-
Welcome to BirdForum, the internet's largest birding community with thousands of members from all over the world. The forums are dedicated to wild birds, birding, binoculars and equipment and all that goes with it.
Please register for an account to take part in the discussions in the forum, post your pictures in the gallery and more.
The rolling-ball effect and pincushion distortion by Holger Merlitz (1 Viewer)
- Thread starter elkcub
- Start date
elkcub said:
Done :t:
Happy New Year to you
D
Pinewood
New York correspondent
Ed.
I have read Dr. Merlitz article, twice, and I think I would need to read it, at least, three more times for a good grasp of it.
Contrary to the practice of many, I rarely pan, rather I look at various segments of my field. In fact, my usual custom is to find something of interest, acquire a target, with the naked eye and then examine it. Needless to write, in matters of perception, there are individual differences, which is why some folks get far more upset over the compromise chosen by Leica or by Zeiss, than I do. I gather that some people pan with a 'scope, where the effect must be very pronounced.
There are distortions which I find truly objectionable as in the Fujinon 7x50 Polaris, but I cannot recall which kind it was, as I returned the glass after very little use. I recall that rectilinearity was lost when viewing buildings. I suppose that it may have been pincushioning at an extreme. At the time I dismissed it as trade off for a very flat field. As that binocular was marketed to the marine and astronomical types, such distortions are of little consequence. There is no rolling ball, panning an ocean horizon and stargazers are little troubled by such distortions.
Happy bird watching,
Arthur :brains:
I have read Dr. Merlitz article, twice, and I think I would need to read it, at least, three more times for a good grasp of it.
Contrary to the practice of many, I rarely pan, rather I look at various segments of my field. In fact, my usual custom is to find something of interest, acquire a target, with the naked eye and then examine it. Needless to write, in matters of perception, there are individual differences, which is why some folks get far more upset over the compromise chosen by Leica or by Zeiss, than I do. I gather that some people pan with a 'scope, where the effect must be very pronounced.
There are distortions which I find truly objectionable as in the Fujinon 7x50 Polaris, but I cannot recall which kind it was, as I returned the glass after very little use. I recall that rectilinearity was lost when viewing buildings. I suppose that it may have been pincushioning at an extreme. At the time I dismissed it as trade off for a very flat field. As that binocular was marketed to the marine and astronomical types, such distortions are of little consequence. There is no rolling ball, panning an ocean horizon and stargazers are little troubled by such distortions.
Happy bird watching,
Arthur :brains:
elkcub
Silicon Valley, California
Pinewood said:
Arthur,
As usual I agree with you. The so-called "rolling ball" effect has never been particularly important to me, although I'm mighty disturbed by pincushion distortion as seen through Leicas. Buildings are an important part of my visual world.
The beauty of Holger's article is that it presents a straight forward mathematical explanation of the design rationale (praise be, in English). I don't know if all manufacturers consider it an issue; however, the article underscsores the fundamental nature of design tradeoffs in general: once parameters are chosen, wisely or not, the essential character of the instrument is forever detemined. My preference is for instruments with Alpha > .5.
Happy New Year,
Ed
