I just bought a Z6I with the tds rec. with 2nd plane. I am wondering now how far will these long range 2nd and 3rd line be off per say if I'm on 6 power vrs 12? I plan on putting it on a 7mm rem mag. I will sight the center in at 3" high at 100 and should be good to 250. Then the 2nd one for 300 and the 3rd for 400. The last for 500. Does this sound about right. I will probably use 12 power for a long shot but what happens at dark an have to lower the power to see better. I do have a lite recticle also. What I don't understand about is when people say that the good thing about first focal is you can turn the scope up to see the X hairs better in low light. I thought the principal was to use low power at low light so you don't magnify darkness?
The swarovski website has a great ballistic program where you can mess around with every possible variable in the equation to figure out where each line should work for your gun/load combo. Of course always shoot live to verify it is correct.
In terms of low light - my FFP TDS was on a 3-12x50 scope. At 8-10x magnification you are still getting as much light as your eye can use through the scope and the reticle is big, bold and right there while the target image is magnified.
I understand using a lower power in low light but in my experience and for my eyes I get the best result cranking the magnification to as high as it can go while still keeping an exit pupil of about 5mm (Objective lense size divided by magnification power). I find if i crank the mangification higher than that the image blacks out quickly. Of course, my low light hunting is mostly out of a stand at last light. If you are still hunting through dark timber then messing with a TDS reticle or scope magnification in what will be a fleeting shot opportunity begs a different scope - my choice for that scenario has been a Leupold 4x33 with heavy duplex reticle.
Unfortunately in my late 30s my eyes don't work nearly as well in low light as they did in my teens and early 20s
