Very interesting answer from Leica on 35mm 1.4

[carstenw]

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My 35 Cron Asph works fine so far. I have not tried the Lux.

[Jamie Roberts]

Tim--your rangefinder needs tweaking, and so do others. Notice I'm not saying "it's completely out" of shape here, but it needs a tweak, is all.

 

My 35 lux ASPH focusses perfectly at the point of focus in the rangefinder. I could post shot after shot showing this, but the fact is it does this.

 

My 50 lux ASPH focusses perfectly at the point of focus too, FWIW..

 

In both of these Lux lenses, though, the RF is set so that at f1.4, the point of focus is very near the back of the focal field. It's not quite front-focussing, but it's very close.

 

As you stop down, the field of focus moves "backwards" till almost backfocussed by f4, then becomes just "in focus" with more equal front with the DOF.

 

This is a perfect solution, I think. Infinity focus is also perfect.

 

Does the focal field change as you stop down? Yes. Does it affect the focal point? No.

 

Leica is correct; the field changes in a way that it doesn't seem to, say, with the 35 R Lux or Cron (or I've never noticed!)

 

If you have a 35 M lens that doesn't do this, then I'd suspect the calibration of the RF first--before any other problem.

 

And why wouldn't you check this, as Carsten says? It's a simple adjustment, after all.

 

Set it up as suggested, working with the 35 first, and you'll be happy with the results!

 

How does mine focus, then? On the 35, up close, if I was to focus on someone's nose at 1.4, their eyes would just be plain OOF. Can't use the nose for the eyes here, folks!

 

If, however, I focus on their eyes, the tip of the nose is right in focus; the ears are usually not.

 

The proof of this setup came today--I got a 75 Lux in fabulous condition!

 

It *does* front focus by the very tiniest, tiniest bit at f 1.4--if I focus on the focal point, it's still sharp-ish, but not as full contrast as it should be (the 75 isn't soft wide open, but it's softer than any other Leica lens I have wide open except for the 80 R lux).

 

This is downright simple to compensate for, and doesn't need anything but the smallest nudge towards the back for perfect focus--again, wide-open, up close.

 

Especially with people, it means I focus on the side of their face (full face) or the back of their eyebrow ridge (3/4) and their eyes--even with the tiny rangefinder--are as sharp as it gets at 1.4!

 

But this is only wide open, BTW--as you get to f1.6 and f2, the focus point is stabilised, but the field is shifting just like the 35 lux.

 

By f 2.8, it's perfect, and easy to focus, even given the small rangefinder focus area.

 

So I just have to say "you gotta believe me" on this. I wouldn't have believed it either if I didn't do this with my own two, not-very-mechanically-oriented hands.

 

I don't think I have a magic M8 or lenses, either. And FWIW, both my Elmarits (24 ASPH and 28 ASPH) focus perfectly--I haven't noticed anything shifting on those.

 

Try this--you've got nothing to lose but your blurry 35mm shots!

 

Couldn't resist, even though I've posted this in another thread too--forgive the double reference

 

http://www.leica-camera-user.com/people/19267-monochrome-portrait.html#post203937

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[egibaud]

Tim--your rangefinder needs tweaking, and so do others. Notice I'm not saying "it's completely out" of shape here, but it needs a tweak, is all.

 

Ok let's say you are right and I decide to tweak my M8.

 

How will other lenses that actually focus properly now will be afected by the tweaking? If I fix the 35lux backfocus, won't I get a front focus with lenses that are focusing perfectly now?

 

Tweaking makes sense to me in 2 conditions only:

 

1- to have 2 M8 bodies and use one exclusievly with the 35 (and other lenses that would have exactly the same back focusing and use the other one with the OK lenses.

 

2- I have no idea about tweaking as I new to M8 and Leica M... so the it would make sense to me if tweaking was possible according to the focal lens being used... but so far this is not what I have grasped out of this thread.

 

So? what do you reckon?

 

Eric

[hiro]

I got interested in reading this thread after having sent my 75 Lux back to Solms for focusing adjustment a couple of weeks ago. My lens is an earlier model (1980) and I never noticed the OOF problem when used with M6 but, at wide open, the focus suddenly shifted backwards by about 6 inches at close range when used with M8. 75 Cron ASPH on the other hand seems to focus okay. It is obvious that even a slight mis-focusing is detrimental for a telephoto lens of this length. I hear that Leica has stopped producing 75 Lux recently and I wonder if this is the reason.

[tashley]

Ok let's say you are right and I decide to tweak my M8.

 

How will other lenses that actually focus properly now will be afected by the tweaking? If I fix the 35lux backfocus, won't I get a front focus with lenses that are focusing perfectly now?

 

Tweaking makes sense to me in 2 conditions only:

 

1- to have 2 M8 bodies and use one exclusievly with the 35 (and other lenses that would have exactly the same back focusing and use the other one with the OK lenses.

 

2- I have no idea about tweaking as I new to M8 and Leica M... so the it would make sense to me if tweaking was possible according to the focal lens being used... but so far this is not what I have grasped out of this thread.

 

So? what do you reckon?

 

Eric

 

That's exactly my problem.

 

I am gearing up to try this though as my second M8 is being replaced and I have a trip next week, I have no fall back should I screw it up other than a 5D, which I'm not keen to use unless I have to!

 

And my concerns match yours.

 

@Jamie, what you seem to be saying is that tweaking for the 35 does then put the 75 out. My longest lens is a 90mm and I used it to shoot the moon (eclipse) a coupla weekends ago. Set at infinity, focus seemed pretty good! Now, if a Allen my way towards 35mm perfection I'll start having to guess focus (as you are doing) with the longer lens. Not sure that's the compromise I want!

 

Best

 

T

[rosuna]

Does the focal field change as you stop down? Yes. Does it affect the focal point? No.

 

That is the key point.

The problem is this: the focus point changes, and the DoF area is a conventional calculation. The DoF graphics of Leica lenses are calculated for 24x36 format and A4 prints (circle of confusion of about 30 microns).

 

The proof of this setup came today--I got a 75 Lux in fabulous condition!

 

You had luck. I would like to have the opportunity of buying a mint 75'lux at a reasonable price!

[lars_bergquist]

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This is getting tiresome. Rangefinder paranoia is even older than lightmeter paranoia. It started in 1932, and I've been along nearly that long!

 

The fact of focus walk because of spherical aberration has been known even longer. It was known even to view camera users, because they had to focus on the screen with the lens wide open. And we have all known the remedy, too: STOP DOWN.

 

Everyone but the most bare-arsed tyro has known since time immemorial that wide open apertures were for emergency use at mid-distances only, NOT for close focusing. Every rangefinder OR reflex finder OR autofocus system is a rat's nest of compromises. Especially when shooting handheld. The subject will move, if even a couple of millimeters, you will move, and there's an unavoidable delay between your decision to fire the shutter, and the actual firing (nerve impulse travel plus mechanical 'lock time' -- rifle and pistol shooters know this, trap and skeet shooters know it even better!) Be glad you haven't got to guess focus.

 

So STOP DOWN. What use is an unsharp picture if you can, with a magnifier, find a sharp blackhead somewhere? That's no excuse.

 

Second, pinpoint sharpness is not all. Can you show me one single famous action photograph, by Cartier-Bresson, Capa, Duncan or Smith or anybody else, that would have been materially improved by a marginal increase in optical definition? Definition is the hobgoblin of people who make pictures without content or expression.

 

I might have added some words about the much-misunderstood subject of depth of field, which has to be substantially re-thought with the change to a smaller sensor -- it should in fact have been re-thought with the advent of enlargements above postcard size! But this posting is already long enough. The only thing I want to add is this: Stop this neurotical self-scratching behaviour. Go out and take some pictures instead.

 

The irascible old man from the Age of Tape Measure Focusing

[egibaud]

The irascible old man

 

that sentence surely defines you. Instead of barking at us, can't you tell all of this without calling us ignorent??? some of us are new to this!

 

I think in 1932 you were a beginner... so I hope people who may have helped you then did not do it the way you are speaking to us today.... or maybe they did this is why you sign The irascible old man.

 

Sharing experience has nothing to do with calling others stupid for not knowing what you know!

 

Eric

[marknorton]

Tim, what happened to your second M8? The honeymooon wasn't very long!

[stunsworth]

Lars, most of what you say is true - especially the last sentance - even if it is put in a errr, strong way :-)

[tashley]

This is getting tiresome. Rangefinder paranoia is even older than lightmeter paranoia. It started in 1932, and I've been along nearly that long!

 

The fact of focus walk because of spherical aberration has been known even longer. It was known even to view camera users, because they had to focus on the screen with the lens wide open. And we have all known the remedy, too: STOP DOWN.

 

Everyone but the most bare-arsed tyro has known since time immemorial that wide open apertures were for emergency use at mid-distances only, NOT for close focusing. Every rangefinder OR reflex finder OR autofocus system is a rat's nest of compromises. Especially when shooting handheld. The subject will move, if even a couple of millimeters, you will move, and there's an unavoidable delay between your decision to fire the shutter, and the actual firing (nerve impulse travel plus mechanical 'lock time' -- rifle and pistol shooters know this, trap and skeet shooters know it even better!) Be glad you haven't got to guess focus.

 

So STOP DOWN. What use is an unsharp picture if you can, with a magnifier, find a sharp blackhead somewhere? That's no excuse.

 

Second, pinpoint sharpness is not all. Can you show me one single famous action photograph, by Cartier-Bresson, Capa, Duncan or Smith or anybody else, that would have been materially improved by a marginal increase in optical definition? Definition is the hobgoblin of people who make pictures without content or expression.

 

I might have added some words about the much-misunderstood subject of depth of field, which has to be substantially re-thought with the change to a smaller sensor -- it should in fact have been re-thought with the advent of enlargements above postcard size! But this posting is already long enough. The only thing I want to add is this: Stop this neurotical self-scratching behaviour. Go out and take some pictures instead.

 

The irascible old man from the Age of Tape Measure Focusing

 

Lars, much as I love irascibility, I can't help but feel that had you actually read the thread you would have realised that a) most of us are aware of all this already and it neither addresses not solves the problem.

 

I am talking about three 35mm lenses in a row which, at F4 (which is, I think we can agree, somewhat stopped down on a semi wide) will render something twenty feet away very clearly OOF and something twenty feet behind that sharp as a pin. That's when you've focussed on the thing twenty feet away.

 

And just so my own irascibility is in no doubt, I would like to clarify: I do take a lot of photos and some of them aren't bad at all. I don't always want perfect focus, sometimes I will actively discard it for creative reasons - but at $3,000 a lens, if it says on the box that it performs perfectly wide open and if other people have examples that do, then that is what I expect.

 

I admire people who's photographic careers began when cameras were steam-driven, I really do. But affection for lack of progress is not one of their more attractive traits.

 

Tim

[tashley]

Tim, what happened to your second M8? The honeymooon wasn't very long!

 

 

Hi Mark!

 

It's being replaced: it had a sensor read-out issue causing weird coloured pixel bloom around areas of immediate transition of brightness. Some examples do suffer from this but my first body continues to behave impecabbly and I'd like a second one that does the same!

 

Best

 

Tim

[Shootist]

Hi Mark!

 

It's being replaced: it had a sensor read-out issue causing weird coloured pixel bloom around areas of immediate transition of brightness. Some examples do suffer from this but my first body continues to behave impecabbly and I'd like a second one that does the same!

 

Best

 

Tim

I would like to know what coloured pixel bloom is and immediate transition of brightness? Did this happen on the edge of a image or anywhere in the sensor area. Like a bright light and right next to it a dark area.

I get the green strip when I have a bright light at the edge of the image and I wondering if I need to send the M8 in with image files to get this corrected.

[Woody Campbell]

. . . I might have added some words about the much-misunderstood subject of depth of field, which has to be substantially re-thought with the change to a smaller sensor -- it should in fact have been re-thought with the advent of enlargements above postcard size! . . .

 

The irascible old man from the Age of Tape Measure Focusing

 

Depth of field on the M8 is easy: one stop for the small sensor and one stop for the fact that you may be printing larger than postcards. Result: 2 stops. If you're at f8 use the f4 depth of field marks. Not precise but neither is the rule that generated the depth of field scale on the lens.

 

Amazingly, Leica gets this wrong in the M8 manual.

[tashley]

Depth of field on the M8 is easy: one stop for the small sensor and one stop for the fact that you may be printing larger than postcards. Result: 2 stops. If you're at f8 use the f4 depth of field marks. Not precise but neither is the rule that generated the depth of field scale on the lens.

 

Amazingly, Leica gets this wrong in the M8 manual.

 

 

I agree with Woody: two stops usually does it.

 

Tim

[tashley]

I would like to know what coloured pixel bloom is and immediate transition of brightness? Did this happen on the edge of a image or anywhere in the sensor area. Like a bright light and right next to it a dark area.

I get the green strip when I have a bright light at the edge of the image and I wondering if I need to send the M8 in with image files to get this corrected.

 

 

Flick through the shots on this thread

http://www.leica-camera-user.com/digital-forum/18949-end-world-we-know.html

The oixel bloom varies from white through whatever the main colours are to random. It's a different phenomenon to the green stripe, which for me has always been very very rare and which I understand will get fixed in 1.1

 

Hope that helps

 

Tim

[Jamie Roberts]

@ Tim and Eric...

 

Eric first.

 

With the tweak, yes, you will get a slight amount of front focus. Actually, it's bang on, since the focus point is always in focus.

 

What you have right now is a small amount of actual back focus--since you can't focus on what you want with a 35mm lens, for heaven's sake!

 

Think about this. You're saying a lens which should be a no-brainer to focus is that way by design. Very odd.

 

FWIW, this is how my adjusment has affected other Leica lenses (I'll let you know about my CV 28 1.9 when it gets here next week):

 

24mm 2.8 ASPH--perfect focus

28mm 2.8 ASPH--perfect focus

35mm 1.4--perfect focus, with perceptible field shift to f5.6

50mm 1.4--perfect focus, with minimal, but perceptible, field shift to 2.8

75mm 1.4--1.5mm front focus at f 1.4 close up (pace Lars--we know); completley gone by f2.

 

This to me is a perfect compromise; I guess I didn't make that very clear I only have one M8, and the front focus on the 75 1.4 is actually within the margin of focus error with the small rangefinder.

 

AT NORMAL DISTANCES, you don't even see this ff effect, because distance increase effective focus.

 

@ Tim, I actually think it is the design of the 75--a very old but optically interesting one--that makes for the ever-so-slight front focus.

 

My 85 R lux on the DMR does this too almost exactly, and it used to drive me a little batty till I realized it.

 

They're very similar lenses, as others have pointed out.

 

So--again. You have nothing to lose by attempting the adjustment. I really don't think your 90 cron is going to be affected at all, since the only effect I've ever seen is a neglible one at f1.4; nothing at f2.

 

Hope this helps

[lars_bergquist]

Lars, most of what you say is true - especially the last sentance - even if it is put in a errr, strong way :-)

 

Steve,

it is a failing of mine, which I freely admit to, that I have short patience with fools. Also, my fuse is not getting any longer with my advancing years.

 

"But behind my back I hear

Time's wingéd chariot drawing near ..."

 

However, every vet knows the syndrome well. Dogs or cats without sufficient external stimulation do start scratching themselves obsessively, until they actually lacerate themselves. Horses bite the manger. One common solution, putting the poor beast away, is not applicable here. Thus my advise to go out taking some pictures. People who cannot find any interesting pictures should lay off photography and go into philately or the collecting of beer bottle tops.

 

A more worthwhile subject might be a discussion of the concept of depth of field. I think I saw somebody using the term 'circle of confusion'. A different thread?

 

The benign wise old man on the top of the mountain ;—)

[Jamie Roberts]

Ok--a demonstration here--just to let you see this...

 

This is the 75 lux in an incredibly darkened room, wide open, and my 3 year old son is watching "The Polar Express" (his favourite movie--he's train mad!).

 

This is an *incredible* lens and system. If anyone's wondering why I love the M8, this is a perfect example.

 

Specs:

• M8 RAW converted to JPEG in C1. No PS.
  
• 75 Lux @ f1.4 @ 9ft; focussed on my son's eye, then re-composed for the shot
  
• ISO 2500 @ 1/16 s, handheld, no filter.

What do you think? Not bad for a handheld 75mm shot in almost total darkness, eh? BTW--I took 5 snaps, they're all in focus.

 

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

 

Oh--and what the heck--here's the 100% crop of the above. No manipulation other than C1.

 

Please allow for the 1/16s here, the worst possible light, and for the percentage of the overall shot this represents.

 

You're also seeing the signature softness of this lens wide open--it's sharp as tacks stopped down.

 

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[lars_bergquist]

Depth of field on the M8 is easy: one stop for the small sensor and one stop for the fact that you may be printing larger than postcards. Result: 2 stops. If you're at f8 use the f4 depth of field marks. Not precise but neither is the rule that generated the depth of field scale on the lens.

 

Amazingly, Leica gets this wrong in the M8 manual.

 

Very true, Woody. There is actually a theoretical/mathematical justification, but this may not be the right place for it. I do think however that Leica should have revised that 1/30th of a millimeter standard way back in 1935 or so – but sitting on an industry standard does of course give you a nice, cosy feeling.

 

And think of all those fine lenses out there with those Neolithic DoF scales!

 

The old man from the Circle of Confusion