Articles by: Peter Poulides

one big light

My son plays tuba in a rock band that’s been practicing at the studio for the last few weeks. I thought it might be fun to shoot some pictures at one of their rehearsals. I didn’t want to spend a lot of time setting up lights and wondered what I could do to get something interesting. They were playing in front of the cyc, but the white floor is in need of a coat of paint and I didn’t want to spend time cleaning that up in Photoshop.

A raw shot from the balcony with just the overhead fluorescents on:

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I turned on a 2K (2,000 watt) tungsten light, widened the beam and just blew out the cyc wall behind them. That gave me some interesting contrast and solved the dirty floor problem since now the light is skipping off the surface of the floor instead of showing all the dirt. I did a little toning, tinting and negative clarity in Lightroom and go something we all liked.

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Playing with Fire : Works

Like most people, I love fireworks. And like all of you, I love taking pictures. So at least once a year I find myself with camera in hand, trying to capture some interesting photos of explosions in the sky. Last Saturday night my wife and I met some other couples near Lakewood County Club. I’ve been attending this little fireworks show for over a decade. There’s a street that bisects the golf course and we stake out a space early and then sit on our blanket while the mortars go off right over our heads.

I tried shooting handheld, with the camera in my lap, so I could still watch the display and enjoy my surroundings. I started out by putting the lens on manual focus and setting it on infinity so I didn’t have the problem of the camera seeking an object in a dark night sky. I played with exposure until I settled on about 1sec at f8 at 200-400 ISO. I jiggled and spun the camera during the explosions, which gave me some interesting patterns.Where it got really neat was purposefully defocusing, holding the zoom barrel in my left hand and twisting the camera body on axis, zooming in during the explosions. The result is the almost aquatic looking images toward the end (my favorites). Even defocused, at the widest end of the zoom the light trails are relatively sharp. As I zoomed in they softened. The only processing I’ve done to these images is changes in exposure, fill light and black level in Light Room to bring out some of the trails hidden in the darkness – a very good example of why shooting RAW can really help.

 

Panoramas at the Dallas Camera Club

I was invited to speak to the Dallas Camera Club last night. I was really amazed to see almost 60 people attending the meeting. The DCC has been around for 75 years and has a very active calendar of meetings, competitions and field trips.They are a great group.

I spent about an hour talking about panoramic images, discussing why you’d want to shoot them, how to make them and then looking at the amazing software available to automatically stitch several images together into a seamless photo. I’ve been using AutoPano Pro for a few years and just love it. There are dozens of programs out there, many of them free or inexpensive. Panorama Tools has been around for a long time and has some great front ends like PT GUI. If you have Photoshop CS4, you already own a great stitching program, but I still far prefer AutoPano for its flexibility and ability to detect and extract panos from a folder of images.

I think panoramas are one of the coolest and most satisfying techniques to come out of digital photography. The images are wide format, more closely matching our natural field of view. You can create big impressive prints with even a low resolution pocket camera since the resolution of each photo is added together into the stitched final image. They look beautiful hanging on a wall and are easy to print at home. Watching the software assemble the images is really amazing.

At the meeting I showed some panoramic sequences from recent travels. I also did a live demo, shooting hand held with a little Pentax pocket camera and dragging the images into the AutoPano software.

These are the raw shots:

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This is the result of the panorama stitch, processed using the “Spherical Projection” setting. This has the best relationship of sizes of the people in the room, but the most pronounced curvature of tables, which were actually in straight, parallel rows. This is what the shot would look like if taken with a scanning film camera like the Widelux or Horizon:

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The same panorama, using the “Planar Projection” setting. The tables look better, but the people at the edges are stretched, as they would be using a traditional super wide angle lens:

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This is the same Planar projection as above, but taken into Photoshop for some warping. I did a Select All, used Transform:Warp, and pulled in the sides. There is less of a stretched feel, but you start to loose the wide format of the panorama:

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I highly recommend shooting some panoramas. With AutoPano, and others, you can shoot multi-row panos, and even shoot any group of images covering a subject, without them having to be aligned, level – or even all horizontal or all vertical, as long as there is overlap in the images the software will find the pano in there.

Gefen DVI Detective

Well, here’s a product I didn’t know existed but was happy to find. About a year ago I built a new machine for the studio, mostly to run Lightroom. I like Lightroom and want to love it, but have had speed problems with it since day one. So I built a quad core machine with 8gb ram, fast ATI card (had conflicts with the Nvidia) and a serious RAID 6 controller from Areca for storage and cache. For my viewing pleasure I got two 27″ displays from Doublesight and glued it all together with Vista 64. The problems began when I had to install a couple of DVI video extension cables to the monitors. Every time the screen blanker kicked in, or when the machine was restarted or came out of sleep mode, the monitors wouldn’t come up at the right resolution or even left to right sequence. About half the time I had to go in and reset the layout and resolution. It was one of those really frustrating things that I let go for two long.

While I was trying to get some HDMI problems solved (another day, another rant!) I asked John Johns, the video wizard at In-Sync, Inc. in Dallas, what he would recommend. He referred me to Gefen, a company that makes a crazy array of video conversion boxes. On their website I found a little box called the DVI Detective and an explanation of what the problem was with my monitors (and my HDMI troubles). Both of those connections transmit an EDID code. According to Wikipedia: “Extended display identification data (EDID) is a data structure provided by a computer display to describe its capabilities to a graphics card. It is what enables a modern personal computer to know what kind of monitor is connected.” As with many things electronic, that doesn’t always work out in practice. What was happening was the EDID wasn’t being picked up and weird things were happening.

The DVI Detective goes inline between the computer and the monitor. You power it up with the included wallwart, push a tiny button on the little box, a light flashes telling you the code is being received and stored, you flip a switch to lock the setting – and you’re done. The power can now be unplugged. I was hesitant to spend 2 x $60 (from Buy.com) on these little gizmos but my problem is completely solved. I love these things.

They are tiny boxes and come with nice, stout turn around DVI patch cables. A solid product that does exactly what it claims to with very little setup. This is what the mess looks like behind my monitors until I dress this up a little:

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I’ve been using the Gefen DVI Detective boxes for a few weeks now and I can happily report that they have completely solved the problems I was having! Money well spent.

Really big prints

I’ve had an Epson 7600 for a few years and always thought of it as a big machine with an appetite for ink and a producer of impressive big prints. Up to 24″ wide by any length. Boy, have I had to recalibrate that thinking! I just got through shooting a job for some interior banners that will hang at the newly remodeled downtown Dallas YMCA. They are being printed on an HP Scitex XL Jet which prints up to 5 meters wide (196″). The images will be full bleed and the size is 9ft x 18ft. I shot using a rented Nikon D3x. I’ve written about that experience here. The resolution of the D3x is roughly 4000×6000 pixels. The long dimension of the banners of 18ft, or 216 inches. Dividing the resolution (6000 pixels) by the printed dimension (216 inches) will give us the maximum pixels per inch that I would get on the print: 6000/216=28. If I crop the image I would have fewer pixels. Is 28 ppi (pixels per inch) enough? Absolutely, because of viewing distance.

When I do my own exhibition prints, I have found that anything over about 150ppi is seldom seen in the print itself. If the image is a technical or highly detailed shot involving product with sharp edges, a super high-res multi image panorama or overlayed vector art or text, then going to 200 or 250 ppi can make a difference. Those images are hung on a wall and viewed from a few feet away – unless you’re like me and always lean in, tip your head, and look to see what kind of detail there is in the print. Its sometimes an unkind thing to do, but I’m always interested in printing technique and it doesn’t get in the way of enjoying the image as art.

These large banners will hang overhead and the minimum viewing distance from a 6′ person’s eyeballs to the bottom of the banner will be 7ft, assuming they are looking straight up. To the center of the banner would be about 11ft. More realistically, the viewing distance as people move around the room will be well over 15ft. If 150ppi is great quality at a viewing distance of 3 feet, then what happens at about 15ft? Subjectively, I can tell you that they look great. I’ve seen the prints at Color Place, who is doing the printing, and was pleased with how crisp they look from a few feet away. The numbers support this. There is a simple, linear relationship here. A viewing distance of 3ft is 1/5th of a viewing distance of 15ft. Take our target high quality image of 150ppi and divide by 5 and you get, yup, 30ppi. There is a good article on this topic here.

The ink droplets from the HP Scitex XL Jet printer that Color Place uses are pretty big. Well, big in the ink jet world. They are specified at 80 picoliters. By comparison, my Epson 7600 has a minimum drop size of 4 picoliters. That’s billionths of a liter, which is small! What that means is that the image from the XL Jet, when viewed closely, has quite a bit of dithering, a kind of noise pattern that results from the low printing resolution. That is actually a very good thing in terms of percieved sharpness. At a distance, that noise actually sharpens the image. Try it yourself. Print a photo, then add noise to it in your image editor. Put them side by side and step back. Often the noisier image will appear sharper.

I visited Color Place when they were printing and finishing the banners. The printer is really big, and so is the head assembly. I complain about buying 220ml cartridges for my printer. These guys buy ink by the gallon. When the print technician saw me photographing the bottles on the floor he said “Oh, that’s just junk ink. We can’t use that. Here’s the new stuff” and then showed me the cabinet with the new gallon jugs.

Perhaps the biggest surprise is how inexpensive this kind of banner printing has gotten. It costs me about $2/square foot in ink and paper to print on my Epson printer. You can get banners made for around $3 to $4 per sq. ft. You aren’t going to hang them in a gallery, but it is a blast seeing images this size.

Laptop tripod tray

I wanted to be able to use my laptop tethered while shooting. I looked into a couple of commercial laptop trays, but they were kind of overkill. I used an extra Bogen Magic Arm and some plywood to make a usable platform. I cut a piece of 1/2″ plywood slightly smaller than the footprint of the Vaio laptop and inserted a 1/4″-20 threaded insert into the center, dressed it with some black gaffer’s tape, and made a strap out of velcro. It gave me a stable, adjustable platform for the laptop.

Warning, don’t try clamping something like this to a carbon fiber tripod. This is a stout, aluminum Gitzo which can take the compression from the SuperClamp at the end of the Magic Arm.