Archived posting to the Leica Users Group, 2008/03/28

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: [Leica] CV 15mm lens on M8
From: hoppyman at bigpond.net.au (Geoff Hopkinson)
Date: Fri Mar 28 16:37:26 2008
References: <032720082322.9068.47EC2C1B000F27140000236C219792676103010CD2079C080C03BF970A9D9F9A0B9D09@mchsi.com> <001301c89066$f510ec10$6b01a8c0@dadquad> <p06230904c4123a9277e7@[10.1.16.146]>

Hi again Henning. As I noted, my initial experience with the frame-lines
being conservative was with the 28, 35 and 50 lengths. I found the Leica
reference that confirms your information. The lines approximate the viewing
angle at the minimum distance for the focal length selected. Leica says that
the 28mm will have approx 9% of the image outside the 18x27mm frame at
infinity. 23% outside the frame for a 90mm at infinity. Correspondingly less
then, as the shooting distance gets closer to the minimum focus distance.
The quoted difference for an M7 and the 28 is exactly the same. The M7
frames approximate a FoV of 23x35mm (about a mounted slide).
So all of the M8 users, including me, that are seeing the conservative
frame-line effect are seeing exactly what their film Ms did with the same
lenses. The differences then, are that we get immediate feedback if we are
looking at the LCD and I would think, more room for parallax error due to
the lower magnification. Cool, another bit of knowledge to squirrel away.
The more I learn about this M8, the more impressed I am with its
performance.

Cheers
Geoff
http://www.pbase.com/hoppyman/e
http://gallery.leica-users.org/v/gh/

-----Original Message-----
From: lug-bounces+hoppyman=bigpond.net.au@leica-users.org
[mailto:lug-bounces+hoppyman=bigpond.net.au@leica-users.org] On Behalf Of
Henning Wulff
Sent: Friday, 28 March 2008 16:08
To: Leica Users Group
Subject: RE: [Leica] CV 15mm lens on M8

At 10:02 AM +1000 3/28/08, Geoff Hopkinson wrote:
>Gene, for me I can just see the frameline for the 24 at the edges of the M8
>finder. I need to slightly move my eye position to see the whole frame. I
>don't wear glasses to shoot. Maybe my eye needs calibration. I might get
the
>6 bit conversion done on my eyeball while it is at Solms. Yes, you might
>ignore the frames and just accept the approximation of the entire finder,
if
>that suits you.
>15mm is only a nominal value anyway, and further will give nominally the
>view angle of a 20mm on a film camera. Then the accuracy is affected by the
>focus distance and you have the limitations of the RF system in general.
>It is all approximation. Also the framelines are effectively quite
>conservative as they are optimized for .7m. I do not know why Leica made
>that decision rather than set up the finder as with the film M's.


It's set up precisely the same as with the film M's. Check it out.

The reason that the lines are set for the closest focusing distance 
for a focal length is so that you don't cut anything off. Better to 
have some spare room around the image than cut off something 
important. Good decision.

Cameras like the M2 and M3 appear to have more accurate framing 
because at that time no lens focused closer than 1m without help. The 
difference in framing between 1m and 0.7m is significant.

90mm lenses have their frame lines set for 1m, and 135mm lenses have 
their frame lines set for 1.5m.




  The effect
>for me, shooting at say 2m is that the actual coverage is approximately two
>frameline widths outside the nominal frameline.
>The practical solution as said by Ted, is just shoot and check for yourself
>
>Cheers
>Geoff
>http://www.pbase.com/hoppyman/e
>http://gallery.leica-users.org/v/gh/
>
>-----Original Message-----
>Subject: RE: [Leica] CV 15mm lens on M8
>
>Geoff,
>
>The 24 frame is the largest, however, the area around the 24 mm frame is
the
>approximate view from a 21 mm lens.  I verified this a year ago at the M8
>seminar in Chicago.   So if you want to use a 21mm lens on the M8, as long
>as you can see the entire viewfinder window, you do not need an external VF
>on the M8.  This would give you the view of a 28mm lens on a 35 mm film M.
>
>Gene
>
>-------------- Original message ----------------------
>From: "Geoff Hopkinson" <hoppyman@bigpond.net.au>
>>
>>  Steve, your 24mm lens virtually fills the M8 viewfinder. That is the
>widest
>>  frameline built-in. I don't know how you can see anything outside that
>>  frameline. Due to the (smaller than 24x36) sensor crop, that frameline
>shows
>>  you an approximation of the crop effect (about the same view angle as a
>32mm
>>  on a film M)
>>  To use a 15mm lens you should use an external finder which is designed
for
>a
>>  21mm lens on a film M.
>>  All of the framelines show less than the actual sensor capture anyway.
>(they
>>  are calibrated for the view at .7m)
>>  The key is to think of the framelines as approximating the view angle,
not
>>  the nominal focal length. Each lens produces the same image at the plane
>of
>>  focus on any M. The M8 sensor, being smaller than 24x36, actually
captures
>>  about 75% of it.
>>
>>  Cheers
>>  Geoff
>>  http://www.pbase.com/hoppyman/e
>>  http://gallery.leica-users.org/v/gh/
>>  -----Original Message-----
>>  From: lug-bounces+hoppyman=bigpond.net.au@leica-users.org
>>  [mailto:lug-bounces+hoppyman=bigpond.net.au@leica-users.org] On Behalf
Of
>>  Steve Barbour
>>  Sent: Friday, 28 March 2008 02:06
>>  To: Leica Users Group
>>  Subject: [Leica] CV 15mm lens on M8
>>
>>  a question here , as my logic becomes  befuddled...
>>
>>
>>  A 21mm lens on the M8 just about fills the M8 viewfinder...
>>
>>  a CV heliar 15mm lens on the M8 is really a 21mm lens, and can be used
>>  with a 21mm external viewfinder...
>>
>>  so... can one also use the M8 viewfinder, as the viewfinder for a CV
>>  15mm lens...?
>>
>>
>>  Why is this so difficult?
>>
>>  (a yes or no answer is inadequate, without some logical explanation...
>>  please)
>>
>>
>>  thanks, Steve
>>
>>
>>
>>
>>
>>  "I never wanted to be famous"
>>  http://www.blurb.com/bookstore/detail/186890
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>  _______________________________________________
>>  Leica Users Group.
>>  See http://leica-users.org/mailman/listinfo/lug for more information
>>
>>
>>
>>  _______________________________________________
>>  Leica Users Group.
>>  See http://leica-users.org/mailman/listinfo/lug for more information
>
>
>
>_______________________________________________
>Leica Users Group.
>See http://leica-users.org/mailman/listinfo/lug for more information
>
>
>
>_______________________________________________
>Leica Users Group.
>See http://leica-users.org/mailman/listinfo/lug for more information

-- 
    *            Henning J. Wulff
   /|\      Wulff Photography & Design
  /###\   mailto:henningw@archiphoto.com
  |[ ]|     http://www.archiphoto.com

_______________________________________________
Leica Users Group.
See http://leica-users.org/mailman/listinfo/lug for more information



Replies: Reply from tarek.charara at pix-that-stimulate.com (Tarek Charara) ([Leica] CV 15mm lens on M8)
In reply to: Message from grduprey at mchsi.com (grduprey@mchsi.com) ([Leica] CV 15mm lens on M8)
Message from hoppyman at bigpond.net.au (Geoff Hopkinson) ([Leica] CV 15mm lens on M8)
Message from henningw at archiphoto.com (Henning Wulff) ([Leica] CV 15mm lens on M8)