Following up from my last post, I wanted to mount a GoPro Hero 8 Black onto a seaplane. For this, my requirements were:

• Method to start/stop recording
• Support recording for up to 4 hours
• Efficient way to get videos out of the camera
• Camera must be waterproofed (water takeoffs/landings involve a lot of splashing)

Method to start/stop recording

After far more study and experimentation than ought to have been necessary, I discovered that the only reasonable way to start/stop recordings is to manually push the button on the GoPro.

All my attempts to start recording via the Android GoPro app resulted in recordings that stopped by themselves after less than 5 minutes. I don’t know why.

Support recordings for up to 4 hours

The internal battery on the GoPro only will record for about 90 minutes. So I needed to power the GoPro via USB while recording.

Efficient way to get videos out of the camera

As per my last post, I found that the only reasonable way to get recorded videos out of the GoPro is to physically remove the Micro SD card and read it on another device (a laptop is the most practical solution).

In theory the GoPro app can download recordings onto a phone, but I discovered this takes longer than there recording itself! I don’t want to wait around for 3 hours after landing to get the 3 hour recording into my phone.

(In case it’s not obvious by this point, I’m not at all happy with the GoPro – the only thing it does well is record video. All other functions are broken or awkwardly implemented.)

Camera must be waterproofed

Last, the camera needs to be waterproofed. You wouldn’t think this would be difficult with an “action camera” supposedly meant for rugged use, but there was no reasonable off-the-shelf solution.

My solution

The requirements above badly conflict with the GoPro design. On the GoPro8 you can’t attach the standard battery door while powering the camera via USB – there’s no hole for the cable.

And if you use an aftermarket door, then the camera isn’t waterproofed. So I had to use hot-glue to seal all the openings to keep the camera dry.

And if you hot-glue the door, then you can’t get the Micro SD card out to read off the videos. (At least, not without scraping off all the glue and re-gluing after every session!)

So my solution:

1 – Use Ulanzi G8-7 aftermarket door, with hole for USB-C cable:

2 – Get Micro SD card extender cable, so card isn’t glued in:

3 – Put SD card inside a waterproof film canister:

4 – Hot-glue everything to seal it.

Step by step:

I chose the shortest Micro SD extender cable I could find (15 cm long); I figure the shorter it is, the less likely it’ll have trouble from latency, capacitance, or noise pick-up.

Then, to get the Ulanzi aftermarket door to fit around the extender cable, I had to grind down one side (bench grinder).

I didn’t want to have a USB-C cable permanently dangling off the camera, so I installed a small right-angle USB-C connector; this lets me glue in the connector (sealing the camera from water) and still disconnect the cable.

I put the end of the extender cable that holds the Micro SD card into an old 35mm film canister (mine is a Kodak one from the 1980s; but you can still buy these canisters online). They’re reasonably waterproof.

I cut a hole in the bottom for the extender cable.

And left enough cable slack inside to reach the card easily.

Put the (removable) cap on the film canister, and the whole thing should be reasonably waterproof – once the gaps are sealed up.

Then, hot glue on all gaps – around the Ulanzi door, around the USB-C adapter, around the cable (both ends – coming out of the camera and going into the film canister).

Then I mounted it on the seaplane.

And used a zip-tie to hold the canister on the back of the camera.

I haven’t tried it in flight yet. I’ll post something here if I get some nice videos.

Last weekend I went on one of the New England Aquarium‘s whale watch tours.

About 6 miles northwest of Provincetown MA, I captured this video of a humpback whale breaching. Just dumb luck.

Pretty impressive.

From Casper WY. It was amazing; I’d never seen a total eclipse before. A partial eclipse doesn’t compare at all.

Here’s about 5 minutes around totality, compressed into 5 seconds (64x real time, exactly):

If you watch the clouds, you can see the eclipse shadow come and go.

Also notable is the city traffic (in the background).

Sometimes I get an idea in my head and just can’t get it out.

Modern digital cameras often have tiny sensors compared to 35mm film.

High-quality 1970s “prime” 35mm lenses had a reputation for being very sharp.

When one of those lenses is mounted on a small-sensor camera, the sensor covers only a tiny central region of the 35mm-sized image formed by the lens – essentially the sensor is cropping from the middle of the image, resulting in a telephoto effect.

This gives rise to the “crop factor” of small sensor cameras – at a given focal length, the field of view of the small sensor is much smaller (more “zoomed in”) than on the original 35mm film the lens was designed for.

What, I wondered, would images from a high-quality 1970s prime 35mm lens mounted on a modern small-sensor camera look like? Especially, could I get super-telephoto effects by mounting lenses that were considered long (telephoto) by 35mm standards, multiplied the “crop factor”?

I had to try it.

35mm film frame vs Pentax Q sensor

Above is a diagram showing the relative sizes of a 35mm film frame compared to the 1/2.3″ sensor in the Pentax Q.

The Q has the smallest sensor of any interchangeable lens camera I know of. While this may make it – ahem – less than ideal for general photography purposes (altho to be fair the latest versions of the Q have moved to a larger 1/1.7″ sensor, a huge improvement), that little 6.17 x 4.55 mm sensor does have an immense “crop factor” of 5.6x (comparing effective field of view at the same focal length – the number isn’t exact because the Q’s sensor has a 4:3 aspect ratio, while 35mm film is 3:2).

Off-topic, but other points in favor of the Q are the tiny flange focal distance of 9.2mm – it can mount just about any lens ever made – and Pentax’s excellent UI. I’m not sure there’s a mass market for a camera like this, but it sure can do some things that no other camera can.

So, while a “normal” 50mm lens on a 35mm camera has a 39.6 degree field of view (horizontal), the same lens on the Q sees only 7.1 degrees.

And – here’s the neat thing – a “telephoto” 200mm lens on a 35mm camera sees 10.3 degrees – but on the Q, only 1.8 degrees. That’s the equivalent of an immense 1120 mm lens in 35mm format. And a super-telephoto 500 mm lens sees just 0.71 degrees on the Q – equivalent to 2800 mm on 35mm.

So, I tried it. I got some Minolta MD/MC type prime (non-zoom) lenses on eBay, mainly because they have an excellent reputation and are a bit cheaper than other brands (because they don’t fit many modern cameras), and an adapter for the Q (also on eBay – remember I said the Q can mount almost anything?).

Here’s what I ended up with:

Lenses tested

Left to right:

• Minolta 50mm f/1.7 MD Rokkor-X PF
• Minolta 135mm f/3.5 MD Celtic
• Minolta 200mm f/4.5 MC Tele-Rokkor  PE
• Minolta 500mm f/8 RF Rokkor-X

From what I can tell online, these are all highly-regarded lenses. The “Celtic” line was Minolta’s cheaper brand, but it seems the economy came from using cheaper materials in the mount, etc. – supposedly it is optically identical the to more expensive “Rokkor” line. And of course, these are all primes – not zooms. Even today primes are generally sharper than zooms; this was even more true in the 1970s before improved manufacturing and computerized optical design.

In the second row you see the Pentax Q with a Tamron 3.5-8mm zoom f/1.8 lens in CS mount, via a “Hawk’s Factory” CS mount adapter (I told you the Q can mount most anything…), and the Minolta MD-to-Pentax Q adapter (just a hunk of metal – no glass).
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