color and exposure adjustments would be overly sensitive with very tightly packed midrange and very stretched out highlight characterization. To view your images more like the human eye, LR uses sRGB-based controls which make subtle changes possible without overdoing anything - especially in the Exposure and Blacks sliders.

Now, before you freak out and assume this must mean all your fine artistic images have been squeezed into an inferior color space - they're not. In fact, all images can be set to open in either a 16-bit RGB Prophoto or Adobe RGB color space - and kept there until final output is determined. The interface simply utilizes an sRGB 'response curve' to control editing.

So your saved master RAW files are just as exquisite as they were when first captured. But where are you taking them? Well, you decide of course, but Martin suggests we use external drives to avoid internal drive/CPU failure catastrophes and maintain portability - unless you have those fancy plug-in hard drives on your tower. I'm doing so with a 160GB Maxtor I picked up from for under $100.

Overall, LR is becoming a well used application on all my images. A quick review and flagging of keepers, followed by color corrections/preset treatments and/or cropping, and a web gallery for immediate distribution to friends and business interests is a simple routine now. Here's where LR really shines. Setup your viewing to scroll through and flag the keepers - use the arrows to navigate and press P to flag or U to unflag. Then perform an initial color adjustment to a good representative image. Select similar frames you want to adjust and use Synch to add that adjustment to all the others. You can still adjust individual frames but this is where LR saves you a bunch of time. You can Synch everything from color edits, cropping, sharpening, noise reduction - the whole scrape or just what adjustments you want to.

After that it's time to make a Collection(s) that will segment the images for printing or web gallery display. You should be able to LR 400 images in a couple hours once you get comfy with this woprkflow. Most of my time was getting the workflow understood and learning keyboard shortcuts.

I PP'd a recent wedding assignment (650+ images) in about four hours - no record but well under my previous methodology- and I'll be twice as fast the next time. I downloaded, reviewed, flagged, color corrected, cropped, and output a web gallery of my Labor Day weekend Boomsday images (350+) in about two hours - I was rockin'!

I can see my use of PS CS quickly being reserved for elaborate web/graphic design and complex image edits (clipping paths, serious cloning, etc.) from here on out - it's just too laborious to use all the time anymore.


Monday, September 3, 2007

Boomsday - The Biggest Fireworks Display in the USA!

This may be little ol' Knoxville's biggest claim to fame other than the UT Vols football team. Boomsday is a $1 million dollar pyrotechnical display of nearly astrological quality. This teaser image is just one the images I culled out from my Labor Day weekend shoot along with a few scenes from the 1982 World's Fair Park as well.

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See the full Boomsday 2007 slide show!

Shot with 18-70 ED and 70-300 ED Nikkors on a D200, I positioned myself within 100 feet of the launch zone - it was a humbling experience. The sheer noise level was incredible. This year they abandoned a popular musical choreography approach and simply barraged us with an endless stream of launches that produced some amazing light and pattern combinations. I shot the entire fusillade nonstop and culled what is presented in the slide show.

Instead of using the traditional Bulb method of opening the shutter, waiting for something interesting to happen and shutting it down manually, I used 1/20-1/60th shutter speeds at a 1250 ISO. This technique more sharply captured the ambient light and action surrounding the launches explosions and seemed to add another dimension to the images.

Much credit goes to Adobe Lightroom for an expeditious review, pick, edit, and conversion of the images into the Flash web gallery. This program is phenomenal for cranking out photo presentations lickety-split and has revolutionized my postprocessing workflow.