Search found 725 matches

by Bill Jurens
Wed Mar 18, 2020 7:17 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 328
Views: 11223

Re: A correct attribution for the "Flash Effect" photo?

I have, as readers will note, and as mentioned earlier, deleted the majority of Mr. Virtuani's commentaries posted on or about 15 March. For the most part, these consisted of redundant and repetitive personal attacks on the moderator and various other forum participants. Although I still find some o...
by Bill Jurens
Sat Mar 14, 2020 4:00 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 328
Views: 11223

Re: A correct attribution for the "Flash Effect" photo?

As readers will note, Mr. Virtuani has, as anticipated, returned with a vengeance and apparently chosen to hereafter 'self-isolate' from further postings to this board. Although I am -- for what I presume are, to most, fairly obvious reasons -- tempted to delete his recent posts immediately, in fair...
by Bill Jurens
Sun Feb 23, 2020 5:12 pm
Forum: Bismarck General Discussion
Topic: Clerical issues
Replies: 3
Views: 323

Clerical issues

As most readers know, earlier in the year contributor Alberto Virtuani was banned from participation until 01 March, 2020. I have since committed to some travel plans which will render my regular access to a computer somewhat problematical during the first two weeks of March. This will quite likely ...
by Bill Jurens
Thu Feb 20, 2020 5:38 am
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 328
Views: 11223

Re: A correct attribution for the "Flash Effect" photo?

Yes, it appears we were talking a bit at cross-purposes. Looking at Bild 146-1990-061-27, which is, I think, the one Herr Nilsson suggested, and assuming the 'as advertised' uncropped negative size of 24x36mm, and a 50mm lens, a quick geometric analysis would suggest we have a situation where one is...
by Bill Jurens
Wed Feb 19, 2020 4:37 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 328
Views: 11223

Re: A correct attribution for the "Flash Effect" photo?

A visual minefield. I was actually working on NH69724, which may not even be directly relevant to the photos you are interested in.

Bill Jurens.
by Bill Jurens
Tue Feb 18, 2020 6:27 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 328
Views: 11223

Re: A correct attribution for the "Flash Effect" photo?

Photogrammetric analysis always engages me, so I took another shot at it. For what it is worth, assuming a 50mm lens, an uncropped 35mm negative, and a distance of 2 meters between the stanchions in the foreground, and using the horizon line to close the geometry, I can calculate an angle of about 1...
by Bill Jurens
Sun Feb 16, 2020 9:03 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 328
Views: 11223

Re: A correct attribution for the "Flash Effect" photo?

Mr. Zurbriggen wrote: "Mr. Bonomi map is the only widely published and agreed, with no alternative, recently confirmed by Mr. Jurens independent work." As ‘just another participant’, I would respond… At least as I see it, it is simply not true that Mr. Bonomi's map is '...the only widely published a...
by Bill Jurens
Fri Feb 14, 2020 6:37 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 328
Views: 11223

Re: A correct attribution for the "Flash Effect" photo?

Mr. Zurbriggen wrote: "No one can claim it is not accepted. Can you show any author who has recently published anything different, disproving Mr. Bonomi map ? Why don't we accept at least to agree to disagree ? Why such others' urgency to insist that the map is not consistent ?" Without being argume...
by Bill Jurens
Tue Feb 11, 2020 9:24 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 328
Views: 11223

Re: A correct attribution for the "Flash Effect" photo?

I would tend to concur that it would be worthwhile making some effort to avoid involving ourselves in the seemingly intractable questions revolving around our opinions of Mr. Bonomi's track chart(s). Some will feel they are worthless, while others may claim they are the best yet produced, or at leas...
by Bill Jurens
Mon Feb 10, 2020 3:32 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 328
Views: 11223

Re: A correct attribution for the "Flash Effect" photo?

Duplicate post on my part, deleted.

Bill Jurens
by Bill Jurens
Mon Feb 10, 2020 3:31 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 328
Views: 11223

Re: A correct attribution for the "Flash Effect" photo?

Herr Nilsson has given an alternative frame format for German motion picture cameras of the era. My data was based on North American standards, which I assumed -- it appears, in this case incorrectly -- were universal, i.e. international, in nature. I trust his figures. The discrepancy between our f...
by Bill Jurens
Mon Feb 10, 2020 8:16 am
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 328
Views: 11223

Re: A correct attribution for the "Flash Effect" photo?

Thank you for digging up some of this old correspondence, which -- reading the associated dates of posting -- is a good demonstration of just how long these particular discussions have been going on. So far as I know, nothing much has changed since then. The tools for photogrammetric analysis certai...
by Bill Jurens
Sun Feb 09, 2020 6:03 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 328
Views: 11223

Re: A correct attribution for the "Flash Effect" photo?

Unfortunately, there is very little about the camera that can be reliably derived from an examination of a photo-print. The focal length of the lens has, curiously, nothing to do with the image on the film plane, and even less to do with the image on a photo-print, which is (or at least, was) also f...
by Bill Jurens
Sat Feb 08, 2020 5:26 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 328
Views: 11223

Re: A correct attribution for the "Flash Effect" photo?

Your math seems sound to me. Enjoyed the diagram you posted, which is essentially the same one used in air-photo analysis, except we use it 'upside down', with the subject horizontal at the bottom and the camera pointed straight down. Note that any 'cropping' would have the result of increasing the ...
by Bill Jurens
Sat Feb 08, 2020 1:33 am
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 328
Views: 11223

Re: A correct attribution for the "Flash Effect" photo?

An interesting question. I'm not accustomed to working with such poor quality images, so I may have to dig into old boxes of creativity not opened in a while. There may be something that can be derived from the convergence lines for the stanchions, both vertically and horizontally, i.e. via the angl...