The chart on each aperture card lists the effective aperture when the bellows are extended for focusing on closer subjects
The aperture column: The physical diameter of the aperture opening in millimeters.
The f: column: Lists the effective f: number at each focus distance. (This is a simple way to compensate for “bellows draw”)
The Focus column: Lists three typical subject-to-camera distances (Landscape photos, group, and portrait photos).
The Lens-To-Film column: Lists the typical bellows draw when this lens is focused at each distance (for reference purposes).
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There is nothing new here, it has all been invented long ago...
Je ne cherche pas. Je trouve. I do not seek. I find, ...Pablo Picasso
Lens Coverage Graphic
120mm f:2.1
135mm f:2.3
190mm f:3.2
250mm f:4.2
285mm f:4.6
Large Format Lenses
4x5, 5x7, etc.
Fall-off
graphic
120mm f:1.6
250mm f:3.4
335mm f:4.6
500mm f:6.9
1000mm 13.7
Very Large Format Lenses
11x14, 16x20++, etc.
Fall-off
graphic
790mm f:5.4
Ultra Large Format Lenses
Mammoth Cameras, Camera Obscura, etc.
120mm f:2.1.RB
Fall-off
graphic
Data
graphic
135mm f:2.3.RB
Fall-off
graphic
Data
graphic
RB67 Compatible Lenses
One of these data sheets will be supplied with each lens.
(click below to download)
Fall-off graphics approximate how a film format fits within the image circle.
(click below to download)
Two articles from 1921 regarding the use of soft focus lenses will help if this is your first experience with historic lenses. (click to download)
Surface Mount flange:
For small, thin boards.
(Technika, Speed Graphic, etc.)
Vignetting may be possible.
Hole precision is unimportant.
Recess Mount flange:
No Vignetting.
Stronger, More secure.
For larger, thicker boards.
Hole precision is more critical.
Lens boards:
There’s nothing mysterious about a lens board. It’s not a precision part of the photographic process, contrary to marketing hype. A simple 1/4” light trap between the board and the camera is all that’s needed.
I use quality 5 or 7 ply Baltic Birch plywood cut to fit your camera, sealed against warping and finish coated with either a satin black or a clear poly finish.The the backside is painted flat black, the lens is mounted with stainless steel screws.
In the photo are two Entrepid boards (a 96mm Technika size & a 139mm Sinar size). also, a. 6x6” Deardorff, & a custom 96mm Technika board.