[Rorschach]

Cool science project! A few more thoughts and ideas....:

1. Have you looked at the drone's APIs and on-board control features? If it has any digital I/O features, you may be able to control the K-1 from the ground through the drone's API with a simple bit of electronics, and the wired remote port on the camera. And if that doesn't work, then a long-range wireless remote control can do that job.

2. Time lapse could work if you program the drone to fly to a grid of locations at set time intervals and hover in sync with camera's time lapse. (Note: you are probably going to want to program the drone to fly a fixed grid for the survey and sensor shots anyway so that your scans are comparable over time.)

3. Wifi range will be curtailed and unreliable if there is any vegetation between the drone and the base station.

4. AF may not work well in UV or IR. But manual focus should be workable for your project even at f/1.4. For example, if your goal is to image a 10 m x 15 m rectangle with each shot (= a pixel size of 2mm on the ground), you'll be flying at about 20.8 m above ground level. If you set a 50 mm f/1.4 lens to focus at 16 m, then everything from ground level up to about 10 m up should be in focus. You can use a DoF calculator (Depth of Field (DoF) calculator | PhotoPills) for other scenarios.

5. You'll probably want to do some experimentation with lenses to check the plane of focus, aberrations, and transmission in UV and IR.


I look forward to hearing more about your project!

Thanks for the input, much appreciated!

1. I have thought of something like that, i.e. a gentle hack :-) However, let's first see what the reply and subsequent correspondence with Pentax Surveying reveals about the UP-1!

2. Yes, we are planning to use pre-programmed flight plan for the most part. It also removes any operator delay, thus saving precious flight time. A battery pack costs around 700 euros so we can't just buy ten of them :-D We'll likely get three sets as that should give a pretty good work flow (apparently takes about 90min to charge).

3. This is true. However, one of the two locations is a rather open fen with no tree canopy to obstruct. The other one is a dry pine forest but not overly dense so we'll see.

4. That's exactly what I had in mind: to use the DoF calculator for each lens being used. I also thought that at the heights we're going to use, depth of focus should be pretty good. So thanks for verifying! Depending on what legacy lenses we end up buying, we will likely use a 35mm f3.5 and a 50mm f2.8 or f4.0 for the UV shoots and Pentax new DFA 50mm f1.4 for visible light and IR scans. Yes, you are right: no AF with the UV work.

5. Most definitely! I have already started by diving into a few oases of information on UV:
35 mm lenses for UV
Ultraviolet Photography
Both sites contain a wealth of information and links!

I will definitely keep updating this thread as we progress :-) It will take months just to make the choices, purchase equipment and assemble it. But hopefully some time in the summer we will start the actual work!

[zapp]

Yes, this one: Matrice 600 -*Simply Professional Performance

It has a payload capability of roughly 6kg, of which the gimbal takes 1,5kg. Still plenty left for a K-1 and a lens

I am also planning to do UV and IR with it, so the camera will immediately go to be modded for that (full spectrum conversion). This voids the warranty, but that's ok.

As you maybe guessed, this setup is for research purposes.

Most people use Canon with Canon hack for this job. Full spectrum conversion is not the same as real UV and anything but near IR. Still need cutoff filter.
You sacrifice the camera if you do the full conversion. Why do you use such a heavy model? Any extra minute of flying time is precious.

[Rorschach]

Most people use Canon with Canon hack for this job. Full spectrum conversion is not the same as real UV and anything but near IR. Still need cutoff filter.
You sacrifice the camera if you do the full conversion. Why do you use such a heavy model? Any extra minute of flying time is precious.

I suppose you did not read some of my comments?

Full spectrum conversion gives the flexibility to use UV, IR, visible light or a combination of those spectra. It is easily possible to get down to 320nm UV which is pretty good. And no, you only sacrifice the warranty, not the camera. By using lens front filters you can still take visible light images as normal.

We want to use the K-1 because it has sensor shake reduction which greatly helps with longer exposure times that are unavoidable with UV in particular, especially when it's not sunny. It is absolutely fabulous that this feature works also with the obscure legacy lenses that we will use for UV! Canon or Nikon are at a huge disadvantage there. The strong high ISO performance of K-1 will also be of great use in UV by keeping shutter times reasonable in cloudy conditions. When doing visible light or IR scans we use Pentax DFA 50mm f1.4 giving us complete weather shielding - an absolute bonus. And finally, the same camera system will also be used on a tripod on the ground, where pixel shift will be useful to have in some applications. Actually, Canon can't really hold a candle in our applications...

Finally, we intend to also use our sensors with the drone so we need the payload capability anyways. Why then choose a lighter and worse camera? We can get quite nice flying time by having 3 battery packs anyways. When the first one is depleted, it goes to charging immediately and the cycle will give us quite a bit of useful working time per day.

[Dericali]

Time lapse is one option that we have considered but it is not optimal as we need to get low aerials of a very large number of vegetation plot that are part of a long-term manipulative field experiment. With manual, legacy lenses in use, would also need to calculate focal distance (i.e. drone height --> distance from lens to the ground) carefully before taking off and setting the lens focus plane so that the resulting images would be in focus.

There is a Finnish company called SharperShape that specialises in measuring and modelling vegetation via aerial surveying. This is for utilities companies mainly.

I'm not familiar with your project but I'd suggest looking at some of the complete package drones designed for agricultural industry, might be easier than putting it together yourself.

[Rorschach]

There is a Finnish company called SharperShape that specialises in measuring and modelling vegetation via aerial surveying. This is for utilities companies mainly.

I'm not familiar with your project but I'd suggest looking at some of the complete package drones designed for agricultural industry, might be easier than putting it together yourself.

Might be easier but would be way more expensive, even with keeping the high price of this equipment in mind. We need to do these aerial scans many times, each time 72 vegetation plots of circa 2m x 3.5m so knowing a bit about their fees for just fieldwork of one day, those type of consultant companies would totally bankrupt us in no time.

SharperShape do look very professional but their service products and expertise aren't suited to our research needs. Like you said, they're more into power line mapping etc.

[UncleVanya]

The dedicated UV lenses by Coastal Optics and Nikon are not an option. Not so much because of the high price but because of those being available only for Nikon F. So there would be no infinity focus without an adapter that has corrective optics...and those optics would not pass UV (almost certainly). So we're going to use a few different fixed focal length m42 lenses. A mix of the oldest tech and the newest possible! I like that

This is incorrect. The Nikon F is adaptable to the Pentax K without any optics. The opposite is not possible. You cannot mount a Pentax K on a Nikon F and get infinity - but you can do the opposite. The mounting is a bit insecure unless you modify your Nikon lenses, the lens only turns part of the way and will not engage a lock pin - however you can drill a new lock pin recess. You can add a small shim (1mm or so) to take up the extra space and get infinity to align closer to the manual focus mark rather than aligning at a shorter distance. Finally you could try to locate an Adaptist mount (Pentax K+ Multi Mount - Adaptist) which would allow a bit more secure mounting.

To be clear I am talking about mounting the nikon lens directly to the pentax mount. This works with non-ai lenses best unless you modify the nikon lenses - which in hindsight may not be rational with this speciality lenses.

[Rorschach]

This is incorrect. The Nikon F is adaptable to the Pentax K without any optics. The opposite is not possible. You cannot mount a Pentax K on a Nikon F and get infinity - but you can do the opposite. The mounting is a bit insecure unless you modify your Nikon lenses, the lens only turns part of the way and will not engage a lock pin - however you can drill a new lock pin recess. You can add a small shim (1mm or so) to take up the extra space and get infinity to align closer to the manual focus mark rather than aligning at a shorter distance. Finally you could try to locate an Adaptist mount (Pentax K+ Multi Mount - Adaptist) which would allow a bit more secure mounting.

To be clear I am talking about mounting the nikon lens directly to the pentax mount. This works with non-ai lenses best unless you modify the nikon lenses - which in hindsight may not be rational with this speciality lenses.

Yes, I read about that hack. But as you say, I'd be a little hesitant to do that to a 5000-6000 euro lens :-D Furthermore those two UV-lenses that exist for the F-mount aren't the most desirable focal lengths as one is 105mm and the other is 60mm. The 60mm might do, but I rather like the idea of getting 50mm, 35mm and 21mm byt using those old legacy lenses and spending a total of circa 500 euros max. Leaves money for other stuff.

[UncleVanya]

Yes, I read about that hack. But as you say, I'd be a little hesitant to do that to a 5000-6000 euro lens :-D Furthermore those two UV-lenses that exist for the F-mount aren't the most desirable focal lengths as one is 105mm and the other is 60mm. The 60mm might do, but I rather like the idea of getting 50mm, 35mm and 21mm byt using those old legacy lenses and spending a total of circa 500 euros max. Leaves money for other stuff.

That makes sense.

[derekkite]

For simplicity you could try something like the intervalor mode in the K1. Your drone likely can be programmed to go to a certain location, then stay there for a set amount of time. The intervalor takes a shot. Then next place. Trial and error can get a simple setup that works within the time constraints of your batteries.

Brute force taking lots of shots is cheaper and simpler than control systems. If you need to trigger you could look at radio control type hardware. It is relatively inexpensive, can operate over the distances you are looking at, and to get a simple two channel to close a set of contacts would be quite easy. Do drones come with an external dry contact that can be operated by logic?

[Bob 256]

I have a K-01 with full spectrum conversion and it works great in the IR. Autofocusing will work as long as the lens being used is fast enough to give the AF system enough information to work with.

I haven't shot any UV, but one problem you might encounter is focusing at infinity since in UV a lens will focus shorter than its listed focal length and the infinity setting might not place it close enough to the sensor. A weak negative supplementary lens from an optician on the front should take care of that (a corrective lens for a person who is nearsighted). Many optical materials will pass the UV you're talking about just like some Pentax lenses so that wouldn't be an issue. Color fringing isn't an issue either since you're only using a narrow band of wavelengths (and basically B&W images).

WiFi commander that I mentioned previously, provides live-view and access to camera & lens controls (for lenses which work with the K-1 that way), so it's worth looking into. The creator has put a lot of time into improving it and its features since it was first introduced.

Good luck with your project. Sound's like a really interesting app for the K-1.

[Rorschach]

I have a K-01 with full spectrum conversion and it works great in the IR. Autofocusing will work as long as the lens being used is fast enough to give the AF system enough information to work with.

I haven't shot any UV, but one problem you might encounter is focusing at infinity since in UV a lens will focus shorter than its listed focal length and the infinity setting might not place it close enough to the sensor. A weak negative supplementary lens from an optician on the front should take care of that (a corrective lens for a person who is nearsighted). Many optical materials will pass the UV you're talking about just like some Pentax lenses so that wouldn't be an issue. Color fringing isn't an issue either since you're only using a narrow band of wavelengths (and basically B&W images).

WiFi commander that I mentioned previously, provides live-view and access to camera & lens controls (for lenses which work with the K-1 that way), so it's worth looking into. The creator has put a lot of time into improving it and its features since it was first introduced.

Good luck with your project. Sound's like a really interesting app for the K-1.

Thanks! Yes, the UV focus shift is a known problem, especially with the legacy lenses that are not dedicated to UV. Not a problem with live view though. With the brute force time lapse approach this just needs to be accounted for when setting the focus before a takeoff. Perhaps that correction lens is also a possibility. I will definitely look at the WIFI commander, sounds great! Thanks!

[photoptimist]

Thanks! Yes, the UV focus shift is a known problem, especially with the legacy lenses that are not dedicated to UV. Not a problem with live view though. With the brute force time lapse approach this just needs to be accounted for when setting the focus before a takeoff. Perhaps that correction lens is also a possibility. I will definitely look at the WIFI commander, sounds great! Thanks!

The UV focus shift issue can mean that infinity focus is impossible even in live view. The UV focus on some lenses can be well past the infinity mark on the lens and past the physical limits of the barrel or focus mechanism. Adjusting the infinity stop inside the lens barrel can sometimes provide enough lens motion to reach UV focus. If not, a relatively simple measurement of the focus-offset for UV can lead to estimating the right diopter of the correction lens which will probably be very modest (e.g., only -0.25 or -0.50 diopters). If you do go this route, get a glass corrective lens because one the consumer "benefits" of many kinds of plastic lenses is that they block UV.

[Rorschach]

The UV focus shift issue can mean that infinity focus is impossible even in live view. The UV focus on some lenses can be well past the infinity mark on the lens and past the physical limits of the barrel or focus mechanism. Adjusting the infinity stop inside the lens barrel can sometimes provide enough lens motion to reach UV focus. If not, a relatively simple measurement of the focus-offset for UV can lead to estimating the right diopter of the correction lens which will probably be very modest (e.g., only -0.25 or -0.50 diopters). If you do go this route, get a glass corrective lens because one the consumer "benefits" of many kinds of plastic lenses is that they block UV.

Yes, definitely have to make sure that the corrective lens -if we need to go that route- is indeed glass and without any kind of coatings or lens cement. Both of those can cause partial or complete blocking of UV...there's a reason why there apparently zero zoom lenses that have decent UV pass through, even among the legacy oldies!

Good tips on the possible infinity issue, thanks!

[UncleVanya]

I wonder if revisiting old Nikon lenses is an option. Despite the mediocre attachment they do focus past infinity when mounted on k mount Cameras. This could offset the uv shift.

[Rorschach]

I wonder if revisiting old Nikon lenses is an option. Despite the mediocre attachment they do focus past infinity when mounted on k mount Cameras. This could offset the uv shift.

Could be but would first have to find out UV test results for them.