[Leica] 24 x 36mm ?

[hoppyman at bigpond.net.au (G Hopkinson)]

Frank, I'd never even considered a difference in image size from different 
focal length lenses. Henning suggests that those from
long teles are markedly different, too.
I'm hazy on rear lens vertex, but I thought that the exit pupil will always 
overlap the film gate, so it won't come into the
calculation. I thought that irrespective of the entry angles at the 
objective the exit angles were similar. They all must produce a
sufficient exit pupil to more than cover the film gate. Any difference in 
the exit angle would only be significant if the depth
between shutter opening and film gate was significant?  Sounds like a job 
for Erwin Puts!

I've probably made a total dog's breakfast of that. Perhaps someone will set 
me straight.
 
Really my posts were about the size of the film gate with different M 
models. From my samples here they do differ as I noted.

I only have M lenses here, but my curiosity is sufficiently piqued now to 
shoot a series of frames from 28 to 135 on the end of my
current film, to see if I can detect any difference. The inquiring hoppy 
wants to know!

cheers

-----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
Frank Dernie
Sent: Friday, 8 June 2007 20:17
To: Leica Users Group
Subject: Re: [Leica] 24 x 36mm ?

I could be wrong here but doesn't the image appear to be projected  
onto the film from the rear lens vertex? or is that exit pupil? If so  
a retrofocus wide angle lens will not project as big an image through  
the film gate as a symmetrical lens of the same focal length. The  
gate is only a couple of mm ahead of the film so it won't be that  
much apart from designs like the hologon.
Frank

On 8 Jun, 2007, at 08:59, G Hopkinson wrote:

> Robert, I follow what you are saying. I'll have to think about  
> that, I have a suspicion that you may be tampering with some laws of
> optics there ;-)
>
> Coming at it my post below from another direction, always 8  
> sprocket holes per frame, consistently much smaller gap between frames
> over complete films shot with varying lenses, with the older cameras.
>
> Today's useless trivia item for film photographers.
> Now I'll shut up before someone beats me up with a bag full of  
> broken digicams.
>
> Cheers
> Hoppy
>
> -----Original Message-----
> Subject: Re: [Leica] 24 x 36mm ?
>
> If you shoot with a wide-angle lens, the negative image will be  
> slightly
> larger, and the wider the lens, the larger the image gets.   The  
> reason for
> this is that the greater angle of the light striking the film with a
> wide-angle spreads the light, and thus the image, slightly under  
> the edges
> of the film gate.
>
> ----- Original Message -----
>
>>> From neg samples here, widths of:
>> 111c Width 36.84 mm     distinctly much tighter spacing
>> M3 36.78mm      gaps visibly not quite as narrow as 111c
>> M6 & M7 35.6mm
>> The difference between the three is easily visible at arm's length. I
>> might speculate that the standard has altered over the long
>> period to allow for ease of handling, for example. Certainly the  
>> oldest
>> camera is extremely precise.
>>
>> So, on these examples the range is actually more than 3.4%
>>
>> Cheers
>> Hoppy
>> -----Original Message-----
>> Lew said:<lew1716@optonline.net>
>>> I'm just off to my darkroom to confirm something that's been  
>>> bothering
>>> me for a while. The standard 35mm full frame format is supposed  
>>> to be
>>> 24 x 36mm or 1:1.5. This should mean that I can print full frame at
>>> 6x9", but (this is the part that's bugging me...) the images from my
>>> Leica negatives never quite fit an opening of this size on my easel.
>>> The only thing I can think of to explain this is that the Leica negs
>>> just aren't exactly 24x36mm.
>>> OCD acknowledged, other comments ...?<<<<<<<
>
>
>
>
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