So, I got my FDN17X friday, and have had a few days to play with it.
I got it zeroed yesterday, but due to typical Pacific Northwest constant rain and fog, didn't get to do much shooting. I'm accustomed to fixed power scopes, so dialing in the diopter was a little harder than i'm accustomed to. I did get it done though.
The Parallax on this scope took me a little bit to get dialed in. The 100 yard mark on the parallax turret is dead on, but infinity on this scope wasn't anywhere near the infinity mark. After setting it parallax free on a distant mountaintop, i marked that spot on the knob with a sharpie.
Like my every other scope i've owned, i ended up with the diopter ring threaded almost all the way into the eyepiece housing for the best reticle image. I'm not sure what that says about my eyes. Aside from the parallax infinity mark being so far off, i like everything about the scope.
I don't have much to compare to, for image quality. My only other scope is a US Optics ST10 fixed 10X. Set up side-by-side, with both scopes set to 10X, my FDN17X has a slightly better image. I set them both up on the dining room table, looking out the sliding glass window at a church cross 236 yards away, and at a building gutter 70 yards away. With the FDN17X i can see little specs of rust on the cross and gutter, that aren't quite visible with the ST10.
This cross is 236 yards away. Even though the rust spots are barely visible in the pic, they are clear and distinct when looking through the scope. Through-scope pics never seem to work well for resolution. Even in high contrast situations, there's no noticeable chromatic aberration when your eye is centered in the eye-box. When you move your eye off-center, some purple fringing occurs. Its hard to keep the camera centered when taking a pic, so you can see some purple fringing along the rooftop edge in this pic.
Here is the gutter pic, 70 yards away. Again, the pic doesn't show the same resolution as is seen when looking directly through the scope. When looking through the scope, you can see the indiviual gravel particles in the shingles. It was foggy and raining when i took these pics. On the left side, 2 mil mark you can see water pouring off the gutter.
The illumination is very good. The first couple settings aren't even visible in the dark (im guessing night vision settings). There are 9 settings, with the last few easily visible in broad daylight. I opted for blue.
The new Er3k turret zero-stop is feature is interesting. I havn't seen any design even remotely like this before. I really like it's simplicity.
The zero stop ony has 1 simple part, a ring which engages a raised boss on the scope body. The zero-stop ring has 3 tiny grub screws around the circumference, which -can- be used to secure the zero stop ring to the turret. Those grub screws are unnecessary and should be loosened out a turn, then forever ignored (maybe even removed and thrown away).
That zero stop ring sits on the turret and rotates freely. After you've zeroed the rifle, you simply position the zero-stop ring on the turret, and rotate it clock-wise until it is stopped against the raised boss on the scope body. Then you put the knob on and float it to zero. Once the top cap is tightened down, the zero-stop ring is pinched between the turret and the top cap. Any clockwise movement past zero is halted by the raised boss. When dialing couter clock-wise for elevation, the turret/knob/cap threads up and on the next rotation the zero-stop ring is above the raised boss, and clears it.
I like to set my zero stop with .5 mils available under my zero, so i can adjust between my suppressed and un-suppressed zero. That was easy to accomplish on this scope. Simply zero, then turn the turret 5 additional clicks clockwise. Remove the knob and cap, set the zero stop and float the turret to the -.5 mil marking. Tighten everything down, and go the 5 clicks counterclockwise back to zero.
Overall, i really like the zero-stop. Its easy to set, and gives a very solid stop.
The elevation turret has the exact same feel as my ST10. Very smooth, yet firm with positive tactile clicks. The click aren't loud, but they have a solid distinct feel. In the dark, with ear-protection on, there would be no trouble whatsoever counting off tenths of a mil.
The windage turret has the same distinct feel to the clicks, but takes a bit more torque to turn. Overall, the additional torque needed to turn the windage knob takes away from the feel. It does however seem to be getting better with every turn. I think the o-ring is just a little tight and will break-in nicely.
Overall, i really like the scope. I had hoped that the glass would blow my ST-10 out of the water, and i'm a little disappointed that its only slightly better, but that expectation may have been a little unreasonable. It's still very good glass, and everything looks fantastic mechanically.
So far, the only thing i dislike is how far-off the parallax infinity marking is. That will not effect the use of the scope though, so i'm happy.
Have a good weekend folks.
Zeroing it is different. You remove a cap screw on top, then adjust the elevation using an Allen wrench. It's stupid easy as long as you dont drop the non magnetic center cap screw. Seems to track well for the little bit I adjusted it. Oh what else... The illumination is great! The drip down subtensions with a floating center dot. Is great. I have 30 mils of useable elevation. It's cool man. I like it. Plenty of windage adjustment. Two full rotations (clockwise) and some change to bottom out elevation into the scope. So, two full rotations back is my windage zero. I bought it for all the features that I enjoyed today! Dony lose the center cap screw... photo is the center cap screw 
