Photographic Technology Question

[cvblarg]

I apologize if this has been asked and answered before, but was hoping to get some basic info about period lenses and distortion issues. Were lens angles standardized, and if so, what were the typical angles being used by the likes of Gardner and Brady for field work both for standard and stereoscopic views? I have read that the stereoscopic lenses of the day could cause fish-bowl effect and also tended to exaggerate vertical height, but that's beyond my basic knowledge. Any help or links are greatly appreciated.

 

[UCVRelics]

I apologize if this has been asked and answered before, but was hoping to get some basic info about period lenses and distortion issues. Were lens angles standardized, and if so, what were the typical angles being used by the likes of Gardner and Brady for field work both for standard and stereoscopic views? I have read that the stereoscopic lenses of the day could cause fish-bowl effect and also tended to exaggerate vertical height, but that's beyond my basic knowledge. Any help or links are greatly appreciated.

Its a GREAT question as all of us here love photos. Lets see if the folks at the https://civilwartalk.com/forums/period-photos-examinations.94/ have the answers.

 

[Old Soldier]

Lenses were fairly simple. Most were reasonably well made at this time - if they used one - as pinhole cameras were still being used. If they were the 'standard' lens ie round with a fairly long focal length, then they were usually good quality, machined glass - the same as used in telescopes. Glass negative were the most usual for formal portrait and landscape views. Most 'distortions' on photos at this time are usually due to the movement during the long exposure time (up to 10 minutes indoors) so most studios were equipped with 'stands' for the subject - to keep them still. They can be seen on a number of these photos:

Most outdoor photos would be arranged on a sunny, calm day for that reason, as anything that moved would be blurred. This applied to both glass negative and tintype. Tintype is a 'direct' positive and, due to the lens, miror image. Glass negatives could be reversed, tintype could not. Tintype was MUCH cheaper and most 'going to war' photos are tintype. They do not weather well. The main identifier is the fastening of jackets and either mirrored or erased buckles or locks on the left of the rifle.

Stereo cameras usually had TWO lenses and they would focus separately on the same plate! They would be slightly offset to one another and would have a 3D appearance when viewed through a propr stereo viewer. The two lenses had to be exactly the same. These are typical cameras of the period:

...............................Box camera....................................................................Stereo camera

Both would require a good solid tripod to be mounted upon to avoid any camera movement during the exposure which would ruin any photograph.

A lot of 'distortion' is also found in the deteriation of the medium over the years. This is often Photoshopped out of the image:

 

[cvblarg]

Here's an article discussing vertical exaggeration in stereoscopic photos.

https://www.asprs.org/wp-content/uploads/pers/1953journal/sep/1953_sep_579-588.pdf

My familiarity with perspective distortion is limited to wide angle (the wider the angle, the more background objects seem distant to the camera and each other) v. telescopic (more magnification, the closer distant objects seem to the camera and each other).

I also know that photos taken of objects much higher than a photo taken pointing at the horizon have a tendency to lean away from the center point of the image (vertical distorition). You see this frequently with pictures of tall buildings/structures if the building/structure being photographed is not directly in the photo center.

Controlling Vertical Distortion in Architectural Photography – Tony & Chelsea Northrup

northrup.photo

I am trying to see how this may have affected outdoor photography during the Civil War, and in particular, to what extent it might affect locating the sites of those historical photos.

 

[Old Soldier]

Here's an article discussing vertical exaggeration in stereoscopic photos.

https://www.asprs.org/wp-content/uploads/pers/1953journal/sep/1953_sep_579-588.pdf

My familiarity with perspective distortion is limited to wide angle (the wider the angle, the more background objects seem distant to the camera and each other) v. telescopic (more magnification, the closer distant objects seem to the camera and each other).

I also know that photos taken of objects much higher than a photo taken pointing at the horizon have a tendency to lean away from the center point of the image (vertical distorition). You see this frequently with pictures of tall buildings/structures if the building/structure being photographed is not directly in the photo center.

Controlling Vertical Distortion in Architectural Photography – Tony & Chelsea Northrup

northrup.photo

I am trying to see how this may have affected outdoor photography during the Civil War, and in particular, to what extent it might affect locating the sites of those historical photos.

Most of this distortion I have seen in relatively modern photos (c1900) when photography was more of a hobby and cameras were more affordable and not treated as optical instruments, as they were around the 1860s. There seems to be relatively little distortion in the photos of the 1860s. It could also be linked to the use of SMALLER lenses (like the stereo camera) too.

Most photographers in the 1860s were aware of spherical distortion and many of their photos were taken at a distance, but I still have problems finding distortion on photos of this era. Here are some old photos from around 1865, taken on the old Stockton and Darlington Railway, and from the Civil War. There is little distortion evident:

I also suspect that many 'distortions' were caused more by the positioning of the camera, mainly which point you wanted to be center, but was above the centerline of the camera. That will alter the perspective and will typically be more evident on stereo as well.