The Great Kurath Re-Tubing

[the elephant]

Same. I don’t care for the round ones, but sometimes that is what fits. My big bugaboo is mixing randomly. We have a local guy who does that all the time. Ugh…

[the elephant]

I built and installed the new 2nd slide today. I also recut four of the tubes for the new 3rd slide circuit (two slides). I cut a tube that ended up not being any good on one end. (Four inches were ovalized so that no inner tubing could be inserted at all, even to lap.) I decided to shorten what I had designed by 20 mm and then regretted this decision. Today I found a length of acceptable tubing (with the same problem, but it was only two inches at one end, and it was much less badly out of round) and spent about an hour fitting an inner slide tube to it. After all that work it ended up being a very nice tube; I am happy with it.

I took the valve section outside and torched off six braces and all the tubing of the three slides and cleaned up everything nicely so that I could put all that old tubing away and could start fitting the crooks and knuckles to the new tubes.

I also took care of a "thorn in my side". I have one Yamaha sousaphone brace on this tuba. I used three of them on the Holton 345, and I dislike taking lots of tools with me in the gig bag. These braces use a Philips head screw. I found some nice 3/32" hex head cap bolts that can use the same tool as the King braces. The post is a bit larger, so I could tap the new threads without any weak or hacked-up threads. Perfect fit. Today I gave the same treatment to the Yamaha brace on this tuba, so now only one tool is needed to take the horn apart.

Here are some pics. I need to go eat supper and shoot up my insulin right now. I'll annotate the pics later this evening.

Here is the Yamaha brace. It is sort of weak and not very attractive, but it is hidden on this tuba, so who cares? It is more than strong enough for my application. But that JIS screw has to go…


I'm tap, tap, tapping…


Much better! And one less tool to have to pack in the gig bag! Also, the quality of Yamaha's screws has always been pretty suspect. And being JIS a regular Phillips driver can strip it out if you're not careful. This cap-head bolt from McMaster-Carr is made of an alloy that is far stronger than it will ever need to be… and I got a small bag of them because it was only 3¢ per bolt more than the crappy ones.


Yep, all this mess has to come off.


All this, too…


… and these braces… and here you see the round Kurath versus the diamond King brace flanges. Firstly, the posts on the Kurath braces suck. They are thin and very soft. All of them are somewhat bent. Secondly, I don't care for round brace feet when they can be avoided. In this case, they will be replaced using the thicker King feet and rod stock.


Okay, so the fitting of the two incompatible tube sets went much faster and easier than it did for the 1st slide, so obviously, I learned something last week. Also, there is no pin brace to hold the outer tubes in alignment. This makes things much easier and faster. (It is not needed as this slide is so small. It almost looks like a euphonium slide to me.








Here is the final, FINAL set of tubes for the 3rd circuit, which will be constructed tomorrow. I lengthened four tubes in my design, so I had to do a bunch of work with the dang jeweler's saw again. Luckily, I have great blades right now, so each cut took much less time than they did last time I did a bunch of tube cutting. (I *really* need to spend time truing up the blade of my mini miter saw.)


Here you can see how many tubes are in the 3rd slide circuit. I made the top slide outer leg long enough to not need a spacer inside the long outer tube.

[the elephant]

Ginger is back. Sorry for my crappy video skills, but I am learning. Your patience is appreciated.

Two points:

1. The slide moves *very* freely. I was afraid it would be too loose, so I used my guppy lube on it. Of course, that stuff is like glue in this cool weather, so it looks like the slide is stiff. I assure you that it is not.

2. The loud *ting* when I removed it normally implies that a slide is out of alignment. Again, it is not. I was pulling on the slide at a sharp angle so I could brace my hand on the 1st slide. Pulling this slide one-handed with this glue-like grease on it was awkward, and it came out pulled to one side and it tinged. Trust me: if it was out of alignment enough to make that horrid sound when pulled properly I would have taken it down and realigned it. The slide is good, people.

[bloke]

I think I mentioned in passing that I addressed some of the same issues on Joe Skillen’s nearly identical instrument… Horrible/nutty OEM number one slide alignment, and the wrong length on another slide…perhaps fifth, as you discovered. I heard him in a recital on that instrument before I ever worked on it, and he sounded great… Really great.

I’m glad re-tubing your instruments makes you happy. Watching your cats makes me happy.

Cats are way more important than tubas.

[the elephant]

The third slide circuit is built and installed. I have much cleanup ahead of me, and one leftover brace that no longer fit once things were aligned nicely. (Meaning that the brace itself, while cute and having a great personality, was the source for all the wonky alignment — from the factory. Ugh…)

As things are right now, I can put the instrument back together and play my gig on Sunday and be mighty pleased. However, I probably will do a lot of fooling around with this tomorrow to clean up as much as I can and do some adjusting. (I made a rookie boo-boo that pissed me off enough to want to put a hammer through my window. [N.B. —> I didn't.] I need to look at the issue some to see what my options are beyond a lot of disassembly, cleanup, and reassembly. Everything fits nicely, so this would not be tragic. I just hate doing work twice. The issue at hand is whether my OCD can overcome my inherent laziness, and I am betting on the OCD winning this one. Perhaps I'll fix it after the weekend is over…)

[Tubajug]

Looking good!

[the elephant]

I will go back and correct my screw-up on Monday. Then I can clean up all my work properly and be at a stopping point for whenever I want to do the two 4th slides and the MTS. (Likely this will be pretty soon as my Christmas freelance work, save for tomorrow, is all 186 stuff, so I can tear this down pretty far at that point. The two 4th slides are rather intricately caged in with stock and removable braces all over the damned place and will take a lot of time, and I also have to rebuild them with the valves installed to the bugle to align all that crapola up to the bugle. So yeah… ugh…

I put it back together just now and did a quickie hand polish to the worked areas to ensure all flux is gone and the ugliest of the black is gone. (No need to go to a church and terrify the locals with my hellish-looking tuba, now. Or is there? Hmm…)


So far the improvements to pitch are pretty subtle but definitely real. I did not steer anything but made a video of the tuner needle while I played to see what was *really* happening. The 3rd valve overtone series is better in tune with itself; the flat pitch is now in tune, and the two that were weirdly sharp are now very close to being on the money.

The leaking was partially due to my work. The alignment of the lower 3rd was so far off as to be laughable when I bought this tuba. The yellow brass Herr Kurath used is *very* soft, so decades of wear to the inner slide legs with pressure hard on one side caused them to be rather loose when correctly aligned. And they leaked. And my thick grease apparently allowed air past because I rarely lubed this horn's slides. Also, I found one press-fit, solderless tube joint. (Surprise!)

The 2nd slide was also way out of alignment.

The 1st slide was *okay* but did not move very well. (This was probably due to that damnable, chunky 5th lever bracket that caused me so many headaches.)

The 5th slide was simply two inches too short to be of any use, whatsoever.

I *know* there are issues with the main slide and can't wait to see whether anything is affected (good or bad) when that is rebuilt. I don't think anything will change when the two 4th slides are replaced as they wer3 rebuilt by me years ago and are airtight and have good alignment, but it would look pretty weird to have six slides with nickel legs and two with brass, so they get pimped out, too.

I had to retain the ugly AF Kurath round-footed braces. The Kings I bought with hopes of using them in place of the ones that I installed years ago did not work out. In fact, I hate them.

I am going to source some brace sockets and buy the flanges from Voigt and make a whole mess of them set for my own use. I am sick of depending on others to do good work or to continue to make what I like. If I buy something from Home Depot for many years, one day I come in and they no longer sell it because not enough people bought it. This happens to me all the time, so Conn-Selmer's simplifying their parts catalog makes sense to me, but as per my life, they "simplified into nonexistence" about a dozen parts I used to order fairly regularly. In the future, I will order at least a dozen of everything from them.

Thanks, CS. Thanks a ton.

Here is the horn after as it looks for tomorrow's gig. I like it. I think I will love it when all this is done. Making the valves removable was a great idea and worth every bit of work and cost. I am loving this about my Holton, too. I wish I could do this to my 186, but the Germans like to solder things directly to each other without a brace between them, and the valve section has about ten such contact points, so to stuff braces into that would require serious alteration to their design, and that ain't happenin'…

[bloke]

SUPER-excellent work...

sidebar: aesthetics
To me (and we all individually like what we like, obviously), round flanges say "EUROPE" and diamond (or even truncated/oval, as that are NOT round - such as Reynolds/Olds) say "AMERICAN".

I view an instrument's appearance "saying" either one being OK.

I like the way those round braces look on that instrument.

With all that nickel-brass on that instrument, no one's going to know it's a Willson, and some people are going to mistake it for BMB.

bloke "just kidding, with the last eyebrow-raiser, above"

[the elephant]

Action shot. The horn plays quite well, and I like the nickel silver a lot. This week I will try to wrap up this project. The second shot shows my beloved "1st batch" blokepiece. It is not for sale and never will be.

[No, the bone player was not on the floor taking pics of me. I made a video of one of the tunes with my iPhone to listen to my intonation when I got home. I grabbed a couple of screenshots from that before I deleted the video.]

[bloke]

(You’re) lookin’good, Wade.

[the elephant]

Today I measured and cut the three tubes for the large side of the main slide.

I screwed up when I measured this tube set on the Kurath back about five years ago. It turns out that the inner slide leg was very slightly rounded inwards, and I did not use my deburring tools before measuring, so it was off by a full millimeter. (That is a mile when trying to fit tubes together for smooth operation that are also airtight. A half-millimeter gap all the way around a tube this size is HUGE.

Anyway, Eva accidentally saved me.

I had ordered a pair of tubes before I had realized my mistake. (Yes, I am *that* stupid.) We shall call them 87 and 88 for this story. After I received tubes 87 and 88 I figured out that they were a good bit smaller than what is currently on the horn. I emailed back and forth with Eva and she told me that there was one larger tube (that we shall call tube 89) that they could custom draw for me. One issue, though: they still had the dies, but no one had drawn tube 89 in years as it had been dropped from production permanently.

Since I was ordering it by itself it was very possible that it would not fit well with the tube 88 I had here at the shop. Because of several technical reasons they would need to draw 88 and 89 together. They apparently did not have any of the 88 tube in stock; the 87/88 pair I purchased was drawn in this manner. They would not spend the money to draw a tube this large unless it was for a customer. I did not want to buy another expensive tube that I would never need, so I demurred.

Eva's suggestion was to use some similarly-sized tubes that they happened to have in stock. These were thicker and are currently used frequently, so finding a well-matched pair would be very easy. She could guarantee the fit of these tubes. I'll call them 689 and 690.

So I ordered four smaller tubes, a #89 (with my fingers crossed) and a 689/690 pair. I am not sure why I dropped the coin needed for the 689/690 pair, because I did not intend to use them and nickel silver tubing is spendy AF. I guess I was worried about ending up stuck with no alternatives and replacement tubes being a month away. These large tubes are rather short, at 250 mm (about 10"), so a measuring mistake could stop the project cold for some time.

And today I took the MTS large leg apart and sure enough, the 87/88 pair was too small, the 89 was too loose on 88 to step up to them, so I turned to the 689/690 pair. They were too large, but the internal bore was only larger by .25 mm, which is like nothing to the sound wave, but quite a bit when getting mismatched tubes to mate up in a usable way.

The dogleg is larger than the slide crook end, which is a problem. but the inner leg mates up with both well enough to use. However, the outer leg (690) is about .66 mm larger than the crook and less than .5 mm larger than the dogleg end. My flute headjoint expander tool that I use for this purpose is not large enough to even contact this jumbo tubing, and my smallest muffler expander is too large by like 7 mm. Redneck DIY auto mechanic that I am, I located a pair of sockets that I could use to expand the end of the crook and dogleg on the Kurath to mate up well (or well enough) with the larger Miraphone tubing.

This took me all afternoon to figure out and then fix. D'OH!

Anyway, once I got the two ends of the tuba to mate up well with the outer slide tube I then measured the old parts, did the math to convert the four parts of the Kurath to the three parts I will be using, PLUS 22 mm of length added so that my MTS is pulled out where I want it when I am in tune 90% of the time (rather than the 2" it must be pulled currently) I then hand cut the inner tube from the 689 and the outer tube and ferrule from the 690.

I have to work on the fit of the crook to the ferrule as there is still a big gap on the outside. (The inside fits very nicely.) The gap between the dogleg and the outer tube is not that bad, so I am done with it.

Tomorrow I will install all this. Then I can take down the small side between the crook and the 5th rotary valve and do the wame work. Because the small side is removable, I want to do this one side at a time to prevent the alignment from wandering out on me. Note that the small side is also four parts rather than the normal three. Again, I suspect he wanted the two sides to match, visually, so he coerced the extra ferrule on where it was not needed and likely did not fit without some lathe work. Whatever. I am going to accomplish what he did, but it will be simpler and stronger, using fewer parts.

Keep in mind that, while the two inner legs (old and new) look very different in size, the NS one is thicker. Internally they are very close. Same for the two outer tubes. The old one is as thick as the new one, but it fits over an inner tube with a smaller OD. In any meaningful way, the bore is unchanged, despite the differences in the thicknesses of the two tube pairs.


Here is the gap I need to work on tomorrow. This is the large end of the MTS crook and the new ferrule. These are huge, as the bore here is over 24 mm! Also, it looks strange with no MTS brace. I intend to re-use the original one.


Here is the new tube set friction-fit to the horn. This will work nicely internally, but it looks odd to me, externally. However, once it is all fitted together better, soldered in place, and buffed up it ought to be very nice.


Here is the small side of the MTS at the 5th valve. This ferrule is 100% not needed, and it makes that leg unnecessarily complicated. Oh, well. It will be in a junk box soon enough.

[the elephant]

So tomorrow I will take down the small MTS side and make sure there is nothing weird hidden inside it with that extra part. Once that is investigated I can measure and cut my three tubes for the small side and then assemble my slide. Then the two outer legs can be soldered to the tuba and the brace added.

Should be fun.

Thanks for reading.

Goodnight.

[the elephant]

OMG WHAT A MESS THIS THING IS!!!

The MTS crook starts out at 18 mm like valves 1, 2, and 3, BUT SMALLER THAN THE 19 mm 4th AND THE 20 mm 5th!

W

T

F

?

Obviously I’m a bit vexed about this, and I have some torturous dent ball work ahead of me to open that crook up to match not only the new slide leg, but everything between it and the 3rd valve.

Can I pick a freaking winner or what?

“Film at eleven,” as the talking heads like to say…

[the elephant]

Well, I'm done for today, so I guess that makes it "11:00", so here's the "film"…

The crook was filled with unpleasant surprises. This is why I put off this slide for so long; I could tell by looking at it that something was screwy. Now I think I know what that was. I have suspected this to be a prototype example, or a production horn that he experimented on before making permanent alterations to the model, (Remember he dissolved his import deal with the Michigan Boys over alterations to the design. Maybe this horn was his testbed; once he had it where he was happy he sold it. Perhaps, perhaps…

My guess: This horn used to have a 19 mm rotary valve and he bodged in a 20 mm one without changing out the MTS crook. For whatever reason, he *did* flare the end of the short tube between 4th and 5th. And he *did* swap the small side tubing pair. But the small end of the crook was installed to a heavily stepped ferrule that moved down from the 20 mm tube's OD to the crook's OD. The crook is paper-thin and the slide tube is thick, so the ferrule allows the bore to step down 2+ mm and the OD to step down 2.5 mm, which is pretty ridiculous!

I (ab)used my flute headjoint expander on the crook end until the new ferrule fit well enough. But the crook continued to shrink until the waterkey hole! The damned thing dropped down to SEVENTEEN MILLIMETERS!

WTF?

So I expanded the end as deeply as the curvature would allow, then I started driving the correctly-sized ball through the crook to make sure there was nothing downstream of the small end's bore size that was any smaller. This took some rather aggressive "shaking" work.

I dropped the correct "bore ball" and four 19.5 mm balls down the large end, then added two large driver balls with a lot of weight to them. I then shook and shook and shook until the driver ball finally hammered its way through the small end. I repeated that about five times, to allow me to lightly tap on areas of the crook exterior beneath where the "bore ball" was sticking.

This crook is quite thin, and I think it was annealed and then never really worked enough to harden it back up. It is *very* soft. This means the shaking method wreaked havoc on the poor thing's shape, leaving terrible ridges and bulges all over. So I spend a good hour with a dent hammer fixing all that as best I could. I was unable to get some of the damage, though.

Once the bore was opened up to match the valve that precedes it in the taper, and I then did all the micro dent work to make the crook look nicer, the whole thing only looks mildly comical now. Before, it looks absolutely strange with that chokepoint in it.

Now, he may have been onto some acoustical secret to fix intonation on his tuba. Benade says that the wave sees a tight bend in the tubing as an enlargement of the bore at that point. The wave does not travel with a flat front, but bumps along the tube touching at nodes/antinodes, and at a tight bend it "sees" the cross-section at that bend as a large ellipse or a big increase in bore. So, giving the man credit for being very smart, perhaps this tightly bent "corner" of the MTS crook choked down ON PURPOSE. (Of course, the other "corner" did not receive this treatment. So there is that… I still suspect that he switched to a larger rotary valve after the tuba had been built. Again, being lacquered was *very* rare for this model of tuba, nearly all having been silver plated. I think this was in raw brass so he could more easily tinker with it. The lacquer that *was* on the thing was terribly flaked and worn off, so it looks like a rattle can job, again, probably done by Herr Kurath at his shop once this horn was finished and he needed to sell it off.

It is funny what tearing down a horn will tell you about it.

I spent an hour tapping, burnishing, and then lightly scratching up the surface to better see all the ridges raised by the shaking method I employed. Once it was reasonable looking I assembled and aligned the inner tubes, ferrules, and crook into a slightly better-proportioned slide.


Once I was happy with everything I buffed the very rough nickel silver outer tubes and ferrules and cleaned up the crook and the joints. I added the brace back, too. It came out looking rather nice, too. The time-consuming dent work paid off. I did not nail that part, but it was well done enough for my personal tuba.


Rear…


Front… I still have to solder the water key and nipple back on.


It is leaning over just a tad, and the small side is still on the tuba, so the slide is actually mounted on the large side but just hanging out in space in front of the small side so I could see what it was going to look like. And I think it will look pretty good. I just hope all this taper rehabilitation does not F up my tuba. Unlike most of my work, I cannot put this back if I dislike the results.

[the elephant]

Great attention to detail!

I also hope you didn’t F your F. I suspect you didn’t and it will be even better after this rework.

[the elephant]

Heh, heh. We shall see…

[the elephant]

Today spiraled out of control very quickly. I determined after an hour or two of practice that I did NOT want to do my two-day gig tomorrow on this tuba. My folder has 24 full orchestra pieces in it, and all but one are suitable for this big boy F tuba…

… except for the overture, which is squarely in the CC tuba lit. It stays buried on loud, low B naturals and As and Gs, and then it hangs on C in the staff forever and a day. On this horn that C is sharp. I can play it dead on using 13, but this is a lot of stuff that is just technical enough that I would want to lazily use open, but the notes are long enough to perceive as being sharp, and I hate lipping stuff. The low B is the one note in the low range that I cannot play in tune without a LOT of lipping. A and G below that are not a problem, but the number of fast ones I have to bang through will end up causing me pain in my hand. (I suspect Presbyterians secretly love low B natural. I have to play hundreds of the things every time I play at this one church.)

So this is a 186 gig.

Now I do not have to have this tuba ready until Wednesday when I have a short rehearsal with the choir of the downtown Episcopal cathedral for my three Christmas Eve masses. That gives me tomorrow evening, Sunday until about 3:00, and then all of Monday and Tuesday, so plenty of time!

So all those niggling things that I was thinking of fixing during this round of work got started today, and at one point I had part of the bugle disassembled, all of the 5th valve section was off and torn down, and a lot of alignment stuff was fooled around with to see if I could improve this horn.

Today I added one of those Edwards twist-barrel braces to the MTS to stabilize its position on the horn. I learned a lot with this tuba, so the work I did to the Holton was informed by all that work and my follow-up experience playing and servicing this tuba. And now this horn is benefitting from the experience I got from the Holton. This tuba had a very minor issue with the two MTS outer tubes not aligning perfectly after the horn had been apart. I used a thinner/weaker brace rod on this than I did with the Holton, and some of them were pretty long. I cannot change that now, but I think I figured out where the horn shifted or bent a tiny bit and decided that nothing had to be changed, but that a brace that physically joins these two outer tubes would be a nice thing to have.

So that got done first. As per the other seven braces that hold this horn together, the bugle gets the short, threaded part and the valves get the long rod part of the brace.



I completely rebuilt the 5th valve slide loop and set it up so that the rotor is canted to one side about seven or eight degrees. This shifted the whole slide assembly over to make the rear piston caps centered within the "window" of the slide so that they can be easily accessed if work needs to be done. Then I rotated the slide assembly back to its original "flat" orientation on the back of the horn. (Rotating the valve caused the slide to kick out and it would have hit me in the belly, so that had to be adjusted, too.) I also replaced the long side of the 5th loop and moved the brace. The brace was installed in the wrong place when I rebuilt the 5th slide, so it was blocking the 4th piston cap. Also, as designed, the 5th slide had two same-length outer tubes and the distance to the lower crook was filled up with a brass inner slide tube and a brass ferrule. These were not fit together very well and they were never aligned correctly. It did not really matter, but it bugged me all the time, staring at that crooked length of tubing. Today I replaced all that with a full-length nickel silver tube and a brass internal spacer, as with the other valves. Now it matches more, and alignment was much easier to get right.





Then I assembled the MTS and the 5th section to one another to make it easier to line all this up with the slides for the first three valves. (All this stuff is sandwiched between the two 4th slides, which are not lined up well AT ALL, so lining up two large subassemblies is easier for me. I can see all the nickel silver tubes on the front of the horn with all these new nickel silver tubes on the back. Even with that help, it is still hard to see how things are fitting with those two wonky 4th slides in the picture. I guess I won't be really sure things are right until I get the 4th slides sorted.



Once everything was assembled I could then check to see how much the span of the MTS crook changed after all that heavy work I did to it. I was hoping it was still good, but nope. It closed up about 3 mm. To keep everything else on the horn lined up as is, and make this fit I decided to rotate the dogleg a little bit. I had to remove it (and three braces) to make sure that it was fully sealed up once it was turned. I got it off and cleaned up and promptly forgot to take a pic of it. I did get a shot of the horn where I annotated what I did. (And it's some real genius-level stuff, too. Let me tell you.)

Here are some shots that show how stuff shifted over a bit after I slapped the MTS crook around for an hour yesterday…

The shift…


It matches with the brace, thankfully, so this will be easy to fix if a little time-consuming…


The solution…


I quit for the day at the point of having all that installed. I did zero clean-up work. I think I even forgot to neutralize the flux. (Whoops. There will be green crap for me to clean off tomorrow afternoon. Dang it!) Tomorrow I will clean up everything and then make sure the MTS/5th are where I want them to live for the next 50 years. I think I may need to heat and shift everything just a bit, but the stupid 4th slides make it difficult to really see what is going on.

Just a fat boy with his tuba.


I took all these to look more carefully at how stuff lined up. Overall this is really good, but in some, it looks crooked, which I can only attribute to one of the 4th slides being front and center to screw up sightlines and such. I need to look at this horn several times again before buttoning it up for the Christmas Eve rehearsal and gigs.














What does an elephant eat for lunch? A turkey-bacon-Ranch po-boy with three kinds of cheese, some Fritos "flavor twists" and a diet DP. Mmmmmmm… Thanks, Mrs. E!


EDIT: I went back to stare at some stuff so I could sleep-think on it. (I do this a lot. I study some problem right before I turn in, and in the morning I wake up and the solution pops into my head immediately.) I over-rotated the 5th valve, so now the pistons appear in the 5th slide "window" a little to the other side.

RATS!

I need to tell myself that how it is right now is just fine.

But I think I will be doing that again before long.

At least I solved the partially-obstructed access to the pistons.

[Three Valves]

^^^

Turkey bacon ranch… I didn’t see the bacon. Did the cat snatch it??

[the elephant]

It was in there, four slices of it, under the bird meat.

[bloke]

You may (??) remember me griping about my pictures of the goofy little Holton appearing to make things seem to be "off" when things were not "off"...

I believe that stuff has to do (mostly) with what 2D-and-curved camera lenses do to 3D objects.

You take pictures better than do I (and [1] I'm not seeing anything that doesn't look right in your pictures, as well as [2] I'm too lazy to fire up my "hot-shot" 6/4 B.A.C. [camera] that Mrs. bloke gave me, and only use my phone), but I believe that I've observed that - when I back up, and zoom in - stuff (bow/slide-alignment) doesn't falsely appear to look as screwy as it does when my (crappy camera phone) is located close to a tuba.

I can't remember what Dennis Bamber's second-try website was called (after wwbw went bankrupt), but I remember that some of the pictures of some of the tubas appeared to be quite "warped", and I attributed that to the camera being too close.

Camera lenses have their limits, and we all know what happens when pictures of very wide groups of people are taken with analog/film cameras (whereas computer programs - today - can shrink outlying people's heads back down to the correct widths).