Leupold 12-40x60 HD compared to Leupold 20-60x80

[LandToSea]

I ordered a Leupold 20-60x80 to replace my 12-40x60 in hopes that it would better enable me to see .223 holes at 300+ yards. I tested the two this weekend at 300-500y and found that the higher magnification helps but the HD will be missed as it would provide an advantage due to the superior contrast in some circumstances. I set the non HD higher power scope at 40x and maxed the HD at 40x and compared and the definition is certainly discernible. I wonder why they no longer offer the 20-60x in HD?

 

[LandToSea]

I called and was told that they just eliminated the HD for the higher power with no detailed insight. I asked if some ghosting was inherent and he couldn't say and advised comparing it to another identical version of the 20-60x80mm model...I do not have that ability.

 

[bruce_ventura]

... I tested the two this weekend at 300-500y and found that the higher magnification helps but the HD will be missed as it would provide an advantage due to the superior contrast in some circumstances. I set the non HD higher power scope at 40x and maxed the HD at 40x and compared and the definition is certainly discernible...

Are saying the that the 60mm HD has better definition than the 80 mm non-HD? If so, then in what way does the higher magnification help you to see bullet holes?

Be aware that as the summer weather heats up, you will see more air turbulence blur when looking across flat terrain. The advantage of a higher mag and larger objective will diminish to zero. If you're looking from a hill top or across a valley, then the bigger scope helps.

 

[LandToSea]

Are saying the that the 60mm HD has better definition than the 80 mm non-HD? If so, then in what way does the higher magnification help you to see bullet holes?

Be aware that as the summer weather heats up, you will see more air turbulence blur when looking across flat terrain. The advantage of a higher mag and larger objective will diminish to zero. If you're looking from a hill top or across a valley, then the bigger scope helps.

My testing has not been on holes yet, i should have made that clear. Just in general viewing of objects there is more definition with sharper contrast with the HD. I am not sure if the 60x will be better than the 40x for this purpose or not yet. It was wishful thinking. I may sell the 60x now and get a Zeiss with similar magnification?

I understand the challenges of mirage but that will be relevant no matter the power or definition, no?

 

[bruce_ventura]

... I understand the challenges of mirage but that will be relevant no matter the power or definition, no?

Mirage is not the same as turbulence blur. They're related, but different optically. Mirage is the wavy, "fun house mirror" image distortion that you usually see at long distance on hot days.

Turbulence blur happens whenever you have a long optical path over flat terrain (i.e. typical shooting range, bean field or desert conditions), It happens at any temperature, night or day (worse case), as long as the ground temp is different than the day temp. Full daylight in the summer is the worse condition for turbulence blur.

Turbulence blur reduces image sharpness and contrast. The blur effect is usually worse than the difference between HD and and non-HD optics. The image blur is worse for larger objective optics.

So, in turbulence blur conditions, the quality of the scope optics does not determine the image quality. A higher mag scope is only making a blurry image larger; it's not providing more detail about the target. If you have good vision, a small 60-65mm HD scope is about right for shooting range work.

For a dual-purpose scope - shorting range and hunting/nature - a 80-85mm HD scope is a good compromise.

 

[LandToSea]

Mirage is not the same as turbulence blur. They're related, but different optically. Mirage is the wavy, "fun house mirror" image distortion that you usually see at long distance on hot days.

Turbulence blur happens whenever you have a long optical path over flat terrain (i.e. typical shooting range, bean field or desert conditions), It happens at any temperature, night or day (worse case), as long as the ground temp is different than the day temp. Full daylight in the summer is the worse condition for turbulence blur.

Turbulence blur reduces image sharpness and contrast. The blur effect is usually worse than the difference between HD and and non-HD optics. The image blur is worse for larger objective optics.

So, in turbulence blur conditions, the quality of the scope optics does not determine the image quality. A higher mag scope is only making a blurry image larger; it's not providing more detail about the target. If you have good vision, a small 60-65mm HD scope is about right for shooting range work.

For a dual-purpose scope - shorting range and hunting/nature - a 80-85mm HD scope is a good compromise.

Good insight, I never was aware of the difference.