Archived posting to the Leica Users Group, 2006/12/28

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Subject: [Leica] Best flash for M8?
From: red735i at earthlink.net (Frank Filippone)
Date: Thu Dec 28 05:11:25 2006

Lucien... the M8 sensor works with all the pixels in the array integrating 
the light at the same time.  It can not work with a slit
shutter and a single flash of light.  That is clear from the Kodak 
literature and application sheets.

BTW, drPreview has the same picture of the M8 shutter as does the Leica 
page.  The middle leaf is apparently painted grey ( or
white, I do not know which) and the outside leaves are painted black.  What 
you see in the picture 
http://www.leica-camera.us/assets/media/img5723.jpg
is the leaf color, not a slit.

Let me carefully define a slit shutter.... when the leaves in the shutter 
are open in a way such that the trailing edge of the
leading leaf and the leading edge of the final leaf are closer together than 
the entire image area.

I remember discussing the R8/9 shutter and the slit shutter with flash.  To 
activate those old discussion points, I reviewed the R9
user manuals, on line.  The use of a flash with a slit shutter was done with 
a burst of flashes as the slit moved across the focal
plane.  This is in agreement with what I said about the operation of the 
sensor.  The sensor in the R8 ( film) is actively
integrating photons during a long period of time.  ( This will sound a 
little bizarre, but film inherently is integrating photons
from the time it is made until it is developed.  It is not dependent on an 
open shutter.  Opening the shutter allows some photons to
actually hit the film sensor.  Not true in the M8 where the sensor array 
must be electrically energized to start the integration
period.) 

This same technique would work with the M8.  Multiple flash burst, a single 
slit shutter, gate the sensor to stay integrating light
for a long period.  But it will not work with a single flash burst.  ( Is 
this a good reason to use the SF24 flash rather than the
SF20 flash with the M8?)  In this specific case. the mechanical shutter in 
the M8 is actually shielding the rest of the image plane
from light, and is working as the shutter in a film camera.  

Agreed.  I stand corrected that in the multiple flash mode  ( what Leica 
calls HSS), the mechanical shutter does have an influence
on the image.  

Thank you Lucien for pointing this out and helping me to understand the M8 
in more detail.

Frank Filippone
red735i@earthlink.net 


-----Original Message-----
From: lug-bounces+red735i=earthlink.net@leica-users.org 
[mailto:lug-bounces+red735i=earthlink.net@leica-users.org] On Behalf Of
lucien_vd@mac.com
Sent: Thursday, December 28, 2006 1:25 AM
To: Leica Users Group
Subject: Re: [Leica] Best flash for M8?

Dear Frank,

The DMR + R8 or R9 use a similar sensor than the M8, and the same  
shutter.

The shutter was designed long before the DMR.

The DMR is working up to 1/8000th in manual mode.

Do you really think that the DMR is capable to order the R8/R9  
shutter to slow down to 1/250 when manually set on 1/8000 on the  
camera body ?

And how do you explain that on the DMR  you can use the HSS flash  
mode, which is a high speed flash mode between 1/350 and  1/8000 ?

AFAIK, the M8 and DMR sensors are both working with a slit shutter  
working steplessly up to 1/8000, as stated in all the Leica  
literature that you will find on the following web sites.

Lucien

http://www.dpreview.com/news/0609/06091501kodakccdleicam8.asp#press

http://www.leica-camera.us/photography/r_system/digital-modul-r/

http://www.leica-camera.us/photography/m_system/m8/

Frank Filippone a wrote :

> Since, according to drPreview, the "shutter" in the M8 seems alike  
> to the shutter in the R8 ( R9 ?), then I can makes some comment
> on the M8 shutter ....  If the shutter on the R8 is fully open at  
> one time up to 1/250 of a second, and then goes to a slit shutter
> for high speeds; and if the shutter in the M8 is the same or  
> basically similar, then the maximum mechanical shutter speed available
> in the M8 is the same, 1/250.  This is true because the M8 must  
> have the entire sensor active at one time to get an image.  A slit
> shutter will not work.  Further, there is no higher speed on the  
> mechanical shutter on the M8 than the 1/250 of a second, or what I
> call a fully open shutter.  Talking flash, there still is no reason  
> for limiting the flash to a shutter speed 1/250 that is obvious
> at this point.

> I am still open to correction and further information may require  
> that statement by me.  But at this point, it is pretty clear to me
> that the image capture in the M8 is totally digital.  That the  
> shutter has no purpose in image capture, and therefore I call it a
> baffle.
>
> What does all of this mean?  That your M8 should never have to go  
> to the shop for a shutter CLA to make your camera capture images.
> Not much more.  But I did have a really good time reading timing  
> charts and understanding how the sensor works..... What's a few
> hours of quiet reading worth?  Priceless?

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Replies: Reply from telyt at earthlink.net (Douglas Herr) ([Leica] Best flash for M8?)
Reply from lucien_vd at mac.com (lucien_vd@mac.com) ([Leica] Best flash for M8?)
In reply to: Message from lucien_vd at mac.com (lucien_vd@mac.com) ([Leica] Best flash for M8?)