Brass Knob on Petzvel / Darlot / etc

**Jac@stafford.net** · 25-Jan-2015, 10:31

Be prepared for a roller-coaster ride, Stone.

The very fact is that regardless of what you read, you will never know how a lens renders for you until you use it. Having a lot to write about means little.
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**Jac@stafford.net** · 25-Jan-2015, 10:33

Originally Posted by Nodda Duma

The difference is about 2-3 hours' labor for a good machinist, including wages and overhead.

In my area, a good machinist is very difficult to find, and when you do find one, he's very expensive. Most 'machinists' today are really CNC machine operators who never knew the real thing.
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**Will Frostmill** · 25-Jan-2015, 10:45

Originally Posted by StoneNYC

Thanks so far, this is all helping toward an end goal of a first bought inexpensive brass lens. It's looking like I'm leaning toward "views" and "hemispheric" mostly because of price, I DON'T want a portrait lens as I'm not into soft focus lenses in the center, I do like the idea of aberrations in the corners and sharp in the middle, but again a nice balance as Jim C. mentioned earlier the Darlot which is what I've been looking at, but which Darlot did you mean Jim?

Thanks.

I've never found one for cheap, but I understand that there are "cheap-ish" petzval formula brass lenses made for early slide projectors (magic lanterns). Some modern, plastic, slide projector lenses also use the Petzval formula.

**StoneNYC** · 25-Jan-2015, 11:12

Originally Posted by Will Frostmill

I've never found one for cheap, but I understand that there are "cheap-ish" petzval formula brass lenses made for early slide projectors (magic lanterns). Some modern, plastic, slide projector lenses also use the Petzval formula.

Thanks, yes I've seen those too, I'm less interested in a projection version, the Hemispheric Darlot brand lenses tend to go for less it seems but SOUND more like what I would want. Which is why I'm trying to figure out how it differs from other lenses, I'm understanding (and correct me if I'm wrong) that the Darlot Rapid Hemispheric is simply slower than the petzval? Like f/4 for the Hemispheric vs f/3.5? For a petzval which also will have more swirl, but will the Henispheric also have some swirl?

And then there's coverage because I want one to cover 8x10 for contact portraits. Though I'm open to starting out with a 4x5 lens if it's cheap enough for trial purposes I suppose.

**kintatsu** · 25-Jan-2015, 11:22

Originally Posted by StoneNYC

I'm just surprised there isn't someone who's used all these lenses on the exact same scene to compare the differences.

I don't think he did them all on the same scenes, but Ansel Adams used a wide variety of lenses. He also kept meticulous notes. By looking at different images where the lens info is available, you can see some of the differences. A quick search for Adon and Ansel Adams came up with several images made with the Dallmeyer Adon lens, and similar results for Dagor. Also check out Edward Weston's stuff, he often noted things like that.

While you may not find all the types you're looking for, there is plenty of info to be found. Patience and InvestiGoogling, especially by using the terms and image search will help get you closer.

I don't know how much this helps, but I hope it provides something useful for you to go on.

**jnantz** · 25-Jan-2015, 13:03

Originally Posted by Nodda Duma

The difference is about 2-3 hours' labor for a good machinist, including wages and overhead. It's also cheaper to paint a room yourself vs hiring a painter. It's not that much of a mystery.

removing a spacer or unscrewing an element a little bit requires a machinest for 2-3 hours labor ?

**8x10 user** · 25-Jan-2015, 13:21

What type of look are you going for? If you want the sharp in the center and soft in the edges look then get a petzval. If you are looking for something with an even field of sharp focus and smooth creamy bokeh then you want a different lens type. How much depth of focus do you want? The lenses with lower DOF and larger apertures sell for more then their less rapid counterparts. An F/5 petzval will be a lot more affordable then an F/3.5. For the smooth and even look then you might want to consider something like a Cooke Series II, Tessar, Heliar, Rapid Rectilinear (F/8), Extra rapid rectilinear (some euryscopes), a dagor, or even a soft focus lens when stopped down. The less rapid Cookes are more affordable and so are the versions without soft focus. Projection petzval lenses are the cheapest petzvals and have the same sort of look but with less features like soft focus and aperture control. Projection petzvals that cover formats above 4x5 are more rare. Petvals that cover 8x10 are quite large, especially large aperture versions. A modern option to look into would be the Cooke XVa.