Tannin
Common; sedentary.
I have a Swarovski ATS80HD with the 20-60X zoom eyepiece. Just now I've started thinking about buying a 20X fixed eyepiece to supplement it. Will I get any benefit from that?
Looking at Swarovski's specifications, I see that the exit pupil diameter is 4.0 mm - i.e., the same as the zoom at 20X. For interest, the 30X is 2.7 mm, the 45X 1.8 mm, and the zoom at 60X is 1.3 mm. I would have thought that that was a key factor, but I haven't noticed any particular difference in this regard using the zoom at higher settings - if it affects vignetting, it doesn't do so very noticably with the Swarovski adaptor and the CP4500.
The thing that attracts me is the wider field of view. At 1000m, Swarovski quote 60m for the 20X fixed (42 for the 30X, 28 for the 45X, and 36 to 20m for the zoom). That suggests to me that at a sensible distance, let's say 50 metres, I can currently see 1.8 metres worth of bird (with the zoom at 20X), but with the 20X fixed lens, I could see 3 metres worth (before allowing for the bit of the round picture that the camera chops off). If that difference translates into reality, it would give me an extra 35% or so worth of picture. Looking at my swans taking off from last weekend, for example, I'd have got that left-hand bird into the picture instead of chopping it off.
(OK, OK, I'd have got another nice picture of my bootlaces, but a perfect me would have got that second swan. You know what I mean.)
So, if I bought a 20X fixed eye piece, would there be a noticable benefit?
I can live with the idea of having to swap e/ps from time to time, as when I find a good spot I'm mostly using the 20X60 in the 20 to 25X range anyway, and one more bit of kit to carry is not the end of the world.
One last question - I see that the 20X is a few MM shorter than the zoom: am I safe in assuming that it wil fit with the Swarovski camera adaptor jus the same?
Thanks in advance to anyone who can answer these questions for me.
Tony
PS: as an afterthought, here is the original, uncropped swan picture I had in mind as an example of why I think a wider field of view would help.
Looking at Swarovski's specifications, I see that the exit pupil diameter is 4.0 mm - i.e., the same as the zoom at 20X. For interest, the 30X is 2.7 mm, the 45X 1.8 mm, and the zoom at 60X is 1.3 mm. I would have thought that that was a key factor, but I haven't noticed any particular difference in this regard using the zoom at higher settings - if it affects vignetting, it doesn't do so very noticably with the Swarovski adaptor and the CP4500.
The thing that attracts me is the wider field of view. At 1000m, Swarovski quote 60m for the 20X fixed (42 for the 30X, 28 for the 45X, and 36 to 20m for the zoom). That suggests to me that at a sensible distance, let's say 50 metres, I can currently see 1.8 metres worth of bird (with the zoom at 20X), but with the 20X fixed lens, I could see 3 metres worth (before allowing for the bit of the round picture that the camera chops off). If that difference translates into reality, it would give me an extra 35% or so worth of picture. Looking at my swans taking off from last weekend, for example, I'd have got that left-hand bird into the picture instead of chopping it off.
(OK, OK, I'd have got another nice picture of my bootlaces, but a perfect me would have got that second swan. You know what I mean.)
So, if I bought a 20X fixed eye piece, would there be a noticable benefit?
I can live with the idea of having to swap e/ps from time to time, as when I find a good spot I'm mostly using the 20X60 in the 20 to 25X range anyway, and one more bit of kit to carry is not the end of the world.
One last question - I see that the 20X is a few MM shorter than the zoom: am I safe in assuming that it wil fit with the Swarovski camera adaptor jus the same?
Thanks in advance to anyone who can answer these questions for me.
Tony
PS: as an afterthought, here is the original, uncropped swan picture I had in mind as an example of why I think a wider field of view would help.