Vintage Brass Lenses

[drew bedo]

<p>I have been looking at old brass lenses lately . . .the ones that used to go for <$20 at the camera shows in the ‘80s and’90s. Now I am interested and have a few questions.</p>

<p>What is the difference between a “landscape” lens and a “portrate”l ens?<br>

Can a Petzval lens be either or both?<br>

Is there a difference between a camera lens and a magic lantern lens in this era of photography (1860-1890)?</p>

[dhbebb]

<p>Landscape lens - will cover the specified plate size edge to edge - small maximum stop. The simplest type is a spectacle lens (single-element "meniscus" lens). the next refinement was an achromat (2 elements of different glass cemented together), then a double achromat ("rapid rectilinear" or symmetrical lens), then an anastigmat (3-element Cooke lens, 4-element Tessar type, 6-element Planar or "double-Gauss" or "plasmat" lens). <br>

A portrait lens is designed to pass as much light as possible and is sharp in the middle but never at the edges. Most famous design - Petzval. No, there's isn't much difference between a camera lens and a magic lantern lens in this era of photography (1860-1890), except that a projection lens doesn't have a variable aperture. Petzval lenses were made for a long time after as projection lenses because of their large aperture and because their elements are air spaced with no cement to turn brown due to heat.</p>

[colin carron]

<p>Portrait / Landscape : I think it came down to the maximum aperture. A typical Rapid Landscape lens of the 1860's - 1880's such as the Dallmeyer 1884 Rapid Landscape lens had a max aperture of f11 and was intended to be stopped down to get best coverage and sharpness. The Portrait lenses of the time were as fast as they could sensibly be to reduce the exposure times when the sitter was supposed to remain still. Photographic emulsions were slow so any help from the lens was worth a lot. So along with the early Petzval type with a max aperture of f4 you could get the Rapid Rectilinear Portrait lens of 1889 with a max aperture of f4. </p>

[drew bedo]

<p>David and Collin: Thanks for the concise clarifiation. This is the type of reply I was hoping for.</p>

[dhbebb]

<p>Slight correction (now that I have a reference book to hand) - a Petzval lens has 4 elements - it has a cemented pair at the front and an air-spaced pair at the back. </p>

[Two23]

<p>Portrait lens--typically a Petzval (1840--1900ish.) Sharp in center, softer towards the edges. It was called a portrait lens because it was a fast lens (e.g. f3.5) so it took less time for exposure to be made on wet plate. People could sit still long enough to use a portrait lens. Still in use in the 1930s due to very classic look. Some portrait artists still use them today for the special bokeh.</p>

<p>Landscape lens--first was the achromatic doublet (1839--1890ish.) These were sharper across the frame than a Petzval, but typically something like f16, f22. Exposure time on wet plate, dags, was too long for portrait use. Ironically, the forward lens group of Petzval is an achromatic doublet.</p>

<p>Projection lens/lantern lens--a Petzval that has no slot for Waterhouse stops. It's a wide open Petzval. Generally no difference in optical quality.</p>

<p>Other landscape lenses, pre-1890. The third popular lens (1866--1900+) was the Rapid Rectilinear (aka Aplanat.) Four elements, symmetrical. Sharp across the frame, relatively fast at f8. These were generally used as landscape/general purpose lenses, but could also be used for portraits.</p>

<p>Kent in SD</p>

[charles_mason]

<p>Wow you guys know a lot about all this. Can you help with which of those old lenses are best for the circular swirly background Bokeh? Thanks!</p>

[Two23]

<p>That would be the Petzval.<br>

Kent in SD</p>

[paolo_servadei]

<blockquote>

<p>That would be the Petzval.</p>

</blockquote>

<p>I'd add that the swirlies are the typical effect of:<br>

1) Fast Petzvals<br>

2) focals used for a larger format than what they were made for</p>

<p>Petzvals have a very large illumination circle, but they have a good definition only in the center of that circle.<br>

That is... if a certain lens was to be used for 4x5", there are good chances that i would swirl if used with a 5x7" film. Even more likely if the Petzval has large lenses (vs.legth of the barrel) and if there is no internal stop (some have a restriction inside the barrel, which reduces the speed of the lens - the stop can be removed by a good machinist)</p>

<p>have fun</p>

<p> Paolo</p>

[thomas_bond_ii]

<p>Hi, I am looking at a Darlot, Paris, B.F. Co. 3 5/8" x 3 5/8" x 1 1/2" diameter No. 2 Hemispherique DA 5413. First would like to know the date (Approx) also it is a LANDSCAPE lens? I am thinking of adapting it to my Canon. I know Petzvals and Rapids brass can be adapted, thanks :)</p><div></div>