British photographic history

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Reversing mirror in a daguerreotype camera

I have a query about reversing mirrors/prisms that could be used as an attachment in front of the lens on an early daguerreotype camera. If the photographer did not want the
photographic image to be reversed from the way it appeared in real life, he had
to utilise such a device. I realise that as the years went by there were lenses
and devices inside cameras that made this no longer a necessity. Unless I am
badly mistaken, however, during the early years, if the daguerreotypist was
taking a landscape or architectural photograph that they wished not to be backwards,
they would need to have the camera lens pointing, not at their chosen subject,
but at approximately a 90 degree angle from what they planned to document. The
relevant direction was concerned with what the angled mirror recorded, not the
front of the lens. This runs counter to how we intuitively think of the way the
19th century photographer or indeed, any photographer, set up their
camera. Thus, if an early calotypist or daguerreotypist wanted to photograph
the leaning tower at Pisa, he might have his camera pointed at a field of cows,
with the mirror picking up the leaning tower situated perpendicular to the cow field.


My question is whether anyone knows of the existence of a photograph showing a photographer with his camera clearly pointed at roughly right angles to the object of his attention?
My first choice would be an original photograph but a painting or engraving
would also be interesting and failing that, a period written description, eg., if
using a reversing mirror, the object to be photographed should be at an angle
from the direction your camera is facing…

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I have been taking notes of the drawings by Daguerre from which the original cameras were made by his son-in-law. There is no mirror or prism shown before the lens but there is a mirror angled behind the ground glass screen to enable easier focusing. A mirror such as you describe is currently used inside Polaroid cameras so that the image from the lens is reflected onto the film laying flat on the bottom of the camera, a simple solution available to the early Daguerrotype user.
Given the fact that most of the pictures made at the time were portraits one must remember that the reversed image is most pleasing to the subject and so lateral correction of the image was not a pressing matter. This does not preclude the existence of correcting devices but I have not seen any illustration of these. I shall investigate further.
Further to my last comment see (I posted a URL of such a device on an early Giroux camera but it does not show in this site, so where can I send it to you )

Peter Knowlden
Dear Peter,

Thanks for your contribution. I think you will find that in Daguerre's 1839 manual there is a 'reversing mirror' illustrated (see plate IV, figure 2, in at least one edition) which could be placed at an angle just in front of the lens. Remember, when Daguerre's invention was announced, portraits were scarcely possible, so getting landscape or architecture views correctly reversed could be important. I am most interested in seeing any kind of picture (engraving or photograph- nobody has yet found one for me) that shows the camera set up at a 90 degree angle to the subject.

Your Polaroid analogy is interesting.

I would be pleased to see your illustration. You can send to:



Alan Greene's book Primitive Photography shows a diagram of a camera with a reversing prism attached to the lens, which would require the camera body to be pointed 90 degrees off from the subject, in order to point the prism assembly at the subject. I think he got the diagram from his source material. I've been thinking about how to create such a device; I would attach it to a filter step-up ring so that it could be firmly fixed to the lens, since any relative motion between the two would creat image jitter on the focal plane. How to attach a glass prism to a threaded metal ring would be the challenge.
Hi Andrew
Process cameras used in the printing industry very often had 90º prisms mounted on the lenses. The technology has changed now so these prisms come up for sale now and then, sometimes complete with the lens. Cooke prisms made by Taylor, Taylor & Hobson are the most common. Alex

Thanks for your input. I do have illustrations of drawings of cameras which use a reversing mirror, though thanks for the tip on Alan Greene's book. Someone sent me a drawing of a tintype camera with a reversing mirror in operation, but I am still looking for a photograph or drawing of a daguerreotype camera actually in use with the lense pointed at a 45-90 degree angle away from the subject to be photographed.


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