Shotgun shot pellet stream heading up to the clay pigeon - advice on lens needed

[jeff.coe]

Hello Friends,

I will be purchasing a Chronos 2.1HD for one specific project ... I won't be using it for anything else.  I need help badly on the lens selection.  I know little / nothing about photography, and zero about high-speed videos.  Any advice you can give me would be greatly appreciated.

The project is to make high-speed videos of a shotgun's shot pellet stream as it goes from the shotgun up toward the clay pigeon.  (No live game ... just clay pigeons.)   The purpose of the video is to tell me if I missed the clay pigeon to the left / right / above / or below.  And to get a sense of by how far I missed ... inches.  So the Chronos 2.1HD will be set up on a tripod behind me, and the video recording will start when I pull the trigger.  (Don't worry about the triggering the camera.)  After missing the clay pigeon, I'll replay the video on the Chronos's back screen to see where I missed and by how far.  Or perhaps on a bigger monitor using the HD feed from the Chronos.

So the video's field of view needs to show from where the clay pigeon is launched and flying to where it gets hit.  And the video also needs to show the shotgun's shot pellet stream from the muzzle flying out to where the clay pigeon gets hit.

Details
- The Chronos will be on a tripod 1-2 yards behind the muzzle of the gun
- The clay pigeon will be launched from between 18-40 yards in front the Chronos, and its maximum flying distance out will be 50 yards
- The clay pigeon will be launched and fly from between 30 yards to the left of the Chronos to 30 yards to the right of the Chronos
- The clay pigeon will fly from ground level to 30 yards high
- The shotgun shot pellet stream will travel out at 1300 feet-per-second
- All videos will be taken outdoors with full sun and down to a cloudy day

With the high speed of the shotgun’s shot pellet stream (1300 feet per second) I’ll have to use the Chronos at very high frames per second.  I don’t know how that should affect my choice of lens.
 
So I need your advice on the choice of lens for this project ...
- There are reasons why I may need to buy the lens from Kron Technologies.  So which lens sold by Kron would you recommend?  Why?
- Which lens from other vendors would you recommend?
- Should I get the Chronos configured with the “Nikon X to C – FotodioX lens adapter?  Or the Canon EF to C – FotodioX?
- Is there an additional lens adapter piece that I need that goes between the camera and the lens?  Should I get it from Kron or some other vendor?
- Should I get a Zoom lens?  What is the advantage and disadvantage?
- Am I correct that I want a lens with the lowest Fxx number possible to let in the most light?
- What about the lens length number (mm) … what am I looking for on that?
- Since I’ll be shooting at a very high frame rate, how does that affect which lens I should get?

Price is interesting because I don’t care about the video’s quality except for being able to see the shotgun’s shot pellet stream as it heads toward and past the clay pigeon.

Thanks for your help …
Jeff

[Visualtec]

I think that's a tall order but very interesting project! If it was me i would automate the clay Pidgeon launcher and set it up so it fires the clay Pidgeon to the sameish place every time then set the lens to focus on that area in the sky, maybe use reflective shot so its easier to see I think it would be really difficult to pull focus that quick to follow the shot maybe it could be done with a stepper motor controlled by the pc that controls the launcher and starts the camera. You would need a quick lens to let as much light in as possible with a wide focus range maybe something like a wildlife or motorsport lens. I would get the MFT adaptor so the lens is more secure then a speed booster MFT to whichever lens you decide on. I think the lens will be expensive for what you want to do. I would maybe rent a few to get what suits you. but I recon  your into thousands not hundreds 600mm is maybe a good place to start but thats just a guess

[Photopage]

Hi Jeff,

The good news is you don’t need to trigger the camera.  Start recording and shoot.  When you miss a target, you stop the recording.  Depending on the model you have 2.5 to 10 seconds to do this after the miss.  The camera records in a continuous loop, writing over the info from 10 seconds earlier (for the 32 gig version)

But I think the idea of a fixed camera will not work if I understand you correctly.  The problem is the large area where the target may be shot.

The launch and fly area of the target is 60 yards wide with the camera in the center.
The target can fly 30 yards high.

The target is launched 18-40 yards in front of the camera, and then travels a further 50 yards out.  (This is more of a focus problem)

So we have a box.  Its dimensions are 60 yards wide by 30 yards high by distance from the camera (guessing here) about 25 yards (18 plus a bit for reaction times) to 90 yards (furthest launch point 40 yards plus slowest reaction time 50 yards).

Let’s just start with the flat area, a box that’s 30 yards high and 60 yards wide.

You have a camera with 1920 pixels wide and 1080 pixels high
If you want to see the whole box you have a limited number of pixels to detect anything in that area.
60 yards/1920 pixels is 0.031 yards which is 1.1 inches per pixel.

Each pixel can only see an area of 1.1x1.1 inches square if you want to see an area 60 yards wide.

The cloud of shotgun pellets would be almost invisible even if they were stationary, because they are not big enough to fill a pixel and they get more spread out the further they travel.
But they’re not stationary, they’re all moving at 1300f/s.  At 1/2000th of a second each little pellet has moved 0.65 feet, 7.8 inches.  So they’re extremely blurry and extremely tiny.   

This video is worth watching https://www.youtube.com/watch?v=fac-03JF3GA. go to approx 20 min.  The pellet stream very spread out by about 40 yards.  The spread is roughly 20 inches in diameter and 8 to 11 feet long at 40 yards!

I can only think of one way to do this that might work, but I think the weight might be a problem for you.
You mount the camera onto the shotgun.  Then use a long lens (focal length of at least 300mm) perfectly aligned with the barrels
Focus at the average distance of your successful shots, let’s say 40 yards.  The shot may be visible a bit before and after 40 yards, because if you are tracking the target after shooting, the shot will be relatively stationary from that perspective.  (Not sure how much).  Also, if you are shooting ahead of the target (to allow for the travel time of the shot) you may need a wider lens like 200mm.   Worth hiring/borrowing a lens to work it out.
Other options may be a helmet mounted camera if you follow the target with your head movement?  This moves the weight from the gun.

Interested to see what others think?  Hope you can work it out.

[jeff.coe]

Hi Photopage,

Thanks for your reply ... these are exactly the kind of thoughts I need to hear because I know so little (nothing) about photography.  It will take me some time to digest what you've said ... I'll be back again with questions.  Hopefully other forum gurus will chime is as well.

One thing that makes me hopeful is that the quality of the video is not important to me.  Example - I have no need to see the individual pellets clearly.  If I could just see a "smear" of the shot pellet stream in the video, it might be good enough to tell me if I missed right, left, up, or down.  The "smear" idea might also be assisted because as you said the pellets do separate over time, so the "smear" in the video might show the whole pellet cloud's direction and position.  Also different pellet types (lead vs. steel vs. size and weight) have very different dispersion characteristics which might be helpful.

I'm also hoping that a low resolution will still be be sufficient for viewing, and will allow the high FPS rates we need.  (However my wife always says that hope is not a strategy.)

So far I've been thinking that the camera would have a fairly wide field of view, because as you said the camera doesn't know where the clay pigeon will be (left, right, up) when the shot pellet stream passes it.  I was hoping a wide field of view would let me ignore the "aiming the camera" issue.  However this may not be realistic for the reasons you brought up.  I need to understand this issue much better.

Thanks again for your thoughts and ideas ...
Jeff

[jeff.coe]

Here is a good video of something very close to what I'm trying to achieve ... https://www.youtube.com/watch?v=0NjLIc44H_U

Many of these videos are losing visibility of the shot pellet stream when it gets further away from the camera, and as it passes / hits the clay pigeon.  Somehow I need to improve this.  I don't need to see the shot pellet stream early in the shot, although it is fun to watch.  Only needed as it passes the clay pigeon.

I may be able to fix some of the fixed camera mount and the field of view issues by deciding ahead of time where the clay pigeon is going to be thrown and hit.  Then I can aim the camera at the "clay break point" ahead of time.  I'd practice that shot some number of times, and then change the pigeon throw angle and the camera's aiming point together at the same time to practice a new shot angle.  This may let me zoom much further in and focus on the "clay break point", which hopefully will let me see the shot pellet stream clearly as it goes past the clay.

Should be fun trying to get this to work ... all suggestions are welcome ...
Jeff

[Photopage]

Hi Jeff,

Seeing the casio video is very encouraging. 
 
The big difference in this example is the guy shooting the video is also following the target or the shooter.  I think he may be more than a couple of yards behind the shooter too.  This gives him the advantage of being able to use a longer focal length lens that only covers a small amount of sky, so the target and the stream of pellets is relatively large in the frame.

For most of us we would be concerned about things going out of focus, but you just need to see the blurry stream vs the target which makes this part a bit easier.

If you can ask a friend to aim the camera while you shoot it changes everything, while keeping your reactions random.

I have seen home made gun stock camera mounts like this https://petapixel.com/2019/03/06/how-to-make-a-rifle-stock-for-your-camera/  and there are a few manufacturers selling them like this one https://sharpshooterindustries.com/index.php/products/sharpshooter-cameramount

If you're used to shooting with a shotgun this style of camera mount might be a more natural, easier adaptation for a fellow shooter to help you out.  And of course there is no need to trigger the camera until after a shot is missed (and you stop the loop recording)

If it was me I'd start by standing 5 yards behind the shooter, and follow their action, trying to keep the shooter in frame as they fire.  Borrow a few lenses to see which focal length works best.  Move closer and closer until the action is too difficult to follow.

I would not look at the camera's rear screen, just look over the top at the target and point. (having pre focused at the approximate distance of impact)

Re gear.... because the Chronos has no automatic control of lenses, there is no advantage buying new fancy auto-focus and auto-aperture lenses.  Old manual focus, manual aperture lenses can be very sharp and often have a more solid feel.  You also get very good value for money.  I recommend you look at old Nikon Manual focus lenses like these
https://www.bhphotovideo.com/c/products/SLR-Interchangeable-Lenses/ci/10209/N/4036297804?filters=fct_brand_name%3Anikon%2Cfct_camera-mount-type_321%3Anikon-manual-focus-ai-ais%2Cfct_focal-length-type_5940%3Atelephoto

Your local camera store may have them even cheaper.

Nikon "f mount" 85mm to 135mm is a good place to start.  You need to order the Nikon to C-mount adapter with the Chronos to fit these lenses.

Canon lenses are great, but they changed mount twice since the mid eighties, and the old manual focus lenses have a different mount to the current mount.  Nikon has only recently changed their mount for the new Mirrorless cameras (z mount) and these cannot be mounted on a chronos.

Any lens made for 35mm film will project a sharp image circle that covers an area the size of a 35mm negative.  The Chronos uses a sensor that is much smaller than that.  So on the chronos it has the effect of zooming in on a small part of the image, making the lens effectively more telephoto than it is with film.  Because of this you get a surprisingly narrow field of view from a 50mm lens, and the longer the lens, the narrower the field.

re Aperture.  Bigger apertures are better and more expensive (and confusingly smaller numbers) f1.4 lets through 2x the light as f2.  F2 lets through twice as much as f2.8.  and so on f4 f5.6 f8 f11 f16 etc 

You will be shooting at f2.8 or better on a cloudy day, and f4 or 5.6 on a sunny day.  You can also increase gain on the camera to make it brighter but the image does deteriorate a bit after a few stops.

Smaller apertures like f8 and f11 greatly restrict the light getting to the sensor, but they also increase the depth of field, which is the area that appears to be in focus.

Sorry there's a lot here...

Hope this helps?

[jeff.coe]

Hi Photopage,

Thanks !!!  This helps tremendously in many ways since I don't know any of this stuff about the apertures and covering the whole Chronos sensor and depth of field etc.  And your ideas about the lenses is invaluable.

After I read your post, I went back and watched the video again and saw what you said about someone moving the camera to track the pigeon.  That won't be possible for me since I almost always shoot alone.  And mounting the camera on the barrel or helmet probably won't work either because the weight will throw off my shooting, although I might try it.  So I'm thinking the predetermined "clay break point" will be the way to go.  I'd prefer taking the same shot over and over again anyway to get better at it.  And after several tries I should be able to get the camera aimed and focused at the right spot.   The manual focus of the Chronos will probably work to my advantage since it won't get confused by the shooter being in front.

This issue gets more complicated when shooting pairs of pigeons ... either "on report" or "simultaneous".  And of course these are the throws on which I need the most practice.  Both cases will require the camera's field of view to be wide enough to cover 2 different "clay break points".  I suspect it will be a case of balancing the trade-off between zooming in far enough to see the shot pellet stream clearly enough but which also narrows the field of view, versus a wider field of view to see both "clay break points" but which also means less magnification.  And the whole "is there enough light" and aperture and depth of focus gets involved in the tradeoff as well.

I think I finally understood your thoughts about not needing to start the camera exactly when I shoot.  Just start the camera sometime before shooting, and let it keep looping/recording the 11 seconds since it will always keep the latest 11 seconds.    I'll still have to stop the camera after the shot(s), but that should be doable.  This will make it much more feasible and won't mess up the pre-shot "mount the gun" routine.  The Chronos 11 second video time should be long enough for both shots.

If I can get it to work, it will be fun at the range because there are usually several guys around shooting.  Once the camera is set up for a specific shot, they can just come over and shoot at the same station and then watch their shot pellet paths on the Chronos.  Everyone will be very curious.  I think the "5-station" range will work best since it has several different throw points/angles that can be set up as pairs, and the shooting station doesn't have to move, so the Chronos doesn't have to move.  So I'd just get the Chronos aimed / focused for a specific pair and then practice that pair for awhile.  Trap shooting should also work well because the throw angles aren't very wide and I'm hoping the field of view can cover both extremes.

I've still got to figure out the specific lenses to try first, and your advice will help very much with this.

If you have any remaining patience with me, could you explain your reference to "increase the gain on the camera to make it brighter"?  I don't know what this means.

Thanks again
Jeff

[Photopage]

Hi Jeff,
Gain is the terminology Chronos cameras use to describe ISO changes.  ISO is a carry over from film photography days to describe the sensitivity of film and is still widely used in digital photography. 

The camera has a sensor with a native ISO of 500 and you can increase that sensitivity using the gain setting.  Increases in gain also increase the noise in the signal to noise ratio of the recording.  More noise makes the image look more grainy, less smooth and silky.  If you keep increasing gain the picture will eventually look like a snow storm.

In your case, where quality is secondary to the information, you can use quite a lot of gain to increase the sensitivity of the camera.  You want that when you're trying to get more depth of field (more focus) which is achieved by using a smaller aperture like f8 or f11.

The Chronos 2.1 is also available in a monochrome (Black and white) version which has a higher native ISO of 1000.  So if you don't ever need colour, that's another option. 

Sounds like you've worked out a few options that might work.

One thing to consider is how you're going to power the camera.  I use mine plugged into the AC all the time because the battery doesn't last very long. 

Cheers,
Col