Rangefinder binos

Formidilosus

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I used my ZEISS RFs on an antelope hunt, temps in the 90s with no issues, might be worth putting them in the fridge to cool them, range something and then hit them with a warm hair dryer to see if there’s a ballistics change. You threw out quite a generalization. Are you talking about any rf (range finder), the ZEISS model specifically, rf binoculars vs regular range finders? Does dropping them change the ballistics?

That’s not a generalization. How do you think they are gathering the environmental data to give to you?
 

Ucsdryder

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That’s not a generalization. How do you think they are gathering the environmental data to give to you?

I didn’t realize you were talking about the “smart” rangefinders, but that leads to another question. So why would they be “wildly off”. I understand that the “smart” rangefinders and RG binoculars pull barometrics, temps, elevation etc but that should make them more accurate, not less. That’s like saying, if you change the elevation the rf will be wildly off.
 

JakeSCH

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I didn’t realize you were talking about the “smart” rangefinders, but that leads to another question. So why would they be “wildly off”. I understand that the “smart” rangefinders and RG binoculars pull barometrics, temps, elevation etc but that should make them more accurate, not less. That’s like saying, if you change the elevation the rf will be wildly off.

It takes time for sensors to come to a "steady" state. If there are rapid changes in the environment it takes time for the sensors to catch up.

We see this on aircraft often, sometimes requiring to fly them for 30 minutes before some sensors represent "ambient". But that is a more drastic change that we would ever see.
 

Ucsdryder

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It takes time for sensors to come to a "steady" state. If there are rapid changes in the environment it takes time for the sensors to catch up.

We see this on aircraft often, sometimes requiring to fly them for 30 minutes before some sensors represent "ambient". But that is a more drastic change that we would ever see.
I’ve heard the same which is why I always make sure I get my binoculars acclimated, which is usually an issue when hunting in cold temps, coming out of a heated truck.
 

Formidilosus

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I didn’t realize you were talking about the “smart” rangefinders, but that leads to another question. So why would they be “wildly off”. I understand that the “smart” rangefinders and RG binoculars pull barometrics, temps, elevation etc but that should make them more accurate, not less. That’s like saying, if you change the elevation the rf will be wildly off.

This and-

I’ve heard the same which is why I always make sure I get my binoculars acclimated, which is usually an issue when hunting in cold temps, coming out of a heated truck.

This one are contradictory.

That’s what I addressed- if you have a RF and are using ballistics that it gives, and you put it inside your jacket to keep warm so that it actually ranges, the temperature will be incorrect for the air that the bullet is going to fly through.


In other words keeping a ballistic RF warm so that it will function produces errors.
 

BjornF16

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But how much does temperature really affect ballistics?

If the ranging device pulls atmospheric pressure (air density) as well as temperature, isn’t the temperature relatively insignificant?
 

JakeSCH

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But how much does temperature really affect ballistics?

If the ranging device pulls atmospheric pressure (air density) as well as temperature, isn’t the temperature relatively insignificant?

That is a fair question, I guess in my mind if it was covered against body for extended period of time and used it the barometer would have different values but maybe it is not enough to be significant.

I do not know enough about the sensitivity of the actual barometers used in the devices.
 

TK-421

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But how much does temperature really affect ballistics?

If the ranging device pulls atmospheric pressure (air density) as well as temperature, isn’t the temperature relatively insignificant?
Get on your solver and play around. A difference of 40 degrees at 800 yards for my primary hunting rifle is a difference of 0.1 mils.
 

Blockcaver

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One of my biggest issues is getting a range on an animal, let’s say an antelope at 1000 yards. It’s easy to “miss”. Any of them have specific technology to make them more “accurate”, and I mean helping the person hit the target with the lazer.
On my hand held, I use scan mode and ensure I get about 3 readings that verify yardage in a row with the laser on the animal, or nearby bush or tree, etc. Way quicker than single shot readings to verify range.
 

BjornF16

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Get on your solver and play around. A difference of 40 degrees at 800 yards for my primary hunting rifle is a difference of 0.1 mils.
But are you inputting altitude and temperature or absolute density?
 

TK-421

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But are you inputting altitude and temperature or absolute density?
Absolute density? I’m not sure what your saying here.

If you want to know how temperature impacts your ballistics, keep everything static and modify temperature. The bigger factor will likely be your MV change, depending on how temp stabile your powder is. Do you have a temp v MV table in your device?

For shooting big game, temp fluctuations from wearing your binos won’t matter to 500 or 600 yards (generic statement). Beyond that it may start to matter. Fortunately, longer shots usually means more time. Time for devices to acclimate (doesn’t take 30 minutes), time to reference kestrel, time to reference hard data, etc.

There’s also devices that you can manually input temperature if you’re really that nervous about it.
 

BjornF16

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Absolute density? I’m not sure what your saying here.

If you want to know how temperature impacts your ballistics, keep everything static and modify temperature. The bigger factor will likely be your MV change, depending on how temp stabile your powder is. Do you have a temp v MV table in your device?

For shooting big game, temp fluctuations from wearing your binos won’t matter to 500 or 600 yards (generic statement). Beyond that it may start to matter. Fortunately, longer shots usually means more time. Time for devices to acclimate (doesn’t take 30 minutes), time to reference kestrel, time to reference hard data, etc.

There’s also devices that you can manually input temperature if you’re really that nervous about it.
The question is whether or not your body temperature affects the ballistic solution generated by the LRF.

My original question was really how does the LRF measure pressure?

If it measures the actual air density and then calculates ballistics, does the temperature really matter? (Drag being a function of air density).

If it measures air density, then applies temperature to determine barometric pressure then solves ballistics, I would think temperature matters.

But I don’t know how the various LRFs with ballistic solvers are applying their measured air data.
 

BjornF16

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Found my answer…in the Ideal Gas Law

Air density is a function of air pressure AND temperature.

So LRF measures both pressure and temperature to determine actual air density (drag).

If your LRF is reading 98° F instead of 32° F, the air density used for the ballistic solver will be incorrect.

Carry on…
 

TK-421

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Yeah, temperature will have an impact on barometric pressure. Here are a couple real world examples from my log book in the last 6 months:

Day 1:
Temperature: 24* F
Pressure: 26.15 in Hg
Relative Humidity: 58%
Density Altitude: 2240

Day 2:
Temperature: 85* F
Pressure: 25.71 in Hg
Relative Humidity: 29%
Density Altitude: 6867

1660317252234.png

It's worth noting that the "differences" columns are from the actual correction. My turrets only allow for 0.1 mil adjustments. So at 600 yards, I'm dialing 3.1 mils for either day based on rounding, and the difference between the dialed correction on my turret and the required correction is going to be +/- 0.05 mils (+/- 1 inch on target) for either day.

Of course environmentals matter, but I've used my LRF binos enough and checked their ballistic solution against my Kestrel (both calibrated to real world data) in the field enough to know that I won't sweat any error from my binos out to at least 500 or 600 yards (sometimes further depending on circumstances). Up to you if you think the real world difference of 0.05 mils will make or break your shot on a 0.6 mil target.
 

josef

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This chart looks like its only accounting for DA changes. The MV change is going to be a much larger factor. In this case it could be 60-100 FPS depending on what powder you're burning. Thinner air plus a faster MV is going to make a decent difference.
 

TK-421

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Look up the page a couple posts. That’s what I’ve already said. But that only matters in the context of this thread if the ballistic solver in your LRF binos accounts for variable MV based on temp. I know mine don’t. I calibrate my solver based on a mean temp that I will experience because that’s the only option. Like I’ve already said, there’s also lrf with integrated solvers that let you manually type in temp. Some can BT to an external temp sensor (put it on your pack). Lots of ways to skin this cat that accommodates the majority of hunting situations.

So again, in the context of what’s being discussed, the discrepancy in the ballistic solution from my range finder compared to the real world correction is minimal out to 500 or 600(ish) yards.
 
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