Hi Asher. I only have a marginal knowledge of all the plate sizes. Yes, full plate was 6.5 X 8.5. Half plate was not quite half but a little bigger at 4.75 X 6.5 I think. 1/4 plate was 3.25 X 4.25, a logical quarter.
I group the antique portrait and pictorial lenses into 3 rough categories. Smooth-sharp, very diffuse, and petzval. Petzval's have the sharp center and lovely surrounding oof bokeh that we all love. The very diffuse are lenses like the Pinkhams and others that have a lot of diffuse glow. These can ve very soft and romantic. Your PS945 actually falls in this category. The most subtle of them all though are the Heliar's and Cooke Portrellic like I used here. They have a very subtle smoothe but sharp effect that many people felt was the pinnacle of portrait type lenses. This Cooke is a "knuckler". It has the 2 large finger rings that can de-focus and add more softness if desired. Photographers like Hurrell used the Cooke lens for the sharp but glamorous look of the Hollywood Portrait era in the 1930's and '40's.
A 12 3/4" Cooke Series II Portrellic will cover 8X10 just fine. The next jump in the series is the 15 1/2" and it will cover an 11X14 especially at portrait distances. I'll go out on a limb and say that I have both Cookes and Heliar's and for some reason the Cooke's get taken along much more often than the comparable Heliar does. They are contrastier and somehow never seem to let me down.
Full Plate is currently enjoying quite a resurrection. Most thought it was long dead. Indeed no new film holders have been made since about 1923. That has driven prices quite mad with the current resurgence in popularity. Horseman is supposedly re-introducing modern holders. We hope so. Both Ebony and Chamonix are making new full plate size cameras now. The proportion of the plate is thought by many to be perfection. I'll admit that I am smitten by full plate size printed on 11X14 with a white rebate. Yes, I do cut all of my full plate film. The European 18X24cm size is close. I have some boxes of film this size I'm cutting down currently. Plus I also cut down 9 1/2" aerial recon film.
Jim,
One unfortunate side effect of the sharp focus of lenses already by the end of the 19th Century was that they were too sharp and harsh for portraits of humans. So portraitist sort the "holy grail" of softness yet sharp focus which might better render the humanity as opposed to the harsh industrial machine look of the emerging art of photography.
So a number of brilliantly simple designs were made to get the lens in focus but use defocus light to illuminate the center of the plane of focus at the same time. This then provided a soft focus with a blurred background. Solution used perforated disks. Cooke obtained a formulation for the lens which was based on the lens curvature. At open apertures the image was just like painting with light from angels. Harsh light was fine to use as this enhanced the effect. Light from a window became a glow from heaven.
I have one such lens!
Jim,
So this format is a "glass plate" measurement and not part of the standard 8"x10" standard derived from paper sheets. I guess you cut film down to that size. Could you explain where the "plate" ratios came from?
Is this Cooke lens a portrait lens or perhaps a process lens?
I wonder about coverage for 8"x10"? Which Cooke lenses would you suggest for portrait besides the PS 945 229mm soft focus lens which I have?
Asher