Thursday, 11 February 2010

micro 4/3: what are the limits to the system

While I am very enthusiastic about my G1 camera (and have eyed carefully the EP-x and GF1) I have been wondering about the lack of lenses in the lineup and wondering if this is
  • an accident,
  • a lack of early investment (while testing the water) or
  • a design issue which will prevent extending the system easily (or make it bloody expensive).

If you're the kind of photographer who buys the camera with the standard zoom and never does anything else then there isn't much meaning in the following post for you.

However if you're the sort of person who likes to (or needs to) extend their system to cover additional things (like a professional or a "soccer mum or dad") then this may be applicable to you.

my G1 FD systemQuite a number of photographers (including me) like to extend their G1 from the basic kit and get it to do more. I for example have used FD lenses by adaptor to fill out what Panasonic does not provide for my G1 or would be simply too expensive.

I picked the FD300 (cheaply) because I wanted more reach than the 45-200 gave, and the FD200 on the right was less than $50 and makes a nice light thing to pop in a backpack for stuff which might crop up when travelling, the 50mm is a great portrait lens and the 28 ... well it was $6 and I thought it might make a better 'normal' lens than the zoom (its a yes and no on that one).

While optically brilliant, none of these have AF or allow the camera to control the aperture ... its all strictly manual focus and manual stop down. The first part is actually less problem than the second if you ask me.

But I don't always want to use manual focus (I'm too spoiled by over 20 years of AF with Canon EOS cameras) and we have not covered anything wide here yet. The standard zoom (while very good) will only go as wide as this:

which is not enough for my tastes in that picture and in places like this:


isn't nearly enough. This interior shot uses a 9mm focal length.

So, some time ago Panasonic announced a few more lenses in their lineup (sorry folks, that link was in Japanese but the pictures are pictures). Notably they added:
  • a 14mm f2.8(with no OIS and therefore no orientation sensor for your pics)
  • a 8mm f3.5 (nice and wide, but again with no OIS...)
  • and a 100-300mm zoom (which appears to have OIS)
this extends the existing selection of:
  • 7-14mm (no OIS)
  • 14-45mm
  • 45-200mm
  • 20mm f1.7 (no OIS)
  • 45mm f2.8 macro
of this only really the 45mm Macro, the 7-14mm, the 20mm the f1.7 and the 8mm are lenses which would likely appeal to any serious user. The 14mm f2.8 is borderline as it sits right where the standard zoom sits (14mm), while offering not even a full a stop faster aperture than the zoom and without image stabilization.

I think that the 14mm (which I've already said isn't really wide) will appeal mainly to GF-1 users who didn't buy the 14-45 zoom kit but bought the kit with the 20mm can add a compact wide to their pockets.

Fair enough ... that makes the GF-1 a nice niche market camera for those who desire a (nearly) pocket sized compact camera with just a few bits n pieces.

If you're after a more versatile camera (which the G1 is) then there are some problems here. If someone is going to give up their Canon or Nikon DSLR I think it might need a bit more in the mix. Looking at the selection available to them (or Pentax, or Olympus) you have quite a lot to choose from.

Now, (getting to my design issue) looking at all of these lenses only the 14mm and the 20mm seem to use a more typical AF where the whole lens element stack moves, the others (especially the zoom) will seem to likely rely on internal element movements for focus.
(NOTE: I am not talking about rotating the front element)

As I said, of all these lenses only the 14 and the 20 (and the Olympus 18mm f2.8) use this sort of focus concept (which is pretty important for low cost designs), the rest use inner element movement for focus.

Its interesting to note that Panasonic can use precious few of the existing 4/3 lenses in anything other than the most basic of ways (yes, they mount, yes they manual focus, and yes the aperture iris is integrated to the camera full list of compatibility here), even their own lenses only work in AF-S mode.

None of this allows photographers to take advantage of their fantastic image tracking AF and other great features of their camera.

Why is this, and what may it mean for the system?

Firstly there is not a lot published about this system and how the AF physically works on the moving the lenses (unlike say Canon, where there is a wealth of information on how their AF systems work), so gathering what I can I found this from the imaging-resource page about the GH1 [emphasis my own]:

.. It turns out that not all lenses are able to move their elements quickly enough to work with the G series' contrast-detect autofocus. Normal phase-detect AF systems are fairly forgiving of focusing speed, because the correct focal distance setting is determined independently of the lens elements' motion: The camera looks at the subject, calculates the correct focal distance, commands the lens to move, and then snaps the shot once the lens reports back that it's moved to the correct setting.

With contrast-detect autofocus, though, the lens has to move multiple times, and must come to rest before the camera can take each "look" at the subject, to determine whether the focus is better or worse than it was at the previous focal setting. In order for the overall focus cycle to be performed quickly, the lens needs to be able to shift focal settings very quickly, multiple times per second. This is a demanding requirement, and not all lenses are up to the challenge.
So, while some current Four Thirds lenses will work just fine on the new Micro Four Thirds system, with full support for AF operation, other lenses will be reduced to "guided manual" focus
Like the Panasonic G1, the GH1 uses a very fast contrast-detect autofocus system, capable of adjusting focus sixty times/second.

Because of a basic law of physics (Force = Mass x Acceleration) if something more massive must be started and stopped fast (high acceleration) it will require more Force, which means more energy and strength.

So the system seems to be limited to use of moving around light weight inner elements or light weight elements.

For existing AF lenses where the entire element moves (as in say a typical 50mm lens), the motors just won't be fast enough and snappy enough to do it, so no AF

I think it poses a critical problem for Panasonic on their lens design, as it means that a mass limit is effectively applied to movements.

It seems to me this is going to be a major restriction for the system, despite its alluring features, there are quite a few restrictions on its implementation (as was the main point of what I was saying).

In fact if we look carefully at the lineup again in this light:
  • 14-45 zoom - uses inner focus to move what is probably a very small element and not have to move it far.
  • 45-200 zoom - probably the same
  • 7-14 zoom - probably the same
  • 45 macro - does not extend during focus (as does say lenses such as the EF 50mm macro or the FD 50mm macro) so works with inner elements.

of all of these lenses Panasonic says on their site that (with respect to AF)

AF tracking is slower than the counterparts in HD movie support Micro Four Thirds lens(LUMIX VARIO HD lens). Also operational noise in AF may be recorded while motion picture recording.


For the Full HD motion picture recording( [FHD] in [AVCHD] ) in DMC-GH1, AF does not work, and it records in MF.

although only the first point applies to the 45 macro.

These limits mean that to me, lenses like the Olympus 300mm SWD will need to be redesigned to make use of advanced focus tracking systems that the G series has (unlikely) and that lens is already 50% more expensive than a similar Canon EF lens which has Image Stabilisation too.

So people who wish to take advantage of these nice camera features are perhaps never going to see lenses other than a few zooms of consumer grade quality.

Unless one is after the GH1 for video work and its HD rated 14-140 zoom then it sort of leaves the G series in a bit of a funny spot.

It makes a nice experimenters / amateurs camera for used legacy lenses, but you have to invest heavily in lenses if you want wide angles (like US$1000 for the 7~14mm, which doesn't appeal to this amateur) or not much less for a Olympus 9-18mm (and the adaptor).

You have to pay big bucks for a normal (try US$399 at present for a lens which is equivalent to a less than $200 Nikon), heck I have a 30 year old Pentax 110 lens which was never that dear, and all they've added are 1 1/3 stops brightness, coupled Iris for aperture and AF.

Telephoto's are so far just a couple of mid range zooms (not really any standout from the Canon USM 100-300 or the Nikon AF VR IS 75-300) so they'd better be well priced.

I notice though that among the bird watching crowd that people don't seem to mind spending up on L series (like a 300mm f2.8 or f4 with IS), paired with a 40D (or heck even a 20D) the amount of price difference between the G1 and the 40D will soon get soaked up by the lenses. These aren't even professionals.

So, with the promise of things being "smaller and lighter" with "high quality" things had better change soon ... cos its looking like the intentions have stumbled into dividing the G series into a pair of niche markets (compact with only a few alternatives and HD video who need stills).

The G1 is not seriously more compact than a Olympus 420 and while I do love its EVF and articulating screen its not the end of the world without them. If I'm stuck using legacy lenses to keep those features (EVF and articulating screen) and miss out on the promise of their great AF system, then its like having a Ferrari but its stuck in the living room, I can only dream of how good it could be to drive.

... at least in my view.

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