P&S mini 35 vs. JVC HZ-CA13 adapter vs. MTF adapters? at DVinfo.net

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Old September 26th, 2007, 06:09 AM   #1
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P&S mini 35 vs. JVC HZ-CA13 adapter vs. MTF adapters?

Hi all
The P&S works well - I used it on a 251 with a Hasselblad lens a few weeks back. DoF is just splendid for my film-look purposes. I understand that it also works with cine primes.

But what about DoF with the JVC adapter ? We looked at it very briefly at a JVC roadshow and had the impression that it does not modify the video DoF.
JVC claims otherwise: "depth-of field and viewing angle are perfectly preserved" - but relative to what ? The cine lens or the fujinon ? Plus only 1/2 stop loss...

Has anyone tested it ?

Also, any experiences with the MTF adapters ?

Thanks
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Old September 26th, 2007, 07:14 AM   #2
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Quote:
Originally Posted by Claude Mangold View Post
JVC claims otherwise: "depth-of field and viewing angle are perfectly preserved" - but relative to what ? The cine lens or the fujinon ? Plus only 1/2 stop loss...
Relative to the same cine lens when shooting 16mm.

My testing was consistent with a 0.0006" Circle of Confusion commonly used for 16mm depth of field charts.

If you are using the universal 0.0010" CoC depth of field charts for 35mm found in AC manual 8th or 9th edition, then find your chosen f stop at the distance desired and move two columns to the left to find the approximate depth of field for 0.0006" CoC.

The 1/2 stop loss is a technical 'disclaimer.' In practical application there is actually approximately a 1 & 1/2 stop GAIN in exposure. Therefore F/2.8 has an equivalent exposure of F/1.7, but maintains the DoF characteristics of F/2.8.
This is due to the optical invariant. The math indicates that the reduction of the image size by 1/2 increases the transmittance by 2 stops (minus the 1/2 stop loss.)

We've discussed this adapter extensively in a few threads and you are also welcome to read my full review for more info.
We will eventually get this published into a web page on dvinfo.net.


We've seen amazing results from the mini35, Brevis35, Letus35/100 and M2 when paired with the HD100/200 series cameras. These are all great adapters of varying build quality, lens mounts, physical size and price, but they all render great looking footage.

I'm not familiar with the "MTF" adapter you mentioned. Is that a brand name? It might be confusing because to me MTF means "Modular Transfer Function."
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Old September 27th, 2007, 06:29 AM   #3
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You've helped me a lot, Tim - many thanks.

Your article is great reading, even though much of it is too technical for me.

But I understand that, basically, for similar results, the JVC adapter is a better technical solution than the mini 35, plus it's less expensive, plus no motor and batteries, plus the 1 1/2 stops gained are immense for someone who shoots a lot of night/dark/indoors scenes.

Do you think it would be practical to use the JVC adapter for shooting documentaries? I'd love to do digital cinematography in this field too, but I didn't go to film school so I have very limited experience with 16mm, the standard docu format prior to Digibeta and DV. I would need a 16 or 35mm zoom lens which gives a reasonable DoF at f4 or f6 or so, as focus pulling is impractical and often impossible. Any lens suggestions, especially one I could get second-hand?

I have a wonderful DP with both still and cine background so the cam is usually manned by a very experienced person.

Here's the link to the MTF adapters: http://www.mtfservices.com/products/...sadaptors.html .

Again, thanks and wow this is a wonderful site !
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Old September 29th, 2007, 04:35 AM   #4
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If you are shooting documentaries then I would stick with the many EFP zoom lenses available and not bother with cine lens adapters. I'm not sure what type of documentaries you shoot, but except for sit down interviews in controlled environments there wouldn't normally be a whole lot of opportunity to fiddle with a lens adapter.

I had a look at the MTF services adapters and it seems that those are probably straight mount adapters manufactured by Zoerk or Les Bosher and MTF is just a local reseller. It looks like they also have the HZ-CA13U COPLA and just aren't specific about the actual model name, instead referring to it as an "Arri PL (16mm) to JVC Adaptor."

Simple mount adapters are available (as you can see on the MTF site) but they have no optical elements. Therefore focal length = focal length. Mounting a 28mm Nikon lens to a Nikon to JVC adapter would have the same field of view and depth of field characteristics as setting your Fujinon zoom lens to 28mm.
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Old September 29th, 2007, 02:32 PM   #5
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Claude:

Please do not take this the wrong way, but it is my belief that if you are working with a DP that you highly regard as you have stated, this is an area that he should be primarily researching rather than yourself.

As a DP I am regularly dealing with directors who have been "convinced" via message boards, casual chats with other folks etc. that they have a bead on some technical aspect of the cinematography and I then have to really work to talk them out of it if it disagrees with my recommendations. It is ironic that one would put more faith in a complete stranger on a message board than the person that one hires to actually shoot their project, but it seems to be happening more and more (Tim is actually one of the most knowledgeable about anything relating to the JVC cameras so you are in the best possible hands here, so this would likely be the exception to the rule).

There is nothing inherently wrong with being educated to the technology. It can just be particularly frustrating as a DP to have a director insist, as they sometimes do, on using a particular camera, configuration or format based on their research while you may have actually had hands-on experience in this area, particularly when they are not forthcoming about the source of their information.

Again, this is not so much directed at yourself, as you seem to be a thoughtful person and I would guess you are sharing this info with your DP and working together on a decision. So please assume this little diatribe is aimed at others who might be doing research for an upcoming project and are planning to make up their mind on these issues before they bring a DP into the fold.
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Old September 29th, 2007, 06:15 PM   #6
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Well said. Thanks Charles - very good points. I've even had directors misquote "facts" to me the I originally wrote on the board!
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Old October 1st, 2007, 09:33 AM   #7
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Charles, your are raising two points. One is, whether participants make professional use of this treasure of information here, or whether they use it to look smarter than the others or as a leverage or whatever.

The second is about how directors and DPs can / should work together.

"if you are working with a DP that you highly regard as you have stated, this is an area that he should be primarily researching rather than yourself."

I can't quite agree, for two reasons:
1- I live and work in Europe and following such sites is not so widespread here, even for excellent DP's. Take the scene files: DPs here don't all know about them. Plus they're not always fluent in English. So I send them the link, or we look at it together, and then try it out, and the DP obviously is the expert about whether it's practical, whether it will achieve the result we want, or whether there might be another way he might be used to.
2 - I'm an architectural historian by training and I actually spend more time in film finance than working as a director, although the latter is the professional love of my life. A site such as DVInfo brings me a wealth of info since I can't hang out as much as I'd like with fellow film people. I love to find out what might be possible even if it's just a guess or really far out, not because I want to take the DP's decisions for him (except for the JVC cam unless there's a special requirement).

"I would guess you are sharing this info with your DP and working together on a decision."

Right. The fun actually begins when we can work together. We talk about the style I want, we try out stuff together, various lenses, settings, speeds, filters, camera movements, we talk to the FX and post guys and we look at film excerpts... I do jury work from time to time so I see a lot of films. I love doing this aspect of pre-production , I love the DP's input and know.how, and I love situations where someone says "I saw this..." or "I read about this... let's try it out !"
The final decision is his, relative to the goal and the budget. I also let the DP decide whether e.g. a particular wide shot will require a jib or a crane.
We also go to test days and rental firms together, try stuff, odd combinations, and visit locations. Plus there's a good production script. On the shoot, we each do our respective work, but we know what the other wants and needs. Then we look at the rushes together.

For me, making a film is telling a story in pictures. (not even necessarily moving pictures - witness Chris Marker's 'La Jetée'). The quality of the film is the result of a good story with interesting protagonists, a good screenplay or outline, and of course a good cast & crew. That's true for all types of films, I believe. So, filmmaking for me isn't about knowing or having, but about doing and sharing with cast, crew and of course, audience.

Getting back to my original post here: when Cedric my DP and I saw the JVC adapter, it was outdoors in bright August sunlight, and no one from JVC was able to tell us how and when it might be better than the mini 35 we've both worked with. Cedric could have posted this but I'm not sure his English is ok. The info I got here will serve three purposes: one, pass on to DP, two, use for rental/purchase decisions, three, broaden film-style use in my work - see next reply
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Old October 1st, 2007, 12:26 PM   #8
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Thanks, Tim. Image genre is only one element in making documentaries. But this is how I see the film vs. video image issue.: Christian Frey's "War Photographer" was shot on Digibeta (plus a micro-camera). Rithy Panh's "Site 2" was shot on 16mm. Both deal with the aftermath of civil war and the horror of executions and mass graves, and hardship of refugees, but from different pov. frey's film from the hurried, globetrotting perspective of a celebrated photographer, Panh's from a refugee family's pov. Both are among present day's most skilled documentary filmmakers, yet their images are so different: ENG-style, nervous, grinding vs. deliberate, searching, revealing. Both are masterpieces IMO.

The equipment has alot to do with this I think. You don't get ENG-style from a 16mm (although you can get WWII-type reporting), and you don't get that deliberateness from a Digibeta. Frey shocks the viewer with anticipation (oh nooo as you realize what you already see in the distance), Panh with revelation (oh my god as focus shifts suddenly reveal it).

So, obviously, there's the DoF issue, and related differences like what focal lenghts do to faces, but not only. IMO film work - because of setup, camera operation, team coordination, focus and also cost of stock - requires more extensive preparation and much more advance thought. plus people who learned it the old way learned much more than just camera operation: image composition, movement, anticipating cuts, edit-in-the-camera and this baggage just came along free with the director or DP expertise.

This is also true for editors : a film editor who has apprenticed with 16/35mm film does entirely different work on an NLE than even a skillful a video editor.

In theory, all of this can also be achieved with video, but why can't it really ??

Building on the JVC camera body, I would like to to put together something which allows me a very deliberate, revealing image construction, yielding entirely different image choices from most of today's work, and thus telling a story really differently. That's why I'd like to try out cine zooms in one of my next pics - it seems at least worth a try, unless it's been tried and found useless already.
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Old October 1st, 2007, 01:44 PM   #9
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Having shot film documentaries, the main difference is that you tend to think twice before hitting the button and when nothing is happening you switch the camera off. It's a matter of deciding on the material you need to tell the story and costs usually meant that you did this at the shooting stage. However, you can still have pretty high shooting ratios at times.

You don't really need a huge team shooting on film, you can actually shoot sound with a two man crew. Although, usually after about half an hour at an interview (with 2 quick mag changes), you're going to need to stop to reload the mags. This used to work rather well, because it gave people time to gather their thoughts.

The JVC adapter doesn't look like it would be the best set up for shooting a handheld fly on wall doc, but could work on a documentary which is mostly on the tripod.
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