3 different slope rangefinders, 3 very different readings! WTH?

I just bought a Nikon Monarch 7i VR. In comparing to the 2 other slope rangefinders we have (Callaway 300 Pro, Suaoki slope), I get 3 very different readings! Here are my backyard shooting results:

Incline of 19 degrees:

Nikon - 24 yards straight distance, 25 yards slope distance

Callaway - 23 yards straight distance, 29 yards slope distance

Suaoki - 24 yards straight distance, 35 yards slope distance

Incline of 6 degrees:

Nikon - 79 yards straight distance, 80 yards slope distance

Callaway - 78 yards straight distance, 85 yards slope distance

Suaoki - 79 yards straight distance, 88 yards slope distance

WTH! These are big differences between yardages, almost a full club difference!

So for those math geniuses, which rangefinder likely has the more accurate slope reading?

Impossible to say. It will depend on your particular trajectory choices and tendencies.

I don't want to sound insulting, but you might want to double check that you actually had the slope functionality turned on for the Nikon. That was really the more surprising result. I can see a 1 yard difference for a flop shot, but not any other type of shot.

Yes, slope functionality was definitely turned off and on for Nikon to get the readings. Went outside and tested it again.

Wondering if Nikon is showing those readings because it's marketed as a "hunting" rangefinder, and not a golf rangefinder....ballistic speed is obviously different between a bullet and a golf ball...just thinking out loud...

> @melcoeb said:

> Yes, slope functionality was definitely turned off and on for Nikon to get the readings. Went outside and tested it again.

> Wondering if Nikon is showing those readings because it's marketed as a "hunting" rangefinder, and not a golf rangefinder....ballistic speed is obviously different between a bullet and a golf ball...just thinking out loud...

>

Yes, that would definitely explain the Nikon readings and make it useless for golf.

Usually the slope calcs assume 45° descent angle I think which would imply the Nikon is way off whereas the other two are reasonably accurate. A more advanced algorithm might assume steeper descent angles for shorter shots and shallower for longer shots, but those angles vary by golfer. Not sure any manufacturer has gone that route.

I'm leaning towards the Nikon being a defective unit...or maybe just suited for hunting and NOT golf...

> @melcoeb said:

> **just suited for hunting and NOT golf**...

At least with respect to the slope being turned on.

So I emailed Nikon asking if the 7i VR can be used for golf. Their response:

"Thank you for contacting Nikon. The software for the Monarch 7i rangefinder was designed for picking up the speed of a bullet not for a golfball or arrow. Using this for any other purpose may affect your accuracy. For further questions or concerns, feel free to call us in at 1-800-NIKON-US."

That answers my question. Nikon is going back. Thanks for the responses.

Excluding your Nikon hunting scope, you've single handedly demonstrated the problem with the slope calculation: It's an estimate.

It's an estimate because it all depends on what your landing angle is when the ball lands. The more vertical the landing angle, the less the slope will affect the distance and the less roll out you will have. Come in at a more shallow angle, the carry distance is different, but the rollout distance is increased.

It's impossible for the logic of the laser to know the landing angle, because it doesn't know what club you're hitting, and it doesn't know your specific trajectory. If you're 150 yards away and you're hitting a 9 iron, or if you're hitting a 6 iron, the amount of elevation will have a different effect on each.

I think it would be better if instead of giving some estimated effective distance, that it just gives you the number of yards uphill or downhill for a given shot and let the player decide what to do with that info. In addition, I've played with guys where they tell me something is uphill or downhill, and there's no way it's right. For example, standing on the tee box of a par 3, and they tell me it's downhill, but you can't see the surface of the green (of a relatively flat green, too). Sorry guys, but the surface is higher than eye level, your scope sucks.

Perhaps that is why Leupold has their software program where you input data, then upload to the unit. This would make those measurements much more accurate.

Tell me more about the what you're inputting into their software?

I do not have it, it was a part of the research prior to me buying the Bushnell Pro XE. Leupold allows you to input info such as elevation, clubs, etc and then when you play it recommends the club after calculating slope, elevation, club ranges, etc

> @larrybud said:

> Excluding your Nikon hunting scope, you've single handedly demonstrated the problem with the slope calculation: It's an estimate.

>

> It's an estimate because it all depends on what your landing angle is when the ball lands. The more vertical the landing angle, the less the slope will affect the distance and the less roll out you will have. Come in at a more shallow angle, the carry distance is different, but the rollout distance is increased.

>

> It's impossible for the logic of the laser to know the landing angle, because it doesn't know what club you're hitting, and it doesn't know your specific trajectory. If you're 150 yards away and you're hitting a 9 iron, or if you're hitting a 6 iron, the amount of elevation will have a different effect on each.

>

> I think it would be better if instead of giving some estimated effective distance, that it just gives you the number of yards uphill or downhill for a given shot and let the player decide what to do with that info. In addition, I've played with guys where they tell me something is uphill or downhill, and there's no way it's right. For example, standing on the tee box of a par 3, and they tell me it's downhill, but you can't see the surface of the green (of a relatively flat green, too). Sorry guys, but the surface is higher than eye level, your scope sucks.

I don't think it could possibly know actual yards up or down though. All it can accurately measure is distance from the user to the target, on one plane at a time. Beyond that I'm guessing it uses accelerometers to estimate the angle the unit is aimed up or down, and then estimate elevation change based on that.

> @larrybud said:

> Tell me more about the what you're inputting into their software?

>

> @Stetson said:

> I do not have it, it was a part of the research prior to me buying the Bushnell Pro XE. Leupold allows you to input info such as elevation, clubs, etc and then when you play it recommends the club after calculating slope, elevation, club ranges, etc

Yeah, on the 5i3 anyway you can input your elevation, temperature, and average distance for certain clubs as a baseline. Then if you turn on the functions it'll calculate the adjusted distance with slope and recommend a club. So in practice here's how I find it works...it'll tell you you're 160 linear, which is 171 with slope, but recommend a 5i instead of your usual 6 because it knows it's a stone cold out. So you pull 5 and take a confident rip knowing math is on your side...Then you dead top it l, and your friends all laugh at you for having spent $600 on a laser when you can't hit any club the same distance twice anyway. ?

> @kwelifan said:

> Yeah, on the 5i3 anyway you can input your elevation, temperature, and average distance for certain clubs as a baseline. Then if you turn on the functions it'll calculate the adjusted distance with slope and recommend a club. So in practice here's how I find it works...it'll tell you you're 160 linear, which is 171 with slope, but recommend a 5i instead of your usual 6 because it knows it's a stone cold out. So you pull 5 and take a confident rip knowing math is on your side...Then you dead top it l, and your friends all laugh at you for having spent $600 on a laser when you can't hit any club the same distance twice anyway. ?

lol

So it sounds like it's using some sort of average landing angle for a given distance since it knows what club your baseline is. Better, but it's still an estimate.

> @larrybud said:

> > @kwelifan said:

> > Yeah, on the 5i3 anyway you can input your elevation, temperature, and average distance for certain clubs as a baseline. Then if you turn on the functions it'll calculate the adjusted distance with slope and recommend a club. So in practice here's how I find it works...it'll tell you you're 160 linear, which is 171 with slope, but recommend a 5i instead of your usual 6 because it knows it's a stone cold out. So you pull 5 and take a confident rip knowing math is on your side...Then you dead top it l, and your friends all laugh at you for having spent $600 on a laser when you can't hit any club the same distance twice anyway. ?

>

> lol

>

> So it sounds like it's using some sort of average landing angle for a given distance since it knows what club your baseline is. Better, but it's still an estimate.

Actually I would prefer that the slope was provided directly. Easier to scale for different yardages and your club selection. That is too complicated for most people, however.

> @kwelifan said:

> I don't think it could possibly know actual yards up or down though. All it can accurately measure is distance from the user to the target, on one plane at a time. Beyond that I'm guessing it uses accelerometers to estimate the angle the unit is aimed up or down, and then estimate elevation change based on that.

You can definitely get the actual up/down yardage from the information that it knows (by the way accelerators measure acceleration, not angles).

1) it knows the slope in degrees

2) it knows the exact distance to the target

The exact distance is the hypotenuse of a triangle. The opposite side (the height) is the distance you want to know.

So let's say 150 yard shot to the target (measured by the range finder), down 4 degrees (measured by the range finder) =

sin(4) * 150=10.46 yards down hill.

e.g. (not to scale! lol)