FAQ Sharing lenses between FS7 and GH5: seeking advise

moldcad

moldcad

Veteran
OK guys, you love those "need expert advise" threads of mine, so here is another one :)

As you know, I'm in the market for a small versatile B-camera for my FS7; I was about to pull the trigger on an A7 when Panasonic GH5 was announced. As I'm really serious about grading my footage, its 10bit 4:2:2 (and 50/50p) capabilities in UHD make me wait. One thing I'm not sure of though, and here is where I need your expert advise again!

Please just take a look at my signature to see which lenses I already own (BTW: was hoping to finally give a proper go to the excellent FF 28-135mm with one of those A7s; oh well - now it's going to serve me as a telephoto zoom on my FS7 only, cropped from FF). But while using my current Canons on both FS7 and GH5, I'd like to buy at least one native, stabilized new Lumix MFT lens; after all a small camera like this should be versatile, mobile and what not, which means its Auto functionalities will be used much more frequently than with proper video work - and adapted lenses will never be as good at it as native ones...

So, given the above, which strategy would you adopt if you were in my shoes:

- Buy the EF->MFT 0.61x Speed Booster XL to speed up my F4.0 Canons by 1.3 stops, and make them work in only slightly increased “35mm stills equivalent” range of focal lengths, plus add some longer telephoto native Lumix lens? If so, which one would you recommend?

- Or, should I adopt the reverse approach: buy the EF->MFT non- Speed Booster adapter to make my Canon lenses work in 2x increased “35mm stills equivalent” range of focal lengths, plus add some native Lumix lens at the wide end instead? If so, which one would you recommend?

I hope I explained my doubts clear enough, and look forward to your invaluable, expert opinions/comments :) TIA,

Piotr

Disclaimer: Should Panny's announcement make Sony come up with A7S/R iii (or whatever it's called) with 4:2:2 10-bit 50p 4K in the meantime, I will be buying FF anyway :)
 
My process does not appear to align with yours. It was thus..

Most of my lenses are good forthe Gh4, what was missing was a wide.

I therefore bought a 12mm1.6 SLM lens so that wide was covered on the GH4 and also a couple of super cheap non boosting adapters..

S
 
Sam,

To really help me out, please answer this very lame question (I really never deallt with any lenses other than FF):

- when a lens description says (like it does for e.g. this lens http://cvp.com/index.php?t=product/panasonic_h-hsa12035e_lumix_12_35mm_lens):

Mount: Micro Four Thirds mount
Focal Length: f=12-35mm (35mm camera equivalent 24-70mm)

- then, on a GH5 or other MFT sensor camera, its FOV will be like that of a 12-35mm or 24-70mm FF lens on FF camera?

Piotr
 
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Yep a MFT sensor is APPROX half the size of a FF sensor (and APPROX 1.5 of an S35 sensor)

So a rule of thumb is a 12mm on a MFT has the same FOV of a 24mm on FFrame

Also with DOF it is two stops so an F2 MFT lens looks like an F4 lens on Full frame.

So yes a 12-35 looks like a 24-70,

If it is a 12-35 2.8 it will have DOF character of a 24-70 5.6 fullframe

I say approx because differnt aspect ratios and actual sensor sizes vary a bit..

Hense my purchase of a 12mm 1.6 which I thought would be a good Bcam FOV/DOF as it would if stopped to 2 match an S35 at 2.8

Play with FOV/Sensorsize here.. http://www.abelcine.com/fov/

S
 
The good part is that you can old lenses wit a converter. When you have a macro-set, bellows e.d. you can use your 4/3 camera. I used my old zuiko OM auto bellow and an old tokina 90mm macro to make macro video.
 
I use the GH4 when I want a compact system, & the 12-35/2.8 is the lens I use most, followed closely by the 35-100/2.8.

Put down a deposit on the GH5, but what I really want is a 10-Bit A7x that doesn't overheat. And a Unicorn.
 
I have an FS7 along with a metabones speedbooster and "smart adapter" (MC-11). I used to use my speedbooster a lot more, however, I started realizing it's limitations. The biggest is that the corners are fairly soft which makes it difficult to crop and pan 4K footage.

I've found that I typically only end up cropping locked down shots, interviews, and more produced shoots. I hardly ever crop run and gun footage.

That being said, it depends what you are shooting. If you plan on cropping your 4K footage a lot then you will probably not want to go the speedbooster route. If you need the low light and corner sharpness isn't that important to you then by all means, get a speedbooster and stick with EF Glass.
 
Thanks guys for the comments. But I really am a complete newbie to non-FF lens nomenclature and usage, so - even with layman's terms explanation from Sam - I'm still uneasy about which route to go while choosing my first native MFT lens for the GH5 :( And I'm afraid I will not have an opportunity to just walk into a shop, ask for the GH5 and a couple of different MFT lenses, and try it out... So please bear it with me, and try to answer my OP question as explicitly as only possible; let's assume a couple of things first:

- no I'll not be cropping my 4K footage, as I always deliver in UHD and not say 1080p
- that said, I don't find the current FS7 footage taken with my Speed-Boosted EF lenses particularly soft in the corners or otherwise affected to a non-acceptable extent, so assuming it would be of similar quality when using EF-MFT 0.64x Speed Booster with these lenses this is not a problem
- what is a problem is which strategy to adopt:

- buy the said 0.64x XL Speed Booster, and use my Canon EF lenses (1.3 stop faster than their native f4.0) as standard zooms while complementing them with a couple of long and fast, native telephoto MFT lens(es), or

- buy the much cheaper, non-boosted EF->MFT adapter, and use my Canon EF as my longer zooms (they would cover the 32mm - 140mm focal range, but still only be F4.0), while adding a faster, native MFT lens for the wide end (say 12-35mm range)... Will the http://cvp.com/index.php?t=product/panasonic_h-hsa12035e_lumix_12_35mm_lens be fine for that?

Please, at least answer yes or no to the last, bolded out question, because - and this is a proof how lame I am when it comes to non-FF lens nomenclature - I'm still unsure whether on the GH5, this lens will produce a 12-35mm, or 24-70mm focal range in FF terms... My common sense tells me that this lens being MFT, it already have the CoC right for an MFT sensor, so it's not cropped any further and as such, it's exactly what the specs say: a 12-35mm lens. But when I go to "Features" tab of its description at CVP under the above-provided link, I read something I don't understand at all:

* 3X Optical 24-70mm F2.8 Constant Aperture. (why 24-70mm ???)

So please help me understand it once and for good; TIA
Piotr
 
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It is not possible to suggest the best pens for you.

That 12-35 2.8 will give you the look of a 24-70 5.6 on a full frame camera.

Personally I use my gh4 for locked off wides and would suggest a 12/2 prime for that

I have also used it for a tight head in multicam interview for that I used a 50 1.4

I've never taken it out as a solo camera because.. Well .. My fs7 is better for many reasons.

That zoom is of course not cheap - a samyang/slr Magic 12 is cheap

Overall I think that mft doesn't really sing (aka have shallow dof) until you lens is f2 or wider
 
morgan_moore said:
That 12-35 2.8 will give you the look of a 24-70 5.6 on a full frame camera.
Click to expand...

Sam - are you 100% positive on this (DoF aside - just the focal range/FoV part)? If so, why is the lens explicitly called "MFT lens" - an FF lens with 12-35mm focal length would give the 24-70mm range on MFT sensor, as due to its CoC being too large it would be cropped 2x. I thought a lens called "MFT lens" not only has the MFT mount, but the CoC 2x smaller than that of a FF lens - thus it's not cropped on an MFT sensor, and 12-35mm FOV is still the 12-35mm one...

As another example of my way of thinking; let's take my Sony FF 28-135mm lens: on the FS7's S35mm sensor, the lens' large, FF CoC gets cropped, which results in the effective FoV corresponding to some 42- 200mm range. But I assume that should I put the Sony APS-C 18-105mm lens on the same camera, it wouldn't get cropped and act as 18-105mm, no?

Would I be so wrong with my thinking?

Piotr

PS. And as to the DoF "not singing" on an MFT camera, I realize that but with the intended use as a mobile B-cam to my FS7, often with Auto Focus when on some stabilizer or alike - the deeper DoF could actually be an advantage (sometimes)...
 
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If Sony doesn't react to GH5 announcement from Panny and doesn't come up with their new A7R/Siii, A9 or whatever they call it - also offering 4K@50/60p and 10bit 422 (at least externally) - yes, I'm going with the Panny...

Piotr
 
FoV has to do with the sensor size. That it's a MFT lens just means it needs less glass to cover the sensor than a FF lens needs to cover a FF sensor. So a 12-35 MFT lens will give you same FoV as a 24-70 lens on a FF sensor.
 
Thanks, Dmitrij :)

It's this fragment of your answer that helped me get rid of my doubts:

"That it's a MFT lens just means it needs less glass to cover the sensor than a FF lens needs to cover a FF sensor"

Piotr
 
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Personally, I used to rock multiple systems as well-known Canon EF, Pany MFT, and Sony E mount. I was in the same boat as you, using mostly Canon adapters and wanting at least one native lens for each so that I can get stabilized shots, steadicam, auto focus, etc when useful.

But in the end, I found it too cumbersome to keep and maintain multiple platforms, not to mention difficulty matching them in post (and I mean more than just FOV, color science between them was often a nightmare).

I ended up selling all my Panasonic gear and going all-in with Sony. Sony makes some great tiny cams now, like the a6500. Built in stabilization and OSPDAF means you don't really need native lenses to get IS and AF, adapted Canon lenses can now do that almost as well as on a native Canon body. The whole thing is TINY, and if the compressed color space is such a concern, it outputs 4:2:2 with the HDMI. Ive seen mathematical explainations that describe (and show) how the color information of 8-bit 4:2:2 at 4k reduced to 1080p are extremely close to FHD 4:4:4, so I'd argue that owning and maintaining a separate system with a smaller sensor and native lenses for what might be a non existent benefit in color space, might not be worth the price of entry.
There's a lot I love about the gh5, but I don't see the benefit of it as a b-cam to what you already have.
 
Thanks M. - your post has been the sort of answer I was hoping for, with lots of ad rem rather than ad personam arguments :)

You're 100% right that keeping all rig Sony would be highly beneficial in my situation, and I already mentioned several times that - should Sony react to GH5 announcement from Panny and come up with their new A7R/Siii, A9 (or whatever they call it) also offering 4K@50/60p and 10bit 422 (at least externally) - I'm ready to wait even longer but stay with Sony.

However, I cannot agree with your arguments about 10-bit not being of real importance for somebody serious about grading. I did try to color match my FS7 with A7Sii and A7Rii sample clips (straight from camera), and my impressions were not optimistic at all for 2 reasons:

- the A7 picture is amazingly sharp, but large single color areas like the blue sky are awfully noisy and banding. Even the "low light king", the A7Sii, produces "busy pixels" - and that's in full sunshine! None of this clips could be of any use without serious NR, which kills the main picture virtue: the sharpness and resolution I mentioned

- when I tried to match those clips' colors to my FS7, the A7 picture fell apart very quickly - I dare say due to only being 8bit. There has been only so much I could do to the A7 picture without loosing color "density" (if this is a right word to describe what I mean; there's not enough "meat" in color information).

Of course a work-around could be to work more on the FS7 picture in order to make the two match - but this denies the advantage of having the best camera as the main one... Also interesting (and discouraging towards the A7) was the fact that for whatever reason, after applying quite a strong NR (which this camera really needs, even the A7Sii as I mentioned earlier) - inevitably the picture became unusable due to the strange tearing in the lower right corner (?!!!). I have no idea whether the post-NR tearing is also an 8-bit picture phenomenon, or some Resolve bug in the way it treats the A7 footage - but frankly, this experiment outcome has been totally unacceptable and has been my main reason for starting to look at the GH5...

Piotr
 
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