victor_randin3

To Bob Todrick: In my 54 I pretty know that nobody in this world,

even a child, is free from politics and other worst words and

problems which human race contrived. Please, be advised that I am

living in the country that hard to call as free country, there are a

great corruption and beggary here, journalists are killed (Gongadze

and others I know), there is no independent press here, and so

on�..but what? There are enough places for me everywhere, but this

forum, to fight these horror things. I think that there are tiny

beautiful islands in this great ocean of problems to spend a short

time, and one of such islands is this forum, as for me. Of course,

this forum is open for any discussion and for everybody, and this is

great.

Yes, a Leica is a camera only, an instrument that was created with

talented engineers, and as for me, NOT any politics, nazism,

nationalism, communism, racism and any other words like these, the

worst human race contrived.

Sorry, a 12505 lens hood is for Elmar/Summaron 36mm mount, but your

Summaron is 39mm mount.

A 1205 lens hood is for Elmar/Summaron 36mm mount, but your Summaron

is 39mm mount.

Bob,

<p>

I shot handhelding with SL2 & 180/2.8 (2 cam), and with R6(or SL2) &

180/2.8 (3 cam, compact version, looks like MC). Simultaneously I

shot with F/F2 & 180/2.8 ED. I couldn't find a difference, the

results are almost same: very very sharp pictures, a little better

with SL2 & compact 180(3 cam) and F2+180ED when shooting light

sourses in a frame (more contrast, best flare control).

<p>

180/2.8 (2 cam)is much hevier than the other two (1'360 gram). So, I

prefer 180/2.8 (3 cam, compact) and Nikkor 180/2.8 ED.

<p>

I payd for 180(2 cam) $450, 180 (3 cam) $900, 180ED $300.

<p>

Regards

<p>

Victor

Since I �ve read Bill Mitchell�s and Jay�s postings I �ve understood

why I don�t like shooting with the M3 & 35mm and M4-P & 50mm.

The M3�s VF shows the entire 100% image of a 50mm lens, while M4-

P,M6� shows only 86% and has 0.72 magnification vs 0.96 of an M3�s.

<p>

Thanks

I used 2.0 /35 Summicron LTM (demo); 2.8/35 Zeiss Biogon LTM; 2,8/35

Topcon LTM; 1.8/35 Canon LTM; 3.5/35 Summaron LTM (coated); 5.6/28

Summaron; 2.8/35 Jupiter LTM; 3.5/35 Summaron LTM (uncoated).

<p>

The best is 2.0/35 Summicron, the worst are 3.5/35 Summaron LTM

uncoated & 2.8/35 Jupiter LTM (low contrast and flare).

<p>

2,8/35 Topcon is so sharp as 2.0/35 Summicron and 2.8/35 Zeiss Biogon.

<p>

1.8/35 Canon, 3.5/35 Summaron (coated), and 5.6/28 Summaron are same

in its sharpness. The last two are very sharp on small f-stop (1/11-

1/22).

<p>

I agree with Bob Todrick, ASPH Summicron 2.0/35 LTM is the best, and

simultaneously allows keep it in the family.

Jack,

<p>

of course Ansel Adams is a great photografer, and I love him,

<p>

however:)

<p>

F/a = relative value of Focal length of lens,

a/F = relative value of Aperture of lens,

<p>

where F is an absolute value of focal length of lens (mm),

a - absolute value of aperture of lens (diameter, mm).

<p>

So, the DOF depends inversely on a/F, or depends directly on F/a,

isn�t it?

<p>

Victor

Jack,

<p>

"Aperture or �f stop� = F/a Where F = lens focal length; and a =

aperture diameter"

<p>

Maybe vice versa, as it is well known from the classic optic:

<p>

Aperture or �f-stop� = a/F, where F = lens focal length; and a =

aperture diameter, isn't it?

We got used to read a value of max aperture of a lens as 1:1.0;

1:1.4; 1:2.0; 1:2.8....and so on. Using your formula we would read

this as 1.0:1; 1.4:1; 2.0:1; 2.8:1 .....32:1... So, this doesn't mean

the value of the relative aperture.

<p>

Though it doesn't matter for your formula of a DOF ;)

<p>

best pics from M,

<p>

Victor

Jim, when thinking hard we could conclude :) that an F-number is a

relation of an aperture diameter to a focal length. The shorter focal

length, the smaller aperture we see, and it doesn�t depend on lens

design: tele-, retro-focus, or obvious.

<p>

A DOF, which is expressed as an acceptable value of a COC, depends

directly on a distance to a subject, and depends inversely on an F-

number (1/1, 1/2,....1/64..., and so on) and a focal length.

<p>

A DOF doesn�t depend on a film/sheet format and on an angle of

coverage of a lens.

This out-of-focus issue pronounces everywhere when at first focussing

a subject in a center of VF (whether RF or SLR cameras), and then

composing it out of a center, especially with wide-open super fast

mid-tele lens at mid-distances. So named a curvature of field does

not solve this problem. We change an angle of view, and therefore we

change a distance to a subject. A camera doesn�t know where our

subject is gone when composing and shoots what it sees in a center

where it has been focused to before. It�s easy to get a sharper

picture when at first composing a subject being out of a VF center,

and then focussing it and shooting. I use a swing or tilt on LF-

camera or pure ground glass on 35mm/MF SLR. But RF-camera does not

give us such a possibility. I got use to use a zone of DOF which

shows RF-spot in M3�s VF/RF. However when shooting with M4-P I �nudge

the focus a bit� as Mr. Mani Sitaraman recommends.

Except of parallax problem that does exist I saw another one: seems

it isn�t a vibration-free camera, as far as it is equipped with a

metal vertical-travelling-curtains shutter Copal (old type with 1/125

sec synch).

This is a post-WWII Leica IIIc. Serial numbers 48000-49500 Hove

refers to 1949/50.

Arild, compare Elmar 2.8/50 vs Summicron 2/50, data from PP, May 1976

<p>

ELMAR 50-MM SER. NO. 2473203

Aberrations 1/3 out 2/3 out Far edge Notes

Coma 4 4.5 5.6 {critical f-stops

Astigmatism 4.5 6.3 6.3 {critical f-stops

Lat. crom. None None None

Long. crom. Blue � Red = 0.12 mm {focus shift

Spherical f/2.8 � f/8 = 0.11 mm {focus shift

Distortion None

Vignetting None Beyond f/4.5

Centering Near Perfect

<p>

Focal Length: Marked 50 mm Measured: 52.0 mm

f-number: Marked f/2.8 Measured: 2.88

Transmittance: 93% T-number: t/2.99

<p>

PERCENT CONTRAST @ 50 LINE PAIRS PER MM:

<p>

F/STOP f/2.8 f/4.0 f/5.6 f/8

CENTER 55 68 73 75

<p>

1/3 OUT 50 66 75 77

2/3 OUT 55 63 78 78

FAR EDGE 40 52 68 75

<p>

PERCENT FLARE: 0.63

<p>

SUMMICRON 50-MM SER. NO. 2583855

Aberrations 1/3 out 2/3 out Far edge Notes

Coma 2.2 2/8 4 {critical f-stops

Astigmatism 3.5 4.5 4 {critical f-stops

Lat. crom. None None None

Long. crom. Blue � Red = 0.08 mm {focus shift

Spherical f/2.8 � f/8 = 0.05 mm {focus shift

Distortion Very slight barrel

Vignetting None Beyond f/3.5

Centering Near Perfect

<p>

Focal Length: Marked 50 mm Measured: 51.9 mm

f-number: Marked f/2 Measured: 1.99

Transmittance: 93.3% T-number: t/2.06

<p>

PERCENT CONTRAST @ 50 LINE PAIRS PER MM:

<p>

F/STOP f/2 f/2.8 f/4.0 f/5.6

CENTER 70 77 82 82

1/3 OUT 66 82 83 83

2/3 OUT 55 69 83 83

FAR EDGE 55 60 76 80

<p>

PERCENT FLARE: 1.0

Martin, thanks for very useful info. To demonstrate partly the

difference between Merklinger�s and hyperfocal method of focusing I

take the SLR camera (Nikon F, 1.4/50) and focus the lens on

hyperfocal distance 5m at f/16 stop. Then look at any subject at

infinity and stop down the aperture to f/16 with pre-set knob. It�s

very noticeable that the subject stays OUT of focus yet, but when

turning the lens ring to infinity mark, the subject becomes as sharp

as possible. You could also watch how the sharpness of images (from

1m to 50m and beyond) is changing when changing f/stop.

<p>

Regards

<p>

Victor

Yes, gentlemen, it is the sound of the "slow governor" switching from

1/15.

Bob, there are all ball bearings, not roller bearings, in the Leica

IIIc-K shutter. Two ball bearings installed in two narrow rollers for

2 ribbons of the front curtain, two ball bearings are installed in

the wide roller (drum) for the rear curtain, and one ball bearing is

supporting the rear-curtain claw. All 5 ball bearings are set on the

shutter shaft to reduce its friction in the rotation.

<p>

Regards,

<p>

Victor

Bob, I can�t find any contradiction between Morgan & Lester manual,

Willy Hahn, D.R. Grossmark and others Leica experts.

<p>

At a risk of telling you what you know I�d like to remind that a

great many varieties of a Leica IIIc (LOOZS & LOOHW) are known to

exist around, which have been manufactured from 1940 until 1951. For

example, these Leicas exist in chrome, black or grey finish with

black or red curtains, some of which are marked or aren't with a

letter �K�, some of them do have or don't the stepped platform under

the film rewind lever, some are engraved or aren't with �Heer

Eigentum�, �W.H.�, ��M�, "Luftwaffen Eigentum�, some do have or don't

the reference to the contract number (38078 or 38079) engraved, and

so on.

<p>

I suggest that very first IIIC�s were manufactured without ball

bearings at all. Then ball bearings were installed in military K-

Leica IIIC�s in 1940. Late its number could be changed from six in

military cameras to one in past-WWII cameras (LOOHW). It�s my

suggestion only.

<p>

At least one ball bearing supporting a rear-curtain claw to enable a

shutter to work over low degree range of temperatures we have found

in the shutter of an obvious version of Leica IIIc (1950), and six

ball bearings � in military Leica IIIc-K (1943).

For me it�s hard to find a first version of Leica IIIc with serial

number from 360175 until about #361000 to confirm my suggestion. I am

not a collector.

<p>

�I thought that the roller, or ball bearings, ought to result in a

quieter shutter.�

<p>

Above mentioned IIIc� and IIIc-K� shutters, which have been CLA�d and

examined by me, sound identically quietly.

<p>

As it�s known a frozen shutter isn�t working. It depends on such

factors as the increasing coefficient of friction of shutter parts

rubbing together because of thickening of lubricants, changing of

linear dimensions of heterogeneous metal parts, and the loss of

elastic features of frost-bound rubberized material of curtains.

<p>

So, the use of ball bearings, antifreeze lubricants reduces the

coefficient of friction to minimum and the use of special rubberizing

materials for curtains makes them elastic even when it�s a hard

frost. But titan curtains for a RF-camera are better, as they are sun

burning proof and frost-hardly.

<p>

Regards,

<p>

Victor

Bob, I can�t find any contradiction between Morgan & Lester manual,

Willy Hahn, D.R. Grossmark and others Leica experts.

<p>

At a risk of telling you what you know I�d like to remind that a

great many varieties of a Leica IIIc (LOOZS & LOOHW) are known to

exist around, which have been manufactured from 1940 until 1951. For

example, these Leicas exist in chrome, black or grey finish with

black or red curtains, some of which are marked or aren't with a

letter �K�, some of them do have or don't the stepped platform under

the film rewind lever, some are engraved or aren't with �Heer

Eigentum�, �W.H.�, ��M�, "Luftwaffen Eigentum�, some do have or don't

the reference to the contract number (38078 or 38079) engraved, and

so on.

<p>

I suggest that very first IIIC�s were manufactured without ball

bearings at all. Then ball bearings were installed in military K-

Leica IIIC�s in 1940. Late its number could be changed from six in

military cameras to one in past-WWII cameras (LOOHW). It�s my

suggestion only.

<p>

At least one ball bearing supporting a rear-curtain claw to enable a

shutter to work over low degree range of temperatures we have found

in the shutter of an obvious version of Leica IIIc (1950), and six

ball bearings � in military Leica IIIc-K (1943).

For me it�s hard to find a first version of Leica IIIc with serial

number from 360175 until about #361000 to clarify my suggestion. I am

not a collector.

<p>

�I thought that the roller, or ball bearings, ought to result in a

quieter shutter.�

<p>

Above mentioned IIIc� and IIIc-K� shutters, which have been CLA�d and

examined by me, sound identically quietly.

<p>

As it�s known a frozen shutter isn�t working. It depends on such

factors as the increasing coefficient of friction of shutter parts

rubbing together because of thickening of lubricants, changing of

linear dimensions of heterogeneous metal parts, and the loss of

elastic features of frost-bound rubberized material of curtains.

<p>

So, the use of ball bearings, antifreeze lubricants reduces the

coefficient of friction to minimum and the use of special rubberizing

materials for curtains makes them elastic even when it�s a hard

frost. But titan curtains for a RF-camera are better, as they are sun

burning proof and frost-hardly.

<p>

Regards,

<p>

Victor

Else 1 cent, please. In terms when the lens and the camera body (M-

Leica working distance is 27.8mm) are adjusted perfectly, but the RF

doesn�t, two case are possible:

1) The RF never reaches infinity, but the lens reaches the infinity

stop. We are forced to focus the lens behind the object (for mid-

distances). This is the worst case, so we can�t cover the focus

discrepancy with the lens/aperture DOF.

2) The RF reaches infinity, but the lens doesn�t reach the infinity

stop. We are forced to focus the lens before the object. In this case

we can cover the focus discrepancy with the lens/aperture DOF.

<p>

However the best way is to adjust the RF :-) There is the screw �

cover on the front panel between RF-windows. After unscrewing this,

the adjusting screw is visible inside the camera. It is very easy to

adjust the RF with a watch screwdriver when a normal lens is set.

Unfortunately, the screw-cover(or the hole) is closed with red Leica

label on the M6.

<p>

Regards,

Bob, I am afraid that I could pass other ball bearing off when taking

down partly the �K� that time (1978). This weekend I have a meeting

with the Leica IIIc-K� owner to clarify if there any ball bearing is

in a K-shutter. Then you will be informed.

<p>

Thanks and regards.

<p>

Victor

"One think that I am curious about though, since the rangefinder is

magnified 1.5X, which presumably makes it an equivalent of about 75mm

view, would this be good enough to use as a framewindow too for a

75mm lens? If so it would be pretty neat. Then again it is round so

it may not be too useful. Any opinions?"

<p>

The 1.5x RF magnification gives the better effective RF base length.

The effective RF base length of TM Leicas is 39mm (RF base length) X

1.5 (magnification) = 58.5mm. Seems, it is impossible to use RF

window as a framewindow for a 75mm lens because of the parallax

error.

<p>

As for shutter noise of IIIc-IIIf I think that if the Leica is

professionally CLA�d the shutter noise isn�t noticeable. Redesigned

(beginning from IIIc) Leica�s shutter is equipped with the damping

mechanism for 1-st curtain which is controlled and tuned with the

screw placed under the bottom cover. When shutter springs tension is

regular, its axles are clean and lubricated, and the damper spring

tension is tuned right too, the shutter is working very quietly,

almost as M-Leica�.

<p>

To Mr. Bob Fleischman. I have owned two grey K-Leicas, which had red

shutter curtain marked with the large white �K�. The only ball

bearing I saw was the one placed under the rewind knob.

Good question, Bill. Just two my kopecks, please. The genuine focal

length (the distance between the focal plane and the plane of max.

sharpness) of any lens is not the same what is engraved on its front

shield, but the same for the whole generation of lens and its

formula. For example the focal length of any Sonnar 2/50 is about 52

mm (don�t remember the exact value). The acceptable error of focus

length is about 0.005-0.01mm.

Zeiss made every Sonnar the same focal length as well as Leitz made

every RF Elmar, Summar, Summitar, Summarit, Summicron, Sunmmilux and

the others its own, but also exactly identical focal length (depends

on lens name/formula and version/generation) in limits of acceptable

error. Only older Leicas (A, B, C) were matched to its Berek�s normal

lens (Leitz Anastigmat, Elkan, Elmar) individually through the hole

in the camera back.

Shapes of Zeiss and Leitz lenses cams are designed in different way.

Any Zeiss lens cam (for pre-M Leicas) has parallel working edge

machining made, while most of Leitz lens cams are of more complex

shape of declining working edge (on which marks of hand finishing are

visible). It may be suggested that individual cams cut for each Leitz

lens depending on its individual focal length. But its focal length

is identical. So, it is right in that sense that working length of

each cam is hand finished to match it to the identical lens focal

length value because of summary error appearing inevitable during

manufacturing process. M-lens cams are mostly machining made.

As it is known the lens cams for LF-cameras are individually made for

each lens, at least by Linhof. They buy lenses from Schneider, Zeiss,

Rodenshtok without cams.

Contax normal lenses are more small and simple in its design than

Leitz�s ones. They have neither helicoid nor cam. Sonnar lenses

4.0/21, 2.8/35, 2/85, 1.5/85, 4.0/135 (which mount on the external

lens seat) also have nor cams nor helicoids. The helicoid with the

lens seat is in the camera body and simultaneously plays a role of

the cam coupling to the lever of moving base of the RF prism.

Was the Zeiss manufacturing process so much more exact that they?

Seems, Zeiss had more advantages in that period. Famous Sonnar 1.5/50

was in producing from 1932, its coated version �T�� from 1935. But in

1932 Leitz from normal lenses had in producing only Elmar 3.5/50,

Summar 2/50, (maybe Hector too) and Leica II, III. Bad coated

Summitar was in producing only in 1939. Leitz Xenon 1.5/50

(Schneider�s formula) and then its analog Summarit appeared somewhere

in early �50s. Sonnar�s formula by Dr. Ludwig Bertele is much better

than Summar�s, the coating quality is also much better than

Summitar�s. The RF-base of Contax is about 110 mm, screwmount Leica

RF-base = 39mm. The quality of Zeiss lens is very high even today. I

have and use a few ones for Leica.

But then Leitz won the competition with his M3& Summicron.

I dont�t know why the DOF marks on the Contax body are about two

stops more generous than the Leica 50mm lenses. Maybe the genuine

focal length of Summicron is a little more than Sonnar�s (?),

somewhere about 54mm (?). But I did not meet exact value of any

version of Summicron�s focal length.

<p>

Regars,

Victor