GH5 So close to grab the GH5S but..

[Samuel Dilworth]

Sensor power consumption (= heat production) has been mentioned as a possible reason for lacking IBIS, i.e. because the sensor needs better cooling. The GH5S uses the Sony IMX299CJK sensor that is specifically advertised as achieving “low power consumption”:

https://www.sony-semicon.co.jp/products/common/pdf/IMX299CJK_Flyer.pdf

Plus, the GH5S has a slightly longer battery life than the GH5 with the identical battery.

These things point to lower heat production than the IMX272AQK in the GH5, not more.

https://www.sony-semicon.co.jp/products/common/pdf/IMX272AQK_Flyer.pdf

Advertising claims and longer battery life don’t conclusively prove lower sensor power consumption, but I seriously doubt the GH5S sensor uses appreciably more power than the GH5 sensor. Why would it? Moreover, even if it did, we don’t know how much headroom there is for heat before IBIS mounting becomes problematic.

 

[IronFilm]

Really? My GH5 ibis plays nicely with gimbal shots and pans. I wonder what I'm doing right or I'm doing wrong

Imagine it on a car mount, driving over a very bumpy road. IBIS can't handle that. With it switched off you'd get a jitter, no IBIS GH5S handles this better.

 

[IronFilm]

I think that’s one of the stories Panasonic spun to explain the omission, but do you believe it? Aren’t the GH5S users mounting cameras on vibrating machines outnumbered by a thousand to one by those trying to hand-hold a shot?

I find it telling that the GH5 had IBIS, the GH5S did not (even though Panasonic probably had the BGH1 in the pipeline, which could have been aimed at the crash-cam people who supposedly didn’t like the GH5), and then the S-series cameras went back to IBIS including the S1H for which Panasonic has a dedicated cine site.

Yes, it is a small niche of users who want a GH5 without IBIS, but still a sizable niche who are pros using the GH5/GH5S as their C Cam / Crash Cam / Car Rig Cam.

The S1 has a much bigger lens mount, thus can fit IBIS with a FF sensor.

The BGH1 came out quite a long ish time after the GH5S.

 

[Samuel Dilworth]

The S1 has a much bigger lens mount, thus can fit IBIS with a FF sensor.

This is a new red herring. The lens-mount diameter has no connection to the image circle size or the sensor size. Have a glance at the proportions of a large-format stills film camera if you doubt this. Extreme example.

The IBIS assembly can extend as far beyond the lens mount diameter as the camera body has room, because it’s not at the flange level but behind it, close to and behind the image plane (sensor surface).

 

[ahalpert]

Imagine it on a car mount, driving over a very bumpy road. IBIS can't handle that. With it switched off you'd get a jitter, no IBIS GH5S handles this better.

Yeah that I can agree with, although it's hard for me to believe they cant design a rock solid locking mechanism for the sensor when you turn off IBIS.

But the original point was about gimbal shots and pans, where I think IBIS plays nicely

Also, people make a good point that the S1H has IBIS and it is probably the most popular mirrorless camera among serious shooters and people who use it as a small camera when their A camera would be too obtrusive

 

[ahalpert]

This is a new red herring. The lens-mount diameter has no connection to the image circle size or the sensor size. Have a glance at the proportions of a large-format stills film camera if you doubt this. Extreme example.

The IBIS assembly can extend as far beyond the lens mount diameter as the camera body has room, because it’s not at the flange level but behind it, close to and behind the image plane (sensor surface).

I dont think this is true. Theres a huge amount of distance for the image circle to enlarge as it travels from the lens to the plate on that camera.

Consider Sony E mount. The IBIS is so much worse than Panasonic. E mount was originally designed for APS-C before being used with full-frame. It has a narrow mouth which I have heard limits the size of the usable image circle and thus the range that the IBIS can shift the sensor.

 

[Samuel Dilworth]

The E-mount doesn’t practically limit the image circle. It limits the minimum f-number of a compatible lens, because an f-number is fundamentally connected to a cone angle of light from the lens’s exit pupil, and if that cone angle is too wide, the mount blocks its outer rays. (This cone points the other way than you might imagine, though, with its point mapped to a specific point on the sensor and its wide funnel at the lens’s rear element. The whole image is formed by millions of such cones all mapped to slightly different spots in the image.)

And the E-mount limits (although only slightly compared to competing mounts) the freedom of the designer to place large elements close to the image sensor. A large element very close to the sensor (as in some fixed-lens cameras) is often used as a field flattener (to reduce curvature of field/astigmatism).

If full-frame Sonys were limited by the ratio of their mount diameter to sensor size, the APS-C α6600 would not be – and yet its IBIS performs about the same. Sony’s system is just not capable of the large-amplitude corrections that Panasonic’s can do, although it works pretty well for small-amplitude vibration – hence the decent CIPA rating in ‘stops’ of benefit. Canon’s IBIS cannot match Panasonic’s either, and the RF mount is larger than Sony’s. The mount isn’t the limiting factor here.

I’m sure Sony will improve its IBIS in the future. Until recently, there hasn’t been much competitive pressure to do so, since Sony had the full-frame mirrorless market to itself.

 

[IronFilm]

This is a new red herring. The lens-mount diameter has no connection to the image circle size or the sensor size. Have a glance at the proportions of a large-format stills film camera if you doubt this. Extreme example.

The IBIS assembly can extend as far beyond the lens mount diameter as the camera body has room, because it’s not at the flange level but behind it, close to and behind the image plane (sensor surface).

Think you've missed the point. Which is squeezing a FF sensor behind an APS-C lens mount is pushing them right to the limit, which doesn't leave much spare for "wiggle room". Imagine if you squeezed a FF sensor into a MFT Mount camera, how well would their IBIS then work, would Panasonic/Olympus still have the best in the business IBIS??

Am sure Sony's IBIS will get better with time, but they've got a much much tougher battle on their hands than Panasonic/Nikon/Fujifilm/etc have.