From: Savageduck on
On 2010-04-02 23:25:46 -0700, "David J. Littleboy" <davidjl(a)gol.com> said:

>
> "Savageduck" <savageduck1@{REMOVESPAM}me.com> wrote:
>>
>> Personally, even if the technology made it "safe" I would not like to have
>> any laser aimed anywhere near my eyes. It is uncomfortable enough with a
>> flash or any other bright light aimed at the eyes.
>>
>> ...this whole debate though is still, for the present, theoretical and
>> fanciful.
>
> Every Nikon and Canon midrange or higher flash does it. Do you hear a lot of
> complaints?

Yup.
My SB-800 does it, and it remains irritating to be on the receiving
end. However I am satisfied with its operation and results I get. We
have all just learned to live with it.

Isn't amazing how something which can make you uncomfortable is
eventually accepted after familiarization?

I still wouldn't want a laser beam of any type directed towards my eyes
(in a non-surgical context), and I find bright lights flashed in my
face irritating.

--
Regards,

Savageduck

From: Ray Fischer on
David J. Littleboy <davidjl(a)gol.com> wrote:
>"Ray Fischer" <rfischer(a)sonic.net> wrote:
>> David J. Littleboy <davidjl(a)gol.com> wrote:
>>>"Ray Fischer" <rfischer(a)sonic.net> wrote in message
>>>>
>>>> Of course, but then the problem becomes one of firguring out just
>>>> what you're focusing on. And no, it's not the same as current
>>>> viewfinder indicators because you can't align the laser with the
>>>> viewfinder indicator.
>>>
>>>Sure you can. There are lots of ideas one could come up with if one tried.
>>
>> For example?
>
>The ones you snipped. Especially the point that you can integrate the laser
>with the viewfinder, so you'd know exactly where it's trying to focus.

But as I pointed out, that doesn't work for interchangeable lens
cameras with through-the-lens viewfinders.

>>>Current viewfinders adjust for framing as focus changes,
>>
>> Worthless for any camera with a changeable lens.
>
>Well, that's how they work. Go pick up a Leica M or Mamiya & or Bronica R645
>some time. Those are all interchangeable lens rangefinder cameras,

Oh, RANGEFINDER cameras.

But that isn't the subject, is it?

--
Ray Fischer
rfischer(a)sonic.net

From: J. Clarke on
On 4/3/2010 1:51 AM, stephe_k(a)yahoo.com wrote:
> David J. Littleboy wrote:
>> But given that there are now good wide angle and good pancake lenses
>> for the 5D2, you'd have to be nuts to buy a FF rangefinder dcam.
>>
>
>
> Do you have the slightest clue why people would be interested in a range
> finder Dcam? Or a range finder camera of any type rather than an SLR?
> Obviously not.
>
> Just because -you- are happy with your latest choice (for this week)
> doesn't mean everyone else on the planet would be.

Actually as a long time Leica user I wonder the same thing myself. The
main benefits of the rangefinder were that you could see outside the
frame and that many found it faster than reflex focus. Autofocus is
faster than a manual rangefinder and with an EVF that works from the
sensor you lose the ability to see outside the frame, so I don't really
see where a rangefinder brings all that much to the party anymore.
From: David J. Littleboy on

"J. Clarke" <jclarke.usenet(a)cox.net> wrote:
>> David J. Littleboy wrote:
>>> But given that there are now good wide angle and good pancake lenses
>>> for the 5D2, you'd have to be nuts to buy a FF rangefinder dcam.

> Actually as a long time Leica user I wonder the same thing myself. The
> main benefits of the rangefinder were that you could see outside the frame
> and that many found it faster than reflex focus.

Really? I find rangefinder focus about the same as SLR split image focusing.
You have to first find detail that's perpendicular to either the patch or
the split prism and then focus. Differences are larger between cameras than
between types. The GS645S was really terrible, the Mamiya 7's OK, and the
Bronica 645R is wonderful.

(Oops: I almost missed your "outside the frame" bit. I have two lenses for
my current rangefinder: one maxes out the built-in viewfinder and the other
maxes out the aux viewfinder, so I don't get that advantage.)

> Autofocus is faster than a manual rangefinder and with an EVF that works
> from the sensor you lose the ability to see outside the frame, so I don't
> really see where a rangefinder brings all that much to the party anymore.

The decent angle lenses I'm referring to are all manual focus, but AF assist
works, so no hunting for appropriate detail.

The thing that puts me off rangefinder cameras is the lack of close focus.
Oh, yes and the flakiness of framing with external viewfinders for wide
angle lenses. And the metering coverage relative to the scene shot changes
with the focal length. And polarizers are a pain. The list is really long.

--
David J. Littleboy
Tokyo, Japan


From: Doug McDonald on

>>
>> The
>>>>
>>> need here is for more precision in range at shorter ranges. My
>>> experience with longer range civil rangefinders is that they are not
>>> all that accurate. (1 m in a 1000 is acceptable for a 1000m range
>>> finder, but 1 m in 5 for focusing will not).
>>>
>>> And at short ranges, a couple meters, critical focus would within a
>>> few cm. So the clock for pulse timer would need to be quite fast,
>>> stable and accurate (or at least calibratable with a temperature table).
>>


I've gotten 1 cm accuracy with rather cheap optics (like $2 laser diode and
$2 detector) and using home-made ECL electronics. The range was many meters,
but the laser was collimated and there was a corner cube at the other end.

Short pulse radar might be easier, using phase detect to get the last
little short distance resoltuion.

Doug McDonald