SilverHalide
Newbie
I know this may sound a little weird. Will someone please kindly explain this to me.
The infinity on my M3's RF unit is short, say the RF images perfectly align when aimed at a subject 1.5 km away, but objects at actual infinity would appear like I could turn the focusing ring a tiny bit further pass the infinity lock.
That is, if I aimed it at a star, I would see the RF image of the star sitting a bit to the right of the actual star. (But a lamp post four standing blocks away would appear perfectly aligned.)
When I shot close-up portraits with a 50 mm lens at f4, focusing at the subject's eye about 1.3 meters away, the pictures came out with the subject's ear, shoulder, or the hair behind the head in sharp focus but not the eyes. It seems like the focus has overshot by about 20 centimeters.
Since this behavior is consistent, I often compensate for it by focusing on the nose or the subject's chest instead of the eyes and the picture would come out perfect. But this method proves to be unreliable at different focusing distances.
I've talked to a few technicians, two of which readjusted the eccentric screw for me looking at a ground glass. Both of them insisted 1.5 - 2 kilometers away is generally far enough as an infinity reference point and thus, they reseted my camera's infinity to the furthest subject they could see from their downtown shops. Which was not very far away at all.
(One of them previously calibrated my Leica IIIa to that very same lamp post and the camera focusses perfectly since, perhaps even more so than any of my M's.)
It bothers me very much that I can't do critical focussing nor enjoying the most my high speed lenses have to offer.
Does this make any sense to you? Can short infinity reference cause my focus to overshoot as mentioned?
Would it help if I'd try reseting the eccentric drum to true infinity myself?
Regards,
The infinity on my M3's RF unit is short, say the RF images perfectly align when aimed at a subject 1.5 km away, but objects at actual infinity would appear like I could turn the focusing ring a tiny bit further pass the infinity lock.
That is, if I aimed it at a star, I would see the RF image of the star sitting a bit to the right of the actual star. (But a lamp post four standing blocks away would appear perfectly aligned.)
When I shot close-up portraits with a 50 mm lens at f4, focusing at the subject's eye about 1.3 meters away, the pictures came out with the subject's ear, shoulder, or the hair behind the head in sharp focus but not the eyes. It seems like the focus has overshot by about 20 centimeters.
Since this behavior is consistent, I often compensate for it by focusing on the nose or the subject's chest instead of the eyes and the picture would come out perfect. But this method proves to be unreliable at different focusing distances.
I've talked to a few technicians, two of which readjusted the eccentric screw for me looking at a ground glass. Both of them insisted 1.5 - 2 kilometers away is generally far enough as an infinity reference point and thus, they reseted my camera's infinity to the furthest subject they could see from their downtown shops. Which was not very far away at all.
(One of them previously calibrated my Leica IIIa to that very same lamp post and the camera focusses perfectly since, perhaps even more so than any of my M's.)
It bothers me very much that I can't do critical focussing nor enjoying the most my high speed lenses have to offer.
Does this make any sense to you? Can short infinity reference cause my focus to overshoot as mentioned?
Would it help if I'd try reseting the eccentric drum to true infinity myself?
Regards,
ClaremontPhoto
Jon Claremont
On a camera infinity does mean the same thing as it does on Star Trek: it means maximum focus.
pvdhaar
Peter
I've two M-mount cameras (one Leica, one Bessa) that both agree that infinity is about 200 meter/yards away. Anything further I can't align. But the interesting part is that they also both are accurate and in agreement to the centimeter (half an inch) in the range from ca 1.2 meter (4 ft) to 5 meter (16ft). And this is the range where it matters most. There's practically no RF lens that has a DOF that doesn't span 200meters to infinity..
I'd say, get the RF properly aligned, and don't muck about with the infinity setting. There are other controls that seem off more.
I'd say, get the RF properly aligned, and don't muck about with the infinity setting. There are other controls that seem off more.
ZeissFan
Veteran
The short version is that you need to have the rangefinder recalibrated.
From what you describe, it doesn't sound like the work has been done properly, because distant objects still aren't in alignment -- which they should be.
If the rangefinder isn't calibrated for infinity, all other focus points will be inaccurate, as well -- which you have also described.
From what you describe, it doesn't sound like the work has been done properly, because distant objects still aren't in alignment -- which they should be.
If the rangefinder isn't calibrated for infinity, all other focus points will be inaccurate, as well -- which you have also described.
SilverHalide
Newbie
Thank you folks!
pvdhaar, I agree with you that closer focusing range matters more than further away. That's why I want mine to be as precise as can be. My IIIa is dead on.
I know it's possible to have the RF misaligned at infinity and still get an accurate close range focus. The problem is, my camera is not aligned at infinity and the close focus is also off by about 15 centimeters or so.
I'm just wondering if these two symptoms share the same cause (short infinity and overshot close-ups). Do they correlate in anyway?
If not, then I will concentrate on getting the close range aligned and forget about infinity.
pvdhaar, I agree with you that closer focusing range matters more than further away. That's why I want mine to be as precise as can be. My IIIa is dead on.
I know it's possible to have the RF misaligned at infinity and still get an accurate close range focus. The problem is, my camera is not aligned at infinity and the close focus is also off by about 15 centimeters or so.
I'm just wondering if these two symptoms share the same cause (short infinity and overshot close-ups). Do they correlate in anyway?
If not, then I will concentrate on getting the close range aligned and forget about infinity.
payasam
a.k.a. Mukul Dube
I may be wrong, but I understand that setting for infinity is the first step, followed by setting the ratio of the angular variation to get near distances right. I have not put it well at all, sorry. You may find something on the Mediajoy site.
planetjoe
Just some guy, you know?
There are definitely two adjustments involved; payasam's right, IMO. I'm not too familiar with Leica RF adjustments specifically, but if memory serves, the inifinity adjustment is done via horizontal alignment (i.e., the screw) and the "angular rate of change" is adjusted at the RF cam follower itself, inside the shuttercrate.
Someone can correct me if I'm wrong about this.
The logic is that one can re-set the "offset" and still be wrong at the other end of the scale. If you recall your elementary algebra, linear equations are similar "two degree of freedom" systems - they have a y-intercept and a slope.
Yikes, that sounded really dorky. Anyway, at work the instruments we use have both a "zero" and a "span" adjustment to get the calibration right, for exactly the same reason. One usually hopes that the span doesn't go out of whack, because it's usually the harder one to re-set.
Cheers,
--joe.
Someone can correct me if I'm wrong about this.
The logic is that one can re-set the "offset" and still be wrong at the other end of the scale. If you recall your elementary algebra, linear equations are similar "two degree of freedom" systems - they have a y-intercept and a slope.
Yikes, that sounded really dorky. Anyway, at work the instruments we use have both a "zero" and a "span" adjustment to get the calibration right, for exactly the same reason. One usually hopes that the span doesn't go out of whack, because it's usually the harder one to re-set.
Cheers,
--joe.
pvdhaar
Peter
There's some generalisation (probably carried over from more basic RF designs) on there being two controls on the RF alignment on the M3.
However, there are 4 adjustments to be made. Infinity, vertical, linearity and overtravel. There's a great online description of how to adjust them all here: http://leicaclub.net/files/leica_m2_m3_m4_basic_repair.pdf
However, there are 4 adjustments to be made. Infinity, vertical, linearity and overtravel. There's a great online description of how to adjust them all here: http://leicaclub.net/files/leica_m2_m3_m4_basic_repair.pdf
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payasam
a.k.a. Mukul Dube
A good thing to download and keep. Peter, thank you.
SilverHalide
Newbie
Sweet! I totally got it now. That PDF was an awesome reading. The operation was a success!
pvdhaar - Thank you so much for the link!
Payasam - Thank you for bringing it up!
Peter - Thanks for the explanation (dorky or no)
Thank you all so much!
I've also discovered some tricks which will speed up the calibration process somewhat. Perhaps I should post them for the whole world to see. Let me test them on the CL fist to see if they're truly universal.
Best regards,
pvdhaar - Thank you so much for the link!
Payasam - Thank you for bringing it up!
Peter - Thanks for the explanation (dorky or no)
Thank you all so much!
I've also discovered some tricks which will speed up the calibration process somewhat. Perhaps I should post them for the whole world to see. Let me test them on the CL fist to see if they're truly universal.
Best regards,
Xmas
Veteran
Silver
You are going to annoy everyone whoes M is post '80, as they need a special tool, in place of your screwdriver.
But otherwise yes please...
Noel
You are going to annoy everyone whoes M is post '80, as they need a special tool, in place of your screwdriver.
But otherwise yes please...
Noel