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Will tv zoom lenses work on a Bolex?


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#1 Dennis Goble

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Posted 16 March 2009 - 03:35 PM

From time to time you see some good deals on tv C-mount zooms lenses on ebay.
Will these lenses work properly on a bolex?
Or are these something you should steer away from?
I'm talking about the manual iris lenses.
Also what is the difference between c-mount and cs-mount?
thanks
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#2 John Sprung

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Posted 16 March 2009 - 05:05 PM

c and cs use the same screw thread and diameter, it's the back focal distance that differs. c is 0.690", and cs is much shorter. cs was only used on low end security guard type cameras, definitely lenses to avoid.

c mount TV lenses were designed for SD -- NTSC or PAL. So, they might not give you the resolution you'd get from even average lenses intended for film. Then again, testing is the only way to know for sure.




-- J.S.
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#3 Elliot Rudmann

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Posted 17 March 2009 - 11:59 AM

From time to time you see some good deals on tv C-mount zooms lenses on ebay.
Will these lenses work properly on a bolex?
Or are these something you should steer away from?
I'm talking about the manual iris lenses.
Also what is the difference between c-mount and cs-mount?
thanks


TV c-mount lenses are of sufficient quality for shooting on B&W, but for color you may notice their weakness; more color abberations, lack of sharpness, even when shooting at deeper apertures.Test test test.
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#4 John Sprung

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Posted 17 March 2009 - 01:56 PM

TV c-mount lenses are of sufficient quality for shooting on B&W,


Not necessarily. Plus-X has plenty of resolution, and may very well show up the difference between a good film quality lens and one designed for NTSC.





-- J.S.
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#5 John Salim

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Posted 18 March 2009 - 05:47 AM

From time to time you see some good deals on tv C-mount zooms lenses on ebay.
Will these lenses work properly on a bolex?
Or are these something you should steer away from?
I'm talking about the manual iris lenses.
Also what is the difference between c-mount and cs-mount?
thanks


I would seriously avoid any 'TV' lenses as they are really designed for a lower resolution 'image capturing' system.
Obviously if it mounts on the camera ( and it can focus ) - it will shoot images....but at a cost of resolution.

John S
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#6 Dennis Goble

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Posted 18 March 2009 - 07:34 AM

Thanks for all the input.

What lens would you suggest for a for a beginner? I would like to have a zoom instead of a set of primes.
I am on a student budget and the camera I have is a rex1.
thanks
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#7 Dennis Goble

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Posted 18 March 2009 - 07:49 AM

I really don't like the bulky look of still slr lenses on a c mount adapter.
But would that be a viable alternative?
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#8 Elliot Rudmann

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Posted 18 March 2009 - 08:57 PM

I really don't like the bulky look of still slr lenses on a c mount adapter.
But would that be a viable alternative?



Absolutely, especially if you already own the lenses. However, one concern is that older SLR lenses are a bit more contrasty than built-for-16 lenses like the switars. They can still give you pretty sharp results though. Nevertheless, on any black and white reversal film, like plus-x, added contrast is usually the last thing you want. Additionally, the focal length of any given 35mm SLR lens on a 16mm camera is effectively doubled. 50mm becomes 100mm, 25mm becomes 50mm, etc. etc.

A zoom lens like the switar c-mount 16mm-100mm is a good choice, especially for it's F1.9 speed. There are cheaper brands available, usually popping up on ebay.
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#9 Elliot Rudmann

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Posted 18 March 2009 - 09:15 PM

Not necessarily. Plus-X has plenty of resolution, and may very well show up the difference between a good film quality lens and one designed for NTSC.





-- J.S.


Yeah, if he's going to be getting 2k Arriscans from his footage, or projecting his reversal film on a big screen then the flaws in those TV lenses will certainly be apparent. Most SD telecine transfers probably wouldn't even pick up the theoretical resolution/sharpness capable in Plus-X shot with switar primes. It's such a picky filmstock that the quality of your image is more dependent on how you expose it, not what lenses you use. Aronofsky and Libatique may disagree with me, but this is coming from my experience in film school, where, once projecting our projects shot on Plus-X, it was clear that the best looking projects were ones that were exposed and focused properly.

We really should know what his end game is going to be in terms of digital transfer.

Dennis, if you're going to keep this camera for a while and shoot a lot of film, I would save yourself the hassle and save up for some 16mm lenses/or a 16mm zoom. You never know when in 10 years, hi-rez 4k scans maybe as affordable as SD transfers today.
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#10 Leo Anthony Vale

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Posted 19 March 2009 - 05:01 PM

However, one concern is that older SLR lenses are a bit more contrasty than built-for-16 lenses like the switars. They can still give you pretty sharp results though.


Yet contrast in a lens is one of the qualities that contibute to sharpness.

An image from a soft but contrasty lens can seem sharper than an image from a higher resolvong lens which is low contrast.

& SLR lenses are mostly on the long side for much 16mm work.
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#11 John King

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Posted 21 March 2009 - 10:58 PM

Hello,

I have used no-name TV lenses with my Bolex and the footage I shot looked good to me. I was using colour film (Fuji 64D) EXT./DAY and the footage looked sharp and natural enough to me. I bought these lenses from ebay member that goes by the name "filmfinds" --EVERY lense I got from him was in GREAT shape, clean and just well cared for, so I HIGHLY recommend him. He is safe to buy from.

I bought some primes from him and a zoom as well. The lenses I used when taking my footage were the primes (mainly a 12.5). But again my luck with these lenses was quite good. But I would still recommend testing and if possible save your money for the Switars and other lenses as others here have advised.

Anyway I hope this helps,

John Mark King
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#12 Dennis Goble

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Posted 22 March 2009 - 12:34 PM

Thanks John. I'll look up your recommendation.

Yes I'll think I'll try a tv lens before I plunk down multi K bucks for a switar
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#13 K Borowski

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Posted 22 March 2009 - 02:15 PM

Dennis, if you're going to keep this camera for a while and shoot a lot of film, I would save yourself the hassle and save up for some 16mm lenses/or a 16mm zoom. You never know when in 10 years, hi-rez 4k scans maybe as affordable as SD transfers today.


Yeah, but there is no way that even S16 '01 resolves 4K worth of information (~12MP per frame). You could conceivable get a better image with a 3.2- or 4K scan, but that is really taking it to the point where you are getting into the realm of diminishing returns.

Shooting softer lenses is an aesthetic sometimes too.

Honestly, I have some TV lenses, and they seem to be sharp like any other. I think some of the things here are more old wives tales than solid scientific testing.

Even if they do tend to be a little soft wide-open, I'm sure the ususal 2-1/2 stop sweet spot from wide open would yield perfectly good results, even at 2K.
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#14 K Borowski

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Posted 22 March 2009 - 02:17 PM

Looking at my TV lens though, it is a 1/2" F/1.5 Canon, so, as always, your mileage may vary.
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#15 Elliot Rudmann

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Posted 22 March 2009 - 10:41 PM

Yeah, but there is no way that even S16 '01 resolves 4K worth of information (~12MP per frame). You could conceivable get a better image with a 3.2- or 4K scan, but that is really taking it to the point where you are getting into the realm of diminishing returns.



You're right Kyle, I should have said 2k. 4k for S16 is overkill and sometimes can accentuate the grain
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