Determining Distances from Photographs

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Robert J. Winklareth
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Determining Distances from Photographs

Post by Robert J. Winklareth » Mon Jan 23, 2006 6:31 pm

Hi all,

There have been various attempts to determine the distance between the Bismarck and the Prinz Eugen from a photograph by geometric means without much success. You can determine the distance from a certain level on a ship to an imaginary horizon or the distance to another ship is visible beyond the horizon, but not the distance to a ship in front of the horizon. There are just no formulae in circular or spherical geometry to enable this to be done. Other geometric techniques also have not been productive

Having been a serious photographer for over 50 years, I studied the issue for some time now, and I finally came up with a procedure to determine the distance to another ship from a photograph. The procedure is not unique, and it could have been derived by anyone with an understanding of photographic optics, but I have not seen it presented before, and I would like to share it with you.

The procedure, however, is dependent upon three factors:

a. The angle of view of the lens used in taking the picture must be known.

b. The photograph must include the total image captured on the negative and not be cropped.

c. The photograph must include a measurable item whose dimensions are known.

Although its development was somewhat involved, the procedure itself is actually quite simple. You first measure the diagonal of the exposed portion of the photograph and then you measure the size of an object of known dimensions within the photograph, such as the height of the tower mast of the Bismarck above sea level. You then multiply that ratio by the actual size of the chosen object (37 yards for the tower mast of the Bismarck). That gives you a tentative distance that still has to be refined.

You then have to determine the angle of view of the lens that took the photograph. The still photographs of the Bismarck during the operation were most probably taken with a Zeiss 35mm military camera with interchangeable lenses. As a long-time user of pre-war Zeiss camera systems, I can attest that the interchangeable lenses probably included a 50mm normal or standard lens (46 degrees), 35mm wide-angle lens (63 degrees), 90mm short telephoto lens (26 degrees), and 135mm medium telephoto lens (18 degrees).

Most photographs are taken with a normal or standard lens. By definition, a normal or standard lens produces an image of a width equal to the distance from the camera. Theoretically, the angle of view of such a lens would be 53 degrees, but lenses with angles of view down to 45 degrees are usually considered to be normal or standard lenses. This includes the most common 50mm focal length lens for 35mm cameras with an angle of view of 46 degrees.

Getting back to the math, you next take half (repeat, half) of the tentative distance found above and divide that by the tangent of half (repeat, half) the angle of view of the lens (the tangent of 23 degrees for a 50mm lens is 0,424). The result is the distance that the ship is away from the camera. It’s as simple as that for those who have an elementary knowledge of trigonometry.

As I said before, the photograph must encompass the entire area of the image captured on the negative. In the case of the Bismarck, that could possibly include those photographs in the original Schmalenbach collection and full size copies made from that collection. The least useful pictures are those published in books, articles, and other documents since they could have been subjected to intensive cropping. The only information that can be derived from cropped pictures is the minimum possible distance to the subject since that would reduce the very first measurement taken of the diagonal of the photograph.

Glossy prints of the Bismarck acquired from official sources, such as the Bundesarchiv, the Imperial War Museum, and the U.S. Naval Historical Center, have the least probability of having been cropped since those activities are dedicated to preserving historical records. I recently acquired four more glossy prints from the U.S. Naval Historical Center to supplement the three that I had acquired earlier.

Insofar as selecting measurable items of known size, vertical measurements are preferred since they are not affected the inclination of the ship. Horizontal objects must be square to the line of sight to provide accurate readings. In the case of the Bismarck photographs, the distance from the level of the sea to the top of the rangefinder on the tower mast is perhaps the best to measure for comparative purposes. Its actual height is 37 yards.

By applying the distance formula to the Bismarck photographs, I came up with the following results as to the distance between the Bismarck and the Prinz Eugen when those photographs were taken:

a. NH69721: 390 yards (50mm lens)
b. NH69722: 1580 yards (50mm lens)
c. NH69729: 1165 yards (90mm lens)
d. NH69730: 875 yards (90mm lens)
e. NH69728: 1030 yards (50mm lens)
f. NH69726: 1010 yards (50mm lens)
g. NH69727: 970 yards (50mm lens)

You will notice that I used the data for a 90mm lens (tan 9 degrees = 0.231) to arrive at the distances to the Bismarck in NH69729 and NH69730. The results were out of the ball park using the data for the 50mm lens normal lens, indicating that Lagemann probably switched to a longer focal length lens to better capture the target area while covering the approach of the British task force, the Hood blowing up, and the fall of Bismarck’s sixth salvo. He apparently left the 90mm lens on until the Prince of Wales turned away and then reverted back to his normal 50mm lens to capture the last six photographs in the series.

Violating the rules, I applied this technique to the broadside photograph of the Bismarck published recently in a foreign military journal because it appeared to be the full size of the picture. Still using the data of a 90mm focal length lens, I arrived at a distance of 1140 yards separation between the Bismarck and Prinz Eugen when the Bismarck passed the cruiser at 0605. Again the results look consistent since the Prinz Eugen had turned away from the Bismarck just prior to that photograph having been taken.

Applying this technique to the battle film, the printed frames of which probably represent the actual images on the film itself, I obtained distances of 1080 yards for scenes comparable to NH69728 and 950 yards for scenes comparable to NH69727. Not knowing the characteristics of the lens used for the battle film, I assumed the theoretical angle of view of a normal lens of 53 degrees. As you can see, the results are remarkably close considering possible measurement errors of 3-5 percent.

You will also notice that these figures vary significantly from my earlier estimates of distances based on the maximum speed of the Bismarck being 30.0 knots. At that speed, the maximum distance that the Bismarck could have been astern of the Prinz Eugen at 0556 was 1100 yards. If the Bismarck had actually been 1580 yards astern of the Prinz Eugen at 0556, she would have had to travel at a speed of 31.5 knots to come abreast of the Prinz Eugen at 0605.

Looking at the new figures, based on my estimated time of NH69722 (0556) and NH69729 (0559), the Bismarck would have had to sail at a speed of 31.1 knots to cover the difference of 415 yards in those three minutes. Similarly, the Bismarck would have had to sail at a speed of 31.3 yards to cover the difference of 290 yards between NH69729 and NH69730 in the two minutes from 0559 t0 0601.

The Prince of Wales Salvo Plot, even after being refined to correct for errors in range and bearing, showed that the Prince of Wales traveled 8500 yards in the 9-minute period from 0553 to 0602. This equates to 945 yards per minute or a speed of 28.0 knots, which is consistent with the figure quoted in Admiralty reports. The plot also shows that in the same time frame, the Bismarck covered 10,000 yards, which equates to 1110 yards per minute or a speed of 32.9 knots.

With a 17.5 percent speed advantage over the Prince of Wales, the Bismarck would still have to be doing 31.7 knots if the actual speed of the Prince of Wales had been only 27.0 knots. With both the photographic evidence and the Prince of Wales Salvo Plot indicating that the actual speed of the Bismarck may have been closer to 31.5 knots, I believe that we have to reexamine that possibility.

Best regards.

Bob

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Post by marcelo_malara » Mon Jan 23, 2006 7:22 pm

Excelent analysis. Can you post the scanned photos for us?

Thanks in advance.

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Post by Robert J. Winklareth » Wed Jan 25, 2006 3:54 pm

Hi Marcelo,

I would prefer to keep this tread open to a discussion of the methodology rather than get involved with the photographs themselves.

If you would give me your e-mail address, i would be happy to send you a nearly full-size copy of each photograph cited. Please contact me at:

robjwink@aol.com

Best regards.

Bob

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Photographs

Post by Bill Jurens » Thu Jan 26, 2006 6:33 am

Your initial hypothesis regarding photogrammetric calculations is incorrect.

In fact there is no justification whatsoever to support your statement that that there are no equations that can be used to compute distances in front of the horizon. The geometry about the horizon line is (nearly) symmetrical. In fact, it's usually EASIER to use photogrammetric methods to calculate distances to objects in front of the horizon, as the object tends to be closer (and clearer) and there is more of the object to see. Any standard textbook on terrestrial photogrammetry (and most that deal with aerial photography) will give you more equations than you can shake a stick at.

The methods you describe, while interesting, simply represent variations on well-known -- one might even say well-worn -- themes of photogrammetric computation. In the final analysis, they all depend upon knowing the scale of the photographic negative, which in these cases we do not. Incidentally, as negatives appear to no longer exist, it is incorrect to assume that archival sources can somehow provide better scale copies than anyone else; in reality they are just making photo enlargements from paper prints that were already (probably) cropped in the initial enlargement process. If they are simply copying paper prints already, then you are photogrammetrically dead in the water right from the get-go.

This is not to say that skilled work cannot derive a fair amount of reliable information even from a paper print, but the methods are obscure, and require a good deal of judgement -- one might even say luck -- to use successfully. In general in such situations I try to do the computation using at least three different methods. If the results agree fairly closely then one can have fair confidence that the computation(s) are correct. If the methods disagree substantively, then any conclusion at all is somewhat suspect.

Bill Jurens

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Post by marty1 » Thu Jan 26, 2006 4:42 pm

I agree with Mr. Jurens – particularly regarding using multiple methods to verify that one’s boundary conditions and/or problem assumptions are reasonable.

I came across methodologies for determining distance and scale within photos in both a NAVFAC Manual, and an Army Field Manual – FM 21-26. These methods require knowledge of negative size, focal length of the camera, real size of object being considered, and size of same object in photo. By solving several equations simultaneously it is possible to determine distance to objects within the 2D world of a photograph. I also came across a number of technical papers on the subject. Many of these references are only a google search away.

My meanderings with radial scales are based upon the same principles employed in optical stadimetric range finders, and/or choke sights. I had no knowledge of the NAVFAC or FM 21-26 methods until after I had already considered the problem from a range finder perspective. The range finder method required knowledge of the photographers position. In addition, it required establishing both height and width of foreground objects as well as their mil height. I did not require any knowledge of the camera, and didn’t realize this information was available until well into the previous thread. I am my satisfied that my range finder method works reasonably well – as long as one understands the source of potential error and its inherent limitations. But if I have accurate camera information, the NAVFAC and FM method is far simpler.

The biggest error source in either of the two approaches remains interpretation of edges on the Bismarck image. But I think – based upon the previous thread – it is possible to reduce the effect of this interpretation on the final answer by reasonable choices of what aspects of the Bismarck we choose to employ for our calculations.

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Post by Robert J. Winklareth » Fri Jan 27, 2006 8:17 pm

Hi Bill Jurens,

Thank you for your critique of my presentation. With respect to my initial hypothesis regarding photogrammetric calculation, I defer to your superior knowledge and experience in the field. When I tried to lay out graphically the situation, I could see no geometric relationships that could be used to calculate the distance to the Bismarck by finite trigonometric means. But being only a novice in the field, I could be wrong.

Perhaps you could enlighten me as to how one can determine the distance to a ship that is before the horizon in a photograph. In the case of NH69722, what result did you obtain by using that technique? I believe that Antonio was hoping that you would come up with something during the long discussion on NH69722 last summer in view of your expertise in the field.

I can understand your reluctance to delve too far into the discussion on NH69722 in view of your admitted lack of familiarity with cameras having focal plane shutters and interchangeable lenses, such as the Leica and Zeiss Contax. You therefore never had to concern yourself, as I did, with angles of view and fields of view inherent in lenses of different focal lengths for 35mm cameras and the characteristics associated therewith.

I agree with the comments in your posting of 21 August 2005 regarding NH69722 in which you stated that others were “barking up the wrong tree” by trying to determine the range to the Bismarck by analyzing the size and definition of items in the foreground. Again I see no geometric way of making such a determination. Marty’s guess of 1200-1300 meters seems low in view of my new figure of 1580 yards minimum and Antonio’s estimate of 2300-2500 yards. Vic Dale has the range out to 3000 meters.

It is interesting to note that in your critique of my presentation you actually found nothing technically wrong with my methodology. The most that you could say against it was that it simply represents variations on well-known and “well-worn” themes of photogrammetric computations. I am pleased to see that you support in a way the methodology presented in my original posting.

In my presentation, I stated that my methodology was not unique and could have been derived by anyone with an understanding of photographic optics, such as yourself. In fact, I even had you in mind when I wrote that. I thought that you certainly would have come up with this solution during the previous discussions of NH69722, but there was nothing forthcoming from you.

I finally had to work out the solution for myself from scratch without the benefit of any textbooks or military field manuals. While I recognize the limitations of possible cropping, that is not to say that one is “dead in the water,” as you suggest. At least it gives one something to work with instead of throwing up one’s hand and claiming that nothing meaningful can be derived from the photographs due to their poor quality, as you have so often said.

In my analysis, I prepared a chart showing the essential elements of information and final results for each photograph using lenses of the four most likely focal lengths for comparison purposes. As a result of this process, it became evident that Lagemann had switched lenses from a normal 50mm lens to a short telephoto 90mm lens. It made perfect sense because he also began taking pictures of the target area some 12 miles away at the same time and needed the additional magnification.

In stating that archival sources can provide better scale copies than anyone else, I was of course referring to commercial publications, which are known to crop photographs for artistic effect without regard to historical significance. If the original photographs from which the archival copies were made were not cropped, then we have a fairly accurate distance figure using my methodology. If cropped, at least we have a minimum range figure that is better than nothing.

You really can’t look at one photograph, or even a few, in isolation without regard to the other evidence at hand. We have to consider official reports, first-hand accounts from eyewitnesses at the scene, authoritative battle diagrams, and the like. They all have to fit together like a mosaic to form an integrated scenario of the circumstances.

Best regards.

Bob

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Photo evaluation

Post by Antonio Bonomi » Mon Jan 30, 2006 2:17 pm

Ciao Bob and all,

I agree with you Bob, in this field Bill Jurens is by far the most expert we can count on.

Please make sure you do not start from wrong assumptions by doing your evaluations.

The NH 697xx photos from National Historical archive, are ONLY PARTIAL reproduction of the original frame photos, so by making your measurements on them you run the risk to start from the wrong base.

Same photos are available sometimes full sized as you well know on Imperial War Museum ( IWM - London ) and in Bundesarchiv ( BA - Koblenz Germany ).

So far I have collected 30 photos of Denmark Strait battle showing the German ships, plus 5 showing the British ships.

Almost all the Nh 697xx photos you are referring to are partial reproductions of the original photo that I have in my hands much bigger and complete.

Than there is the famous PG film and the original signed paintures ( made by Ltnt J. C. Schmitz-Westerholt ) which do have historical value been made by a battle witness that was on board Prinz Eugen and was part of the Propaganda Kompanie ( PK organization ) just like Lagemann and F.O. Busch were part of.

Did you see the painture that was on Ober Kommando of Kriegsmarine from 1941 till 1944 and than donated to Admiral Lutjens family ?

As it is obvious and logic, while printing them the editors enlarge and cut pieces of the original photos selecting only the ones they like the most, that happened to my article as well as you can check.

But to study them you need full size in good quality and you need them all.

Closing, I made a trigonometric calculation of the photo and not only it is possible, it is quite easy to be made.

The 1300 meters evaluation made by Marty you refer to was not on Nhh69722, but on another photo.

On August 21st, 2005 Marty evaluated 1300 meters been the distance between Prinz Eugen and Bismarck on a photo taken after the battle, the one were all the used cartridges are on the main deck and some on the upper deck ( very interesting position for the cartridges to be Bob, guess how come they can be there at all ??? ), please verify.

So be careful not been confused,... on Nh69722 Marty evaluation was 2400 meters if I recall correclty, .. but again you can just verify yourself.

Marty wrote on August 11th, 2005 :
I estimate the angular height of Bismarck – as measured from Lagemann’s presumed position (and my imaginary optical range finder) – to be about 14-mils. Thats less than 1-degrees. An object with a known vertical dimension of 33-meters and an angular height of 14-mils yields a range of approximately 2400-meters.
Herr Nilsson ( Marc ) was on same type of range between 2300 and 2700 meters depending on some variables in consideration.

Similarly during my work last summer with Bill Jurens on 3 different methodologies, we ended up on same range, between 2300 and 2700 meters.

So an average of 2500 meters which are 2735 yards if I made a correct conversion all made by several persons with different methodologies and on different timeframes.

As said on the other post, lets see the parameters of your one to check and compare.

Ciao Antonio :D

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Post by Robert J. Winklareth » Mon Jan 30, 2006 8:07 pm

Ciao Antonio,

The primary reason for my original posting was to describe the methodology for determining the distance from the Prinz Eugen to the Bismarck from the various photographs for comparison purposes and not necessarily to come up with finite figures. Even though I posted the results of my analysis I knew that the NH photographs provided by the U.S. Naval Historical Center were at least slightly cropped because they did not measure up to the 2 x 3 ratio inherent in 35mm frames (24mm x 36mm).

The NH photographs were copied from the photographs in an official report by Paul Schmalenbach and other officers on the operation, and it is most likely that those photographs were slightly cropped. As I said, the 1580 yard figure for the separation between the Bismarck and the Prinz Eugen at 0556 when NH69722 was taken really represents a minimum distance. If all of the photographs were cropped to the same degree, would still be useful for comparative purposes.

If you have photographs that cover a wider area, they may have been derived from the original negatives and would therefore yield more accurate results than mine. Using my methodology, what results do you get for each of the photographs that you have acquired? If there is a consistent proportional difference between your photographs and mine, I could apply a factor and still use my photographs for analysis purposes.

My only problem is that according to the Prinz Eugen War Diary, the Bismarck was directly in Jasper’s line of sight to the Prince of Wales at 0609, if not even a minute or so earlier, causing the order to be given for the Prinz Eugen not to shoot over the Bismarck. Using the Prinz Eugen’s Battle Sketch and projecting a line toward the known position of the Prince of Wales at 0609, we know where the Bismarck should have been at that time.

Schmalenbach confirmed that the Bismarck came between the Prinz Eugen and the Prince of Wales by reporting that he glanced occasionally at the Bismarck as she was coming up on the port side of the Prinz Eugen during the latter phase of the battle. Captain Brinkmann’s endorsement of both of those reports attests to their accuracy and makes it impossible to just ignore.

If the Bismarck had been 2400 yards astern of the Prinz Eugen at 0556, she would have had to sail at a speed of 33.0 knots, 6.0 knots faster than the Prinz Eugen, to make up that distance on the Prinz Eugen, sailing at 27.0 knots, and come abreast of the Prinz Eugen even as late as 0608. In the broadside view of the Bismarck, her guns are trained about 15 degrees forward of her port beam (75 degrees from her port bow), so the Bismarck was probably still not quite in the Prinz Eugen’s sights at that time, a minute or so earlier.

It does not seem possible that the Bismarck could have traveled at a sustained speed of 33.0 knots in the 12 minutes from 0556 to 0608. If you can reconcile that minor little point, we may not be so far apart after all.

I’m sorry if I misinterpreted Marty’s distance of 1200 yards. The topic was NH69722, so I naturally assumed that was what he was referring to.

Best regards.

Bob

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Post by Ulrich Rudofsky » Mon Jan 30, 2006 8:30 pm

I have not been in the darkroom for many years, but I remember having to decide what to crop in photos of pathology specimens, since the format of the "35 mm" Leica/Leitz microscope camera did not fit into a 5X7 inch print. Whether you use the original “35 mm” negative (that is actually 36 mm x 24 mm) or “35 mm” negatives made from a positive photograph, there is always some cropping in the usual British-US formats of 5 in. x 7 in. or 8 in. x 10 in. prints, since the formats are not in the same relative proportions. So each time these copies of copies are copied you have to decide what to loose and you never know what errors may have been accumulating over the years of recopying.

I would guess that the persons taking the original photos or printing these photos for the first time, from which copies and recopies were later made, ever knew to what extent and extreme scrutiny and attempted analyses they would have to endure. I would advise caution about the reliance on distance measurements in photos unless the original uncropped version exists and supporting camera data exist. And even then......I was always able to go back to the original histology mircroscope slides, and that is not possible in the Bismarck post-mortem.
Ulrich

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Photo distances

Post by Antonio Bonomi » Mon Jan 30, 2006 10:21 pm

Ciao all,

@ Bob,

no problem Bob, it was easy to get confused among the photos on the previous post, so now you know what were all the evaluations.

I exactly used your approach, with the '' Tangent x '' trigonometry approach and been a techical guy I know trigonometry pretty well.

YES, it was a 50 mm fixed focal lenght lens with a 46 degree angle.

So you have to take the most complete photo, and you will realize that it will be proportional to a 24 x36 mm negative as it must be and apply the evaluation.

That is what I did to evaluate the first salvo photo.

So if you read thru my post, and evaluate all the measures and methodologies used, you will verify easily what I am saying, you have already all the measures, distances and formula used.

Moving into the last firing sequence, I see you are now focusing on something important, what was Prinz Eugen doing on last part of her track before ceasing fire at 06.09.

My invitation to look at the photo were Marty evaluated distance been 1300 meter was written on this purpose.

You will recall the description of Jasper saying that after 3rd turn Prinz Eugen was running a course that did not allowed forward turret group to bear to the enemy ( PoW ), his view was obscured by the funnel smoke.
Consequently he passed command to Ltnt Albrecth on the aft director which fired aft turrets precisely till the end.

Now on the photo I invited you to look at, were you can see all fired cartridges, you will notice some cartridges on the upper deck of Prinz Eugen.
Many are on the main deck of course, but few are still visible on the upper deck.
Now if you study Prinz Eugen unloading cartridge mechanism you will realize that the used cartridges were downloaded from the bottom back part of the turret.
This mean that for some time Prinz Eugen fired the aft turrets straight thru the stern ( and on this situation teh forward group of course cannot bear to th etarget of course, just as Jasper wrote ) otherwise it is NOT possible for those cartridges to be there on the photo.
Easy and elementary using famous Sherlock Holmes words, but one must know Prinz Eugen fundamental to understand it.

Now if you go on Prinz Eugen official battle map and on Prince of Wales official battle map and you connect the 2 ships at 06.08 you will realize exactly that situation, and Prinz Eugen still firing at PoW while Bismarck was not yet under Prinz Eugen firelane.

In fact Prinz Eugen was passing on Bismarck bow moving from east to west on course 270 ( from Port to Starboard of Bismarck ) while Bismarck was coming south on course 220.

On Bismarck they saw what was going on and ordered to Prinz Eugen NOT to shoot over the flagship, and soon after to cease fire.

There are 2+3 photos were you can clearly see this event sequence with clear Prinz Eugen wake visible on the sea and Bismarck coming.

Just verify it all and make your own evaluations, I made already mine as you know and now are available for everybody in printing thru my article on the battle.

@ Ulrich,

YES, you are right, those photos have been cutted and reprinted loosing quality way too many times.

They have been censored for sure, it is proven.

Who knows how many are out there still never seen by anybody ??

Last May I have found several new ones never printed :shock:

Some are taken surely out of the PG Film that is made on 35 mm negative as well and does shows distances as well.

So far I am taking some measurements only to have a very general idea of the distances between the 2 German ships, with very large tolerances due to what you correctly explained.

We definitively need to find more material, but we are progressing on right direction now and compared to 3 years ago today we know and have much more.

But on this first salvo photo due to the availability of so many Prinz Eugen mechanical details of the turret plates, the Bismarck full shadow and the confirmation of the lens been a 50 mm it is possible to determine the distance between Prinz Eugen and Bismarck with a good approssimations with an easy trigonometry calculation.

Ciao Antonio :D

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Post by marty1 » Mon Jan 30, 2006 11:13 pm

The attached image was something I sent to Ulrich a couple months back. It is basically a solved example of the method detailed in FM21-26 & NAVFAC manuals for developing appropriate photo scales.

This isn’t my “mil” scale method -- but I think I have already detailed my approach to developing a radial scale sufficiently in the original thread on this topic. I won't bore you'all by repeating any of this material.

Best Regards
marty

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BS fist salvo photo distance evaluation

Post by Antonio Bonomi » Tue Jan 31, 2006 5:01 pm

Ciao Marty and all,

what one can say on top of this addittional demonstration : :clap: :clap:

We now have half a dozen different methodologies all driving for same average results.

Some like the above one well sustained from defined procedures and technical stand points.

Thanks Marty for showing us the addittional example.

Ciao Antonio :D

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Post by Robert J. Winklareth » Wed Feb 01, 2006 8:42 pm

Hi all,

Antonio is correct in stating that NH69722 covers only a portion of the original photograph, and I thank him for referring me to the photograph in Fritz Otto Busch’s book “Prinz Eugen in the First Battle,” which has a more complete view of the scene. By enlarging NH69722 to cover the same area as shown in the book version, I came up with a result that closely resembles Antonio’s figure and even exceeds it when you consider resizing it to 2 x 3 (24mm x 36mm) format and final trimming.

By just expanding the area in NH69722 to that covered in the book picture, I get 2550 yards. By going further and resizing the photograph to a 2 x 3 format, I get 2680 yards. By going even further and considering that each edge of the photograph may have been trimmed by 1/8-inch in the printing process, I fet 2700 yards. This again is just the minimum, and the distance could be even further if evidence of additional cropping is uncovered.

This is all part of the analysis process. You continue to work outward as other versions of a photograph are uncovered that show a larger area of coverage than in earlier versions that you have. You don’t just call it quits because of the possibility of cropping and make no attempt to find out what the distance to another ship might be, especially of this information is significant to resolve an important issue.

A distance of 2700 yards is about 1-1/2 miles, and in view of a large area of the ship being included in the original photograph, one cannot help wonder if the original photograph was actually taken by a normal lens or might have been taken by a wider angle lens. The still starboard views as well as the battle film all seem to indicate that the Bismarck was about 1000 yards from the Prinz Eugen at that time, and it is hard to reconcile that figure with 2700 yards. There is little suggestion of cropping those views, and especially the battle film.

Perhaps it would be helpful to verify that 2700-yard distance by examining the subsequent photographs in the series. Since Antonio is already familiar with my analysis methodology, perhaps he could tell us all what the separation was for each of the subsequent photographs and the estimated time of each photograph. That should enable us to determine the efficacy of the Bismarck’s progression in relation to the Prinz Eugen and verify the sequence of the photographs.

I believe that this will help us arrive at a consensus regarding the photographic evidence, and from there we can reconsider the apparent conflicting information in the Prinz Eugen’s War Diary and resolve any remaining inconsistencies with the other documentary evidence.

Best regards.

Bob

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Photo estimation

Post by Antonio Bonomi » Wed Feb 01, 2006 10:59 pm

Ciao Bob and all,

I am glad you were able to determine yourself the correct distance showed by the first salvo photo.

Now we are all on the same level of estimation, around 2500 meters or 2700 yards more or less.

My personal opinion is that we are a bit over estimating the distance because of the small shadow of Bismarck since the hull is deep on the water, but that will bring back to the 2300 meters range, not more than that in any case.

I can confirm you the lens were 50 mm fixed since the angle is 46 degrees as confirmed by several measurements you can make on Prinz Eugen turrets mechanical details distances among each others.

Of course we can measure all the other photos same way, I did it already and I can do it again since I found new ones after I did it at first.

But before moving to the other photos I think it is helpful to evaluate what Bismarck did after this photo and before the Film and next photos will show us were Bismarck was after 06.03.

Did you ever took a look at those painture photo ??

http://www.forum.marinearchiv.de/viewto ... =5122#5122

Those are made by a battle witness that was on board Prinz Eugen just to do this job, a war reporter during the battle, and shows Bismarck at 06.00.

So we have a unique ( so far ) chance to evaluate what Bismarck did and were Bismarck was on the time elapsed between 05.55 ( first salvo or Nh69722 ) and the next available photo at 06.03.

Can you see were Bismarck sailed compared to Prinz Eugen ??

Can you see the Prinz Eugen wake clearly visible ??

Did you read were the painture was from 1941 till 1989 ??

Ciao Antonio :D

Robert J. Winklareth
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Post by Robert J. Winklareth » Fri Feb 03, 2006 9:51 pm

Hi Antonio and all,

I want to thank Antonio for providing the link to the Marinearchiv posting. I fully agree that Lt. Schmitz’s painting is an accurate representation of the Bismarck in action. It shows the Bismarck continuing to fire at the Prince of Wales for some time after passing the Prinz Eugen on the port side of the cruiser, and it conforms exactly to my own concept of the battle. It also depicts the Bismarck’s guns trained somewhat forward of her port beam, exactly as shown in the several photographs of the Bismarck in action.

As I said before, my problem is tying up all of the loose ends to account for every bit of evidence uncovered in one way or another, either accepting the evidence as fact or providing a rational explanation to the contrary. Some time ago, Antonio posted his reconstruction in detail on the Bismarck-class website, and it virtually the same as his article recently published in Storia Militare. The diagram of the overall battle scene appears to be identical to the one used in the article, except for the addition of the photographs and difference in language.

In that earlier posting, Antonio included a large-scale diagram showing the tracks of the Bismarck and Prinz Eugen with tick marks every minute throughout the battle.. That diagram was very helpful in understanding his version of the battle, and more specifically, the relative position of the German ships to each other during the battle. Unfortunately, Antonio did not include that diagram in his article for whatever reason.

Since Antonio proclaimed his reconstruction to be the one and only official version of the battle, and that all three webmasters supported that claim, I assume that Antonio considers his earlier posting to be completely accurate. Therefore, can you, Antonio, explain why the large-scale diagram of the tracks of the German ships shows a separation between the Bismarck and Prinz Eugen as being only 1275 yards at 0556 when Photo NH69722 was taken?

Obviously, either the calculated figure of 2400 yards or the plotted figure of 1275 yards must be wrong, and the actual figure could be anywhere in between those two distances or even outside those limits. When I realized this discrepancy, I began to consider whether Photo NH69722 had been taken with a wide-angle lens. A 35mm lens could reduce the distance to 1660 yards and a 28mm lens, not yet considered, could get the distance down to 1330 yards, which would be reasonably close to his diagram figure of 1275 yards.

In another area of concern, Antonio’s detailed diagram of the tracks of the German ships, shows the Bismarck recrossing the track of the Prinz Eugen at about 0608-1/2 when she was at a measured distance of 1340 yards astern of the cruiser. If the Bismarck had maintained a speed of 30.0 knots compared with 27.0 knots for the Prinz Eugen, it would have taken the Bismarck nearly 15 minutes to come abreast of the Prinz Eugen at a maximum rate of closure of 100 yards per minute.

Lt. Schmitz’s painting exacerbates the situation by showing the Bismarck continuing to fire at the Prince of Wales some time after passing the Prinz Eugen. That would add another few minutes to the time factor, bringing it close to 20 minutes. This would seem to indicate that the battle was still being fought at 0628, long after the battle was actually over at 0609. Do you, Antonio, have any explanation for this apparent discrepancy as well?

Best regards.

Bob

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