C300 + B4 lenses
 

Hi guys

I'm looking for some specific experience with using C300 and B4 broadcast lens through an adapter. I understand the principle of engaging the doubler (+ adapter) to cover the sensor. I'm trying to understand equivalent focal length/fov this gives. I'm interested in the using the Canon HJ18 !

Anyone with any experience I'd love to hear about it !?

Mat

Re: C300 + B4 lenses
 

I too would like some info on anyone doing this. I have a nice Fuji 4.5 HD wide with 2x and would love to hear how hard it is to work with it on the C300

Re: C300 + B4 lenses
 

I remembered a post on Newshooter about a mtf adapter for B4 lenses and whilst not directly about C300 it might be of interest if you've not read it already.

News Shooter | New MTF Services lens adapters: Electronic EOS to Sony F3/FS100/Panasonic and B4 to EOS/Sony F3/FS100

Re: C300 + B4 lenses
 

Hi
Yes I'm familiar with the adapter, indeed it is probably the one I'd buy.

I'd just like to hear of anyones experience with it?

....and also fully understand the equiv FL I'd be dealing with.

So if I take an HJ18x28 It's 504mm at the long end. With the doubler we go to about 1000mm. On a 2/3rds format at 3.93 crop this puts us at nearly 4000mm equiv right ?

So with a c300 and adapter. We've added the 1.5 to the 1000mm (lens with doubler) = 1500mm. Should I then take into account the c300 crop of 1.6ish so 2400mm ?

Is this correct...?

Mat

Re: C300 + B4 lenses
 

OK, so thinking about this again. If this adapter+doubler is magnifying the image circle to the c300 chip size there would be no crop factor. So I'm thinking 1500mm is the 35mm equiv for the HJ18 on the c300!? anyone...?

Re: C300 + B4 lenses
 

I think the correct way is that the 2X is adding back to the coverage of the c300 chip. I would still like to hear how it works. lens becomes fully manual since no power for the zoom. However some of the B4 cine style fuji zooms can be had for really cheap prices now .and B4 to B4 doublers are out there too. Seems like an experiment waiting to happen.

Re: C300 + B4 lenses
 

I have been PMed on this item from a number of other persons as well. I'll try to find out if a demo unit is floating around and get back to the group on it.

Re: C300 + B4 lenses
 

You may want to hunt around for, or PM Alister Chapman who was the co-creator and is a regular here, especially in the XDCAM sections. His video covers most of your initial questions.


I had a play with his, on an FS700 - approximately the same chip as the C300. A bit of a culture shock if you're used to FS100/C100 size and weight, but less than a full-on ENG camera.

My use case would be for Event/Conference filming where a long reach and a reasonable wide are needed for at least one camera, to finally convert a C100 into an EX1/EX3 equivalent. I wasn't comfortable with it as a run-around camera as, with the battery and the lens (and a support rig for the FS100/700 definitely), it was a bit of a beast.

If I didn't have a pair of EX1s, I'd have this setup (a matched pair actually) for conferences.

Re: C300 + B4 lenses
 

OK. So I have had a demo unit of this adapter for over a week, and I have only had tonight for a few hours and will have a few hours tuesday night to play with the unit before needing to ship it back to our nice friends at ZGC. They had the unit at CineGear at the time I asked if I could demo the unit. They kindly shipped it to me soon after the show and as it would happen I then had a full week of work. Sorry for just now getting back to the evaluation. I just wanted to update this thread in order to let you guys know that I've not forgotten about looking into the unit. I'll followup with a full article soon, however I can say it is a very nice piece, and that it is refreshing to once again have a zoom lens that holds focus working on my C300

IF you guys see this thread and have certain questions you would like me to address Please let me know.

Sorry for the short notice.


Thanks

Re: C300 + B4 lenses
 

Article is now available to read. Thank you

Re: C300 + B4 lenses
 

Article....On this subject? Have I missed a link!

I managed to do a very quick test with an HJ18 and a Super 35 adapter on the C300. Unfortunately the epic kit it was in was due back so I only had 20 mins.

I wasn't that impressed with the results. The images were, I guess unsurprisingly, much softer and gave lack luster colours than with the Canon stills lenses I'm used to on this camera.

If I get this kit again I will try and give it a better test.

Mat

Re: C300 + B4 lenses
 

A 2/3" B4 lens on any S35mm camcorder will never match a decent prime lens or high end DSLR zoom for image quality. At the end of the day the image will be very very similar to what you would have if you used the same lens on a 2/3" camera.

Why? There is so much glass and so many elements in one of these lenses to achieve both a large zoom range and par focal focus that the optical quality is somewhat compromised, generally these lenses have lower contrast and more CA. They are designed as much for convenience (one lens to do everything) as they are image quality. The lower contrast is often mistaken for lower resolution and will ultimately make the images appear softer than a simpler high contrast lens. B4 zoom lenses have a certain "look" to them that is different to the look you get with a nice prime lens or a typical DSLR zoom. Most DSLR zooms are not par-focal and most only have very limited zoom ranges, 4x being the most common, this makes the optical design much simpler and as a result it's easier to get good image quality.

So, the end result when you put a B4 lens on an S35 camcorder is something that looks like it came from a 2/3" ENG camera. This shouldn't really be a big surprise, as at the end of the day it is the lens that governs everything else. All that said what you gain is the ability to zoom in and out over huge ranges without any focus shifts, to be able to work as you would with an ENG camera without the expense or hassle of having to have a second camera. Then when image quality is paramount you can switch back to primes or DSLR zooms.

Re: C300 + B4 lenses
 

Is the any footage online showing the difference with a B4 mount 2/3 lens vs a Canon lens. I know there are a lot a variables with glass but a rough Idea would be interesting to check out.

Re: C300 + B4 lenses
 

I'm just bumping this thread again and wondering what your findings were Craig on the B4 adaptor?

Re: C300 + B4 lenses
 

I have a related question for Alister or anybody else that relates to B4 lenses on a large sensor camera:

Would it be a viable approach to window the sensor and have the B4 lens operate in its intended focal lengths?

This would open up these large sensor cameras to double as a true eng camera without the light loss and retain the wide angles.

For me it would be o.k. if the "windowed" sensor area could only do a solid 720p image. The functionality would be a real justification to buy a large sensor camera knowing your could use broadcast lenses in their intended range.

Thanks for your thoughts.