Broadcast Lenses with the Canon C500 II

DustinSchmidt

DustinSchmidt

Well-known member
Has anyone used B4 lenses with the Canon C500 II? I know there is a mount for it and it's possible with the Super16 crop, but I haven't heard of anyone actually doing it or seen any articles out there discussing it. Just curious about anyone's personal experience.
 
I can't speak from a Canon perspective, only Sony. I have both of MTF's B4 adapters. I have the B4 to S16 and the B4 to S35 adapters (up to 4K). Whilst neither are as good s a purpose built cine zoom lens, I have used them on numerous broadcast jobs (HD) and had no complaints. In fact, the opposite. Even as recently as two weeks ago, I set up two Sony cams with MTF's B4 to S16 adapters for a company doing a live basketball shoot. These two cameras were shooting HD alongside three Sony PDW-F800. During the game they emailed me a couple of frame grabs off these two B4 S16 adapted cameras saying how happy they were with the results. Obviously, you have to make up your own mind as to these adapters' suitability for your own jobs.

One thing I find is critical with them is setting up the backfocus. Bear in mind, B4 lenses were designed to work through a beam splitter prism. That being the case, the RG and B paths are designed to focus on three separate sensors. Not on a single sensor plane. For their adapters, MTF and Abakus in the UK and IBE in Germany developed and built multi-element optical groups which compensated and refocused the three RGB paths to converge correctly on a single sensor plane. This is a very finally adjusted refocusing exercise carried out by these element groups. To ensure you get the optimum out of these adapters, a good lens and critical back focusing needs to be carried out. This will help minimize spherical aberration, coma and CA. For that reason, I backfocus my lenses on an electronic waveform monitor while shooting a resolution chart. There is no ambiguity then about "Is that backfocus correct or not?" When the testchart waveform on the waveform monitor reaches its null point, the exact point where the waveform changes between in focus and out of focus you KNOW the backfocus is 100%. Believe me when I say that this can make a big difference on how much CA a lens exhibits.

Sharpness does not only depend on resolution. The modulation at lower spatial frequencies is essential. In other words: Contrast in coarse details is significantly more important for the impression of sharpness than contrast at the resolution limit. The resolution that delivers sufficient modulation (20%) at 16 mm and 35 mm is reached at a detail size of 0.006 mm, which corresponds to a spatial frequency of 80 lp/mm. A good contrast high MTF HD B4 lens should be delivering somewhere in the order of 55lp/mm. A top of the range, HD lens can hit 80lp/mm. For HD, 50 lp/mm is way more than acceptable.

Chris Young

If you want the nerdy nitty-gritty on how all the above affects performance, have a look at Cambridge in Colour here:

https://www.cambridgeincolour.com/tutorials/lens-quality-mtf-resolution.htm

Here is an example of the MTF B4 S16 adapter being demoed by MTF:

 
Wow, this is really fantastic. Thank you for taking the time to respond with such detail and helpful information. I really appreciate it.
 
This is useful info. I sometimes end up using my c500 MKIi’s in S16 mode on live events. I don’t need 4K, but I do need the extra reach. Something like renting the 50-1000 CN-E is a little hard to do and out of budget. Are there any B4 lenses that are worth buying used for this type of work? I see a wide range of used prices, but I never worked in the broadcast space so I’m not sure where to start on b4 lenses. It might also not be worth the cost when adding in a 2/3 to S16 adapter.
 
Just some observations on lenses. The Royal Australian Navy's main video production facility asked me to come in and help them select HD lenses for their newly aquired PDW-F800s when they came out. In a studio set up for some serious testing with all the necessary WFMs and Vectorscopes, chip charts, resolution charts and DSC ChromaDuMonde charts and Sony's best grade #1 BVM reference monitors we headed into a number of days of testing.

Trying to keep this short, but do not write off the top end B4 STD glass from either Canon or Fujinon. This is what we discovered. If the camera used has ALAC v2 (Sony) or CAC (Panasonic) circuits. These are the Chroma Aberration circuits that talk to the HD lenses that have ALAC or CAC correction lens files built into them, then these lenses perform pretty well, but not necessarily brilliantly in regard to horizontal and vertical CA fringing on high contrast edges. BUT if the camera does NOT have ALAC or CAC circuits to talk to ALAC or CAC equipped lenses, in the majority of cases the very top end B4 SD lenses without ALAC or CAC circuits matched and often outperformed the ALAC/CAC equipped HD lenses.

When I quizzed Canon and Fujinon about this, they were a bit sheepish in their answers. It turns out the very best glass they could manufacture went into their very top end SD lenses. When HD lens production started, that very same "the best glass" went into their HD lenses. They didn't suddenly "discover" even better glass for the HD line. The main difference being the coatings were different to cater for the higher frequencies and finer detail now being recorded by these new HD sensors. So the very best glass from both manufacturers went into their top SD lenses. As soon as HD lens production started, this glass then went into the HD production line. The next best glass then went into their top of the line SD line and the lower rated HD professional lens ranges.

Obviously, ALAC and CAC circuits were able to compensate for any CA issues lenses may have. One of Fujinon's visiting engineers said to me "Without having ALAC or CAC compensation to fall back on the very last of the SD lenses had to use the very best glass available and had to be assembled meticulously and very accurately to minimize any CA issues." In other words, those lenses when used on cameras that do not have Chroma Aberration circuits to rely on for correction often offer better CA performance than HD lenses that rely on ALAC and CAC circuits when used on cameras that don't have ALAC or CAC..

One of the last emails I received from this Fuji engineer said, and I won't mention his name because he would probably be chastised by his superiors for the following statement. A quote from his email.

"Hi Chris,
It's good to hear happy endings!
We wanted to sell more new products, but fortunately our old SD lenses are still good quality for HD cameras..."

The last of the Fujinon SD lenses designated as A series "Digi Power" and the last of Canon's lenses designated as J series "eIFxs" are in this category of having the best glass tuned for best performance but without reliance on electronic circuitry to correct CA issues.

All totally useless information if not needed but useful to know when shopping for B4 lenses to use with adapters on S16 crop cameras when using the MTF, Abakus and IBE adapters.

If I was a Canon owner looking for HD S16 shooting, I am pretty sure I would go for the IBE HDx1.4 Converter with IBE's PL UMS Mount. With its interchangeable mount it can fit a variety of cameras, PL, EF, E-Mount, Nikon etc. There are a number of mint looking ones up on eBay right now.

Chris Young

https://www.ibe-optics.com/converter

https://www.bhphotovideo.com/c/produ...converter.html
 
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