james holdsworth
Consulting Biologist
I hate to dig up this old chestnut again but I'm just flummoxed by comments made recently, and in several threads, by Alexis Powell that the 42 mm HT's have ''significant astigmatism.''
Now then, the vast majority of users have commented that edge sharpness / or sweetspot size in the HT was better than the FL. Many users seemed to have little comment on these aspects, suggesting that they either didn't care or it didn't present itself as a problem. There were exceptions - some saw an overly small sweetspot, Henry thought the optics and aberration pattern nearly identical to the FL and I recall two users that noted unacceptable astigmatism.
To me, I see a big sweetspot - like twice the size of my 10x42 FL and much improved edge sharpness, especially in the lower half of the FOV.
So, what's the reality? Am I just a brand homer glossing over the faults on his expensive toy? Are my eyes and technical abilities just not able to detect this astigmatism...or, does the HT actually have the improved optical qualities that I [and most users] seem to see?
Attached are a series of photos taken from my backyard - note these were handheld, focus [even in the centre] could likely be improved and ignore the alignment as they are all a bit off. Still, I wanted a target that showed well the outer 2/3rds of the FOV, including the quality of the outer 10% or so as well as illustrating the extent of image degradation off-centre. Target was est. 100 m distant, lighting very harsh and it was windy, so branches moving a bit which might blur the very tips.
So I see sharpness extending well out from centre, almost no image loss at 12 / 3 / 6 or 9 o' clock, even at the very edge, and very little or almost no astigmatism - certainly not significant in any way. Feel free to zoom in on them, to the limit of resolution - I needed to resize significantly to get them to fit.
Am I doing this wrong? Are my impressions off-base? What are the opinions of the forumers here? Remember, these were hand-held and are not perfect but [to me] seem representative to what I see in the field.
Now then, the vast majority of users have commented that edge sharpness / or sweetspot size in the HT was better than the FL. Many users seemed to have little comment on these aspects, suggesting that they either didn't care or it didn't present itself as a problem. There were exceptions - some saw an overly small sweetspot, Henry thought the optics and aberration pattern nearly identical to the FL and I recall two users that noted unacceptable astigmatism.
To me, I see a big sweetspot - like twice the size of my 10x42 FL and much improved edge sharpness, especially in the lower half of the FOV.
So, what's the reality? Am I just a brand homer glossing over the faults on his expensive toy? Are my eyes and technical abilities just not able to detect this astigmatism...or, does the HT actually have the improved optical qualities that I [and most users] seem to see?
Attached are a series of photos taken from my backyard - note these were handheld, focus [even in the centre] could likely be improved and ignore the alignment as they are all a bit off. Still, I wanted a target that showed well the outer 2/3rds of the FOV, including the quality of the outer 10% or so as well as illustrating the extent of image degradation off-centre. Target was est. 100 m distant, lighting very harsh and it was windy, so branches moving a bit which might blur the very tips.
So I see sharpness extending well out from centre, almost no image loss at 12 / 3 / 6 or 9 o' clock, even at the very edge, and very little or almost no astigmatism - certainly not significant in any way. Feel free to zoom in on them, to the limit of resolution - I needed to resize significantly to get them to fit.
Am I doing this wrong? Are my impressions off-base? What are the opinions of the forumers here? Remember, these were hand-held and are not perfect but [to me] seem representative to what I see in the field.