The problem with the LX100 is that dust is reaching the SENSOR.
The problem with the LX100 (aka Leica Typ 109) is the great shame on Panasonic who didn't fix it and continued it in LX100II (aka Leica D-LUX 7) without fixing. And on Leica who allowed it.
Look, any single quality zoom for M43 itself costs and weights much more than the whole LX100
After searching for a while, I have to agree with you - that's why I moved one sensor up insize - the APC land and the X-T100
And this is a big problem with the whole concept of "the smaller sensor gives you less bulkiness". No, it does not,
the whole concept is wrong. Speaking the "camera+lens combination" we clearly see, that camera's body bulkiness accounts for only a small share of the whole bulkiness; better optics drive the process with the larger diameter of the optical elements, thus more weight of the lens' structural components (they must be not only mechanically strong, but also very rigid to ensure the accuracy required by optical preciousness).
Let's recall that for any (abstract) structure if you geometrically upscale it, the weight of the structure increases proportionally to the 3rd power of the linear size increase. If you have one stone cube 1'x1'x1' and the other stone cube is 2'x2'x2' then that second cube will be
eight times heavier than the first.
For the complex structures like lenses, things are much more complicated but the weight of the lens (of the same given schema) unanimously increases if we upscale its diameter. Not so straightforward like with the stone bricks, but this is just physics.
Look at the famous M43 zoom lens
Olympus Zuiko Digital ED 14-35 mm f/2.0 SWD - it weighs 915 grams! Guess, why the FF zoom with similar focal length and aperture will be neither much heavier nor much bulkier? (you may check this on any other brand's lenses of similar characteristics).
The answer is pretty simple. This "F-number" thing actually just means
the ratio of the system's focal length to the diameter of the entrance pupil - what can be simpler than this?
So,
for the lens (of the given focal length) it's maximal aperture unanimously defines (dictates!) the diameter of the optical elements! And the diameter of optics dictates weight of the whole lens structure.
Note:
sensor size does not have any direct(!) influence on this.
The influence of the sensor size is indirect -
for a given (desired) AOV, with a smaller sensor you need a smaller focal length to achieve it. So
for the given maximal aperture and AOV, the lens for the smaller sensor will be proportionally smaller by diameter... and have less weight.
But if we take the lens of a given focal length and given maximum aperture, we get exactly the same diameter of optics, no matter how large the sensor is.
An example. Say, we want to get our "50mm equivalent AOV" with f/1.4 on 2 sensors: one is "FF" 24x36mm (crop factor 1.0), the other is M43 (crop factor 2.0).
For the FF sensor, we (obviously) need the lens with 50mm focal length and (see above) the diameter of the optics should be 50/1.4 = approx. 36mm. Suppose, this lens weighs 400 grams.
For the M43 sensor, for our desired AOV we need the 25mm lens (50mm / crop 2.0) and the diameter of the optics should be approx. 18mm. What will be the weight of this lens (given we are using the same materials - glass and metals and plastics - and same technology)? Given the diameter of optics is 2 times smaller, if lenses were stones, we could expect this small lens to weight 50 grams only! Wow, what a potential gain! But stop...
Panasonic Leica Summilux DG 25mm F1.4 weights 200 grams. Something already went wrong, no?
So we see that downsizing the sensor may bring us some extra gain
due to smaller focal lengths needed... or may not. It depends more on materials and design.
But we can be pretty sure, that given the equal absolute focal length and the equal maximal aperture, two lenses will differ in weight and size only due to the difference in design and materials, at the same time
sensor size doesn't matter at all. M43 16-80 F2.8 zoom and FF 16-80 F2.8 zoom of the same optical scheme will both have similar size and/or similar weight (like around 800-1000 grams). Because of F2.8 - to get F2.8 at 80mm, we need the effective pupil diameter of about 29mm in both cases (in reality the lenses of this kind are using filter threads of around 72-77-82mm, like this).
In fact, with 2 times smaller sensor the size of the camera body did not downsize to 1/2 of the FF camera size, and weight did not decrease to 1/8
So the declared size and weight gains are, in fact, a myth, it's fiction. Even the decrease in the price was not so significant (if any at all).
Why RX100 is so miniature? The sensor size matter indirectly, again. Actually, the RX100 lens is not 24-70mm - in reality, it is
only 8.8-25.7mm focal length. For 1" sensor, this is what you need to get the needed range for AOV. So it needs only 9.2mm for its "nominal" pupil diameter! Of course, it's much easier to design and manufacture the small lens to be very good, your optics are miniature even compared to M43.
What?! X-T20 is fast enough (X-E3 too). Stop and think a bit, you already get plenty of knowledge from this thread. Speaking "speed" we are not speaking "speed of a standalone body" but "speed of the body+lens combo", always. X-T20 is very fast when combined with any of XF F2.0 lenses - AF works at the top-DSLR level of speed.
Again, it's probably an error on my side, I'm not 'Speed' is equivalent to 'Autofocus Speed'? The RX100 V strong point for parents is continuous autofocus and Eye AF.
X-T20 has both and is better in both than any compact, given the lens is sufficiently good.
When reviewing the X-T100 according to the DPreview review:
"To broadly sum up, we find that the X-T100's autofocus system is not up to the task of handling moving subjects, even when tracking an approaching subject, which is relatively easy for many competitive modern cameras.".
Which lens did they use for the test?
On the X-T20 they say:
'Although Fujifilm has suggested face detection is improved on the X-T20: now making it available in continuous shooting mode, but we weren't particularly impressed, it struggles particularly under dim lighting (the face-detect box will toggle on-and-off randomly unless the subject is staring right at you).'
Which lens did they use for the test?
If I am to guess, I would say AUTOFOCUS is a Camera feature,
No. AF is the feature of the body+lens combo.
Example 1. XF 35mm F1.4 lens is known for its somehow outdated and slow AF behavior. With the arrival of the new X-T3, owners of 35/1.4 discovered, that the AF suddenly became much faster!
It turned out that on the entry-level bodies this same 35/1.4 is badly slow, on middle-range bodies - somehow slower than desirable, on X-T3 - no problems at all.
One lens, different bodies - different results.
Example 2. Someone in Fuji forum here was dissatisfied with AF performance of his lens for rapid action while shooting sports (I can't recall, was it 18-55 or 55-200). He got the XF 50-140 F2.8 zoom... and was pleasantly surprised with the AF speed. Later he tried some of the F2.0 primes... and was surprised even more pleasantly.
I observed this many times in my Canon days: the same body, but with different lenses, your AF behaves
very differently. Take 24-70 F2.8 L USM pro-grade zoom and you have fast and reliable AF, take L-rated pro primes - even better and faster, but with consumer-grade lenses... so-so. The cheap "plastic" kit lens was a complete disaster.
One body, different lenses - different results.
and the speed the focus is being changed is based on the LENS and the CAMERA? or it's a wrong guess here?
Yes, the combo of the camera body and the lens. I think that with XF F2.0 lenses even an entry-level body (X-T100, X-A5) would produce acceptable AF, but with XF 35mm F1.4 (not to mention XF 56mm F1.2)... I doubt. Put an XC kit lens on X-T3 body - I think it will be something acceptable, but... far from shiny.
X-T20 with 16-50 will be slightly better or on par. With 18-55 - considerably better. With XF 35mm f/2.0 - much better (but no zoom, zoom by feet only). These are my own and personal, subjective (but educated) expectations.
Well, the RX100V is more expensive compared ot the X-T20 kit, and probably will give me much less nicer pictures over higher ISO, so X-T20 has an option to be superior with lens in the future, so leaning towards the Fuji.
A friend of mine raise a nice argument today. When your out for a bar, or just hiking during the day, you can use your phone. Right - it doesn't have any real zoom, but I hardly use zoom.
You hardly use zoom... so maybe the prime 35mm fast lens is better for you?
Phones are so strong today, that while the IQ of a recent phone is not near the RX100V, it's not very far off for day shooting where ISO and Sensor size is not much of a problem. He said he think I should get a Camera I can grow 'into' (so in 1-2 years I can get better lens), because there is a chance that in two years from now, the smart phones cameras will be very close to RX100V, but no where near a Mirrorless Camera with good lens.
This is very reasonable. I already wrote somewhere that the biggest market pressure "from below" goes from smartphones and in a few years the whole class of the small-sensor compacts (less than 1") will be eaten away by them and will disappear from the market.
But smartphones need to be thin, so they have a "natural", physical limit on the camera sensor size (just no space to place anything larger). So my guess is, 1" cameras will survive - see above about F-number and lens size. Also, there are some physical limits on the pixel density (diffraction!) so smartphones with their tiny sensors would not be able to compete with M43 and APS-C seriously with regard to IQ.
Also, XF 35/2 on X-T20 makes it pocketable enough to carry with you to parties, events and elsewhere. Less than 500 grams total, I guess. And your photos will (probably) be the best among others
optics create the picture, the sensor captures it. Smartphones have no physical space inside them either for optics or for a sensor.
And how Leica could tolerate this obvious mistake, I wonder (they are selling LX100 under the Leica brand!).
yes if we will test Canon 5D4 with sharp prime 50mm F1.4 (shh! sit silently!) and Fuji with the cheap XC consumer "kit" zoom(!) then we know who will win the race, but we will never tell you something...