Well I just spent 30 minutes comparing the Victory FL 50mm to the Tangent Theta 56mm and all I can say is "Wow, does the TT ever blow this Zeiss out of the water". It beats it in every way. Clarity, contrast, colour, edge sharpness, brightness, close focus (the TT beat it by 20 yards on 5x), and actual zoom.
Of course, the TT has the lens size advantage so it might account for a lot of its superiority. But after a few minutes of testing, I found that looking through the TT was so much more pleasing to the eye and felt like it offered stress relief after looking through the Zeiss. My eye craved the Tangent Theta because it is simply that good.
The Victory was definitely outstanding but showed its flaws against the better glass. It couldn't achieve the clarity of focus and I found myself running the parallax knob back and forth looking for perfection. The Tangent Theta achieved this immediately.
Looking at a red truck parked behind evergreens, the difference in colour rendition was obvious. A brighter red and a greener green for the TT. Brown twigs stood out more clearly and almost shimmered with the TT whereas with the Zeiss they blended in more.
The TT also gives more zoom for each setting on the dial. I'd have to turn the TT to "5" to match the Zeiss' "6". Not a big deal, but in close focus the TT is simply amazing. With both set at 5x, the best close focus with the Zeiss was around 35 yards but the TT had perfect focus all the way in to 15 or less!
Looking around the sight picture, the Zeiss edges were soft and harder to find, and there was little but noticeable chromatic abberation, which surprised me. The TT had a solid edge with perfect clarity to each edge and comparatively, I could look all the way around without other parts of the picture darkening or diminishing. The TT is outstanding in this regard. It speaks to the larger exit pupil afforded by its larger lenses, but it's like a cavern in there, big and bright. I could find no chromatic abberation either, even while looking at the edges of brightly-lit snow patches.
As much as I hoped for Zeiss Victory FL to better the Tangent Theta 525P, it didn't. As the saying goes, you get what you pay for. I'm not sure how TT is sourcing such fine glass but it could explain the ultra-premium price. Whatever they are doing internally with their lens geometry is working, too.
I know Zeiss can do better, and maybe they have with the HT glass and V8 scopes, but I don't own one and can't compare. If anyone has one and wants to, I'm in.