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Loss of resolution when using 35mm still lenses on a 16mm cine camera?


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#1 David Mellet

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Posted 07 October 2013 - 12:01 PM

Hello,

 

I recently acquired a Bolex 16mm camera I would like to use with a c-mount adapter that will let me use 35mm still lenses on the camera.

 

It is the single port Bolex. So it will not have the reflex prism in the light path.

 

My question is, all things being equal, will I see a resolution loss when using 35mm still lenses as they are designed differently.

 

Will a nice c-mount Switar prime give me sharper images over a Nikon 35mm still lens?

 

Thanks.

 

David


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#2 Simon Wyss

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Posted 07 October 2013 - 12:34 PM

Why less resolution?

 

No, no, a lens’ resolving power is independent from the image area cropped out its picture circle. You only have to keep in mind that the so-called normal focal length of the standard 16-mm. format is an inch or 25 mm. So a 24 mm is a wide-angle lens to a SLR photo camera but a normal lens to 16. An f = 28 mm still can be considered as normal, perspective-wise.

 

The problem you may encounter is that SLR lenses do not match the flange focal distance which is 0.69" or 17,52 mm with 16-mm. film cameras. So the still camera lens might require re-mounting, something not necessarily what you wish to do to your objectives and purse.

 

The Kern Switar basically follow the six element double Gauss design like Schneider Xenon, Angénieux S 41, Berthiot Cinor, and many other makes. A Nikkor 50-2 or a Canon 50-2 are about the same, only bigger. Ciné lenses reach about one additional stop of aperture due to the less stringent demands of filmers. In other words, too good a picture is not visible, the finest details go lost in the film.

 

But there is a film that has more resolving power than the best lens you can find for your Paillard-Bolex H 16 M. Gigabitfilm 40.

 

The best C-mount lenses are the Kinoptik Apochromats from Paris, France. You can buy them new. They can cost you couple grand easily.


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#3 Heikki Repo

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Posted 07 October 2013 - 12:46 PM

With a non-reflex Bolex I'd suggest you stick to C-mount lenses. Reason? Adapters to C-mount are quite often in some ways lacking. I bought for my Eclair ACL a Contax to C-mount adapter from Ebay. The first adapter was otherwise quite nice but the flange focal length was wrong: I could only focus to objects really close. Next adapter was advertised allowing focusing to infinity -- which it does, but unfortunately I can also focus past infinity! Infinity marking on the lens and all other focus marks are off. Through the lens focusing it is then!

 

With Bolex H16 M you haven't got any way of making sure your focus is right. Thus I recommend staying with lenses that you can trust to have the right markings on them so that you can use cine tape or estimate the correct focus.


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#4 David Cunningham

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Posted 07 October 2013 - 01:02 PM

You won't have a "loss of resolution" by using a 35mm still lens on a 16mm movie camera.  However, you should use a very good lens as cheaper still lens are frequently not that good in the first place because they are expecting a film format that will be blown up a whole lot less than a 4x3 16mm movie film frame.  A cheap still lens is going to expect to project a sharp image onto a 36x24mm frame that will rarely ever be blown up past an 5x7.  So, it's overall "sharpness" and "resolving power" is probably not going to be as high as a lens designed for a high-end movie camera expecting to project it's image on a 10x7.5mm frame and then be blown up to 20x15 feet or more.  

 

Plus, you are now "zooming in" on the center of the frame the lens was designed for.  You're only using the middle 25% (or probably less) of the lens image area and THEN blowing that up to 20x15 or more!

 

So, I guess the short of the story is if you use a VERY good and VERY high quality lens, you will have good results.  If you use a cheap amateur photo lens, you'll get cheap results.


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#5 Chris Millar

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Posted 07 October 2013 - 03:41 PM

Slightly different perspective coming from large format... (11x14", 8x10" etc...)

 

(edit>> I see David talked about the same thing)

 

Using similar focal length large format lenses on smaller formats often gave poor relative results compared to lenses with lower coverage (i.e. designed with the smaller format in mind) - this is once they were both blown up to the same print size (or contact printed 1:1 in the case of the larger format).

 

Reason: the larger lenses were built with coverage in mind, not sharpness as that was a relative given due to the format size. But once you only concentrate your interest in a smaller subsection and enlarge it the apparent sharpness has a functionally related reduction.

 

All other things being equal as a lens designer you wouldn't place sharpness where it wasn't required, it'll only increase manufacturing cost and perhaps some specification number relevant only to people who opt to chase that kind of stuff in the face of reality.

 

Mind you, the difference between a 16mm frame and a 35mm frame isn't quite the same as the differences I was talking (e.g. 8x10" vs 6x7cm) - and it all depends on the manufacturer of the lenses... Basically>> YMMV


Edited by Chris Millar, 07 October 2013 - 03:42 PM.

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#6 Tom Chabbat

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Posted 07 October 2013 - 06:30 PM

There's multiple factors such as shorter focal lengths have a better resolving power, small glasses are easier to make in better qualities, and the short focal flange of c-mount permits retrofocus-free designs above a 17mm focal length (even less if you're not using a reflex camera). Using 24x36 lenses under the 50mm focal length and 24x18 cine lenses under the 28mm focal lengths will therefor not be pertinent on a 16mm camera. And I didn't mention that smaller designs admits wider aperture (apertures above f/2 are standard in 16mm). And last but not least, 16mm cine lenses, made for cine use with smooth apertures and precise focus with no breathing are cheaper than photo lenses. So you'll be better off using 16mm lenses. Take the adapter only if you seek extremely narrow angle of view, a 100mm lens having the same angle of view in 16mm as a 270mm lens in 24x36.


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#7 David Mellet

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Posted 07 October 2013 - 06:58 PM

Thanks everyone for weighing in so quickly. I guess my worry was what David Cunningham mentioned. With the 35mm lens you are using the center of the lens and zooming in and not using the full optical properties of the curvature of the glass so when doing that will the image go soft?

 

I have a nice Switar but it is an odd 16mm focal length (not real wide but not normal for sure) and I'd like to use some Nikon glass with a c-mount adapter.

 

So that brings me to the worry about which c-mount adapter to buy because Heikki Repo's comment has me worried I will get a bum adapter and have everything out of focus entirely.

 

The parrellex viewfinder is fine for my intended framing but non-sharp images are not.

 

SO I should hit "flea bay" and try and stock up on some c-mount glass?

 

Ugh... I hate buying stuff from that site.

 

And my local craigslist doesn't have the population to draw real filmmaking equipment.

 

Me and simply one 16mm Switar is so depressing right now...

 

David 


Edited by David Mellet, 07 October 2013 - 07:00 PM.

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#8 Heikki Repo

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Posted 07 October 2013 - 07:17 PM

Yeah, Ebay certainly isn't the best place to find pristine lenses. Usually one has to service them even if they are in good condition according to the seller. These days Switars aren't even that cheap -- all micro fourthirds users are buying them to get that vintage look and it isn't uncommon to have to pay over $200 USD for something that is in dire need of cleaning and servicing.

 

You could always buy some new glass too, although these might not have the same "look" as cine lenses -- at least resolution doesn't seem too bad: http://kowa.eu/lense..._serie_1_hc.php


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#9 David Mullen ASC

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Posted 07 October 2013 - 07:31 PM

In theory the lens designed for the smaller format would be better because it has to be -- with a larger format, your lens can resolve fewer lines per millimeter because there are more millimeters. But in reality, it's more complicated -- many lenses made for 16mm cameras are quite old and are quite variable in quality.  Some C-mount lenses are excellent however.  But keep in mind that lenses made before the last few decades are more or less handmade at all levels, so just because one lens is great doesn't mean that every copy made of that lens was great.  Kubrick used to order 6 or 10 copies of every lens he bought and then keep the best one, send the rest back.


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#10 David Mellet

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Posted 07 October 2013 - 08:28 PM

In theory the lens designed for the smaller format would be better because it has to be -- with a larger format, your lens can resolve fewer lines per millimeter because there are more millimeters. But in reality, it's more complicated -- many lenses made for 16mm cameras are quite old and are quite variable in quality.  Some C-mount lenses are excellent however.  But keep in mind that lenses made before the last few decades are more or less handmade at all levels, so just because one lens is great doesn't mean that every copy made of that lens was great.  Kubrick used to order 6 or 10 copies of every lens he bought and then keep the best one, send the rest back.

 

WOW. Thank you for personally weighing in Mr. Mullen. I greatly admire your work and thank you for responding to my humble c-mount lens question.

 

It looks like despite my fear of ebay, I may have to go that route and hope I get some good c-mount glass.

 

I found these, almost a complete set of Som Berthiot Cinor lenses that look really good.

 

http://www.ebay.com/...o-/131012350617

 

and

 

http://www.ebay.com/...o-/131012374752

 

and

 

http://www.ebay.com/...o-/131012332232

 

I wouldn't have a nice wide, but I'd almost have a nifty prime lens set if I snag these.

 

Does anyone have any experience with the Cinor lenses from Som Berthiot?

 

If so, will these go for a lot and simply break my heart drooling over them or could I win each for about $100?

 

I can't seem to find these lenses in previous auctions so I don't have a reference point.

 

Does Som Berthiot make a 10mm Cinor off hand?

 

Then the kit would be complete!

 

Thanks, Mr. Mullen and everybody else too.

 

David


Edited by David Mellet, 07 October 2013 - 08:30 PM.

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#11 Tom Chabbat

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Posted 08 October 2013 - 04:27 AM

I own some Cinor, they are soft and lack contrast... If you want some kind of diffuse look without the need of Pro-Mist filter, that's the way to go. But if you want more contrast and sharpness, look instead for other Switars (not the RX series if you have a H16 M) or Angénieux. Some Schneiders can also be pretty good. I think the Berthiot always has been some kind of cheap lenses.


Edited by Tom Chabbat, 08 October 2013 - 04:29 AM.

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#12 Heikki Repo

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Posted 08 October 2013 - 05:16 AM

Searching for those lenses in Flickr might give you some idea, there are people using them on MFT cameras. That won't tell you about the resolution or angle of view because the sensor size and thus the used area of the lens is different than on R16 camera but it can be useful regardless.

http://www.flickr.co...=berthiot cinor


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#13 David Mellet

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Posted 08 October 2013 - 12:59 PM

Right on. Those are some nice leads. Thanks!


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#14 Rene Renault

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Posted 11 October 2013 - 09:36 PM

I own some Cinor, they are soft and lack contrast... If you want some kind of diffuse look without the need of Pro-Mist filter, that's the way to go. But if you want more contrast and sharpness, look instead for other Switars (not the RX series if you have a H16 M) or Angénieux. Some Schneiders can also be pretty good. I think the Berthiot always has been some kind of cheap lenses.

 

This may be true for the Pan Cinor c-mount zoom lenses but not for the Cinor B primes.

 

The ones the original poster referenced on eBay are the "Cinor B" series primes.

 

Stopped down two stops, they are incredibly sharp with very good contrast.

 

I have shot lots of footage with the Cinor B primes.

 

Only thing better is the Kinoptik Apochromats but they will cost as much as a good used car.

 

The Cinor B's even beat the Switars in my honest opinion.

 

Nice lenses for sure.

 

Rene


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#15 Tom Chabbat

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Posted 14 October 2013 - 06:38 PM

Didn't know about this "B" series distinction. Was it to indicate a lens coating ? I have simples Cinor 1.9/10 and 2.5/75, very muddy, few contrast, even lower than some of my lenses from the 1930's. Stopping down doesn't seem to change much. I always assumed Berthiot was a cheap brand because we can find them in huge quantities and very cheaply. And aside from the Pan-Cinor, they never seem to have produced prime lenses for 35mm movie cameras. Even if you look at vintage ads, Berthiot lenses were often sold as the cheapest option (they were effectively cheaper than the switars for example). It really seems they were aimed at amateurs. Can we see somewhere some of the work you shot with them, René ? I'm really curious to see what "good" Berthiot can look like !


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#16 Gregg MacPherson

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Posted 14 October 2013 - 06:58 PM

One thing to consider. It may have already been pointed out. The center part of lens elements are often sharper, so some of the loss of final projected resolution due to cropping may be offset. At the risk of spiking the eBay prices on certain East German Zeiss primes, some good evaluation or sample use of certain Jena lenses has been done. Looks nice. But it wasn't the S16 format. I think it was maybe BMCC. Look for the "I bought a zebra farm" thread on bmcuser.com. Frank was the guy, also has some pages up on the web with some advice and screenshots.
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#17 Gregg MacPherson

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Posted 14 October 2013 - 07:06 PM

I ran into trouble with the post edit tool. So just posting here.

Found it. One of Frank's blogs.
http://frankglencair...modern-cameras/
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