19Mar Preparing for the Panasonic GH4 – Lenses
As I mentioned before, I went ahead and pre ordered the Panasonic GH4. The specs are pretty amazing and the $1699 price tag makes it one of the most attractive 4k camera offerings on the market. However not many people have had their hands on the camera, so the Panasonic GH4 is still a little bit of an unknown. I’ve only seen anecdotal statements about ISO and image quality, but it’s been enough to tempt into the Panasonic world. Would I recommend you start selling off your current gear to pick up a GH4? Probably not, but if you already have a camera and the time and budget to take a chance on a second camera, go for it.
I’ve only ever played around with the Panasonic Gh3 and Gh2 on a few random shoots. Because of that I haven’t looked into micro 4/3 lenses in over a year, so i’m just starting to do some research on a starter set of lenses for the Gh4 body. I called up a few friends who have done a lot of shooting on the Gh3 over the last year and got a list of their recommendations. Out of the 4 people I talked to the Olympus 12-40mm f2.8 and Panasonic 12-35mm f2.8 O.I.S. where to first lenses to be mentioned.
In the micro 4/3 world the crop factor is 2x. So a 12-40mm is equal to 24-80mm on a full frame and the 12-35mm is a 24-70mm equivalent. Both of these lenses fall into the $800 to $900 price category, besides the small focal length difference, the only other thing of note is that the Panasonic 12-35mm has image stabilization while the Olympus 12-40mm f2.8 does not. In my discussions a few of them said they’d gone with the Olympus because of the build quality, while the others said the image stabilization was a big plus on the Pansonic. No one really had any complaints about either lens so the question on this one is, which one should I buy? I know a few of you are Panasonic owners so let me know if you have any input on this. I’ll definitely buying one of these to get started.
I actually took notes during these conversations and the one lens that seemed to be universally loved among the whole group is the Panasonic 35-100mm f2.8 O.I.S. lens. This is equivalent to a 70-200mm f2.8 lens with image stabilization. Apparently it’s made out of plastic which is a downside, but it’s also less than half the size of my Canon 70-200mm f2.8 IS making it a very nice telephoto lens to travel with. At a street price of just under $1000, the Panasonic 35-100mm f2.8 O.I.S. lens is also pretty reasonably priced compared to my full frame equivalents. Between this and the 12-35mm (or 12-40mm) lens most general use stuff is covered pretty well.
As for wide angle there was a little bit of grumbling, apparently there isn’t really a perfect 16-35mm f2.8 equivalent. I have yet to do more research, but all of them said the Panasonic 7-14mm f4 was probably my best bet. At around $850 it’s pretty close in price to a used Canon 16-35mm f2.8. F4 on a micro 4/3 body is a little disappointing but 7-14mm is a 14-24mm full frame equivalent so that’s actually a bit wider than I was expecting. I didn’t realize there were any lenses that wide in the micro 4/3’s lineup.
I will probably pick up the Olympus 12-40mm f2.8 or Panasonic 12-35mm f2.8 O.I.S. and see how well the Panasonic GH4 works out in test shots. If I fall in love, i’ll probably sell off some gear and pick up the other two zooms. After that, if i’m still happy I’ll moving on to some good primes, maybe I’ll start with the Panasonic 25mm f1.4. If I get that far, I’ll post some of my lenses choices when I get there.
March 19th, 2014 at 7:52 pm
Deejay, what is your take on the additional mount they sell with the XLR ports? I read somewhere that supposedly you can still get 4:2:2 footage out of the HDMI port – which would actually be great, and cheaper, if you hooked it up to something like an Atomos Ninja.
What are your thoughts? Are you just more interested in the 4k aspect? I’ve seen some footage and it’s super sharp.
March 19th, 2014 at 8:44 pm
I actually just got an email back from Panasonic asking about that. The HDMI port on the GH4 does infact output 4:2:2 10 bit if you have a recorder that can handle it. If you look at the adapter box you’ll notice that it actually plugs into the HDMI port on the camera. That’s because it’s taking the 4:2:2 10 bit signal out of the hdmi port (at up to 4k) on the camera and converting it to SDI. I believe the ninja is limited to 8 bit 4:2:2 but like you said it’s a pretty good value. I already own a ninja so it’s an even better value for me.
As for the 4k aspect, I’ll probably be playing around with internal 4k recording as soon as I can get my hands on some U3 class SD cards (and the camera of course), but I don’t think I’ll be using an external recorder for 4k anytime in the near future. I think the biggest benefit to recording 4k in camera is the ability crop and the ability to create 2k files from the 4k image. I’ll have to do some math and get a better handle on how much space a 200Mbps and 100Mbps will eat up when recording at 4k. I’ll post my thoughts on memory cards and 4k once I’ve had a chance to dig a little deeper into the specs.
May 21st, 2014 at 6:10 pm
The Ninja2 records 10bit tonal values @ 4:2:2…
10-BIT 4:2:2 QUALITY
So why record 10-bit from the sensor of a camera, if it’s 8-bit? Well, if you want to edit, use CG or 3D effects, green screen or add titles and transitions, these will all be 12-bit or more. If you record 8-bit like most cameras, when the 12-bit or higher graphic is inserted into the timeline, the colours are ‘crushed’ down to 8-bit, making the result extremely poor quality. We bypass the 8-bit and record 10-bit colour registries to ensure your video plays nicely with all computer effects.
Thus, it will work fine recording 1080p 24fps 4:2:2 10bit from the HDMI Out on the GH4. The canon 5d mark ii is another story. First of all, you won’t get 24 fps out from the hdmi port, so you have to reverse telecine your 30fps footage that’s recorded onto the Ninja. Also, it’s only 8 bit, so you’ll be recording 4:2:2 8 bit @ 30fps. Another reason to get the GH4… 10 bit HDMI out @ 24fps –> Ninja2
Then wait for a 4K recorder that’s not so top heavy on your wallet…
March 19th, 2014 at 8:16 pm
GH3/GH2 shooter here.
35-100 is definitely one of my fave lenses! Definitely think it is a must buy.
On the wide side, I shoot the Oly 9-18 and have no problems with it, other than it’s not awesome for low light.
So pleased with the 35-100 that I may pull the trigger on the 12-35 by Panasonic next.
Also would add the 45mm 1.8 is another must have and is pretty inexpensive. Go to portrait/interview/close up with shallow DOF lens.
Samples here with those lenses:
https://www.youtube.com/watch?v=axm1Ac2STV4
https://www.youtube.com/watch?v=-3kCx409DRE
On a side note. I have had no luck with Tascam regarding my stuck XLR in the DR60D. Do you have a more responsive email I can reach them by? Their customer service sucks.
March 19th, 2014 at 8:56 pm
Thanks for the info Russ. I’ll start with zooms and move on to primes once I’ve had a chance to really get used to the gh4.
Man you’re still fighting that stuck XLR input? As for direct contact, I used to have a card for the Tascam marketing rep when I wanted review units, but he moved on last year and I never got any updated contact info from tascam. I’ll catch up with them at NAB in a week or so and see if I can get someone solid for you to e-mail. Have you tried contacting the people you bought it from? Here in the B&H is usually really good about resolving that sort of problem.
March 19th, 2014 at 8:32 pm
I have been shooting with GH2 and GH3 cameras for a couple years. That 12-35mm is my “go to” lens, as it is reasonably fast and I like the 24-70mm equivalent focal range. At the long end of the lens, stabilization certainly helps, so that may be a deciding factor for you. The overall “look” of the lens is fine; not overly cinematic, but not sterile, either.
The 25mm/f1.4 is faster, has nicer bokeh and is more cinematic, so I intend to pick one of those up, eventually.
BTW, you might also consider the 20mm/f1.7 “pancake” lens. It is reasonably sharp, with fast focus and its small size makes the MFT format light and compact for travel. You can find these used, and although they look like a toy, they are well worth having.
I often shoot video in all-manual mode, using adapted lenses. You may be able to use a lot of the glass you already have, if you don’t mind shooting manually.
Ultimately, the right lenses for you are whatever works for the type of shooting you do.
I look forward to seeing how the GH4 works out for you.
March 19th, 2014 at 8:36 pm
The DMW-GMC1 wide angle conversion lens converts the 14 mm lens into an 11 mm. and both are so tiny that you can keep them both in your pocket if you have to. it’s a great alternative for people who can’t afford the Panasonic ultra wide zoom lens
March 19th, 2014 at 8:41 pm
@dave I’ve heard that the 20mm lens is slow and noisy when autofocusing.
March 20th, 2014 at 9:20 am
The 20mm was slow focusing on my GH2, but much faster on the GH3. I have the original version, and don’t know if the new version is improved. Yes, there is some motor noise from the lens, but as I always shoot audio externally its not an issue.
March 20th, 2014 at 3:56 pm
Thanks for the heads up on the 20mm Dave. I’ll probably pick up the 25 f1.4 as my first prime, looks like you can get it used for around $400.
March 19th, 2014 at 8:50 pm
I read over on the Personal view forum that if you shoot at 4k and later convert down to 1080p you get 4:2:2 color.
March 19th, 2014 at 9:11 pm
I think Cineform is working on a converter that will allow you to do that.
March 19th, 2014 at 9:18 pm
sorry DJ, I misspoke. Here is what I read over on another forum:
“Also, down sampling 4K 4:2:0 to 1080 will give a result equivalent to 4:4:2 not a true 4:4:4. If you need to understand this in detail look it up on Wikipedia , all the info is there.
My workflow will be to produce everything at 4K including graphics & effects and then down-sample for delivery. Also keep in mind that the software one uses for conversion is also very important to keep the quality at a high standard.
March 20th, 2014 at 4:14 pm
No problem Dan, there’s a lot of information to remember. It might be pretty cpu intensive to render your Graphics and effects at 4k. As for converting I think Cineform has plans to release downsampling software that will do just what you mentioned which would give you a lot of color space to work with in post.
March 19th, 2014 at 9:06 pm
DeeJay, glad to hear you are coming over to join me on the dark side (MFT side that is). I am a long time convert from a Canon 7D (moire dealbreaker) to hacked PAnasonic GH1/2 cameras for the video IQ & low moire. I skipped the GH3 and have pre ordered the GH4. Glass is also on my mind:
I am looking at the same lenses as you, but, not ready to pick up anymore glass except a speed-booster to get more use out of my Nikkor AIS glass.
I had read that the Pana 12-35 despite being a constant f2.8 does have a density shift when zooming. There are many some videos of it on YT. Then I was at B&H last week and saw it first hand while looking down the barrel of the camera and on the screen as I zoomed on a neutral surface. Density shift is going on even in full manual mode.
I did the same test on the Oly 12-40 and I recall I DID NOT see any density shift. I am curious to know what your 4 friend have to say on the topic. I think that a bigger deal then OIS or no OIS.
I think the early reports of the OIS being jittery were solved by firmware. Some users of the 35-100 have reported it too.
There are lots of user reports here: http://www.personal-view.com/talks/discussion/3283/12-35mm-f2.8-panasonic-lens-topic/p16
March 19th, 2014 at 9:19 pm
I’ll shoot them an e-mail, it’s kind of a small sample size. No one mentioned a shift when zooming but the Olympus guys said it was a “better built lens” for whatever thats worth. I don’t think I’ll be getting rid of my Canon gear anytime soon but the gh4 might be replacing my C100. I really need to film a review video on that before I kick it to the curb. Anyway thanks for the input!
March 20th, 2014 at 2:22 am
I’m a Gh3 shooter and the 12-35 is my work horse that’s on the cam 90% of the time. Not sure about that density shift. Will look into it, but this lens is it solid one for me. Here’s a video a shot with the GH3 on solely the 12-35.
http://vimeo.com/84198260
Native micro 4/3 lenses are great because they’re small but if you have a lot of Canon or other glass, you should think about adapting with speed booster or dumb adapter and see how that works for you before buying more. Native fast wide angle lenses are tough. I’m looking for one now and not sure what to do.
I also have the 25MM SLR magic T0.95 which is a great lens for lowlight and very sharp wide open. Because you don’t get as much much bokeh with the smaller sensor, it’s good to have some fast glass.
March 19th, 2014 at 11:28 pm
Deejay,
I’m not sure if this was mentioned by the other people who commented but you need to consider the new focus feature (DFD- Depth from Defocus) on the GH4. It only works with Panasonic lens and it’s what makes the focusing on the GH4 super fast.
I own the GH3 and a few Panasonic lens and the 12-35 2.8 is my everyday go-to lens. …love it!
Just my two cents.
Love your site! keep up the great work!
-Manny
Check out the review by “The Camera Store” http://youtu.be/2XHBKNI8xBE
March 20th, 2014 at 12:26 am
Bought the 12-35 and 35-100 as soon as the GH3 was released. It’s everything I wanted it to be, yet everything it wasn’t. Still a great lens and super sharp. The 35-100, I probably would’ve kept but sold it both.
If I may suggest if you are only planning to use it for video and not just photography, consider the Sigma 18-35mm F1.8. That plus a speedbooster in Nikon mount covers a good length. If Metabones ever makes the EOS>m4/3, then I’d pair it with a Canon 24-105mm and be more than satisfied, or fork out to match with Sigma’s Art version.
March 20th, 2014 at 1:01 am
The biggest difference between the 12-35 & the 12-40 is that the Olympus 12-40 has a focus mode that gives you hard stops and repeatable focus. I’m not sure if other camera systems with fly-by-wire lenses are similar, but Panasonic bodies have “variable focus control” where the amount of focus varies based on the speed you turn the focus ring.
This helps get more precise focusing by turning the focus ring very slowly, but for video it means that the concept of repeatable focus marks does not exist for most fly-by-wire lenses. Some Olympus lenses (such as the 12-40) have a “switch” that gives you hard stops and repeatable focus.
If repeatable focus matters, get the Olympus.
Also, if you’re interested in the 25mm f/1.4, you might also want to check out Olympus’ 25mm f/1.8. Both are excellent lenses but the Olympus is $100+ cheaper. If I didn’t already have the Panasonic 25mm, I’d definitely be looking into the Olympus.
As someone else noted, the Olympus 45mm is stellar as well. Sharp wide open and renders a beautiful image.
You may also want to look into the Metabones Speedbooster to open up your wide-angle options. For example, getting a Nikon mount Speedbooster will allow you to use compatible lenses (e.g. Tokina 16-28, Samyang 14mm f/2.8, Sigma 18-35, etc.) on a Micro4/3 camera with a wider field of view than on an APS-C camera (1.42x vs 1.7x). In addition, you also gain a stop so the image is also brighter. All in all, not too bad.
Feel free to contact me directly if you have any other questions.
March 20th, 2014 at 1:22 am
Have a try with Panasonic lenses before buying: they could be too clinical and contrasty. Also color rendition is not for everybody. How they’ll behave with the GH 4 Cine mode is stil unknown. If you don’t need OIS you should consider the Speedbooster route. Then the Sigma 18-35 1.8 would be unmissable. For a goid wide, I suggest the Tokina 11-16 2.8 (Speedboostable). A Rokinon/Samyang set of primes + Speedbooster is also a popular choice. Furthermore, since you can crop the hell out of 4k, you are open to the world of amazing vintage (and not) c-mount zooms and primes.
March 20th, 2014 at 4:06 pm
Thanks for the heads up! I’ll probably hold off on the speed booster for a little while and stick to zooms first to see how I like the camera. Do they make the Sigma 18-35mm f1.8 and Tokina 11-16mm in m4/3 mount? I haven’t seen them anywhere.
March 20th, 2014 at 5:19 pm
Noooo…. you explicitly do *not* want them in a m4/3 mount! In my opinion the best mount to get new lenses in is Nikon F (due to Nikon F mount’s long mount registrar, gives you the most flexibility for the long term future. Plus Nikon F mount lenses are as a rule of thumb much easier to adapt than Canon due to their more common manual controls. You just need to look at the Canon EF to m4/3 vs Nikon G to m4/3 adapters or speedboosters to see this is obvious).
If you get a m4/3 mount you can not use a focal reducer with it, thus why you want to get it in a Nikon F mount.
I do agree completely about a Tokina 11-16 f/2.8 + the Sigma 18-35mm f/1.8 would be an awesome killer combination for any GH camera! (the Sigma is a tad bit pricey for me just now as got some other priorities, hopefully I will get it before the end of the year though. But the Tokina is going to be one of my very next purchases) Add in a 50mm prime and a Rokinon 85mm f/1.4 for the longer end, and you’ll be pretty well sorted.
March 20th, 2014 at 6:14 pm
I actually sold off my tokina 11-16 when I went full frame and picked up a 16-35mm f2.8. I think i’m going to start with the Olympus 12-40mm f2.8 to get things started.
March 20th, 2014 at 12:08 pm
Great discussion on lenses, I am looking at some M43 glass as well. Thanks for all the suggestions. Looks like I might be heading over to the dark side as well.
March 20th, 2014 at 3:44 pm
Come on over Dave!
March 20th, 2014 at 12:44 pm
http://www.dpreview.com/news/2014/02/12/olympus-confirms-development-of-7-14mm-f2-8-and-300mm-f4-pro-lenses
Olympus is set to release a 7-14 2.8 lens.
March 20th, 2014 at 3:58 pm
That 7-14mm f2.8 looks nice. Maybe I’ll hold out for that.
March 20th, 2014 at 4:16 pm
Hi, as for the 12-35 2.8 Panasonic lens I have tried it extensively and being the only alternative in that range, large aperture I guess it’s ok but I’m very disappointed with the stabilization. It does help a lot compared to a non stabilized lens but it does not “float” the picture like for instance a Canon stabilized lens. I get these bad micro vibrations in the picture when shooting handheld and have to use post production stabilization for all handheld clips. It might be me but compared to Canon it’s no way near as effective.
March 20th, 2014 at 4:42 pm
After hearing from everybody in this post and talking to my friends, I think I’ll be going with the Olympus 12-40mm f2.8. I was able to play around with it a little today on the GH3 and it felt pretty decent, but I think it might take me a little while to get used to the look of a 4/3s camera.
March 20th, 2014 at 5:21 pm
Hey Mike, did you see the comment above?
=======================
I think the early reports of the OIS being jittery were solved by firmware. Some users of the 35-100 have reported it too.
There are lots of user reports here: http://www.personal-view.com/talks/discussion/3283/12-35mm-f2.8-panasonic-lens-topic/p16
March 22nd, 2014 at 2:26 am
Hi, yes and the lens was actually with the latest firmware but still no calm “floating” picture compared to a Canon but these “micro vibrations” persist. But, since everybody else seems happy the lens might be a duck.
March 20th, 2014 at 5:37 pm
As I explained above, I reckon Nikon F mount for filmmakers is the way to go (almost no matter what camera body you’re using, though personal I use one of the GH series already). Due to them being the most “future proofed” (well, as much as anything can be in this very fast moving industry).
This makes sense, as lenses are going to hold your investment a lot better than camera bodies will. And while I will likely change between many different camera bodies and even brands over my career, I’d like to keep on using my glass as much as I can for as long as I can.
Also I believe this provides by far the best value (important as my budget was very limited), thanks to Nikon F mount being the longest continuously produced mount for DSLRs, so there are heaps and heaps of vintage and other second hand bargains to be picked up.
As well as gives the greatest future potential use as the Nikon F mount is the most versatile one when buying lenses. (kinda like how the m4/3 mount is the most versatile for a camera, but in reverse) You can see this is a rather important point for me
No need to keep on selling and buying lenses continuously as cameras change. Instead purchases would be towards growing the collection, not simply turning it over to match the mount of whatever is the current hot new camera.
Anyway, there are many different paths to building up a perfect lens collection for yourself.
Personally I’ve gone for the path of primarily Nikon F mount with Nikon F to Micro Four Thirds adapters (also have a Nikon F to m4/3 focal reducer, this one: http://www.personal-view.com/talks/discussion/9086/rj-lens-turbo-m43-adapters/p1 )
My dream lens collection which I’m building up towards (currently got a Nikon 50mm f/1.8D and a bunch of other cheaper Nikon F mount lenses from this: http://www.gh1-hack.info/wiki/pmwiki.php?n=Main.ShootingMoviesWithHackOnVeryTightBudget Which is what I initially started out following):
#1 Tamron 17-50 f/2.8
#2 Nikon 35mm f/1.8G DX
#3 Tokina 11-16mm f/2.8
#4 Rokinon 85mm f/1.4
#5 Rokinon 8mm f/3.5
#6 Tamron 70-200mm f/2.8
I do have a Panasonic kit lens too that came with my Panasonic GF3, and I purchased a Panasonic 14mm f/2.5 too. Probably will be getting a Panasonic 20mm f/1.7 at some point too. But primarily getting Nikon F mount lenses, and the native Micro Four Third lenses are just supplementary.
I’ve also got my notes and thoughts collected together on my Amazon Wishlist I created to track this:
http://www.amazon.com/gp/registry/wishlist/140OXHDTVTUJI/?sort=priority&itemPerPage=25
March 20th, 2014 at 6:10 pm
Don’t think I’ll be getting any Nikon F mount, sorry David. I’d like the option to use AF as well as MF on the Gh4.
March 21st, 2014 at 12:55 am
Fair enough, I feel AF is never going to be reliable enough to rely upon what you’d want to choose as artistically suitable in the moment. (AF isn’t a mind reader!)
And the focus peaking (and other focus assists) GH4 and other cameras (and monitors) offer means Auto Focus isn’t quite so important.
So for me, an AF lens is just a minor supplementary addition, rather than at the core which I build my collection around.
March 21st, 2014 at 9:21 am
On Canon cameras I set the focus point to center. You focus with the center point then frame so you never have to worry about AF finding what you want because you tell it what you want in focus and for me it’s much faster than hand twisting a focus ring. Don’t get me wrong, I still have some full manual focus lenses in my collection, most of which are in my EOS-M kit, but for normal work my L series primes with full time manual and AF are the best way to go for my work.
March 20th, 2014 at 5:56 pm
Mike – Did you update the lens firmware on the 12-35mm?
The first version of that lens would show micro-jitters even on a tripod if the stabilization was on. The firmware update fixed that; no micro-jitters whatsoever. I rely on the stabilization for video, but the Olympus has some features that may be more important to others.
March 22nd, 2014 at 2:29 am
Hi, yes but firmware update didn’t help those micro-jitters, probably got better because previously as you say it jittered by it self even locked down on tripods, but it’s just that it can’t smooth out hand held jitter like other stabilizers do.
March 21st, 2014 at 1:05 am
Let us know how it goes Deejay.
Here’s a video of the 12-35 iris issue: https://www.youtube.com/watch?v=u2vjROGkgUA At this price, it’s a deal breaker for video (to me).
March 21st, 2014 at 8:54 am
That looks pretty bad. I just picked up a used Olympus 12-40mm f2.8 for $750 as a starter which seems like a pretty decent deal.
March 21st, 2014 at 9:05 am
Where did you find such a new lens (Oly 12-40 f2.8) at that price?
March 21st, 2014 at 9:22 am
Ebay, picked it up this morning. Accepted a best offer.
March 21st, 2014 at 11:28 am
This is a non issue in real life.
March 21st, 2014 at 11:26 am
I have been shooting with the 12-35mm and 35-100 since the day that they were released. Also the GH3. I am so pleased with this setup. No rig required because of the O.I.S. I have my GH4 on pre-order. Also I would highly recommend the 7-14mm as well. It was the first professional lens from Panasonic and is a good as anything from C or N. The F4 aperture is not a problem for me.
May 24th, 2014 at 9:25 am
Alan, what about the “fly-by-wire” focusing issue? Does it bother you when shooting? Do you have a blog post about this issue?
April 1st, 2014 at 1:19 am
You know it has just been physics all this time, yeah? “Constant aperture” is a misconception in the sense that although the resulting f-stop might hold wide open at 2.8, it’s not a physical measurement of the opening all the time. To the extent that a lens is designed so that zooming is changed by magnification of the front group, the opening looks constant; but by the back group, the opening creeps. This is still a so-called “constant aperture” scenario either way. And because the aperture is not mechanically linked to the zoom in this case, the aperture jumps positions electronically as the focal length changes.
May 22nd, 2014 at 11:53 am
hi there, I’m looking to purchase the gh4 with the sigma 18-35 f 1.8 lens and I’m just wondering if it mounts directly onto the camera or il need some sort of adapter been a canon user never used panasonic or sigma products before?
June 1st, 2014 at 8:51 pm
Lens choice for the GH4 17.3 x 13mm sensor, shooting @ DCI 4k with an effective megapixel @ ~16.05 (going the simple math… 4608 X 17.3mm) will require a lens that that can deliver a resolution of ~236 lines per mm or 118 line pairs per mm. You need some good glass to resolve the fine details for this sub 5 micron pixel pitched sensor. Glass is something you don’t want to apply a budget formula to if you’re doing some serious 4K Post that involves visual effects. I guess for those of you that are just “hobbyists”, it doesn’t matter. I know this because I’ve worked on feature films utilizing the ACES workflow with various cameras, including the RED EPIC.
You don’t want to down sample 4K 4:2:0 8 bit to 1080p to obtain 10 bit luminance via pixel binning. One might think you can get great 10bit from 4k 8bit, but there are areas of quantization in your source 4k (large blocks of pixels that are forced to the same color values via the AD) that can be much larger than the pixel matrix that you are subsampling from, no matter what the algorithm you use, the blocks remain visually. Effectively , you are smoothing just the contrast border areas of those quantized blocks, and later if you push the gamma in color correction, they will re-appear. If you want to experiment with it, sure why not.
4:2:0 footage is going to be converted to DPX 16 bit linear frame sequence, then you toggle your viewing LUT in the App. 3D footage generated for your VFX shots will be rendered out in openEXR format 4x32bit float which also will be linear, so you gotta watch the gamma curves and don’t LOG it up
These will integrate together in 32 bit space in your high-end compositor. You’ll render out 2K proxies that you can toggle on & off. For serious green screening, rotoscoping, tracking and edge cleaning, you’ll want to work in 4K. Sometimes you can get away with the 2K. You don’t want to just reformat to 2K in the pipeline, because you’re not reducing the internal processing of the 4K for the computer (not talking about mercury engine gpu processing in adobe cc…). That’s why you hear people saying I’m still getting the same FPS in my viewport even though I reformatted and cropped in my nodal pipeline… well duhhhh, you’re still reading 4K footage from the Raid dude! Thus, creating 2K proxies is essential for this workflow! If you did an offline in FCP for instance, then you’ll use an xml python script in the compositor to conform (this is for vfx, not Resolve to do color correction after primary grade, proxy gen., offline edit and back roundtrip blah blah blah…) in Nuke (which is what we usually use… not Adobe AFX).
Again, you don’t want to convert to 1080p at first, because you’ll lose the ability to pan, zoom your 4K footage to get the best framing for the shot. Silly if you ask me, why shoot 4K in the first place. You might want to check your 1:1 ratio on an inexpensive 4K monitor; they sell for ~600 dollars now, and good enough to do the job (although it’s UHD for that model anyway…).
I’m really speaking in general about this because it gets way more complex than this for the big screen, so I’m not going to get into ACES block diagram and its concepts, colourspaces, and transforms: RICD, IDT, LMT, RRT, RDT, ODT… and perceptually uniform coding; log-exp-power function math; 1D and 3D LUT interpolation and so fourth. I would look into future proofing your 4K investment and get some good glass, cause we all know some of you guys want to own a RED Epic or Arri Alexa someday, and are working your way up to it (baby stepping… ;)) Cheers!
Zeiss 21mm Nikon F-Mount ZF.2 would be a very nice choice for the GH4… learn to work a prime and stay away from zooms!
Although all this is nothing to solving Navier-Stokes equations in fluid dynamics…