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2/3 inch lenses on Canon C300?

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Nik Read
2/3 inch lenses on Canon C300?
on Aug 3, 2013 at 11:21:00 pm

Hi all,

Just wondering if any of you have had any experience in using 2/3 inch lenses with the C300? I am just about to take delivery of the camera and the biggest thing that concerns me is the fact I will lose the ability to be as flexible in my shooting. (I currently have a Sony PMW350) My biggest concern is having to keep changing lenses all the time, as there doesn't seem to be one "do it all" lens to go to, that's why I started wondering if I could use my existing Fuji zoom.

I have looked online and found this adapter that claims to allow you to use 2/3 inch lenses but it seem a little too good to be true?

http://www.broadcastwave.co.uk/index.php?route=product/product&product_id=1...

Just wondered if you guys could he'd any light on it or had any other options or ideas?

Kindest regards
Nik


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Todd Terry
Re: 2/3 inch lenses on Canon C300?
on Aug 4, 2013 at 12:23:24 am

It's very hard to say, without trying it... which I know is not a very helpful answer.

You've linked us specs to the MTF adapter, but what we really need are the exact coverage specs on the particular lens that you intend to use... that's the important part.

That adapter might let a particular B4 mount lens fit... but that doesn't mean that lens will cover the sensor. That it, the circle of its projected image might not be large enough to completely cover the sensor from corner-to-corner.

Lenses are not generally made to cover more of an area than they have to. That's why all 35mm-format lenses can be used on a 16mm camera (assuming the mount is right), but not that many 16mm lenses can be used on a 35mm camera.

So, that lens might cover the sensor fully... or it might slightly crop the corners, or it might fairly severely vignette. It's hard to say without trying it... but considering a 2/3" sensor is roughly the same size as a 16mm film frame, I'd be pretty surprised if that lens would cover your C300's S35mm-sized sensor.

Compounding the problem is the fact that since the lens was not designed to do that, it might be difficult to find those particular specs on it that would let you know if it will work. The specs will probably say that it covers a 2/3" sensor... but probably won't tell you how much larger a sensor that it theoretically could cover, since it wasn't really designed for that.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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Todd Terry
Re: 2/3 inch lenses on Canon C300?
on Aug 4, 2013 at 12:37:08 am

Just a PS... also keep in mind that the field of view will be radically different for the same lens depending on whether you use it on a 2/3" camera or a 35mm camera like the C300.

For example a 50mm lens is about a "medium" lens on a 35mm-format camera. That same 50mm lens will be more like a short-telephoto on a 2/3" camera.

That's because while the size of the circle of the projected image from the lens is always the same, with the 35mm sensor it uses a much bigger chunk of the circle... whereas with the 2/3" camera it only uses a much smaller piece of that image, only about a fifth of that that the 35mm uses.

That's something to keep in mind when deciding if the focal length range of the particular 2/3" lens will work for you with the C300. The lens will be much wider on the C300 than it was on the 2/3" camera from start to finish throughout all the focal lengths.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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Nik Read
Re: 2/3 inch lenses on Canon C300?
on Aug 4, 2013 at 6:04:40 am

Todd

Thank you so much for your very thorough answer, I appreciate you taking the time. There was also a short film by Alister Chapman showing how the converter worked and demonstrating its use. Yes you're correct it does seem to go against all the obvious "rules" and that was why I flagged it up, wondering if anybody had any experiences of working this way. I guess I'm looking for a lens that will be the solution for the C300 for most of the time and I think I'm slowly coming to the realisation that there is perhaps no such thing... Have you had any experience of Canon's 18-200 lens? I'm wondering if that will offer a good degree of flexibility?

Thanks again for your time Todd.

Regards
Nik


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Todd Terry
Re: 2/3 inch lenses on Canon C300?
on Aug 4, 2013 at 7:47:48 pm

Well Nik I might have spoken too soon in that long diatribe I wrote.

It could be that that's more than a mechanical adapter, on second look there does seem to be an optical element in it, which might be there just to "spread" that small image out to make it cover the S35mm-sized sensor. That could very well be the case. Unfortunately the website is a bit facts-free on how that works (or at least what I could quickly find). I didn't see a video. Assuming that company has taken all that into account, then it would work.

The upside would be that the focal lengths then would probably be right and transfer from one sensor size to the other without that radical change.

The downside would be light loss... firstly from that optical element in the converter (every new piece of glass in a lens eats some light), but moreso from the fact that it would be taking a 2/3" image and spreading it out over a much bigger surface area to cover 35mm... about five times bigger. So the picture the sensor sees would be much dimmer and ergo the camera as a whole is less light sensitive.

But again, it might work. It was considering this just an "adapter", usually a mechanical fitting to allow you to attach a lens to a different-mount camera. On second look this seems to be more of a "converter" which might indeed allow you to do that. Serves me right for talking out of my ear in an uneducated way.

Still though, the thing is pretty cheap... you'd think a true "converter" would be a fair bit pricier than that.

And no, I haven't used the Canon 18-200. Unfortunately I really have zero knowledge of SLR lenses, my only experience is really with cine lenses so I'm woefully uneducated regarding what's going on in the still-lenses world. I rarely shoot zooms, either... it's almost always primes with me. The only zoom I ever use is the Russian Foton 37-140mm, and then only rarely (a great lens, but slow as molasses).

Sorry if I jumped the gun.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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Nik Read
Re: 2/3 inch lenses on Canon C300?
on Aug 5, 2013 at 8:37:55 am

http://www.alisterchapman.com/2012/09/18/video-overview-of-mtf-services-b4-...

Hi Todd

Here's the video explaining how it works, I'd value your opinion greatly. Sounds quite interesting.
Regards

Nik


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Todd Terry
Re: 2/3 inch lenses on Canon C300?
on Aug 5, 2013 at 2:47:26 pm

I watched it, Nik...

Yes, it does work exactly as I imagined, it basically "blows up" the lens' image so that it is large enough to cover the S35mm sensor.

Eh... I'm not sure what I think about it. I'm not crazy about the idea for a couple of reasons.

Firstly, personally for me I wouldn't use it because I never shoot ENG style. I use primes, I rarely use zooms. And when I do, I don't want or need a servo-controlled zoom, I prefer an old-fashioned cine-style zoom. But... that's all dictated by my shooting, which is all very cine style. If I were shooting more "news style" (and already had a killer B4 lens) then it might be appropriate.

You know the positives already, so I'll just play Devil's Advocate and point out what, to me, are the downsides.

Firstly, is light loss... which I suspected. The guy in the video admits you have a 2 1/2 stop light loss... which is huge. That means you will need five times as much light compared to not using the converter. That might not be too much of an issue, especially if you are just planning to shoot primarily daytime exteriors. Also, the C300 is soo light sensitive that you can increase the ISO to account for that. But, of course as a general rule lower ISOs are better. I usually try to shoot with the C300 as low as it will go, although 850 is considered "optimal." I've shot much higher, though, and it still looks good.

Secondly... not every lens will work. You must use one that has a built-in 2x converter, which frankly I think adds some image degradation. I've never seen an ENG lens that looked as good with 2x on compared to how it looked without it.

Thirdly... this guy gives a bit of conflicting info. For one, he says DoF will be decreased, and he says DoF is a function of the focal length of the lens. Well, who knows? In theory, the depth of field should be the same as it is with that same lens without using the converter, at a given f-stop. And DoF is a function of the focal length of the lens combined with the f-stop and the sensor size. So his info isn't totally complete.

Fourthly... I'd really want to see some true image tests. The samples he showed seemed to have a fair bit of barrel distortion in them, to me. You'll notice a lot of the comments were from people who wanted to see a true test with proper charts, etc.

Fifth... the guy admits this is not as good as a "proper" cine zoom lens.

To wrap it up, would I use this? I might, if I had a really really great HD B4 lens and wanted to use it on, say, a Canon DSLR.

Would I use it on my C300? No, personally I wouldn't.

The C300 is such a fantastic machine, I just hate to see an inferior lens cobbled onto it, which is what I think would happen in a lot of cases. Remember that no matter how nice and expensive your C300 body is, that is not the most important part of your camera rig... the glass is. By far. Glass is really the place you want to make an investment. Just as an example, when we travel to distant locations (which isn't that often), I never ship ahead or check as baggage my little case of lenses. Everything else, yes, but not my lenses. They are by far the most valuable part of the equation... and from a purely financial standpoint they are worth a lot more than all of the other gear... definitely a lot more than the camera itself.

The good news is, that higher-end lenses (especially cine lenses) are a good investment. In five years my C300 will be absolutely worthless, I won't be able to give it away because by then there will be something so much better/easier/faster/smaller/cheaper. The lenses, though, will not have depreciated... in fact they will have increased in value. Mine were already 20 years old when I bought them abut six years ago, and I probably paid a fair bit more than the guy who bought them brand new. And since then they've probably doubled in value again (thanks to so many people wanting vintage cine lenses on Alexas, Epics, C300, C500, etc.).

Hope that helps. I don't mean to be hatin' on the converter because it is an interesting option... but I don't think it's one that I would choose.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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john sharaf
Re: 2/3 inch lenses on Canon C300?
on Aug 5, 2013 at 3:15:04 pm

Todd's been very gracious in explaining the reasons that using a 2/3" lens through a convertor on a 35mm sensor cameras are not sound. I'll add a few more negatives:

1. 2/3" lenses are designed for CCD prism cameras with 1920x1080 sensors. The color focusing takes into account the path of the prism, without which there will be error.

2. Most 35mm sensor cameras have more and smaller pixels requiring a smaller circle of confusion for proper focus. These lenses will exhibit no where near the sharpness of cine lenses.

3. The additional flanges involved in inserting the adapter increase the chance of backfocus and other alignment issues.

4. The additional length and weight of these ENG lenses without proper means of lens support will stress the lens mount on the camera both short and long term. Many of these less expensive cameras have notoriously weak lens mounts (as opposed to the Alexa for example).

Finally the Brits have an idiom, "Horses for courses", essentially meaning use the right tool for the job; in this case this is re-purposing the wrong tool for the job with a rather expensive adapter. Going forward, as Todd suggests, your lens collection is what will survive and have value. This adapter scheme will only look worse on a 4K camera.

Fujinon makes two Cabrio lenses which mimic the ENG design, 19-90 and 85-300, These are ideal for hand holding and run and gun. Yes, they're expensive but will be amortized over 20 years. I have the 19-90 and use it every day. It's very functional and user friendly with the built in motors, no need for lens support, Cooke i lens metadata and powering in some cameras, etc. But honestly, it is not as sharp as the bigger, heavier but half the price 18-80 Alura, which I also own. Based on the need for HH or quality I will choose one over the other.

I am aware that price and economics is involved in and actually determines many creative decisions in the image making process, but at some point, if you aspire to be a professional and are making equipment ownership part of your practice, you do yourself a disservice by buying anything but the best kit possible.

JMHO

JS



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Nik Read
Re: 2/3 inch lenses on Canon C300?
on Aug 5, 2013 at 8:38:52 pm

Guys...

As before thanks so much for taking the time to go into so much depth with your thoughts and to share your expertise. It really is a minefield and all I know at this stage is that I'm looking to better my set up i.e. move from an ENG style camera to a more cinematic style model. I guess there just isn't a quick or inexpensive way of doing it, and the sooner I realise that the better....!

Thank you again, it's very much appreciated.

And yes you're right, "horses for courses" is a very English saying, one we use over here a great deal...!
Take care

Nik


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John Fishback
Re: 2/3 inch lenses on Canon C300?
on Sep 6, 2013 at 7:58:49 pm

Here are a bunch of much more expensive B4 to (you have a choice of cameras) adaptors sold by AbelCine: http://www.abelcine.com/store/Optical-Adapters/. They note a 2 to 2.5 stop light loss.

John

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