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by Bill Jurens
Sat Feb 01, 2020 2:09 am
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 343
Views: 18432

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

The 'raspberry jam' metaphor, though I think intended to illustrate the FORM of a given argument rather than it's content, does not seem to have gone over very well. Perhaps we might rephrase it using "Mean Temperature in London, England" instead of nostril temperature, and "Number of births in Pari...
by Bill Jurens
Wed Jan 29, 2020 7:32 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 343
Views: 18432

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

My thanks to all for keeping the discussions thus far reasonably collegial and on-topic. Makes the moderator's job considerably easier. Let's all try to be careful to avoid 'creeping escalation' however -- it can sneak up on a thread in rather subtle fashions. I suppose what we are discussing here r...
by Bill Jurens
Tue Jan 28, 2020 8:53 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 343
Views: 18432

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

O.K. Reading the memo again, I can see that I somewhat misunderstood what you were getting at. That being said, were the proposed tracks themselves not, at least in part, derived from the photos? If so, of course they will match, but only because it's a circular argument. One can't use the tracks to...
by Bill Jurens
Tue Jan 28, 2020 5:10 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 343
Views: 18432

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

Mr. Zurbriggen wrote: "[the photos] all match Bismarck on course 220° and Prinz Eugen on course 280°as per drawing posted by Mr. Virtuani (from Mr. Bonomi), same for Mr. Nilsson drawing with Prinz Eugen on 270°." Thanks for your commentary. MIght you describe the detailed methodology whereby compass...
by Bill Jurens
Tue Jan 28, 2020 5:52 am
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 343
Views: 18432

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

Attempts at any sort of photogrammetric analysis of this photography are, at best, extremely "iffy". I visited the Naval Historical Center website and noticed that their digitized images seem to contain what appears to be a slight curl on the right-hand side, which suggests that they were not made o...
by Bill Jurens
Fri Jan 24, 2020 7:06 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 343
Views: 18432

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

P.S. I'm certainly glad to see that reasonable commentary and criticism seems to be the new order of the day in our discussions. This has become (again) a pleasant place to visit, and makes the moderator's job much, much, easier.

Bill Jurens
by Bill Jurens
Fri Jan 24, 2020 6:22 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 343
Views: 18432

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

Photogrammetrically, all items in a photo tend to recede in a radial pattern away from the exact point at which the camera was pointed, which is -- at least in English terminology -- called the 'principal point'. Very long ago, we used to make maps using a device, appropriately defined as a 'radial ...
by Bill Jurens
Thu Jan 23, 2020 6:45 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 343
Views: 18432

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

That's what I suggested earlier. The chances of having a photographer wandering about the weather decks and basically just getting in the way in a combat situation are pretty slim. That's why my guess was that the photo was exposed from inside the galley, looking through an open air port. The geomet...
by Bill Jurens
Thu Jan 23, 2020 5:00 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 343
Views: 18432

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

My estimate is something in the vicinity of two meters assuming a 35mm camera ( or a "press camera") , held at eye level. If it were a twin-lens, or some of the Graflex press types, the camera would be held somewhat lower and the distance correspondingly greater. Perhaps three meters... Without more...
by Bill Jurens
Thu Jan 23, 2020 2:32 am
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 343
Views: 18432

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

The angle between the camera and the muzzles can be determined -- if one has a sufficiently sharp image -- by measuring the ratios between the major and minor axes of the ellipse cast by the circular muzzles on the image plane. The ratio is related to the tangent of the angle. But the images I've se...
by Bill Jurens
Wed Jan 22, 2020 5:03 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 343
Views: 18432

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

The photo geometry to estimate Bismarck's distance goes roughly as follows: The vertical offset of the muzzles, assuming they are horizontal and using drawings of the mount as a guide for the distance between the muzzles, allows one to construct a line angled downwards pointing at the camera. The he...
by Bill Jurens
Mon Jan 20, 2020 11:59 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 343
Views: 18432

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

There is an unspoken and very subtle assertion being made when it is said that 'History is written by the winners.", the implication being that the history is therefore not to be trusted or is in some way inferior to history written by the 'losers', which is often assumed -- usually well after-the-f...
by Bill Jurens
Mon Jan 20, 2020 4:07 pm
Forum: Announcements, News and Updates
Topic: New Moderator
Replies: 30
Views: 12464

Re: New Moderator

As mentioned yesterday, I have taken the action of deleting significant portions of material posted by Mr. Virtuani in January as being inappropriate, offensive, and repetitive. Although these attacks were primarily pointed at myself, similar action would have been taken had any other participant to...
by Bill Jurens
Sun Jan 19, 2020 11:22 pm
Forum: Announcements, News and Updates
Topic: New Moderator
Replies: 30
Views: 12464

Re: New Moderator

I was unaware of Mr. Virtuani's parallel postings on this thread until very recently. The content and tone of the more recent postings by Mr. Virtuani speaks for itself. He has made his points and stated his positions. Repeatedly. Although I could respond, and have before, I honestly feel it pointle...
by Bill Jurens
Sun Jan 19, 2020 4:46 pm
Forum: Bismarck General Discussion
Topic: A correct attribution for the "Flash Effect" photo?
Replies: 343
Views: 18432

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

My own calculations and analysis, done via a method essentially identical to that used by Herr Nilsson, and using identical source material, would suggest that the photographer would be at or near the rail with the mount trained at only about 35 degrees off the centerline. I feel it unlikely that th...