Monday, November 28, 2011

Fall Flying

US Hang Gliding Team member Dustin Martin and D|Focus contributor Ryan Voight got together over Thanksgiving for a little filming session at Point of the Mountain in Utah.  After a few days of less-than-ideal conditions, we finally got a good day to get some shooting done.

We mounted a GH2 and 7-14 lens on Dustin's glider, and tried to get some air-to-air formation flying action.  Here are a few frames from the video:

All photos by Ryan Voight

Wednesday, August 3, 2011

Panasonic GH2/NikonD300s Photo Comparison

Words and imagery by Ryan Voight, D|Focus contributor
Nikon's D300s was their second DSLR to include video functionality (following the D90). The D300s walks the fine line between consumer and pro gear... it is (was?) Nikon's highest level DX format camera (IE not full-frame). It has a large, highly weather sealed magnesium body, and most functions have their own designated buttons- something most consumer cameras don't include. For the past year, the D300s has been my go-to photo AND video camera.

The Panasonic GH2 is best described as a mirror-less DSLR. Picture a DSLR operating in 'live view' mode, all the time. By removing the mirror, the camera is considerably smaller and lighter than a traditional SLR or DSLR. But can it measure up to a 'real' DSLR?

It's a small and light package, but it's feature-rich. It takes 16 MP photos (15MP when set to 3:2 aspect ratio, the standard for DSLRs), vs 12.2 MP for the D300s... but the big upgrade is the video capabilities! This little camera records beautiful full 1080 HD video at 24 frames/sec... or 720 HD at 60p- perfect for slow motion effects. GH2 video is captured using the AVCHD codec. The other really nice thing is that this camera allows full-manual control over video recording- something the Nikon lacks.

The more I play with the video, the more I am impressed. I've begun to think of this little camera as a film-like VIDEO camera, that also takes photos. Here's a quick sample of how sharp the video looks:

Wing-mounted GH2 shooting 1080 HD @ 24 fps

But for me, the question has remained... how good of a PHOTO camera is it? I had some spare time yeserday, so I headed up American Fork Canyon to see what I could find to take some test photos of. I noticed the river that follows the road (or does the road follow the river?) was still quite high- and I had my sticks in the car, so I thought some slow shutter speed water shots might be a good test.

Because it was very bright (direct sunlight in some cases), I had to stop down to F/22... this meant everything was in focus... which isn't my favorite effect. In some of these shots, particularly ones where I was lazy and zoomed in, rather than get closer, the foreground has very little separation from the background. I figure with was about the lens and shooting parameters much more than the camera... but I'll have to do more testing...

Click an image to see it larger

All of these photos were taken with the 14-140mm Panasonic 'kit' lens. I believe they were all at f/22, with shutter speeds around 1/6 sec, all at ISO 160.

Obviously, this little camera is capable of taking some nice images! I'm not convinced that it takes better images than my Nikon D300s- which I have absolutely loved everything about, except for it's video capabilities. The GH2 photos require a quite a bit more 'developing' to get the colors how I like them (or even how I remember it looking in real life). GH2 photos also tend to favor a cooler tone, versus the Nikon favored warmer photos- I prefer warmer, looks less 'digital'...

The Nikon D300s is only 12.2 MP, but the color reproduction seems much better, and much more true-to-life. I'm not really surprised by any of this, the D300s is a fairly pro-level camera, and the GH2 is clearly consumer oriented. I had originally planned on selling the Nikon... but now I'm torn... When I ordered the GH2 I was ready to trade some photo quality for vastly better video capabilities... but now I'm having a hard time biting that bullet....

Here are some Nikon D300s images for comparison (different location, different day)...

Also worth mentioning- I'm editing the GH2 images using Photoshop RAW... and I edit the Nikon images using Nikon's Capture NX2 software. I absolutely love photoshop (for some things)- but I have been very, very impressed with Nikon's software, and feel it is a better tool for developing digital photos. Unfortunately, although not that surprising, the Nikon software does not support the GH2's raw file format...

Friday, July 8, 2011


Here's the start to the 2011 European tour that includes the Swiss Nationals and the World Championships.

Flew over to Zurich from LA with Jeff Shapiro on the 4th of July. Swiss Nic and Steve Blinkensop picked us up at the airport and we headed to Nic's home in Baden (originally a Roman town). Upon unpacking my glider in Zurich, I found a large dent in my leading edge tube.

Nic had a spare tube that need to a slight modification, so Blinky and Carole helped my get the tools to fix it. Dustin arrived later and we had some fantastic home-made green curry a la Blinky.
The next morning we were off to Fiesch with 4 gliders, 10 harnesses and 4 bodies crammed in Nic's sweet Mercedes. driving south past Interlaken we drove the car onto a train that took us through a tunnel deep through the Alps. In Fiesch we met up with Derreck and James to register and parade through town.
Weather looked pretty bad and there were doubts as to whether we would fly at all, but day one turned out great.

Monday, January 17, 2011

On Gear Ratios & Modules etc.

A question about pitch, module and gear ratios came in today so I though I should share this info as it may be useful to others. First some gear nomenclature.

A round gear's Diametrical pitch is defined as its number of teeth divided by its pitch diameter.

Pitch Diameter is NOT the overall outer diameter of the gear, its the diameter of the gear to some point about half way up the gear teeth. Its a small difference from the over all diameter of the gear if we are talking relatively small teeth (like those used by follow focus units) so its not that important to differentiate.

A gears Module(mod) is just the mathematical inverse of the diametrical pitch.

The cine standard is 32 pitch (measured in number of teeth per inch) or 0.8 mod (measured in millimeters per number of teeth)

So, some math specific to the D|Focus:

Pitch = # teeth / Pitch diameter,

D|Gear is ~4" pitch diameter,

# teeth = Pitch * Pitch diameter = 32 teeth per inch * 4 inch = 128 teeth

Module is the inverse of pitch, so Mod = Pitch Diameter / # teeth

However, for whatever reason we measure module in millimeters, not inches. 4" = 101.6mm

# teeth = pitch diameter / Mod = 101.6 mm / 0.8 teeth per mm = 127 teeth

Discrepancy in # teeth in theses 2 calculations is due to inaccurate measurement of pitch diameter (I just measured it with a ruler, could get out my CAD drawings and get an exact measurement, or count # teeth but I'm lazy.)

The drive gear's pitch diameter = 1.5 inch so it has 48 teeth

128 / 48 = 2.667, so the D|Focus + D|Gear as a 2.667 to 1 ratio

So one full, 360 degree rotation of the D|Focus knob will give you a little more than 1/3rd (~135 degrees) the rotation on your lens' focus ring.

There are also some other modules (0.5, 0.6) used on Canon and Fuji broadcast, ENG, 2/3" style cameras.

Types of gears:
The D|Focus, uses 2 general types of gears. The Drive and lens gears are called Spur gears. Pretty much the simplest type of gear. The gearbox used Miter gears which are used to change the direction of motion. Some other follow focuses use helical gears to accomplish this.