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What’s the difference between a pre-set and non pre-set lens?


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#1 Adam Paul

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Posted 16 November 2005 - 06:53 PM

What?s the difference between a pre-set and non pre-set lens? Which is better?
Will a 10mm cover S16?
Thank you.
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#2 Clive Tobin

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Posted 16 November 2005 - 08:06 PM

What?s the difference between a pre-set and non pre-set lens? Which is better?


A preset lens lets you set the final F-stop ahead of time. You would focus wide open, then turn the preset ring until it stops (without having to look at it or count clicks) and you will then be at the preset aperture.

A fully manual lens usually has click stops. So if you focus wide open, then you count the clicks to get down to your desired filming aperture before you start running.

More desirable is an automatic diaphragm (and I don't mean automatic exposure.) You focus wide open, then push a button to close down to the preset aperture, at which point the camera also starts running. This is available on some of the zoom lenses for Bolex cameras, if you are using the camera's built-in spring motor.
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#3 Boris Belay

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Posted 16 November 2005 - 08:22 PM

Adam, As Clive points out, pre-set or non-pre-set does not determine the quality of the lens, at least not its optical quality (but it's ease of use).
If, as I suspect, you mean to talk about pre-set SWITAR lenses (ie, those lenses made by Kern for Bolex in particular), they are supposed to be better only because they were designed later and with better optics. So yes, a pre-set Switar is generally better than its earlier 'click aperture' equivalent.
As for 10mm. lenses covering Super-16, it entirely depends on the particular brand and model. A focal length does not define the amount of film surface that is correctly rendered (covered), just the field of view a lens 'takes in'. So you need to be more precise about which lens you're wondering about.
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#4 Adam Paul

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Posted 16 November 2005 - 08:50 PM

bobolex, you were right, I was talking about Switars. I was wondering if the 10mm Switar covers S-16. Thank you.
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#5 Marcus Frakes

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Posted 17 November 2005 - 04:15 AM

bobolex, you were right, I was talking about Switars. I was wondering if the 10mm Switar covers S-16. Thank you.


Bobolex, a lens came with my NPR package (thanks again btw) that says "Macro-Switar 1:1,1 f-26mm H16RX" It fits on the NPR mount and I can focus. But I assumed this was meant for a Bolex camera only (because of the "RX")? Isn't it more geared towards close up work like animations??
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#6 Boris Belay

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Posted 17 November 2005 - 10:06 AM

Marcus, Congratualtions on the Eclair purchase !

Yes, the RX-branded lenses were made specifically for Bolex RefleX (to correct the optical aberrations of the fixed prism). So RX lenses should only be used on Bolex RX cameras (Rex-0 -> Rex5, SB, SBM, EBM, EL, and none other), and those cameras should use these lenses.
So the basic rule is : "If Bolex Reflex, then RX lens", in simple logic terms.
One main exception is that most (but not quite all) fixed focal lenses 75mm. (3") or longer are not "RX" branded as the aberrations mostly do not matter for telephoto lenses -- so the Switar 75mm 1:1,9 sold with the better Rex kits was never Rx-specified (but the Switar 50 1:1,4 was).

Specifically, it's more complicated. Here's most of what I know, brand by brand :

Angénieux zoom lenses were specified for Bolex RX, on most lenses from the late 60's on (particularly the 12-120/1:2,2 and mighty 9,5-95/1:2,2). It's easy to see as the base of the zoom is silver (instead of the usual black C mount), with H16 RX engraved in black. They're also identified as "Type C" around the rim ("Type A" were models with reflex viewfinders built in, and "Type B" were all others : reg. C mount, Arri, Eclair, etc.)
Less easy to identify are the earlier Angénieux models (admitedly a bit old now) : for instance, the 17-68/1:2,2 (silver body) was classified as "Type L1" (built-in reflex VF), "Type L2" (all other mounts), and "Type L3" for Bolex Reflex, with the cryptic "Special P." engraved around the central rim of the lens. It took me a while to figure that one out : I thought the P. may stand for Pathé, but it's for Paillard, which was the French's preferred way of referring to Bolex cameras in the 50's.
As far as I know, no Angénieux fixed focal lenses are RX-specified, so use at your own risk... (that includes the common 10/1:1,9 and the great 25/1:0,95). Angénieux then stopped bothering with Bolex specificities in their (somewhat) more recent zooms, which were not even offered in C mount anyway.

Schneider (Kreuznach) lenses are simpler (German systematicity!) : they engraved all of their made-for-Bolex-Rex lenses with the "RX" brand, including their (less common) zoom lenses, and these are all in the black series. The only confusion may arise from the fact that some of these black series lens are inscribed "Für Bolex" but not "RX" : as far as I understand, that's because the black series lenses were originally designed to Bolex's specifications (generalized, convenient size for the turret, same front rim diameter,...), so "For Bolex", but not all of these were for H16 Rex cameras, only the RX ones.
The silver Schneider lenses, whether from the 50's, 60's or recent ones, are not RX-specified : proceed with caution...

SOM/Berthiot is the 3rd main supplier of Bolex lenses (besides Kern, obviously). Again, their RX-specified lenses are clearly labeled "RX" or "H16 RX", either on the front rim or around the mount. These include the 25/1:1,4 and 10/1:1,9 notably.
There are more exceptions here, however. A little known one is the Berthiot Cinor 25/1:1,8 which is listed as RX-compatible in Bolex catalogs of the mid-60's and was sold as a cheaper alternative to the Kern Switar 25/1:1,4 (it is sometimes identified as a Lytar 25/1:1,8).
None of the SOM/Berthiot zoom lenses were RX-engraved, but most are compatible with H16 Reflex cameras nevertheless, notably the Pan-Cinor 17,5-75/1:2,3 ; 17-85/1:2 (both models) ; 12-120/1:3,3 ; and of course the tiny 17-85/1:3,8 Compact, which was sold as the only zoom that could be mounted on the turret along with other lenses (usually a 10 and a 25).
One little known fact that makes for good deals : SOM/Berthiot was a French state-owned company linked to the weapons industry and it was re-organized in the 70's into the SOPELEM, which kept producing those nice lenses for a while. Furthermore, Sopelem made a deal with Rank Taylor Hobson, who distributed their zoom lenses ("Montal" range) in the UK : again, the same as the SOM Berthiot lenses (17-85, 12-120,...) but generally better, since they are more recent. And often a great bargain, since people don't know what they are.

Kern, even after it became independant of Paillard Inc., always branded their lenses as RX or not (except, obviously for 75mm. and above). This includes even the very latest Multi-Coated series, since some were also produced for H16M (single lens, non reflex cameras), and therefore are 'regular' C-mount specified. So both ranges of regular and RX-specified lenses are clearly identified by Kern (thanks!).
Only one exception (there had to be one) : the very first lenses produced by Kern for the H16 Reflex (original 1957 model) were labeled as "DV" in red, rather than the more explicit "H16 RX" that came soon afterwards. So all DV lenses are RX lenses, but you know they're old.
As a side note: the "AR" mark on Kern lenses denotes an Anti Reflection coating (appears in the early 50's). So it's not incompatible with the RX brand as it is sometimes thought (AR vs. RX lenses), in fact all RX lenses are coated, but the "AR" is dropped out of the engraving probably because of the room necessary around the rim of those small lenses to fit the "H16 RX" mention. And the "DV" lenses still have the "AR" inscription too.

Besides that, I can't think of other brands that made lenses for the Bolex Reflex models. So lenses from American makers such as Kodak, Elgeet, Wollensack, Bausch & Lomb,... as well as Japanese (Canon, Soligor,...), British (Cooke, non-Sopelem RTH, Dallmeyer,...), or German (Zeiss in particular) are not specified for H16 Rex's to my knowledge. Which means, and that's the final confusing bit, that they may work, possibly, maybe, perhaps, at some opening, on a case by case basis. But it's trial and error and you're likely to waste film in the process.

As for Super-16 compatibility, that's another question. Who has hands-on experience with either kinds of Switar 10mm shooting Super-16 ? I think the pre-set version does cover it.

-B
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#7 flavio filho

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Posted 01 June 2013 - 01:38 PM

Hello.

Very interesting post.
I was wondering the difference between AR and RX lenses and now it's clear for me, thanks.
I'm considering buying a Kern 75mm AR, but in terms of quality and sharpness of image, would itbe any differen to buy a normal or a AR one? Maybe the AR have inferior image quality due to quality of glass as they're older?
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#8 Scott Pickering

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Posted 06 September 2017 - 09:17 PM

How much is a non preset 10mm lens worth?


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#9 Dom Jaeger

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Posted 06 September 2017 - 11:11 PM

Check the sold listings on ebay for an idea of what people pay. If you wait for an auction you can pick them up for as little as $100, buy-it-now prices will vary from about $250 to ridiculous amounts like $600 from shameless re-sellers like Calkovsky.


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#10 Jon O'Brien

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Posted 06 September 2017 - 11:21 PM

I just bought a RX Switar f1.8 16mm for $235 AUD from Germany. Postage included.

 

Here's a question just to throw out there, if anyone feels motivated to answer. I've also got a Nikkor f1.8 50mm SLR lens, and am using it on a C mount adapter on a Bolex H16 S-16. I notice focusing with the ground glass that it goes beyond infinity. Eg. objects that should be focused at infinity are sharp just before the focus ring gets to infinity. Then it goes maybe a 3mm more of a turn on the focus ring and it goes back out of focus. But as long as all is fine, and I get the image I want on the GG, all is good? Am aware of the stopping down to approx. f4 on 50mm non-RX lenses and bigger. Thanks.


Edited by Jon O'Brien, 06 September 2017 - 11:30 PM.

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#11 Simon Wyss

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Posted 07 September 2017 - 12:18 AM

A lens tech can adjust the infinity stop. Basically, it’s about tightening the set screws of the focus ring when the system is focused at a cloud, the moon or something else far away. A collimator can be used as well in conjunction with a high grade front mirror and a special lens in the light path. This works also in a basement, with rain or just confined to a table.

 

The Kern-Paillard Switar 10-1.6 consists of ten elements in five groups. That is already some glass. These wide angles should actually cost more than the three and four elements Yvar 75, 100, and 150 mm. As Dom sais, some people ask pharmacists prices without offering any warranty. They should be shot with hot cheese goes a saying in my country.

 

Schema Switar10-1.6.jpg


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#12 Dom Jaeger

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Posted 07 September 2017 - 01:03 AM

Some lenses deliberately allow the focus travel to go past the infinity mark, other stop right on infinity. If infinity is sharp before you reach the mark then the lens back-focus setting is a bit shorter than the camera flange depth, but as long as you're only eye-focussing and you can reach infinity it's not really a problem. Stills lenses tend to have minimal focus marks and a short focus throw anyway, so the scale isn't of much use.

 

With wider angle lenses where it can be hard to accurately judge focus by eye (especially through a small viewfinder), a reliable focus scale can be a helpful gauge of where to set focus.

 

With zooms a back-focus discepancy is more of an issue - it will cause the focus scale error to get worse as the focal length decreases, and the lens won't hold focus through a zoom (something demanded of cine zooms more than stills ones).

 

In professional cinematography accurate focus scales are still expected and checked during prep.


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