Jump to content


Photo

Panning Photography


  • Please log in to reply
41 replies to this topic

#1 a_tifoosi

a_tifoosi
  • Member

  • 268 posts
  • Joined: February 05

Posted 08 July 2022 - 10:34

Just yesterday I was reading Gary Doyle's fantastic biography on Ralph de Palma (Gentleman Champion: Golden Age Books, 2005) and came across a picture (p. 222) that depitcs Johnny Aitken at the Sheepshead Bay Speedway in 1916. The image is credited to be from the William Collins Collection —unfortunately, I haven't been able to find it on the net. What really drew my attention was the panning effect: the car is on focus [sic] while the grandstand at the background is totally panned.

 

At first I thought that I had never seen this panning effect on such an old picture, but then the image of Jacques-Henri Lartigue taken during the Grand Prix de l'ACF 1913 came to my mind. In any case, this picture has become very popular because it combined the panoramic photographic technique with a focal plane shutter or 'slit-scan' distortion (explained here).

 

In Lartigue et les autos de course (Motors Mania, 2008), Pierre Darmendrail explains that (...) to create the impression of speed, Lartigue used the panoramic photographic technique, rather uncommon at the time, and which consisted in following the movement of the subject by panning the camera at the same speed. In his diary he notes that the idea had first occured during the 1912 ACF Grand Prix to photograph Boillot's Peugeot. It is true that some of the photographs of the race had been taken using this technique, but Lartigue is mistaken as to the time at which the idea crossed his mind as he had already been experimenting with the method for a long time: as early as 1908-1909 there are pictures of model aeroplanes that he and his brother Zissou built, photographed in full flight and obviously using the panoramic technique.

 

Indeed, Lartigue had first employed this photographic technique —during a motor race— on occasion of the Grand Prix de l'ACF 1912. Page 73 depicts the picture of Georges Boillot —it can be found too in the albums of Lartigue: here (p. 23/144)— where it can be easily observed that the photographer was following the motion of the car with his camera:

 

Capture.jpg

 

It is clear that the 'slit-scan' distortion was very common at the time because of the use of cameras with a focal plane vertical shutter. As an example, this page from La Vie au Grand Air no. 460 (13 July 1907), where funnily all pictures had been taken statically —note the frozen background— with a shutter speed of 1/2000 sec:

 

Capture.jpg

 
I presume that Lartigue could try this rather new panoramic photographic technique because of his position of a young, free, wealthy, amateur photographer —as opposite to the professional photojournalists that were being published in magazines.
 
Do you get to know pictures of pre-1912 motor racing that show this panning effect?
 
 
Thanks!
Narcís.


Advertisement

#2 Nick Planas

Nick Planas
  • Member

  • 349 posts
  • Joined: April 08

Posted 08 July 2022 - 10:55

I've always been fascinated by the 'slit-scan' distortion - the effect was (and still is, I think) captured by motion-picture cartoonists so that whenever there was a high speed chase or race, the cars always have elliptical wheels leaning forwards (various Disney, Hanna Barbera, and e/g Wacky Races movies).



#3 backfire

backfire
  • Member

  • 117 posts
  • Joined: March 12

Posted 08 July 2022 - 17:51

I'm not sure that any of the "speed distortion" was ever intentional. The high shutter speeds could only be achieved by a focal plane shutter with the ability to get "effective" high speeds by allowing the opening blind to be closely followed by the closing blind causing the moving slit. This is why all focal plane shuttered cameras have maximum shutter speed for using with flash (the maximum speed in which the shutter is fully open for a moment).

In these old action shots the shutter was open a lot longer than the effective speed but had the exposure effect of that high speed. The real shutter speed was probably around 1/50 sec., so the car will have moved across the frame during that time, so if the shot is not panned the image will still be fairly sharp but distorted. 

I would guess, not being used to panning techniques, as perfected by the early motorsport snappers, Lartigue possibly got the iconic shot by accident, apologies to him if I'm wrong.



#4 Glengavel

Glengavel
  • Member

  • 1,300 posts
  • Joined: September 06

Posted 08 July 2022 - 18:05

If you pan at just the right speed would it reduce or increase the distortion? I think if the shutter slit is descending the car will have moved forward slightly and so the distortion will have reduced.

#5 backfire

backfire
  • Member

  • 117 posts
  • Joined: March 12

Posted 08 July 2022 - 18:17

If you pan at just the right speed would it reduce or increase the distortion? I think if the shutter slit is descending the car will have moved forward slightly and so the distortion will have reduced.

It would decrease to distortion to almost zero if you were very accurate, as the car would not be moving in the frame. To get perfect front to back sharpness (in any camera) or lack of distortion in a vertical focal plane camera,  it's much easier stand well back with a long lens (with a wide lens the front of the car moves through the focal plane at a different speed to the rear). Sorry, I'm waffling now.



#6 a_tifoosi

a_tifoosi
  • Member

  • 268 posts
  • Joined: February 05

Posted 08 July 2022 - 21:06

If you pan at just the right speed would it reduce or increase the distortion? I think if the shutter slit is descending the car will have moved forward slightly and so the distortion will have reduced.

 

If the panning is perfectly matched to the car's speed, there would be no distortion whatsoever.



#7 a_tifoosi

a_tifoosi
  • Member

  • 268 posts
  • Joined: February 05

Posted 08 July 2022 - 21:53

Unless mitaken, I think that we are mixing two different topics:

  • Panoramic photographic technique.
  • Focal plane shutter or 'slit-scan' distortion.
This picture from Lartigue depicts René Croquet (Th. Schneider) on occasion of the Grand Prix de l'ACF 1913:
si.jpg
Source: Lartigue albums, which can be found here (p. 22/144). Note that Lartigue identified the picture wrongly; sometimes this error is still being reproduced.
 
The picture above has become very popular because it combines both panning and slit-scan effects. The curtains moved from bottom to top. The race car tilts to the right because the car itself moved quite quickly compared to the curtains. The spectators lean to the left because Lartigue was panning the camera from left to right to follow the car.
 
At that time, the focal plane shutter distortion was quite common —be it an example the pictures of the Grand Prix de l'ACF 1907 published by La Vie au Grand Air. Such a distorsion was never intentional, but caused by the specificity of these old shutters/cameras.
 
On the contrary, the fact of following the motion of the car by panning the camera was obviously intentional. As an example, the picture I have previously posted that depicts Boillot during the Grand Prix de l'ACF 1912. In this case there's no apparent slit-scan distortion —this shot was rather frontal, so the relative speed between curtains and the vehicle motion was probably minimized—, but the background is clearly blurry because Lartigue was panning the camera.
 

I would guess, not being used to panning techniques, as perfected by the early motorsport snappers, Lartigue possibly got the iconic shot by accident, apologies to him if I'm wrong.

 

In my opinion, yes and no. I agree that the overall effect —where the car tilts to one side and the spectators lean to the opposite side— was probably accidental. But the use of the panning technique, as used in 1912 —or, according to Pierre Darmendrail, in 1908/09 while shooting model planes—, was probably intentional.

 

 

Narcís.



#8 Doug Nye

Doug Nye
  • Member

  • 11,524 posts
  • Joined: February 02

Posted 09 July 2022 - 05:51

Wouldn't it simply have been a natural reflex for the cameraman to follow the progress of the object he is trying to capture - rather than attempting to time his shutter release for the fleeting instant the car he was trying to photograph might, just, be in frame?  It would have been the same if the passing subject had been a race horse, or a running figure although relative speeds would have been less...

 

In any case experience would quickly have proved how fixed camera/passing subject would almost certainly capture an unsatisfactory image.  Unless the cameraman was seeking a blur.

 

DCN



#9 D-Type

D-Type
  • Member

  • 9,699 posts
  • Joined: February 03

Posted 09 July 2022 - 16:53

Given the weight of a glass plate camera, I'm wondering whether it would be possible to pan one if it were mounted on a tripod?  (I'm assuming the car is on a level road)



#10 backfire

backfire
  • Member

  • 117 posts
  • Joined: March 12

Posted 09 July 2022 - 17:02

Given the weight of a glass plate camera, I'm wondering whether it would be possible to pan one if it were mounted on a tripod?  (I'm assuming the car is on a level road)

I think that's very true, although there is some evidence of panning - the car is slightly sharper than the background. 



#11 robert dick

robert dick
  • Member

  • 1,298 posts
  • Joined: October 02

Posted 09 July 2022 - 17:44

Photo taken by Nathan Lazarnick in May 1907 during the 24-hour race on the Point Breeze track near Philadelphia, Pennsylvania:
Ralph Mongini in a Matheson (from the Detroit Public Library)

https://digitalcolle...ream/IMAGE/view
 



#12 ellrosso

ellrosso
  • Member

  • 1,616 posts
  • Joined: May 07

Posted 10 July 2022 - 23:49

You can pan a large format camera on a tripod but you need a fluid head (cine camera) head which you can adjust to keep it level through the pan movement otherwise you will get an arc happening through the pan. I have done it with a 6x17cm (2 1/4" x 7") Linhof panorama camera - its possible but was very restrictive.

I ended up doing it hand held which worked out fine. A 4x5" field camera with side handles would probably be even easier - Linhof made a beauty for aerial work years ago. 



#13 a_tifoosi

a_tifoosi
  • Member

  • 268 posts
  • Joined: February 05

Posted 11 July 2022 - 05:54

Photo taken by Nathan Lazarnick in May 1907 during the 24-hour race on the Point Breeze track near Philadelphia, Pennsylvania:
Ralph Mongini in a Matheson (from the Detroit Public Library)

https://digitalcolle...ream/IMAGE/view
 

 

:clap:  Many thanks, Robert. What a magnificent picture.



#14 Odseybod

Odseybod
  • Member

  • 1,800 posts
  • Joined: January 08

Posted 11 July 2022 - 13:03

Don'tforget that just to add to the fun, many of these early cameras showed the photographer the image he was shooting reversed laterally and/or vertically. So, adopting the role of M. Lartigue, you pan your apparatus smoothly left to right to follow the racing car, yet you see it travelling right to left.

Incidentally this was still the case for some time with any camera having a viewfinder with prisms. The first Leuca universal finder from the 1930s, for example, cleverly showed you the coverage in reverse of all fenses from 35mm to 135mm. You soon learn to disengage brain when shooting with it trackside (if it was ever engaged in the first place), though airshows are rather more complicated as you have to factor in the up-down element too.

#15 ellrosso

ellrosso
  • Member

  • 1,616 posts
  • Joined: May 07

Posted 11 July 2022 - 21:41

Yes Tony, that's quite a tough one. I borrowed a Hasselblad with eye-level finder and 250mm tele lens from the studio I was freelancing out of in Adelaide to use at ASGT (mix sports cars and sports sedans) round at AIR. Ended up just pointing it and panning as it totally did my head in.

Ended up OK though as out of 1 120 roll b/w I had 2 shots published in Auto Action report. Bit of luck mixed in too though.....



#16 robert dick

robert dick
  • Member

  • 1,298 posts
  • Joined: October 02

Posted 20 July 2022 - 08:24

From The Automobile Magazine, July 1905:

atmagjul05p507.jpg
atmagjul05p508.jpg
atmagjul05p509.jpg
 



#17 a_tifoosi

a_tifoosi
  • Member

  • 268 posts
  • Joined: February 05

Posted 21 July 2022 - 07:40

Many thanks, Robert :clap: !

 

To be honest, I am not sure to understand the explanation behind the statement the upper parts of the wheels travel faster than the lower parts.

 

Apart from that, the focal plane shutter or 'slit-scan' distortion is very well described.

 

Funnily, there is no reference to the possibility of reducing the distortion by following the movement of the subject, i.e. panning the camera, at the same speed. The large cameras, the image being reversed, etc. didn't make it obvious.



#18 Collombin

Collombin
  • Member

  • 8,596 posts
  • Joined: March 05

Posted 21 July 2022 - 08:20

I am not sure to understand the explanation behind the statement the upper parts of the wheels travel faster than the lower parts

Essentially the wheel as a whole is moving in a horizontal direction. From the point of view of an observer, the rotational motion of the wheel sometimes offsets this horizontal motion as it's moving the opposite way (eg at a point where the wheel is touching the ground) but as that point on the wheel rotates and reaches the top the rotational motion is in the same direction as the overall horizontal motion reaching a peak complementary point when it gets to the very top of the wheel.

Hmm. Explanations haven't come very far in 117 years, have they?

Edited by Collombin, 21 July 2022 - 08:21.


#19 D-Type

D-Type
  • Member

  • 9,699 posts
  • Joined: February 03

Posted 21 July 2022 - 08:38

I wonder. . . 

With a horizontally running blind (vertical slit) of a modern, say 1990s pre-electronic0 camera such as a Nikon or Pentax, I think you still get distortion but the effect will be to either shorten or stretch the whole image depending on the direction.  This will only be apparent on a side-on shot. The wheels will be oval, but not leaning forward, they will be taller than they are wide, or longer than they are high depending on the direction.  I don't know if I have ever noticed this effect, but this is probably because most shots are 3/4 front or occasionally rear views and not side on..



Advertisement

#20 Doug Nye

Doug Nye
  • Member

  • 11,524 posts
  • Joined: February 02

Posted 21 July 2022 - 11:03

Really?

 

GPL-76-Italian-GP-Regazzoni.jpg

 

Panning Photo Copyright: The GP Library

 

DCN



#21 Odseybod

Odseybod
  • Member

  • 1,800 posts
  • Joined: January 08

Posted 21 July 2022 - 18:00

My non-scientific brain reckons the degree of wheel ovalness (ovoidity?) would be very dependent on the shutter speed selected. The selected speed would have to be slow enough to allow each part of the wheel to to be exposed on the next area of the film as the shutter opened, until the whole frame had been exposed.

 

(There's a lot of helpful arm-waving going on here to explain the principle - surely that helps?)

 

But because longer lenses mean shorter shutter speeds, in order to avoid camera shake, it's very rare nowadays to have the ovoid wheel problem (if it is a problem). Maybe time to try to simulate it over the weekend with a train and a standard lens?



#22 Nick Planas

Nick Planas
  • Member

  • 349 posts
  • Joined: April 08

Posted 22 July 2022 - 06:16

Hmm. Explanations haven't come very far in 117 years, have they?

I remember trying to explain this 'oval wheel' phenomenon to a group of young friends, and all but one got it. I tried a different tack but still he didn't get it. After a couple of other attempts I gave up. I was thinking 'there's always one' but it could just have been my choice of words. 'Twas ever thus, I'm sure.



#23 ellrosso

ellrosso
  • Member

  • 1,616 posts
  • Joined: May 07

Posted 26 July 2022 - 07:39

So much of this topic is about the vertical slit focal plane shutter, shutter speeds and large format film. I remembered these attached shots taken by Kiwi George Silk on a specific camera which runs MOVING film across the camera in front of a slit shutter. This really accentuates the distortion but is essentially the same

phenomenon as the early shots shown on this thread. Also the shutter is spring loaded - how much bearing that has is open to conjecture. The story and pics are from US Camera 1962. Fantastic classic book if you ever find one in a bookstore. I will put up some of my own experimental shots after this post.

TNFGeorge-Silk-pics.jpgTNFGeorge-Silk-text.jpg



#24 ellrosso

ellrosso
  • Member

  • 1,616 posts
  • Joined: May 07

Posted 26 July 2022 - 08:00

These shots were taken on either a Fuji Panorama 6x17cm camera. The b/w of Brock at Murray's Corner in 1997 was taken on a 150mm tele - equivalent to maybe a short tele (65mm) on 35mm. The color of Brock at Murray's was taken on the same lens but much closer to the car - hence very narrow space in focus. Both shot at 125th second. The Griffins Bend shot is on 65mm (std for the pano camera and equivalent to maybe 20mm on 35mm) at 60th sec shutter speed. The rerason I have put these in is to show the difference between a leaf shutter and a vertical slit shutter. These are large format lenses to give coverage to a piece of film 7" wide. They have the leaf shutter actually built into the lens rather than a shutter in the camera in front of the film plane (the leaf shutter closes in a circular fashion). You get distortion but it is not actually making the wheels ovoid and leaning forward. The point of focus is extremely narrow but it is pin sharp. Using the camera is a bit of a lottery as you have to transfer you exposure and focus over from a 35mm camera and the viewfinder is not coupled so you have to guess your framing too.

8171-R-Brock-97-TNF.jpg2636-R-Broc-97-TNF.jpgTNF4271-R-Brock-97.jpg


Edited by ellrosso, 26 July 2022 - 19:43.


#25 ellrosso

ellrosso
  • Member

  • 1,616 posts
  • Joined: May 07

Posted 26 July 2022 - 08:24

And so to 35mm with its tiny piece of film. You get distortion of a kind but nothing like the large format film. The Geoff Brabham shot was taken on a 135mm tele at 1/60th sec. The Audi at Stop/Go corner was on a 35mm w/angle from memory at 1/30th sec. This was Thursday practice day and I was very close!
The reason the Audi shot is included is because the focal plane shutter is travelling vertically rather than horizontally in the Brabham shot (and virtually every shot you see in print taken on 35mm). The distortion on the highlights of the rear wheel is a bit different but still no wheel distortion. The size of film makes a big difference. Hope this doesn't confuse the issue even more! TNF1793-R-GBrab-81.jpghttps://i.postimg.cc...-R-GBrab-81.jpgTNF3088-R-Audi-97.jpg

#26 Kvadrat

Kvadrat
  • Member

  • 982 posts
  • Joined: August 01

Posted 16 August 2022 - 02:12

This year's London Formula E race.

 

E-2-2-14-08-22-13-00-Eurosport-1-HD-ts-s
 
E-2-2-14-08-22-13-00-Eurosport-1-HD-ts-s


#27 a_tifoosi

a_tifoosi
  • Member

  • 268 posts
  • Joined: February 05

Posted 16 August 2022 - 06:28

Interesting. I understand that the fisheye effect of the wide-angle lens might be partially contributing to the wheel distortion (?)


Edited by a_tifoosi, 16 August 2022 - 06:28.


#28 a_tifoosi

a_tifoosi
  • Member

  • 268 posts
  • Joined: February 05

Posted 10 November 2023 - 12:07

Just today I got to know this picture from Robert Demachy: "En vitesse", which dates from 1903. Interestingly it used the gum bichromate process to manipulate the blur of the speeding car and amplify the dust cloud —hence looking more like a painting than a photograph. Just a few years later the panning technique would be used to reflect the same idea of speed.

 



#29 10kDA

10kDA
  • Member

  • 978 posts
  • Joined: July 09

Posted 16 November 2023 - 12:20

Came across this photo of the Douglas XB-42A depicting a leaning hanger due to the phenomenon discussed here.

 

a7138840-144-Douglas_XB-42A_during_a_low



#30 Michael Ferner

Michael Ferner
  • Member

  • 7,151 posts
  • Joined: November 09

Posted 16 November 2023 - 12:52

Naahhh... They were built that way on purpose!  :p



#31 2Bob

2Bob
  • Member

  • 581 posts
  • Joined: November 05

Posted 16 November 2023 - 23:20

I have only just got around to reading this topic (scanning really, pun intended) but wanted to add a little about "The curtains moved from bottom to top.". My first camera bought for me in about 1957 (I think) by my photography mad father so that I could take photos of car racing was a Purma (once again i think, old age and memory come into this) which took square negatives using a curtain (or slit really) that moved. Interesting is that it had a fixed apature but exposure was varied by which way the camera was held ie normal way up the slit moved from left to right driven by a spring. Held one 'side' up (90 degrees to normal) driven by spring and gravity and other side up against the spring and against gravity. 'Shutter' speed being something like 1/50 of a second, 1/125 of a second or 1/500 of a second. Naturally I used 500th of a second for moving cars! The few photos I still have from Gnu Blas 1957/8 don't seem to show any distortion fgor what it is worth..

#32 a_tifoosi

a_tifoosi
  • Member

  • 268 posts
  • Joined: February 05

Posted 15 January 2024 - 17:57

DCN's latest book on Maurice Louis Branger's motor racing photography contains some mind-blowing pictures where the panning effect can be clearly observed, as early as 1903! Two clear examples are found in:

 

  • Page 73: Denis de Boisse (De Boisse) during the voiturette race of the Circuit des Ardennes (23 June 1903)
  • Page 64: Henri Farman (Panhard) during the Gordon Bennett (2 July 1903)  

 

Amazing :clap: !



#33 Doug Nye

Doug Nye
  • Member

  • 11,524 posts
  • Joined: February 02

Posted 15 January 2024 - 20:39

Thanks for the mention.  Here's the fearless Denis de Boisse shot by Maurice Louis Branger.

 

GPL-BRANGER-360mm-1903-064-Circuit-des-A

 

Photo by Branger from The GP Library

 

DCN



#34 Odseybod

Odseybod
  • Member

  • 1,800 posts
  • Joined: January 08

Posted 15 January 2024 - 21:22

Two rather nerdy points occur.

 

The road surface seems unusually solid and dust-free, hence the intrepid pilot's lack of goggles (though impacts with the local insect life might still have been a worry).

 

And clever Monsieur Branger has used just the right shutter speed to give us a hint of the wheel spokes while keeping the vehicle sharp - I'd guess the plate camera equivalent of 1/125th of a second, maybe slower? All part nowadays of the black art of choosing the perfect compromise between too slow - everything blurred - and too fast, freezing the moving elements to the extent that everything looks static. Aircraft propellers are a particular challenge ...



#35 Nick Planas

Nick Planas
  • Member

  • 349 posts
  • Joined: April 08

Posted 15 January 2024 - 22:27

Thanks for the mention.  Here's the fearless Denis de Boisse shot by Maurice Louis Branger.

 

GPL-BRANGER-360mm-1903-064-Circuit-des-A

 

Photo by Branger from The GP Library

 

DCN

It struck me how I expected to see the wheels slope forwards as in so many shots from that era, but the driver IS sloping forwards! He looks almost like Quasimodo, as if he was moving faster than the car. Can't blame that on the shutter  :rotfl:



#36 dolomite

dolomite
  • Member

  • 1,182 posts
  • Joined: March 01

Posted 15 January 2024 - 23:30

It struck me how I expected to see the wheels slope forwards as in so many shots from that era, but the driver IS sloping forwards! He looks almost like Quasimodo, as if he was moving faster than the car. Can't blame that on the shutter  :rotfl:

 


The wheels would slope forward if the camera remained stationary as the car passed. Instead because the camera is panning to follow the car it's the background that that is moving relative to the camera, hence the effect is to make the trees and people in the background slope backwards.

#37 Catalina Park

Catalina Park
  • Member

  • 6,768 posts
  • Joined: July 01

Posted 16 January 2024 - 10:21

The car is stationary, it's the tree that's moving.



#38 Michael Ferner

Michael Ferner
  • Member

  • 7,151 posts
  • Joined: November 09

Posted 16 January 2024 - 10:47

Movement itself is just an illusion of the mind...



#39 small block

small block
  • New Member

  • 189 posts
  • Joined: March 05

Posted 16 January 2024 - 13:45

M. de Boisse appears to be wearing that fashion horror of the 1970s - a 'wet-look' nylon jacket!



Advertisement

#40 elansprint72

elansprint72
  • Member

  • 4,027 posts
  • Joined: September 08

Posted 18 January 2024 - 07:24

The “elliptical wheel question” seems to have been around ever since man tried to photograph any wheeled vehicle passing by! The type of plate camera at the time of Lartigue would normally have had a slit curtain focal plane shutter with the slit moving vertically; the simplest explanation I have found is:
“the bottom of the picture is taken first, then as the slit moves upward the rest of the picture is taken. So the bottom shows where the car was at the beginning of the shot, the top shows where it was at the end of the shot, and it moved forward during that time.”
Variables in the mix are- shutter speed, speed of vehicle, distance from camera to vehicle and focal length of lens (wider lenses tend to have greater barrel distortion).
Of course those guys would not be looking at any image in the camera, they would have a simple wire-frame viewfinder on top of the camera to act as a guide; I’ve used this on my Speed Graphic and it’s a brilliantly simple device.
From what I read even digital cameras, where the shutter is essentially an on/off switch, have the possibility of these aberrations, stacked sensors and other fancy electric gee-gaws are beyond the comprehension of my aged Mechanical Engineering brain!

#41 PCC

PCC
  • Member

  • 1,062 posts
  • Joined: August 06

Posted 18 January 2024 - 17:51

Very clear explanation Pete, thank you!

 

I'd guess that one other variable would be the speed of the pan relative to the speed of the car. Impossible to measure, and difficult to repeat consistently, but in those days photography was expected to be difficult.



#42 robert dick

robert dick
  • Member

  • 1,298 posts
  • Joined: October 02

Posted 22 January 2024 - 09:10

A few details concerning the Denis-De Boisse, because it's not fully apparent on the Branger photo that it was a sophisticated racing voiturette.

The engine was furnished by De Dion-Bouton, a specially prepared 12-hp two-cylinder (100 x 110 mm, 1,7-litre; automatic/atmospheric intake valves, two carburetors), output about 20 hp at 1,600 rpm, transmitted by an expanding band clutch to a three-speed gearbox/direct in third, in unit with the differential. The rear axle was of the De Dion type, with the De Dion axle/tube placed below the differential/half axles.

Top speed was about 90 km/h, when de Boisse was crouching forward.


n6bidyab.jpg

Gearbox/differential/De Dion axle/without the half-axles:
5ya6kgx8.jpg

Kilometre sprint Dourdan, October 1903 (Jules Beau collection/Bibliothèque Nationale/Paris):
gp6v6f4p.jpg

Gaillon hillclimb, November 1903:
kjpnplrt.jpg
 


Edited by robert dick, 22 January 2024 - 09:13.