Someone Please Tell Me: Difference between Cooke Series II and VI

[Richard K.]

What differences would one see in photographs taken by the Cooke Portrait Anastigmats Series IIa vs Series VI? Other than maximum aperture, are there other differences, eg. in softness rendering? I have an opportunity to buy them from an acquaintance (way) out of town. Thanks!:)

[ederphoto]

The only difference as you mentined is the maximum opening size . As for the image itself , if you are shooting outside it means blurred background , but that is not going to happen because you will need a very high shutter speed and that's out of the question with large lenses such 14", 15" or 18" . If shooting in the studio , it will allow you to use less powerful lights . The lowest setting on my Visatec is about 200 watts and that's too much for a Cooke at f4 . If the difference was so important , George Hurrel , one of the most famous Hollywood photographers would have gone for a series II instead of the series VI as he did . Other thing to note is that most hollywood portrait photographers were using lights from 200 watts to 1,000 watts ! Meaning they had to stop down quite a bit !

[8x10 user]

Larger apertures have a more distinct Bokeh with greater separation.

I cant say much about the Vi but the soft focus effect seems to be more pronounced when a larger aperture is used. Emils photos with his IIa are the softest I've seen from a TTH Cooke triplet. This would make sense as there would be more glass surface to generate spherical abberation when the elements are moved into the softer configurations.

For this type of lens it is best to select your aperture and softness setting based on your own artistic preference for the scene or subject. Depending on your format you might be able to use a Sinar behind the lens shutter to control exposure. Otherwise most use the Packard shutter/ ND filters / development compensation combination, use the Jim Galli shutter trick, or they shoot wet plate so the exposures are several seconds.

[ederphoto]

The solo purpouse of the soft focus device is to add sofness . The sharp part of the image should remain unaltered . If more softness is added to the image because the lens was used wide open , that would mean that the lens is not completely sharp fully open . This is not the case with Cooke lenses , they are sharp all the way . If you look close at a Canon 85mm 1.2 or a nikon 55mm 1.2 you will see that they are soft , but a cooke lens is compretly sharp except for the DOF that is more shallow and that could give a false impression of more softness when if fact you get more out of focus . I understant the ideia of more softness with open , that's how some lenses like a Verito and Struss work . The background separation is a fact with faster lenses and so are the faster shutter speeds . One thing is certain , any cooke lens is a cooke lens and they are all great ! Even the rebranded ones !

[Mark Sawyer]

...One thing is certain , any cooke lens is a cooke lens and they are all great ! Even the rebranded ones !

What lenses did Cooke make that were rebranded?

[goamules]

Yeah, I'll take a few of those. Unless they are from that shyster seller on ebay that, because they happen to be a triplet, calls B&L magic lantern lenses "Cooke Triplets."

[8x10 user]

Yes, faster lenses have more background separation, that is why many people use them; artistically for selective focus photography.

The Cooke design is very sharp wide open. When all three elements are in there proper "sharp" location the lens is well corrected for the three major forms of aberration's including chromatic abberation, spherical abberation, and coma (as well as field curvature). Because it is free of these forms of astigmatism the lens was called the Cooke anastigmat.

When either both of the front elements, or the rear element, are moved closer to the aperture, spherical abberation is introduced into the image and the lens becomes soft focus. As with all soft focus lenses the apparent DOF is increased ever so slightly. The EFL is also reduced, this is why it is best to apply soft focus before doing your final focus adjustments.

Spherical abberation occurs when the inner and outer part of the lens focuses at different points (focal lengths). It is the inner part of the lens that creates the image forming portion and the outer part of the glass is left out of focus to create the glow.

So when used in the soft configuration, having a larger aperture should increase maximum softness in the way that a vertio is softer then a vertiar. I noticed this seems to hold true with Emils photos from his 305mm F/3.5. I personal have only used the F/4.5 versions of the Cooke triplet, so far, but I now own a 20+lb F/3.5 monster of my own :D ... However the aperture came apart during shipping so the lens will need service before I can use it.

I can say the IIa is an impressive looking and very large optic. On the softest setting, the glass is right up close to the aperture. Although I have do not have a formal education on lens design. I'm fairly sure having the giant glass element so close to the aperture will mean more softness versus the smaller element of the 4.5 of 5.6 versions.

Emil's pictures seem to back up this theory.


http://www.largeformatphotography.info/forum/attachment.php?attachmentid=142432&d=1447883049

[Mark Sawyer]

The Cooke design is very sharp wide open. When all three elements are in there proper "sharp" location the lens is well corrected for the three major forms of aberration's including chromatic abberation, spherical abberation, and coma (as well as field curvature). Because it is free of these forms of astigmatism the lens was called the Cooke anastigmat...

Astigmatism is a completely different aberration, the inability to focus both the horizontal and the vertical on the same plane.



So when used in the soft configuration, having a larger aperture should increase maximum softness in the way that a vertio is softer then a vertiar...

The Verito wide open at f/4 and the Veritar wide open at f/6 have about the same softness, (albeit a different look). More spherical aberration was designed into the Veritar so it would be soft at f/6. The goal was to have a soft 14-inch lens that was small enough to fit into a modern shutter.

My overall impression of the Cooke Portrait Lenses is that they don't go as soft as Pictorial-style soft lenses, regardless of aperture size. Cooke's will soften skin texture, but they don't get the pronounced softness or the halo of light around the highlights that Verito's will. For that, you'd need the Cooke RV/RVP/Achromatic Portrait Lens.

[8x10 user]

Hmm, I did not know that about the vertiar, very cool.

I like the Gundlach achromatic a great deal, I'd love to find an RVP to compare it to.

[Emil Schildt]

I'd love to find an RVP to compare it to.

Not RPV but RV so close...

[Mark Sawyer]

Lovely image, Emil! A nice thread on the RV/RVP/Achromatic Portrait Lens here: http://www.largeformatphotography.info/forum/showthread.php?94655-Rapid-View-Portrait-(RVP)-Pictorial-lens

[8x10 user]

Gundlach Achromatic, stopped down to ~8

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