GH5 GH5 M43 depth of field

H

heguy

Member
Hi there,

I am debating about getting the GH5 to replace my Canon 5Dmk 2 . My question is relating to using it as a Bcam, do you find it problematic to match a s35 camera sensor depth of field wise , being M43 with focal length FOV ?

Could somebody post an interview frame taken with the GH5? All I see is closeup on youtube ,so shallow DOF is easy . I'd like to see a medium shot of somebody in a limited size room . Thanks !


Jean
 
heguy said:
do you find it problematic to match a s35 camera sensor depth of field wise , being M43 with focal length FOV ?
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With the right lenses it's relatively easy. Take whatever FF lens you would use, cut the focal-length in half, and open-up 2 F-stops on your m4/3 lens to match the look of the FF shot.

So a FF 50mm lens becomes a 25mm lens on a m4/3 camera and f/4.0 becomes f/2.0.

For wide-angle work you will likely have to use native m4/3 lenses because the focal-length will be pretty short, and you may not be able to open your m4/3 aperture by 2 F-stops, so your DOF will increase.
 
In practice, no videographer "tries to match" the DOF of a full frame DSLR with a cropped sensor camera. You select the best tools at hand to make the shot you want and adjust exposure, framing, and DOF to achieve optimal results. If it's a "cinematic" look you're after, a full frame camera produces excessively narrow DOF. The sensor size closest to Super-35 motion picture film is APS-C (1.5x crop factor), which is not that much larger than typical MFT crop factors.
 
Lpowell said:
In practice, no videographer "tries to match" the DOF of a full frame DSLR with a cropped sensor camera.
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...But if your only frame of reference at the moment is entirely based upon FF cameras, you can do simple math to establish what m4/3 gear would give you the same look.

Personally I find it funny that the whole "crop factor" number is based upon FF cameras that traditionally have had little to do with film or video production.
 
Here's a frame for a shoot we did in the upstairs of a restaurant. GH5 with Sigma 18-35 (at 35mm, no speedbooster). Personally I've never had any issue getting shallow enough DoF. On the contrary, I always felt I had more trouble keeping my subj in focus on the 5D back in the day. Another thing you can do if you're worried about it, go slightly wider than you normally would and just move the subject closer to the camera and further from the background.

match - gh5 - 2_1.1.5.jpg
 
Hey there,

Not trying to match a full frame DSLR, it would be more like the Bcam of a C300 mk2 or F55 or EVA1 . As mentioned it would replace a 5D that I sometimes use for that purpose .

J

Lpowell said:
In practice, no videographer "tries to match" the DOF of a full frame DSLR with a cropped sensor camera. You select the best tools at hand to make the shot you want and adjust exposure, framing, and DOF to achieve optimal results. If it's a "cinematic" look you're after, a full frame camera produces excessively narrow DOF. The sensor size closest to Super-35 motion picture film is APS-C (1.5x crop factor), which is not that much larger than typical MFT crop factors.
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Since you probably have Canon lenses on hand, I would suggest renting a GH5 and canon to m43 smart adapter as well as a Canon to m43 smart Speedbooster and do a little comparison. I mention the smart adapter because I assume you are using EF electronic lenses so you need the smart adapter to control iris.
 
DOF is only a problem on M43 without fast quality glass. S35 allows for a shallower max DOF which is most often undesirable in cinema, but also allows a nice ideal DOF at a lens mid range sweet spot f/4-f/5.6 ballpark. This also allows use of cheaper glass.

If you have fast quality glass that looks good opened to f/1.4-f/2.8 DOF on m43 is no problem at all.
 
filmguy123 said:
S35 allows for a shallower max DOF which is most often undesirable in cinema, but also allows a nice ideal DOF at a lens mid range sweet spot f/4-f/5.6 ballpark. This also allows use of cheaper glass.
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The DOF difference between S35 and m4/3 is only ONE F-stop.

So if your S35 sweet spot is f/4.0 - f/5.6, then your DOF matching m4/3 sweet spot is f/2.8 - f/4.0, which is pretty easy to find.
 
TheDingo said:
The DOF difference between S35 and m4/3 is only ONE F-stop.

So if your S35 sweet spot is f/4.0 - f/5.6, then your DOF matching m4/3 sweet spot is f/2.8 - f/4.0, which is pretty easy to find.
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exactly! But most lenses if they are an f/2.8 lens won't look optimal wide open. So an f/1.4 to f/2 lens is best for shooting f/2.8. Depending on glass of course.

And it rules out a lot of native or non-speedboosted zooms for m43 if you want to shoot around f/2.8, and especially if you want to shoot one-stop down.
 
I have a PL 25mm 1.4 m4/3rd's lens that would be impossible to shoot a feature wide open with, except for totally static shots...nothing would be in focus...
 
fboonzaier said:
I have a PL 25mm 1.4 m4/3rd's lens that would be impossible to shoot a feature wide open with, except for totally static shots...nothing would be in focus...
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On FF a f2.8 lens would be just as difficult which is why I always scratched my head over the obsession of FF DOF. m43 provides just enough control over the DOF without providing an unrealistic unmanageable level of DOF.

A lot of Hollywood movies are shot f4-f5.6 because the focus pullers would walk off the set otherwise but also because optically lenses tend to do better in that range. Not only in terms of detail but contrast and a good balance of sharpness between the center and corners of the frame.

It is also important that 99% of Hollywood movies are shot on s35mm and not FF. s35mm is about the same size as APS-C. So if movies are shot with a 1.5x crop sensor and typically around f4-f5.6 you can see m43 provides more than enough DOF control. m43 glass is some of the only glass that can actually look production level quality at f1.4 or f2.0 which easily puts it within the range that most movies are shot at.

Lenses like Rokinon are darn impressive but I wouldn't be caught dead shooting with them at f1.4. Typically only f2.8 or f4 starts to look decent on those lenses. A lens like the Panasonic Leica 42.5 f1.2 lens looks insanely detailed at even f1.2. There is a lot more to cinematic quality than just a lack of noise. Optical detail/contrast/balance is equally important.
 
Shirozina said:
GH5 + Metabones speedbooster = s35.
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Yup. With that said a speed booster is not needed to achieve a similar look. There is only a stop difference between m43 and s35mm and thats typically not hard to achieve on m43 glass. Especially since a lot of FF glass doesn't always look great wide open. If you like to shoot with a 28mm f2.8 on s35mm then a 20mm f2.0 m43 lens will give you the same FOV and DOF and will likely look fantastic at f2.0. The 20mm pancake comes to mind. Yes the compression of the FOV may be slightly different but we are only talking a 1 stop difference in compression which is minimal. If having that exact match to s35mm is really that important (which in the real world it is not unless you are trying to do a VFX match move with a 3D environment) then you can use a Speedbooster. Keep in mind there isn't really a s35mm standard and all the cinema cameras use slightly different sizes of sensors so you will never get a 100% perfect match. Its physically impossible which is also true when trying to match one s35mm camera to another camera. Its really useless semantics at that point however.

I will say the one area where larger sensors do have an advantage over m43 is affordable zoom lenses. f5.6 on a $100 FF zoom lens would match the DOF on m43 with a $1000 f2.8 zoom. So fans of zoom lenses are at a pretty significant disadvantage on m43. FF f2.8 zooms would need a f1.4 zoom on m43 which is almost impossible to do. Optically I wouldn't expect much from that $100 FF zoom lens vs the really well made f2.8 zoom lenses for m43 but it is still a much more affordable option for DOF and low light control. Thats why sometimes FF can actually be cheaper. The body may be $3000 but then you can get a decent set of zoom lenses for a couple hundred bucks. The GH5 is $2000 but you need a set of f2.8 zooms for another $2000 to match the sensitivity, FOV and DOF of that FF setup. We don't use m43 for the cost however. We use it because it kicks butt and I don't break my back hauling it around in a backpack.

Knowing this I really wish Panasonic would figure out a way to produce more affordable f2.8 zoom options. Even if that means some optical sacrifices or limited zoom ranges similar to the Sigma 18-35 f1.8. Yes zooms can be adapted to m43 and that is a great option but sometimes a native lens is a better choice for performance and reliability of features.
 
Agree - m43 has seen a bunch of quality zoom lenses released (Leica has a whole series, the Lumix 12-35 and 35-100) - all high quality. But no one is focusing on making quality, lightweight zooms around f/2. I'd own the whole Leica zoom set if they went that route.
 
filmguy123 said:
Agree - m43 has seen a bunch of quality zoom lenses released (Leica has a whole series, the Lumix 12-35 and 35-100) - all high quality. But no one is focusing on making quality, lightweight zooms around f/2. I'd own the whole Leica zoom set if they went that route.
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Olympus made 14-35mm and 35-100mm f/2.0 zoom lenses for the older Four Thirds mount (which is adaptable to Micro 4/3). They don't really autofocus well on Micro 4/3 cameras, but are still usable as manual focus lenses and they are very good optically, even wide open.

The problem is that they are rather large and heavy lenses. The 35-100mm f/2 is about the same size and weight as a full frame 70-200mm f/2.8 zoom. These Four Thirds f/2 zooms were also on the expensive side compared to most Micro 4/3 glass. Which may explain why Olympus hasn't produced updated versions of these lenses with a native Micro 4/3 mount.
 
davedv said:
The problem is that they are rather large and heavy lenses. The 35-100mm f/2 is about the same size and weight as a full frame 70-200mm f/2.8 zoom. These Four Thirds f/2 zooms were also on the expensive side compared to most Micro 4/3 glass. Which may explain why Olympus hasn't produced updated versions of these lenses with a native Micro 4/3 mount.
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I would expect at least a 2x price increase going from f/2.8 zooms to f/2.0 zooms, which not many people are willing to pay.
 
TheDingo said:
I would expect at least a 2x price increase going from f/2.8 zooms to f/2.0 zooms, which not many people are willing to pay.
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And yet the Sigma f1.8 zooms are reasonably priced and look fantastic. Granted they are a limited zoom range but that doesn't stop a ton of people buying them and adapting them to the GH4/5.
 
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