Calling service line: Do we really mean that you see court between ball and line?

[BabblingPsychopath]

Another thread got me thinking about this.

If you are calling your service line, and a serve is hit right at you, how far "long" would the ball have to be before it was humanly possible to in fact see court between the ball and the line? I.e. you are really seeing court over the ball as it hits.

A little simple trigonometry shows that if you are average height, standing up straight, and AT the baseline, the "shadow" of the ball hides 8.17 inches of court (from it's midpoint).

So technically, are we calling serves that are long by 6 or 7 inches in? Or does our brain do a little calculation of "I know where the ball landed so it must in fact be long"?

[Jack the Hack]

Originally Posted by BabblingPsychopath

Another thread got me thinking about this.

If you are calling your service line, and a serve is hit right at you, how far "long" would the ball have to be before it was humanly possible to in fact see court between the ball and the line? I.e. you are really seeing court over the ball as it hits.

A little simple trigonometry shows that if you are average height, standing up straight, and AT the baseline, the "shadow" of the ball hides 8.17 inches of court (from it's midpoint).

So technically, are we calling serves that are long by 6 or 7 inches in? Or does our brain do a little calculation of "I know where the ball landed so it must in fact be long"?

I try not to call balls out unless I actually see them out. This is really tough on the serve, especially if the opponent is serving fast or with heavy spin near the line.

My wife has told me that I consistantly give away at least 6 points a match on second serves that I don't call out in the tournament matches she has watched. I've gotten similar input from people on my USTA League team. This makes me wonder if you are on to something here.

By the way, I also firmly believe that your mind does play "calculation tricks" on you that tell you where the ball landed... and many players do rely on this. To me, this is the "feel" that people describe in knowing whether a ball went in or out depending on how they hit it.

[drakulie]

Originally Posted by Jack the Hack

I consistantly give away at least 6 points a match on second serves that I don't call out

Same here. People I play against and spectators always say I'm extremely generous with line calls.

[grizzly4life]

yeah, i started a similar thread a few years ago, but alot of people didn't seem to clue in to what i meant.... you explained the physics better than me, i suppose.

but yes, to actually see the space between the ball and the line, you have to be really high... i do think that easily 95%+ of people, including me, do a little depth perception calculation (or whatever you want to call it... you can see beside the ball and infer, but you certainly can't see the space between ball and line).

i mostly get good line call comments from my opponents... although one guy got ****ed and said that the ball sometimes skids so what looks easily out by depth perception. thought it was an interesting point... BTW, i realize i'm not really doing the lines properly. i think a decent opponent should call their own serves out to a certain extent (NOT the close ones)

[WBF]

Yep.

I won't call unless I'm certain it was out, and it results in too many generous calls. Personally I don't mind, I've just tried to improve my game to the point where it doesn't matter whether I miss a few calls.

As for the previous post, on calling your own balls out, I agree as well. I won't stop a point, but if the opponent misses it, and I saw it clearly out, there is no way I'm taking a point I don't deserve. Personally I'd say it's *more* competitive than a player who takes points he doesn't deserve, but others don't see it that way.

[tbini87]

over 8 inches of the court being hidden by the ball seems like a lot, but i am not a physics guy. but i was thinking at least 4 or 5 inches, which leads to most people playing balls that are a little long on the serve. i don't always see the court between the line and the ball though, so i guess i just trust my instincs. i usually play balls that are close, because it keeps the match running more smoothly. if it is too close to call out then it was in.

[spot]

Here is the proportion as I have it. Say its a 6 foot tall guy is standing on the baseline to return serve. (say its right down the t- he is looking dead on to the center line to make it easier. The player's eyes would be at 5'6". (66 inches). Say the ball is 2.4 inches tall when it hits the ground. (regulation balls are betweeen 2.575 inches and 2.7 inches, forward deformation is around .2 so 2.4 is my best guess. There are 18 feet between the service line and the baseline. (216 inches) After that its a simple proportion because you are looking for the distance between the ball and the service line when you can just see the back of the service line over the ball. A diagram would make it more obvious. But at this point its a simple proportion. (2.4/x)=(66/216) You solve for X and you find out that the ball would have to be 7.8 inches away from the line in order to see over it.

Of course this is why its preferable for the net player to call the service line in doubles.

[WBF]

This is why when I play on grass or hard courts, I double fault far more often than clay courts. I love the mark. But hate the surface. Sigh.

If only grass courts had marks, and it never rained.

[callitout]

This seems like an especially difficult version of the ball which the pros inaccurately challenge most often--the ball hit on the baseline which they think is out.
I've actually changed my own practice and started calling more of those in--basically being even more careful on the deep baseline ball not to be inaccurately calling one's opponents best deep shots out...but clearly its very hard to see from right on top of it.
As to the serve I basically dont worry about it and assume that I will be playing some deep serves, because it is so difficult to call.

[tbini87]

Originally Posted by callitout

This seems like an especially difficult version of the ball which the pros inaccurately challenge most often--the ball hit on the baseline which they think is out.
I've actually changed my own practice and started calling more of those in--basically being even more careful on the deep baseline ball not to be inaccurately calling one's opponents best deep shots out...but clearly its very hard to see from right on top of it.
As to the serve I basically dont worry about it and assume that I will be playing some deep serves, because it is so difficult to call.

i thought you would just "call it out"... your name is very misleading.

[BabblingPsychopath]

Originally Posted by grizzly4life

... i think a decent opponent should call their own serves out to a certain extent (NOT the close ones)

But technically they aren't allowed to (at least on first serves).

[Supernatural_Serve]

The test isn't seeing court between the line and the ball. The test is "any part of the ball touching the line"

They aren't the same thing.

Its simple. If you have doubt, even a moment's hesitation to consider it, then you have to give the opponent the benefit of the doubt.

This isn't a trig problem.

Its a best effort objective judgment call devoid of bias problem.

[chlsmo]

Originally Posted by Supernatural_Serve

The test isn't seeing court between the line and the ball. The test is "any part of the ball touching the line"

They aren't the same thing.

Its simple. If you have doubt, even a moment's hesitation to consider it, then you have to give the opponent the benefit of the doubt.

This isn't a trig problem.

Its a best effort objective judgment call devoid of bias problem.

I think this is the problem. I mean the OP says the ball has to be over 8 inches out before it is obvious that it is out, Example; You can see court between the ball and the service line. So this implies that the ball can be 6 inches or so out and still look like it caught the line. So in my mind balls that are 3-7 inches out are almost always going to have grounds for doubt thereby requiring them to be played, if you go by the "If there is any doubt its out, it must be in" mentality.

I played a tournament yesterday where I must have played a more than a few of these on my opponent's serve, because he did not even react to my returns thinking the ball was obviously out. I was mildly irritated, but I said nothing.

What is the math for whether the server can see his own ball out vs. the returner?

[Loco4Tennis]

i agree in the ruling of calling balls in/out, if there is a slight dought in my mind that it could have been out, then there is a small portion of me that thinks it was in as well,
99% out and 1% in is still 100% in!!
i do see your point on how hard it is to see the ball sometimes and your provably right on this thaery of yours, but i am going to play and act like i want the other person to play and act with me, if i hit a ball and he is not sure if it was in or out, then i want him to make the same call i would make, and that is to call a ball out only when he is 100% sure it was out

[Loco4Tennis]

Originally Posted by Supernatural_Serve

The test isn't seeing court between the line and the ball. The test is "any part of the ball touching the line"

They aren't the same thing.

Its simple. If you have doubt, even a moment's hesitation to consider it, then you have to give the opponent the benefit of the doubt.

This isn't a trig problem.

Its a best effort objective judgment call devoid of bias problem.

i agree with what your saying here, not 99% but 100%
just give the point and keep-on-playing,
you wont stress over it and you'll provably play much better than if you dwell over the points you thought you should have called out,
not being 100% correct all the time is part of the game, its the human factor which also what makes this sport fun

[michael_1265]

Originally Posted by BabblingPsychopath

Another thread got me thinking about this.

If you are calling your service line, and a serve is hit right at you, how far "long" would the ball have to be before it was humanly possible to in fact see court between the ball and the line? I.e. you are really seeing court over the ball as it hits.

A little simple trigonometry shows that if you are average height, standing up straight, and AT the baseline, the "shadow" of the ball hides 8.17 inches of court (from it's midpoint).

So technically, are we calling serves that are long by 6 or 7 inches in? Or does our brain do a little calculation of "I know where the ball landed so it must in fact be long"?

There is one additional factor which might affect the perception of "in" or "out". I think that you are making the assumption that the line between the head of the receiver, the ball, and the server is exactly straight. In reality, as soon as we sense the direction of the serve, we move into a position from which we can hit a backhand or a forehand. This results in a slight offset, allowing us to view the ball from a better angle, and reducing the "blind spot" that you have described.

That being said, if somone hits a flat, hard serve directly at you, the blind spot definitely come into play.

Mike

[callitout]

Originally Posted by tbini87

i thought you would just "call it out"... your name is very misleading.

yeah, I always thought it was amusing when I heard college players say, "when in doubt call it out"...but in reality that's not a great way to play.

[BabblingPsychopath]

As the OP, I thought I would clarify my point/question.

We all know that we are to give the benefit of the doubt to the opponent. But you hear this described with some slightly different phrases. This thread was prompted by another thread, which contained the question "did you see court between ball and line?" Do we consider this the necessary criteria? I would have to say no.

We hear "if you don't see it out, it is in." But what would it mean to see it out other than in seeing court between ball and line?

So, can you know it is out without seeing it out? I would say you can. If I see a serve land 7 inches past the service line I can know it is out without actually observing the separation. But, is this sufficient grounds for an out call?

[Nellie]

I do not understand the issue. If you see that ball lands well behind a line, of course you can call it out, even if you do not see a space between the ball and line. I can generally tell from the front, visible portion of the ball where a serve is landing in relation to the service line. I think that the expression that a part of the court was seen between the line and ball is meant to emphasize of the supposed truth of a call.

Also, according to you math, it would be no different whether you are calling a ball at the baseline versus a serve at the service line, except the distance you are typically standing behind the service line is farther and the service is typically faster.

Per previous poster's comments, it would seem to make a big difference where you’re positioned relative to the ball. I think that it why it is generally much more difficult to call serves hit at you than balls hit in the corners, where you can see the ball path at an angle. I guess that is why I am much more generous when calling serves hit to my body.

On a similar note, I get annoyed in doubles when the non-receiving partner makes a call that a serve near the side/center line is wide. From that angle, the receiver has a much better angle to judge the location of the serve.