Re: [Leica] Electronic dependance

[Doug Herr <71247.3542@compuserve.com>]

On Tue, 12 Jan 1999, Eric Welch wrote:

[Doug Herr wrote:]
>> I use manual exposure for the most
>>critical exposures and a 10% or 20% inaccurate shutter speed on a
>>mechanical camera will give me a more accurate exposure than the 25%
error
>>which the electronic camera guarantees if the correct exposure is midway
>>between the available half-stop increments. 
>
>Where did you come to the conclusion that electronic shutters are
>inaccurate, or only go in half-stop increments? First of all, your manual
>shutter is twice as inaccurate by your reasoning. It only goes in whole
>stop increments. Second, mechanical shutters are inherently less accurate,
>or repeatable than electronic shutters. The difference is you know what
>shutter speed you're using, and you have to tweak the aperture to get what
>you want. Where with a mechanical camera, you are using a less accurate
>shutter and tweaking both shutter speed and aperture. I'll take the more
>accurate, repeatable shutter speeds. And the fact is, 1/10 stop seems to
be
>what the limit for discerning exposure differences is with chrome film.
>
>You want differences that are accurate, then put the electronic shuttered
>camera in auto exposure, and adjust your exposure with the AE lock or with
>the exposure compensation. Then you've got an infinitely variable shutter
>that is just as accurate as when it's set at definite stops. 
>
>You set the shutter speed on 1/125 for example in an R8 and an M6. Which
is
>closer to 1/125? The R8. Why? Because electronic shutters are more
>accurate. You want to increase the speed 1/2 stop. Set the R8 at 1/180.
>Adjust the aperture up 1/2 stop, perfect representation of the EV up a
half
>stop. Try that with a mechanical shutter in the M6. Any way you slice it,
>electronic shutters are more accurate, and since you're always adjusting
>aperture against shutter speed, just as flexible in real terms, if not in
>terms of using specific shutter speeds between 1/2 stops. Even then, you
>can indirectly adjust that in AE.


Eric,

Please re-read my post.  I wrote that the electronic shutters are more 
accurate but that given the way I use a camera I don't see the benefit
of the improved accuracy.

Perhaps I should have gone through the entire description of how I work
with long lenses hand-held requiring the fastest possible shutter speed
therefore requiring the lens to be used at maximum aperture.  The 
mechanical shutter I'm using is the one in the Leicaflex SL, which is
continuously variable, not a 1-stop increment shutter.

I wrote that the electroniclly-controlled camera with only half-stop
shutter speed increments IN MANUAL MODES will guarantee a 25% exposure
error if the correct exposure is between shutter speed increments.  If 
I adjust the aperture I'm not using the fastest possible shutter speed 
and it's more likely I'll get a perfectly-exposed photo of camera shake.

AE compensation has not worked well for me because my left hand is on 
the lens, a good distance from the exposure compensation control.  
Moving my left hand to the camera body will make me drop the lens 
(no picture).  The AE shutter speed "lock" is more of a shutter speed 
"hold", meaning I have to delicately HOLD the shutter release while 
the rest of my hand maintains a vice-grip on the body while the left 
hand focusses and follows the critter.  I lose the "lock" and get an 
inaccurate expsoure.

I've used the AE "lock" and exposure compensation on the R4sP and with 
the long lenses have found AE to be more of a bother than a benefit.  
I work much more quickly and with better results under these conditions 
with the SL's continuously-variable shutter.

I'm not totally put-off by electronic cameras.  I prefer the R4sP in an
AE mode for my "happy snaps" of the family (with any film, even chromes).
It's been very accurate and reliable for these photos.  The implementation
of manual-metering features in electronic cameras will need much 
improvement before I can be satisfied using one for my wildlife photos.

Doug Herr
Sacramento