I have been wanting to do this for a while so today was the day. I took two of my rifles to my steel range to check the difference in time in usable light when acquiring a target. The two scopes are SN-3s, 5.5-22. One has a 44mm objective and the other is 58mm. Both scopes were initially set at 22 power. It was after sunset and overcast. I concentrated on two steel targets, both 4" painted white but heavily dinged so about 50% paint showing.One target was at 400 yds and directly in front of a large hickory tree with light grey to dark grey bark which provided low contrast compared to the target. The other target had a varied leaf background with fairly bright leaves giving good contrast compared to the target. It was at 410 yds. I had the guns side by side on the ground and went from one to the other looking at each target for a few seconds at a time and alternating guns about every 30 seconds. It was clear that the 58mm objective had a brighter sight picture from the start. When I started it was easy to acquire either target with either scope. After about 15 minutes of good sight pictures it became harder to acquire the low contrast target with the 44mm scope. I continued using both scopes for about 10 more minutes until it became difficult to center the crosshairs on the 44mm scope on the low contrast target. I determined that the sight picture was too degraded to make an accurate shot. I was still able to get a good sight picture on the high contrast target with the 44mm scope. During the test I also turned the power down to 17 on each scope to see if the additional light would provide a better sight picture. While both scopes showed a brighter field of view the smaller size of the target image zeroed out any advantage of the increased light. I could not determine an advantage either way for slow, deliberate target acquisition. However if I were trying to find a target in the field of view quickly such as in a competition I would definitely use the lower power. I changed power on both scopes several times during the test always alternating between 17 and 22.
When I determined that I could not acquire the low contrast target with the 44mm scope I started the time. I applied the same sight picture criteria to the 58mm scope and determined that lost of quality sight picture occured 6 minutes later. The same results apply to the high contrast sight picture but about three minutes later for both scopes.
While this was not a highly objective test I do think that it gives a good idea of the difference in the relative usefulness in terms of minutes of good sight picture between the two scopes. I plan to conduct this test again also using my two NightForce NXS scopes, a 3.5-15x50 and a 5.5-22x56. I will also check the 5.5-22x56 against the USO 58mm. I might even throw in a Leupold 6.5-20.
Any useful comments or suggestions on test protocol are welcome.
Update with NF scopes.
I went back to my range today to compare my USO SN-3 3.8-22x58 against my NF NSX 3.5-15x50 and 5.5-22x56. See the original test above for testing protocol. I had about 15 minutes of good light before I started noticing a deterioration of sight picture. The first thing that was immediately apparent was that the NF scopes had much better contrast. It was so noticable that the sight picture in the USO looked slightly foggy when compared to either of the NF scopes.
The USO came back from USO after some repair about four months ago and I have no reason to suspect that it has degraded since being repaired. The NF just has better glass. Also noticable is that the eye box is more generous in the NF. In fact If you do not hold your eye dead center behind the USO it looks very foggy. I have not seen that condition in a scope before.
I began the countdown when I could not see a sight picture good enough to get an accurate shot. The first to drop out was the USO. The low contrast was the limiting factor in my sight picture. Two minutes, thirty seconds later the NF 3.5-15x50 dropped out. One minute later the NF 5.5-22x56 was unusable.
The limiting factor on the NF scopes was not target visibility but cross hair visibility. The fine cross hairs in the NPR-1 reticule just could not be discerned in low light. If the cross hairs in the NF were as coarse as the USO then I could have added approximately two more minutes to the acceptable sight picture time. This is just a fact to deal with when comparing FFP reticules with SFP reticules. I turned on the illumination on the NF scopes but the brightness of the crosshairs washed out the image of the target. I had the illumination turned down so that it could not be seen when I first started the test. I would have turned it down more but as most of you know it is a pain to adjust the brightness on the NF especially in low light.
We can compare the results in the first test with today's test and see that from the first scope to drop out to the last is only 9-10 minutes. We can also conclude that the coarse cross hair that is characteristic of a FFP design set on high power is an advantage in low light conditions. I have not seen much of a disadvantage of a coarse cross hair in good light conditions on long range targets that are typically shot in tactical competitions.
Here is what I wish for after these tests. I would like to see NF come out with a FFP NXS in the 4-20x50 range or maybe the 5.5-22x50 in FFP. The 15 power is just a little low for me when shooting very small targets at 400 yds plus. I am talking about golf balls and such. I would also like to see glass in USO equal to the NF. I have no agenda when comparing scopes. I like both NF and USO. I particularly like the EREK knob on my USOs.
OK all you powder burners, hash it out and chop it up. What do you think? Any one else have tests that can shed more light on the path to optical perfection? I may do some more under different conditions.
When I determined that I could not acquire the low contrast target with the 44mm scope I started the time. I applied the same sight picture criteria to the 58mm scope and determined that lost of quality sight picture occured 6 minutes later. The same results apply to the high contrast sight picture but about three minutes later for both scopes.
While this was not a highly objective test I do think that it gives a good idea of the difference in the relative usefulness in terms of minutes of good sight picture between the two scopes. I plan to conduct this test again also using my two NightForce NXS scopes, a 3.5-15x50 and a 5.5-22x56. I will also check the 5.5-22x56 against the USO 58mm. I might even throw in a Leupold 6.5-20.
Any useful comments or suggestions on test protocol are welcome.
Update with NF scopes.
I went back to my range today to compare my USO SN-3 3.8-22x58 against my NF NSX 3.5-15x50 and 5.5-22x56. See the original test above for testing protocol. I had about 15 minutes of good light before I started noticing a deterioration of sight picture. The first thing that was immediately apparent was that the NF scopes had much better contrast. It was so noticable that the sight picture in the USO looked slightly foggy when compared to either of the NF scopes.
The USO came back from USO after some repair about four months ago and I have no reason to suspect that it has degraded since being repaired. The NF just has better glass. Also noticable is that the eye box is more generous in the NF. In fact If you do not hold your eye dead center behind the USO it looks very foggy. I have not seen that condition in a scope before.
I began the countdown when I could not see a sight picture good enough to get an accurate shot. The first to drop out was the USO. The low contrast was the limiting factor in my sight picture. Two minutes, thirty seconds later the NF 3.5-15x50 dropped out. One minute later the NF 5.5-22x56 was unusable.
The limiting factor on the NF scopes was not target visibility but cross hair visibility. The fine cross hairs in the NPR-1 reticule just could not be discerned in low light. If the cross hairs in the NF were as coarse as the USO then I could have added approximately two more minutes to the acceptable sight picture time. This is just a fact to deal with when comparing FFP reticules with SFP reticules. I turned on the illumination on the NF scopes but the brightness of the crosshairs washed out the image of the target. I had the illumination turned down so that it could not be seen when I first started the test. I would have turned it down more but as most of you know it is a pain to adjust the brightness on the NF especially in low light.
We can compare the results in the first test with today's test and see that from the first scope to drop out to the last is only 9-10 minutes. We can also conclude that the coarse cross hair that is characteristic of a FFP design set on high power is an advantage in low light conditions. I have not seen much of a disadvantage of a coarse cross hair in good light conditions on long range targets that are typically shot in tactical competitions.
Here is what I wish for after these tests. I would like to see NF come out with a FFP NXS in the 4-20x50 range or maybe the 5.5-22x50 in FFP. The 15 power is just a little low for me when shooting very small targets at 400 yds plus. I am talking about golf balls and such. I would also like to see glass in USO equal to the NF. I have no agenda when comparing scopes. I like both NF and USO. I particularly like the EREK knob on my USOs.
OK all you powder burners, hash it out and chop it up. What do you think? Any one else have tests that can shed more light on the path to optical perfection? I may do some more under different conditions.
