Jeelan,
You can test the brightness of a 65mm Swaro scope even before your dealer receives one. Just cut out a 65mm stopdown mask from black paper or cardboard and tape it to front of your ATS 80 sun shield. Flipping it in and out of the light path will give you an instantaneous comparison of the image brightness between 65mm and 80mm.
Henry
Henry, that for that suggestion.
My dealer received their stock of the ATS 65 on Fri so i didnt get a chance to follow through on your suggestion. Instead I popped in to the store on Sat to try it out.
They are in the middle of the city but have a balcony the next floor up so he was happy for to me play around with the scope out of the way of other customers on their shop floor..
I had taken my ATS 80 and 25-50x eyepiece so spent a bit of time with each scope, swapping the eyepiece back and forth.
Physically the ATS 65 is quite a bit smaller than the dimensions themselves would suggest. Obviously its a lot slimmer but shorter as well. It definitely meets my criteria of a "travel friendly" scope.
I have a Sirui VA-5 that I use for the Swaro 80 and I'd taken a second quick release plate to attach to the bottom of the ATS 65. With the 25-50x eyepiece attached, the scope was back heavy - i had to slide the quick release plate forward by a good 30mm to allow the scope to balance on the head. Once i'd adjusted the balance, I started assessing the view..
Given I was at the store around 11am on a bright sunny day, the view really wasn't any different between the 80 and 65mm. Both had similarly sharp, contrasty views with a flat field. The 65mm objective was slightly wider when i framed the view against fixed dimensions (no. of window panes on a building about 200m away)
I tried looking at resolution in shadows but again, couldn't see any difference to my eye.
Where I DID notice the biggest difference was ease of use. I've already noted in previous threads that I'm struggling to find
consistent comfortable eye placement with the 25-50x eyepiece. On the ATS 65, i found it even more finicky. Slight movements of my head would induce kidney beaning. I had reduced tolerance to tilting my head and almost had to align with the eyepiece dead straight to get a clear view... Once I started started focusing on this aspect of comparing the two scopes, i wasn't sure if it was because of the reduced exit pupil on the smaller scope or what but i just found the ATS 65 a lot LESS comfortable than the 80 particularly when switching between the two.
Now I had intended to use the ATS 65 with the Swaro 30x SW fixed FL eyepiece, but even then i assumed that the comfort level would have been identical to using the 25-50x at 25x. As I didnt have the 30x eyepiece on hand, I couldn't tell, however on the 25-50x eyepiece there was certainly a difference in ease of viewing from one scope to another...
Having accepted that the quality of the views between the two sizes would be identical in all but maybe 5-10% of my viewing, the more I focused on the comfort and viewing ergonomics, the more i saw a larger than expected gap between the two scopes - particularly when I could switch from one to another to compare...
After about half hr, I had made my mind up that I wasn't going to pursue the ATS 65 any more.
So I'm now rethinking my requirements re portability and wondering if I should just stick with the ATS 80 and make that work i.e. buy a slightly bigger backpack for travelling or even carry the scope on its own (with a SOC) slung over my shoulder - most airlines allows a separate small video/camera bag so the scope should be no different as a standalone piece of luggage...
but either way, those are my thoughts on the ATS 80 vs ATS 65.
cheers
Jeelan