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David Hegar
05-07-2010, 10:21
Hi all,

I have a nagging thought about how reliable it is for Leica M bodies in keeping the film properly aligned within the film guide rails.

Is there any possibilities for the film inside the Leica M, mine is M6, to ride over the film guide rail (the rail that is the tallest) instead of sitting flush within guide rails?

Furthermore, what's keeping the film to stay within the guide rail knowing that the length of the film canister can vary slightly from one brand to the next brand (i.e. film canister can shake from side to side inside the camera)?

My question starts from the unexplained and seemingly random front focus problems I'm having:
I shot the same scene 7 times in a row using Nokton 50mm at f/1.5, and 4 out of 7 the images came out front focusing by about one feet (I was shooting at about 15 feet away from the subject). At other times, the focus can be off by about 4 feet, but it can also be spot on...all within the same roll of film.

So I'm thinking perhaps the film inside the camera rides over on top of the raised film guide and effectively altering the focus plane.

As a note, I compared the film guide rails in my Nikon FM2 and in that particular camera Nikon put a raised screw at the end of the rail that makes it impossible for film to ride over on top of the guide rail.

Any thoughts or idea how to solve this problem?

Btw, I found this article...do you think he is on to something?
http://oak.cats.ohiou.edu/~schneidw/vico222/leica_frontfocus.html

Thank you,
David

Chriscrawfordphoto
05-07-2010, 10:32
Is the film centered on the film between the sprocket holes or is it shifted up or down to where it overlaps the holes?

payasam
05-07-2010, 10:36
I have used Leicas since 1965 or so and have owned them since 1985; but this phenomenon is new to me, unheard of. I have had no such experience even when using "modern" film cassettes in the IIIc and older Leicas, which were designed for cassettes 2.2mm taller.

Was your camera on a tripod for all seven exposures? Did you re-focus for each exposure? Why, in the first place, did you make seven exposures of the same subject or scene?

David Hegar
05-07-2010, 10:41
Hi Chris,

This is what I'm trying to figure out.

I am sure that the film holes ligned up with the sprockets, hole for hole. But of course I can't verify if the film actually sit flush within the guide rails once the bottom plate is closed.

It's this seemingly random front focusing problem within the same roll of film that get me stumped.

-david

Is the film centered on the film between the sprocket holes or is it shifted up or down to where it overlaps the holes?

chrishayton
05-07-2010, 10:47
Doesnt the pressure plate keep the film flat?

David Hegar
05-07-2010, 10:50
Payasam,

I'm a documentary wedding photographer, and part of my work is to capture the right moment at the right time with just the right expression. And that kind of approach requires me to shoot the same scene more than just one time. My approach is to "work the scene" (i.e. anticipate-wait-shoot...and then anticipate more, wait some more and make it better). So I'd camp out at my position not far from the bride and groom, and wait and shoot (and realized that my timing is off so I wait again and shoot again) until I feel the "perfect" moment is captured.

I just got my first Leica M6 and before I can trust it for my wedding work, I had to test it with the same rigueur as if I'm capturing the moments in wedding. So I hope that answered your question about the tripod use. I didn't use tripod in weddings and I didn't use tripod when testing my Leica M6. Besides, if it is a camera shake the whole scene will be slightly blurry.

And I did my best to check and recheck the focus during those 7 shots in a row.


-David



Was your camera on a tripod for all seven exposures? Did you re-focus for each exposure? Why, in the first place, did you make seven exposures of the same subject or scene?

David Hegar
05-07-2010, 10:57
Wrt to pressure plate: I would like to think so too.

But I'm new to Leica system (M6), so I don't know if there's any quirk I should be aware of.

The link that I provided above ...does it warrant to be considered? Or is it just a false causal and effect?

-David

Doesnt the pressure plate keep the film flat?

payasam
05-07-2010, 11:01
I didn't suspect camera shake, David, but change of camera position between shots.

My advice is to try ophthalmic lenses of different powers between eye and finder. It may be that one of them is what you need. The eye is an instrument, and your best may not be good enough if that instrument is not working correctly. I speak from experience.

David Hegar
05-07-2010, 11:42
Hi Payasam,

Yes, I just realized what you meant when you asked about the tripod.

Regarding tripod: I suspected myself of swaying forward or backward when I shot those 7 sequence. Maybe I did sway, but maybe I didn't sway at all. But I'd think from a distance of 15 feet away and using 50mm lens my sway, if I did sway, it would not result in front focusing by about 1 foot.

I'm almost 40yrs now, and my eye doctor said bad things start to happen at 40 years old. Yay!



I didn't suspect camera shake, David, but change of camera position between shots.

My advice is to try ophthalmic lenses of different powers between eye and finder. It may be that one of them is what you need. The eye is an instrument, and your best may not be good enough if that instrument is not working correctly. I speak from experience.

Chriscrawfordphoto
05-07-2010, 12:16
Wrt to pressure plate: I would like to think so too.

But I'm new to Leica system (M6), so I don't know if there's any quirk I should be aware of.

The link that I provided above ...does it warrant to be considered? Or is it just a false causal and effect?

-David

I think its a false cause and effect. My M6 always puts the image slightly off center so that the edge of the picture skims the edge of the holes like the page you linked to shows, and my pictures are always exactly focused. If you are getting consistantly front focused results then either your camera's rangefinder is off or the lens' focus cam is off, or both.

Tom A
05-07-2010, 12:17
If the film is properly located on the sprocket drive (both top and bottom) - there should be no problem. in the picture the "teeth" sticking up through the perforation as they should. The film rails does not "orient" the film - just provides a surface for the film to slide along. The "tulip" is just a catch for the film - the key is the sprocket drive.
The cassette height is not critical if everything else is done right as the the film is pulled along. Check that the rewind is engaged properly so that the cassette is fully "in".
It could be that your M6 has had someone change the baseplate from the older style that can handle IXMOO cassettes to the flat lock one and this can cause the "elevation" difference. Depends a bit on the vintage of your M6 - early ones had the open/close of the IXMOO - later (1 think at around #2000 000 got the flat locking disc one).

David Hegar
05-07-2010, 12:36
Chris and Tom A: Thank you for the suggestions.
I will pay a close attention to the rewind next time I'm loading a film

@Tom A: how can you tell between the difference of baseplate? Is there any link where I can compare what baseplate should go into M6? My M6 ss starts with 168xxxx

It'll be so much easier if the problem shows up 100% of the time. But noooo, it decides to show up whenever it wants to but not all the time.

-David

Ronald M
05-07-2010, 13:39
Impossibe on a M if the sprocket holes engage the film which I always check when loading. Your M needs a repair if the sprocket take up is not alligned with the rails.

On pre 111F cameras, if you don`t use the Leica cassettes or shim up the magazine/ film can, the film can drop some putting some image into the sprocket area.

David Hegar
05-07-2010, 14:18
Ronald,

I checked my developed negatives and they do not show the problem where the image are on the sprocket area (the holes).

Is that what you meant?

-David

ChrisLivsey
05-07-2010, 14:44
@Tom A: how can you tell between the difference of baseplate? Is there any link where I can compare what baseplate should go into M6? My M6 ss starts with 168xxxx


David, I'm not Tom but I can guide you to a shot of his that will hopefully clarify:

http://www.flickr.com/photos/rapidwinder/4251626733/

The base plates right and left are the variants, the shot has text if you hover the mouse.

or

http://www.rangefinderforum.com/forums/showpost.php?p=1228126&postcount=17

Chriscrawfordphoto
05-07-2010, 14:46
Ronald,

I checked my developed negatives and they do not show the problem where the image are on the sprocket area (the holes).

Is that what you meant?

-David

Thats what he meant. If the image was centered on the film and didn't intrude on the sprockets, the film is NOT riding up on the rails....the rangefinder is just out of adjustment. Or the lens is. Or both. Send to DAG or Sherry or Youxin and get them checked and adjusted.

David Hegar
05-07-2010, 16:19
Ok, this is my Leica M6 (I bought it from this forum). Here's the picture of the bottom of the plate:
http://www.rangefinderforum.com/photopost-classifieds/showproduct.php/product/21542/cat/3

It seems that that it's the older style, yes?

Now, given what I know now about the older style of bottom plate, should I be worried about it?

-David

David Hegar
05-07-2010, 16:30
@ChriLivsey: Thank you for the link. So much I don't know about Leica.

@ChrisChrawford: I dread the worst of having to send everything to be serviced. But I'll just have to do it when I'm sure it's not user error.

Tom A
05-07-2010, 17:33
[QUOTE=David Hegar;
@Tom A: how can you tell between the difference of baseplate? Is there any link where I can compare what baseplate should go into M6? My M6 ss starts with 168xxxx

If your M6 starts with 168xxxx - it should have the old style baseplate. The smooth disc version came later. I dont know if it makes a difference - but it could be allowing the cassette to sit too "low".

David Hegar
05-07-2010, 22:27
Hi Tom,

My M6 comes with the old style baseplate.

I can see the potential problem if the newer baseplate is used with the older M6, but in my case my M6 uses the old style baseplate: http://www.rangefinderforum.com/photopost-classifieds/showproduct.php/product/21542/cat/3

Btw, that's my M6 in the above link. I bought it here in this forum.

-David


[quote=David Hegar;
@Tom A: how can you tell between the difference of baseplate? Is there any link where I can compare what baseplate should go into M6? My M6 ss starts with 168xxxx

If your M6 starts with 168xxxx - it should have the old style baseplate. The smooth disc version came later. I dont know if it makes a difference - but it could be allowing the cassette to sit too "low".

John Elder
05-07-2010, 23:13
You should retest using a tripod. Eliminate human error as possible cause. Test more than 1 lens. If only one lens displays the problem, have the lens calibrated. I assume you are shooting wide open.

David Hegar
05-08-2010, 20:46
I will do that, John.

-David

You should retest using a tripod. Eliminate human error as possible cause. Test more than 1 lens. If only one lens displays the problem, have the lens calibrated. I assume you are shooting wide open.