Category Archives: Photography

Video with telemetry – Part II

Photography

Adding high quality sound.

In Part I I described an inexpensive way of making in-car videos with telemetry overlays. Using a capable and inexpensive Sony Action Cam, sound was recorded using the two forward facing microphones and was not especially good, with lots of wind buffeting in the cabin of the convertible used, and generally poor sound quality. Given how small the Action Cam is, that’s hardly unexpected.

Sony’s manual is indescribably bad when it comes to explaining the use of external microphones. There is one passing reference to them but no indication where to plug them in or words about what works. After much searching I determined that the external mic shares the same 3.5mm socket used for an external power supply, and the only reason I came to conclude this earth shattering finding is that there’s an almost invisible microphone symbol on the access door underneath the camera which also conceals a Micro HDMI-Out socket (to route movies to your TV set) and a mysterious expansion socket whose purpose I have yet to divine. Quite how Sony can make such a fine product and not spend a few minutes documenting connectivity is a mystery to me. But then just about everything about this terminally confused corporation is a mystery.

It gets worse. Sony provides a small screw-on baseplate which adds a standard 1/4″ tripod socket for the Action Cam. The snag is that, once attached, this blocks the access door where the microphone (or power supply – you can choose one or the other, not both – what were they thinking of?) socket is. A moment’s tinkering disclosed that it’s possible to reverse the tripod plate and it still just clears the access door. While the plate now juts out, looking generally ugly, it does not intrude on the lens’s field of view and the whole thing is pretty solid. This is how it looks on the 1/4″ RAM Mount plate:


The power/mic socket is circled.

There is just enough room for the microphone plug:


The external microphone is plugged in.

Sure, hunt around a lot and you will find that Sony makes a skeletal frame for the Action Cam which allows proper tripod mounting with access to the sockets in the base. However, reviews at Amazon disclose that this silly-priced accessory is flimsy and made to fail. Pass.

Now for the choice of microphone. Something with a directional (not omni-directional) sound field to cut down on extraneous sounds is called for here. The microphone will be moved to the rear of the vehicle, where the engine is, using a 6 foot extension cable to better capture the glorious sounds of a high revving flat six. Further, a self powered mic is essential as the additional drain on the Action Cam’s small battery would be unacceptable with an unpowered microphone. Recall that the extension mic makes it impossible to use an external power supply with the Action Cam as the same socket serves for both mic and power.

To alleviate power issues, I bought a couple of spare rechargeable batteries and a charger for all of $18 – the Action Cam does not come with a charger:


Click for Amazon.

The cells are easily inserted in the back of the Action Cam, even with the camera mounted on the inside of the windshield.

Reading a handful of Amazon reviews disclosed that the best price:performance microphone is the Takstar SGC-598 for all of $33.


Click for Amazon.

The mic is directional, compares favorably in reviews to the ten times costlier professional Rode, uses one AA battery (allegedly good for 100 hours – yeah, right!) and has the frequency response and sensitivity distribution I was looking for:


Takstar frequency response and sensitivity.

Further, the mic has a bass cut filter to reduce wind roar and includes a sponge sock for the same purpose. There’s also a +10dB sensitivity switch, though with the mic in close proximity to the motor it’s not required in this application.


Orange arrow denotes my power-up reminder label. Red circled LED glows red
when the battery is dying. Green oval denotes anti-vibration mounts.

I stuck a large ‘Power!’ label to the body of the mic to remind me to power it on before use. The rear green LED illuminates when the mic is on, changing to red when the battery is low. There are eight rubber anti-vibration ‘springs’ upon which the mic is suspended in its mounting frame and a further eight spares are included in the box in the event of wear and failure. A thoroughly well thought out product at a great price.

The mounting base is a standard camera accessory shoe with a locking knob. As luck would have it, the removable covers for my vehicle’s optional hard top are the exact diameter of the locking knob, so it’s a matter of moments to pop one of these covers off and insert the mic in the opening thus disclosed, for a perfect and secure fit. Sometimes you get lucky. For those looking for the right vehicle to fit this mic, you can figure it out. (Hint: It’s not an SUV).


The Takstar securely installed – literally ‘plug-and-play’

Now we are ready to ….errr, truck.

The Light L16 camera

Cameras

Thinking outside the (DSLR) box.

The last time a seriously funky camera concept came around I wrote excitedly about it, promptly doing a 180 a few months later describing the device as a solution looking for a problem. I was right second time and the Lytro company making this ‘after the event focus’ camera has been through multiple management changes and recapitalizations since, as it heads for bankruptcy. Its technically appealing technology had little popular appeal.

Now something perhaps even funkier has come along, the Light L16 which by using 16 lenses seeks to emulate FF DSLR quality with a 52mp image in a breast pocket-sized package. It will retail for some $1700, if it is ever made, that is. The makers claim that, like the Lytro, after the event depth of field adjustment is permitted (Lytro, to be exact, permits retrospective focus point selection, but the results are conceptually similar).


The Light L16.

My attention to the L16 was drawn by A friend of the blog who read my revisit to Ed Hebert in the preceding column here, where I mentioned that Ed had just earned his Masters in Information Technology, with a concentration in Digital Media Arts and Web Technologies. He writes:

” Of personal interest to me was the fact that Harvard now offers a degree of “Masters in Information Technology, with a concentration in Digital Media Arts and Web Technologies”. When I went there the first time, I was laughed at for suggesting a course in photography. When I returned 20 years later on a fellowship, there was a single course in photography that limited admission to 18 students (over 300 applied).”

The MIT Technology Review has an interesting piece on the Light L16 here.

Recent Nvidia cards in the Mac Pro

Mac Pro

Catch 22 lives.

For an index of all my Mac Pro articles, click here.

To apply for a job, you need to have a few years of experience. But in order to gain experience, you need to get a job first.

Like logic applies to the dilemma of installing the latest Nvidia GPU drivers in your Mac Pro.

Here’s the background. The GTX680 GPU came from EVGA and was made for the PC, along with like GPUs from many makers including Nvidia, Zotac, PNY, Gigabyte – they all worked well. Typical port configuration was one DVI-D, one DVI-I, (both DVI ports limited to 2560 x 1200), one DisplayPort (4k and down) and one HDMI 1.2 (limited to 1080p).

The last Nvidia card sold as ‘Mac compatible’ was the EVGA special version of the GTX680. That one showed the full Apple boot screen on cold start.

Thus you had three choices when buying a GTX680:

  • Buy the EVGA Apple certified one and pay through the nose
  • Buy a PC version, save $150, and get no splash screen during a cold start
  • Flash the card’s ROM or have it done for you to restore the boot screen

Who needs a boot screen? Only those poor unfortunates who insist on running Windows under BootCamp. You install OS X on one volume of a drive, Windows on another then when cold starting, hold the Option key on the keyboard and the spinning cog (through OS Mountain Lion) or progress bar (Mavericks and later) changes to a display of all bootable drives. You elect the BootCamp drive and proceed in your misery. Want to revert to sanity? Reboot holding the Option key and select an OS X volume as the one to start from.

Users who merely need to choose between different OS X boot volumes or drives can do so in System Preferences->Startup Drive. Rebooting will make the volume or drive chosen the new boot drive.

The snag is that if you boot into the Windows volume, you must have a working boot screen to see other volumes if wanting to revert to OS X (or Linux or Ubuntu or whatever). If you can’t see the boot screen because your GTX680 is an unflashed PC variant you cannot get back into the OS X volume.

Things get worse. After the GTX680 was discontinued Apple ceased marketing ‘Apple certified’ Nvidia cards as they stopped making the classic Mac Pro at the same time, so there was no need in their cynical eyes to allow classic Mac Pro users to stay current with the rapidly evolving field of ever faster and more capable GPUs.

With the Nvidia GTX7xx generation you could still use the native drivers which came with OS X but you could not get a boot screen unless the card was flashed.

Then, with the current, and exceptionally capable GTX9xx generation of GPUs, not only did you lose the boot screen, you also needed to use Nvidia’s own drivers to make the card work as the GTX6xx/7xx ones were no longer compatible. To get there, while still using an older card, you would download the Nvidia drivers, which install as a preference pane, and then go into System Preferences->Nvidia and choose the Nvidia driver in preference to the OS X one. Reboot and your old card would continue working fine. Now power down, swap to the latest and greatest GTX960/970/980 and all was well.

Here’s where the Catch 22 comes in. Apple decides to release an ‘improved’ OS X – minor or major release. Chances are it breaks the driver so after a few days, Nvidia releases the upgraded driver. They are very good about this as it means continued sales of their latest cards to the Mac Pro set. But you cannot wait or, worse, have set your Mac Pro for automatic updates of software. You come in in the morning , OS X El Crapitan has been installed unknown to you overnight and you are welcomed with a black screen, as the OS is no longer compatible with the previous generation Nvidia driver on your boot drive.

There are several ways to exit this dilemma:

  • Keep an old Nvidia GT120 card installed if you can spare a PCIe slot – any slot. They can be found for $50-75, typically come with one DVI and one mDP port, include a boot screen and 512MB of vRAM, and will even drive the excellent 30″, 2560 x 1200 Apple Cinema Display. Mine does. Not much use for video but it fixes the problem. It’s single width, needs no auxiliary power cable and uses very little power. It’s also dead silent. You transplant your DVI or mDP monitor cable to the GT120, the display comes to life, you update to the latest Nvidia driver, switch the data cable once more and all is well.
  • Unplug your GTX9xx card and replace it with an older card which delivers a boot screen and allows you to update drivers. A real pain but it gets you there if you kept that old card handy.
  • Boot from a backup drive which has the older working OS on it, update drivers and clone over to the regular boot drive. This will leave you on the older OS but at least you will be functional.
  • Do it the smart way. Get hold of a Mac laptop, and set up your Mac Pro for Screen Sharing in System Preferences->Screen sharing thus:


    This is how you want your Mac Pro – not your laptop – to look.

  • Now go into your Mac laptop’s Finder and you will see your Mac Pro listed in the left hand column – red oval (don’t ask me why it has that cryptic description):

  • Click on ‘Share Screen’ – green oval. You will have to login using your Mac Pro’s username and password. Now you can see the Mac Pro’s display feed regardless of whether the Mac Pro’s screen is black or working properly. Download the latest Nvidia driver, install it, turn off Screen Sharing on the laptop, reboot the Mac Pro and you are up and running again.

Some architecture

Nikon lenses, Photographs

A great way to end the year.

Few things beat a crisp, sunny day in San Francisco, and the city’s propensity for preserving its old buildings means more subject matter for an itchy trigger finger.

These were all snapped today on three classic ‘metal era’ MF Nikkors from my copious inventory on the D3x – the 35mm f/2, the 85mm f/1.8 and an all time favorite, the 200mm f/4, an outstanding optic for picking out gorgeous period details.

The absence of autofocus for this type of subject matter is anything but a hindrance. If anything, the more contemplative approach required is a benefit.

Processed in LR6, some verticals straighened in PS CS5, some juice added here and there in Snapseed.

Nikkor 20mm f/2.8 AiS lens

Nikon lenses

Still in production.

The most remarkable thing about the Nikon Nikkor 20mm f/2.8 AiS lens is that Nikon continues to make it. It’s available new for some $650 – not cheap – and will work on just about any Nikon body, film or digital, since the groundbreaking Nikon F of the 1960s. This example belongs to a friend of the blog for whom I volunteered to create lens correction profiles for use with Lightroom or Photoshop to correct linear distortion and vignetting. As a general rule, the wider the lens the greater is the incidence of these aberrations.

My 20mm Nikkor of choice is the original and massive 20mm UD f/3.5 Nikkor which is nearly a half century old. Mint examples can be found for around $300; many are available and there is no excuse for buying a ‘beater’. It has outstanding center resolution at all apertures, with the edges catching up by f/8. You can read about it here. The current 20mm AiS is much smaller, and both lenses are manual focus only:


The old UD Nikkor is on the D2x at left.


The current 20mm AiS optic is on the D3x at right.

Where the UD adopts the early ‘all metal’ finish of the classic era, the AiS uses rubberized focus and aperture rings. Both lenses are manual focus.

Despite the high price, Nikon does not fit a CPU to the lens so the user has to manually dial in the aperture and focal length on the Nikon body if any lens profile is to be automatically recognized in LR or PS; the CPU I have fitted to the UD dispenses with this need. You can always tell LR which profile to use if you forget to dial it into the body or dial in the wrong one.

The owner of the 20mm f/2.8 AiS shown here advises that Lightroom CC (the cloud version) no longer permits profiles to be dialed in manually, but Photoshop CC does. So if you are solely a Lightroom user and need to manually input profiles, I recommend you use the stand alone Lightroom 6 desktop version, still available. Adobe really does no want you to do that, preferring to steer you to the rental model of the CC version, but follow my guide here and you can download it easily. Given that PS and LR are pretty much stalled and at the end of their development cycles, there’s little justification for buying the CC version with its purported ‘constant updates’. A disingenuous business model if ever there was one, but that’s Adobe for you.

CPU on the UD is arrowed.

Given the narrow rear flange of the AiS, installation of a CPU would be a trivial process, and I describe that here.

I created the lens profile for the AiS using Adobe Lens Profile Creator in the usual way, at f/2.8, f/4, f/5.6 and f/8. After f/8 nothing changes. Here is the profile invoked in the Develop module of Lightroom 6 – LR 3-5 will work just as well. The profile is placed in the User’s Library directory as explained in the above link. To ‘see’ the directory in Finder be sure to hit the ‘Option’ key when in Finder->Go as the fools at Apple have seen fit to hide it in recent releases of OS X.


Profile invoked in LR.

While the profile says ‘D3x’ in the title it is non-body specific and will work with any Nikon digital image, FX or DX (APS-C). In practice the profile does an outstanding job of correcting the fairly pronounced vignetting at wider apertures, as well as correcting the minor but very complex linear distortion which is of the ‘wave’ or ‘moustache’ type common in Nikkor 20mm lenses – both my UD and my (now sold) 20mm f/3.5 Ai lens exhibit it. The vignetting is slightly less pronounced – uncorrected – than in the old UD, but there is little in it between the two and after applying the respective profiles there is no difference in this regard.


Top right corner at f/2.8 – no profile.


Top right corner at f/2.8 – with profile.

The profile cannot correct for chromatic aberration and the AiS exhibits red fringing (the UD displays green fringing, by contrast):


Red fringing in the AiS at f/2.8.

A quick tweak in LR removes the fringing:

Here are the settings:


Removing the AiS’s red fringing in LR6.

How does the extreme corner definition compare with the UD? As my earlier UD review discloses, the UD is optimized for center sharpness at full aperture (f/3.5) so the corners suffer. Yet despite that the UD is clearly superior in the extreme corners as the image below shows. This would make a 72″ print and was taken in very overcast, low contrast conditions, a very challenging environment for any lens:


Extreme top left corner – AiS on the left, UD on the right. Both with lens profiles and color correction applied.

So maybe not all progress is forward. You get two thirds of the bulk and weight but lose corner resolution at full aperture with the newer lens. The UD maintains an advantage in corner resolution at all apertures, though the difference falls as the lenses are stopped down. While I do not publish them here, center resolution of the UD is 1 stop better than for the AiS through f/5.6, after which the two lenses are identical.

You can download the lens correction profile for the 20mm AiS Nikkor by looking for it here.

Here’s a far better illustration of how the ‘wave distortion’, seemingly common to 20mm Nikkors, is corrected. These were taken by the lens’s owner:


No profile – see how the lintel drops then rises – top right hand corner.


With profile. Red chromatic aberration remains to be corrected but the ‘wave’ is gone.