Zeiss or Sightron? Feedback

[bruce_ventura]

Optics are very subjective. I suggest you look through, run the knobs and let the scope make the decision for you. I've owned several of the products you're speaking of. Sightron, Mark 4, Zeiss Conquest, Vortex PST amongst others. I have never once had a glare problem in either of my Sightron SIIIs in field conditions (the only place I have tested them). To my eyes they are extremely clear and the tracking mechanism is flawless. The Conquest line is fantastic too. There are pros and cons for all the scopes you've listed.

I'm curious. How would you define a "glare problem"? How would you know if it occured? I've been designing optical instruments and weapon sights for over a decade and I haven't found a way to assess glare in the field. So, I would be interested in knowing how you do it.

I'm not talking about lens flare or other obvious image obscuration effects, although they can occur as well. I'm referring to what is called veiling glare, which tends to uniformly degrade image contrast. It is usually the dominant effect that limits image contrast when the target is marginally illuminated and surrounded by higher illumination terrain or sky - very common in big game hunting. All someone would notice in the field is a loss of image contrast, but they probably wouldn't have a clue why.

I specifically look for evidence of veiling glare when I evaluate scopes at SHOT. I do this by looking through the scope around the spot lights in the ceiling (but not directly at them). In the large halls, it becomes very easy to see glare because the ceiling is dark. In my lab, I use a large integrating sphere - the standard method for making quantitative measurements of veiling glare. The test I've developed for SHOT Show mimics the lighting conditions in the integrating sphere. This test is very definitive, but is nearly impossible to do in the field.

Glare is not a deal breaker for all types of shooting. For big game hunting, especially at long range, it's definitely important. For target shooting at a range, for example, it's not so important because other effects, like atmospheric turbulence, usually limit image contrast. Comparing scopes at the range is not a definitive test of optical perfomance. The target illumination is usually good, and turbulence is usually the limiting effect.

 

[brentc]

I'm curious. How would you define a "glare problem"? How would you know if it occured? I've been designing optical instruments and weapon sights for over a decade and I haven't found a way to assess glare in the field. So, I would be interested in knowing how you do it.

I'm not talking about lens flare or other obvious image obscuration effects, although they can occur as well. I'm referring to what is called veiling glare, which tends to uniformly degrade image contrast. It is usually the dominant effect that limits image contrast when the target is marginally illuminated and surrounded by higher illumination terrain or sky - very common in big game hunting. All someone would notice in the field is a loss of image contrast, but they probably wouldn't have a clue why.

I specifically look for evidence of veiling glare when I evaluate scopes at SHOT. I do this by looking through the scope around the spot lights in the ceiling (but not directly at them). In the large halls, it becomes very easy to see glare because the ceiling is dark. In my lab, I use a large integrating sphere - the standard method for making quantitative measurements of veiling glare. The test I've developed for SHOT Show mimics the lighting conditions in the integrating sphere. This test is very definitive, but is nearly impossible to do in the field.

Glare is not a deal breaker for all types of shooting. For big game hunting, especially at long range, it's definitely important. For target shooting at a range, for example, it's not so important because other effects, like atmospheric turbulence, usually limit image contrast. Comparing scopes at the range is not a definitive test of optical perfomance. The target illumination is usually good, and turbulence is usually the limiting effect.

I may not be quite as savvy about testing glare as you, but I've never had a problem getting a crystal clear image in varying light field conditions at any distance with the Sightron SIII. I'm not all that interested in the science behind optical design. All I know is the SIII works extremely well as a long range hunting scope despite the optical design flaws that may exist in a controlled environment.

The only way I test is on the gun. I adjust the focus until I see my target crystal clear, which is very easy, and send rounds down range. Maybe I've encountered what you're talking about, but my untrained eye never noticed anything abnormal, which means I probably just shot through it.