Thanks for all the interesting feedback. But I do not understand why
you find hyperfocal work to be difficult. I assume you're talking about
the lack of a distance scale which (as near as I can tell) appears to be
missing not only on the 14-42 zoom lens but on the 20/1.7 as well.
The 14-42 at least has focal length marks at 14, 18, 25, 35 and 42mm.
So build yourself a hyperfocal table for these focal lengths plus the
20mm. Lets start with 14mm as an example.
For the greatest DOF we'd like to use the smallest practical aperture.
For a 12 MP 4/3 sensor diffraction starts to show itself beyond f/5.6.
So, plan on shooting at f/5.6 or maybe f/8 which can be determined by
experimentation to find where the best results are obtained. Also,
let's use a moderately strict CoC for 4/3 of 0.015mm (resolution 67
lines/mm)
For 14mm my DOF calculator says the hyperfocal distance is 2.36 meters.
But to be on the safe side and to make sure we've captured infinity
let's round up to 2.5 meters (or maybe even 3 meters). The near focus
distance is still just half of that so we've lost very little foreground
while assuring infinity focus and making measurement easy and
non-critical. Next frame the photo so you know the focal length in use.
So, how to set the focus distance with no distance scale? Easy. Carry
a string in your pocket with major marks every meter and maybe minor
marks at 1/2 meter intervals. Pick an object that's easy to focus on,
measure off the distance with your string and then focus the camera and
leave it at that distance by switching the camera to manual focus.
Now lets do the same computations and build a table for all the marked
focal lengths using f/5.6 as the aperture for all
Focal Computed Rounded
Length Hyperfocal Up Dist.
------ ---------- --------
14 2.36 meter 2-1/2 meter
18 3.89 4
20 4.81 5
25 7.50 8
35 14.69 15
42 21.15 22
Obviously, by the time you get to 25mm you're using a pretty long
string.. or else using a shorter string multiple times or else not using
these long focal lengths for hyperfocal photography or else learning to
pace off the distance fairly accurately and maybe adding a small safety
factor.
What? After framing the photo it appears that the lens is set at about
23mm. What to do? Just use the hyperfocal distance for the marked
focal length next up the scale. You guess the lens is at 23... use your
hyperfocal table settings for 25mm.
In any case it really isn't very hard. :-)
ps: For f/8 the computed hyperfocal distances are
14mm 1.66 meter
18 2.73
20 3.37
25 5.26
35 10.29
42 14.82
Chuck Norcutt
On 2/13/2011 10:24 AM, manuel viet wrote:
> Le dimanche 13 février 2011 15:26:35, Chuck Norcutt a écrit :
>> But I haven't given up on Olympus yet. I don't see ever abandoning full
>> frame but I can imagine adding a micro-4/3 camera to the stable. If I
>> do it will be Olympus in order to gain sensor based IS. But it will
>> also have a usable viewfinder as well as an articulating view screen for
>> ease of macro work. Perhaps the VF-2 viewfinder meets my criteria
>> already. But I've never seen one. For that matter I've never seen any
>> micro-4/3 camera of any brand. Hasn't Oly promised a pro version of the
>> Pen things? Maybe that will also satisfy my concerns about focusing speed?
>
> For the sake of objectivity, let me put that first : I love µ4:3. I use my
> e-p1
> more than I ever used any other DSLR, and probably more than I ever used my OM
> and other film cameras.
>
> But I am an amateur, in all the meanings of the word. I appreciate the colors
> and ease of use the e-p1, but I'm not making a living on it, and, God forbids,
> I don't have to bind to some clients' wills or assignements. And it's a
> blessing, because no µ4:3 camera is playing in the pro league, and none will
> until a while, in my humble opinion.
>
> - AF is slow. Not dog slow, mind you, but the current contrast detection
> technology can't compete with phase AF, and phase AF can't work without a
> mirror box. Exit EVIL cameras here. The contrast detection has been pushed
> almost to its limits now, but you can't shoot comfortably sports for instance.
> Panasonic lenses help a bit here, because they were wise enough to have a
> single moving lens inside the assembly for focusing, speeding up the process
> (faster motor, lighter load). Still, not in the DSLR league.
>
> - Prices for native lenses is confiscatory, to put it mildly. You can forgive
> a
> 300 € price tag for the Pany 20/1.7, it's a beauty (but still, it's quite
> steep for what amounts to a pancake with a normal field of vision, one of the
> easiest optical formula to build !). But ~ 230 € for the Oly 17/2.8 is armed
> robbery, plain and simple. The promise of µ4:3 was lighter, cheaper lenses.
> Where are they ? Not even Canikon dares setting such ingnominous prices for
> mid-range prosumer lenses. This is subjective, but this 17/2.8 is worth
> between 75 / 100 €, realistically. Other native lenses are on the same sorry
> trend. What saves the system as a whole is the ability to use almost any MF
> lenses from other brands with an adaptater. And maybe now that Schneider-
> Kreuznach has joined the µ4:3 group, there will be a modicum of new blood and
> cold reason to expect (they made Pentax clones, notoriously good *and* cheap).
>
> - I suspect the electronics innards are quirky, and certainly not up to pro
> quality. The body has a marked tendency to (over)heat after a certain time
> span of use, and this can't be good if you expect to work for a couple of
> hours straight.
>
> - You can't tether the camera. While not absolutely necessary, this is a sadly
> missing pro convenience. Missing too, a 'screw to camera sole booster battery
> pack' with 2nd shutter button.
>
> I will stop here the con's list, and let others add their own griefs or pro's
> to it. µ4:3 are very very nice cameras. I've never regretted the 450 € for
> body+zoom kit and the 300 € for the 20/1.7 I spent on it. It's almost perfect
> for what I do (I wished there was a way to setup conveniently hyperfocal,
> though, because at the moment, it's pure guesswork, and even the panasonic LX2
> is better and more precise at this). But it's an amateur camera, and it can be
> very frustrating at times. Be sure of that. You have to decide if you can live
> with it or not, but it won't go away by magic.
>
> Cheers,
--
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