JVC GY-LS300 test with B4 2/3" ENG lens plus low light comparos.

[Christopher Young]

I’ve just been fortunate enough to have a loan of a JVC GY-LS300 for a couple of days. Thanks to Noel Oakes from JVC here in Sydney. I had a pretty lazy weekend this week it being a holiday long weekend in Sydney so I managed to find some time to grab a few shots on the 300.

For me the 300 is interesting as it covers so many areas. S35 with interchangeable lenses, HD, 50p @ 50-mbit and a pretty keen price point. The 4K/UHD for me is an added feature but not a high priority as I have no corporate client demand for it and there is no way the work I do for broadcasters calls for it. For me 4K/UHD would have to support 50p because for me the 25p motion in UHD on any subject matter that has rapid movement in it is totally unacceptable.

JVC themselves say that this camera has not been designed with full cinematic type profile settings or the ability to shoot LOG files. Plus it has no LUT capability / implementation. Knowing this I looked at the camera from the point of view of being able to use it in an ENG / Sports shooting role shooting in HD.

With that objective in mind I fitted the LS300 out with an MTF B4 2/3” to MFT adapter. Cobbled together a rail support system from an FS700 Movcam kit chucked on an SD 18x7.6 Fujinon ENG lens and hit the road. See attached pics.

I was hoping JVC’s rather unique VSM (Variable Scan Mapping) would enable the camera to use a B4 ENG lens without its 2 x converter engaged. Using the MTF B4 unit on any other S35 camera requires the doubler to be engaged and when this is engaged there is about a 2.5 stop light loss. Sure enough the 300 could work without the doubler as the VSM can remap / crop and can be adjusted to fit the image circle thrown by the 2/3” lens. There is an HD setting plus there are other scan percentages that seem to work with the 2/3” lens. I ended up not using the VSM on the 2/3” lens as I ended up with some pretty bad CA problems in areas of the image that were over exposed. I would suggest that this more of a lens issue than anything else. Switching the VSM back to S35 mode, 100% scan in other words, seemed to eliminate these CA problems. It did mean though that the MTF B4 adapter had to have the doubler engaged on any 2/3” lens that is fitted.

All in all this makes for a pretty keenly priced outfit that is quite capable of shooting many HD jobs where a full servo zoom ENG type lens is required, like most sporting coverage calls for.
There is a download clip available here showing the sort results you can expect from this GY-LS300 / B4 ENG combo for those interested in having a look. This was shot at 50p and 50-mbit .MOV. Forgive my bad for a couple of rain / dust spots that turned out to be on the lens filter. My fault for not checking the filter first!

JVC GY - LS300 + Fujinon 18x7.6 + MTF B4 S35 adapter- HD 50p 50-mbit CYV modified color-exposure-latitude tests 06.06.15 [5K].mp4

https://www.sendspace.com/pro/dl/wwej5r

Something else that may be of interest to some of you is the low light / gain performance of the LS300 compared to a couple of other cameras. For this totally subjective exercise I used AVCHD 50p 28-mbit on all three cams so that at least when it came to codecs we were comparing apples with apples. I say subjective because the three cams used had totally different lenses of varying lengths. The only consistency here was that all three cams had the lenses set to f/4.0 for the shots. The cams used were the Sony PXW-X70 as I know some of you are considering this against the LS300 in spite of the fact that the X70 is a 1” sensor. Thankfully with the latest v2.0 firmware upgrade on the X70 its XAVC-L 10-bit 422 50-mbit codec can now be handled by most NLE software. The third camera used is now running four year old technology which is a long time in this field of rapid camera development. It was one of the first of the Super 35 cameras that started to grab the imagination and it is the Sony NEX-FS700.

The three low light clips covering these three cameras can be downloaded here:

JVC GY-LS300 Gain test 09.June.15.mp4
https://www.sendspace.com/pro/dl/i3scoi

Sony PXW-X70 Gain test 09.June.15.mp4
https://www.sendspace.com/pro/dl/ggds46

Sony NEX-FS700 Gain test 09.June.15.mp4
https://www.sendspace.com/pro/dl/phjwg0

Chris Young
CYV Productions
Sydney

[Piotr Wozniacki]

On another note, Chris:

Just looking at your 300, I thought whether - using a step-up ring - it would be possible to use my Letus Elite 35mm adapter on the 200 JVC model? This would allow for a 35mm DOF on a camcorder with rather small chip, should it be possible? In which case, how about crop factors? What real-world length I'd get from say my vintage Canon FD 1.4 50mm?

[Rohan Dadswell]

Thanks for this Chris - this is exactly the kind of set up that has got me very interested in the JVC.
I have several B4 lenses as well as a collection of Micro 4/3 and Canon lenses - If I can use them all on one camera it seems like a no brainer.

I'm surprised that the CA was less with the doubler engaged, on my Panasonics it was using the doubler that caused issues - so much so that I never really considered it a viable option

Planning to take a couple of lenses up to SMPTE next month to see how they perform.

[Christopher Young]

Piotr ~

Looking at the specs on paper yes I think you could use the Letus and get similar results as you would using it on an EX 1/2" sensor camera. The EX cameras are 1/2" sensors with a diagonal measurement of 8mm whereas the the JVC 200 is a 1/2.3" sensor with a diagonal measurement of 7.7mm so pretty close in size. Like with most of theses mix and match pieces the only way of finding out would be a real world test I guess. Would be interested to hear your results if you do give that a try out.

Chris Young
CYV Productions
Sydney

[Christopher Young]

Originally Posted by Rohan Dadswell

I'm surprised that the CA was less with the doubler engaged

Rohan ~

Yes you would think that but one has to understand that a 2/3" lens image circle was designed to just cover a 2/3" sensor. On a 2/3" camera when you put the doubler in the lens image is greatly increased to magnify the image by 2 x but in doing so a massive amount of light is lost because it is not hitting the sensor. A lot of photons going to waste plus doubling the image magnification doubles any aberrations present in the lens. With the B4 adapter which has a .5 magnifier in it already plus the B4 lens doubler engaged the lens image circle is now tailor made to fit the S35 sensor so no lost photons. In effect what you get is basically a lens that is designed to work with an S35 sensor and works surprisingly well in reality. I've shot a lot of stuff including NRL rugby with this combo on an FS700 and everyone has been very happy with the results. The increased dynamic range of an S35 sensor and the practicality of a parfocal ENG type servo zoom is a very useful combination in my book. To boot it's pretty cost effective if you already own B4 glass and that why I wanted to give the GY-LS300 a run because there a a few people thinking the same way you are, me included. Roll on SMPTE!

Chris Young
CYV Productions
Sydney

[Paul Anderegg]

Chris, with the B4 lenses wide angle is comparable to how they look on a 2/3" camera?

Wondering about an old cheap Canon J11x4.5BIRS on the LS300. :)

Paul

[Christopher Young]

Paul ~

With the MTF adapter the optical field of view you get on a B4 lens on an S35 sensor is basically the same as if the lens was mounted on a 2/3" camera. The depth of field though is akin to the DOF you would expect on a S35 camera. So the Canon J11x4.5BIRS you mentioned would need to have its wide end multiplied by 2.5 to give you an idea of the DOF on an LS300. In this example the Canon 4.5mm lens would have the DOF of an 11.25mm lens fitted to an S35 sensor. That's pretty wide! Proviso the B4 lens used MUST have a 2 x doubler to enable the B4 image circle to cover the S35 sensor. The MTF adapter I have was the first of these sorts of adapters to come out. There are others out there now. If you want a bit more explanation on MTF B4 adapters check out Alistair's review here:

MTF B4 2/3" to Super35 lens adapter overview. - YouTube

All in all I have found the combo of a B4 adapter to an S35 camera a pretty economical setup. it greatly expands the capabilities of the current crop of S35 cameras at a fairly reasonable price. I'm not saying this is a substitute for a Fujinon Cabrio or Canon cine zoom but there again it's nowhere near the price or the weight of those pieces of glass. To date not one client has commented negatively on the images delivered by this type of B4-S35 setup. That's why I wanted to test the LS300 with this combo because along with its codecs and bit rates choices the LS300 looked like a prime candidate for a B4 merger.

Chris Young
CYV Productions
Sydney

[Matt Grover]

Hi Chris,

What effect, if any, did you notice on the picture resolution by using that much crop with VSM?

I've just come across this camera and the potential flexibility of it is very attractive, especially if using B4 lenses is truly viable.

Cheers

Matt

[David Peterson]

So it did FHD even when down to a 2/3" crop??

[Christopher Young]

Originally Posted by Matt Grover

Hi Chris,

What effect, if any, did you notice on the picture resolution by using that much crop with VSM?

With the VSM scaled all the way down to HD the resolution of the images didn't seem to be visibly affected to any great degree regarding sharpness but there again I wasn't pixel peeping it on charts etc so purely a subjective observation. I didn't go any further with the exercise because with the VSM wound down to HD using the lens I had there appeared to be a reasonably unacceptable amount of CA evident on highlight to dark transitions. With the MTF B4 adapter setup where the whole sensor is being used the results IMHO were considerably better. You can get an idea on those results by downloading the MP4 who's link appears in my first post in this thread. I would suggest that any lenses that are going to be used on the 300 must be tested carefully to ensure that you are getting the best combination of camera / lens performance. I think a number of shooters will get a whole range of varying results while trying to chase down that perfect combination of glass and camera.

Yes David it did do full HD when the VSM was scaled right down. In fact there is a VSM setting specifically labeled 'HD.'

I look forward to testing the camera with the new firmware that has just been released. Hopefully in the next week or two.

Chris Young
CYV Productions
Sydney