Rangefinderproblems on new M9s

[wattsy]

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I find some of this confused. Note, a few people do use "front" and "back" in this context in the opposite sense, and maybe "near" and "far" are preferable.

 

Yes, I'm rather surprised by Wilson's post. In all the years I've been on this (and other) forums, 'front' and 'back' focus have always referred to where the focal plane appears in relation to the intended focus point. In other words, if I focus on your eye and find your ear in better focus, the camera (and/or lens) is suffering from back focus. If the tip of your nose is more in focus, than the camera (and/or lens) has a dose of front focus.

[cliffp]

An "arit" is a summarit. I didn't coin the abbreviation , honest!

[cliffp]

Ian

 

According to your definition (which to me is more intuitive) my lens is front focusing. BTW do you think a 1cm error at 1m using f2 is acceptable?

[ArtZ]

By normal situation, presumably you don't mean at f2. I have taken a few shots at f2 of flowers etc and they have been out of focus. I know that at around 1m the dof is +/- 1cm but with the inevitable focusing error (human error, poor eyesight etc) it is easy to get the subject outside the zone where things are acceptably sharp. Maybe I shouldn't expect to use f2 at close range?

 

Cliff,

 

I don't know what others think. I think at f/2, your Summicron 90 APO ASPH with 1 cm front focus, should be OK.

 

Depth of field

Near limit: 0.99 m

Far limit: 1.01 m

Total: 0.01 m

 

In front of subject: 0.01 m (50%)

Behind subject: 0.01 m (50%)

 

Hyperfocal distance: 135.1 m

Circle of confusion : 0.03 mm

 

Personally, I wouldn't do it. It's very simple to compensate 1cm when you use f2

 

I suspect you will probably get more than 1cm on the Summicron 28... and that will be also OK

[wattsy]

BTW do you think a 1cm error at 1m using f2 is acceptable?

 

Yes, I think it probably is. Since the M8 came out (giving us all the opportunity to easily judge focus) I've gone from being a bit obsessive about these kind of focus inaccuracies to being quite philosophical about small focus errors (such as 1cm at 1m focus distance). When it comes to real world shooting (as opposed to shooting targets, etc.) there are so many potential pitfalls - subject and/or photographer movement, focus and recompose errors, dodgy eyesight - that a little bit of imperfect focus here and there is just something that goes with the M territory.

[cliffp]

It's very simple to compensate 1cm when you use f2

 

By compensate, do you mean move forward after focusing? I have tried doing this or twisting the focus ring a small amount and neither have worked. How do you compensate? (I can imaging that focusing on a feature further back would work but there often isn't anything suitable, given that it has to be high contrast - maybe that 1.35 magnifier would help)

[cliffp]

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Ian

 

I certainly agree on the pitfalls. I have observed a great deal of variability due to eyesight/poor light/low contrast subject/poor apparent sharpness due to incorrect exposure/irritating subjects that won't keep still (though the 90mm helps due to the reduced intimidation factor). It would be interesting to know what Leica consider the acceptable error to be. I would be surprised if this wasn't published. In my field (electronics) any component has very detailed specifications in regard to its design parameters. These are usually ranges but the limits are known.

[ArtZ]

By compensate, do you mean move forward after focusing? I have tried doing this or twisting the focus ring a small amount and neither have worked. How do you compensate? (I can imaging that focusing on a feature further back would work but there often isn't anything suitable, given that it has to be high contrast - maybe that 1.35 magnifier would help)

 

Cliff,

 

Not after focusing but during focusing. It's hard to explain. When you move backwards (counterclockwise) the focusing ring (from 1m to infinity), you just select focus "just before" you get the viewfinder completely aligned; and "just after" when you move the focusing clockwise (from infinity to 1m).

[giordano]

The 1/3rd-2/3rd rule applies at close focussing distances only. Once you are at say 3m on a 50 mm lens, it is more like 50/50.

 

To be quite clear, it's 50/50 (more usefully described as 1:1) only when the distance to the subject is such that the reproduction ratio is also 1:1*. At all other distances there is more of the depth of field beyond the focus point than in front of it, but the proportions vary with all the various factors that affect depth of field any time.

 

Once you reach the hyperfocal distance, the depth of field beyond the focus point is infinite, so the before:beyond ratio is 1:infinity.

 

And at a distance somewhere in between, the before:beyond ratio is 1:2 ( same as one-third to two-thirds). What's interesting - at least to me - is that this distance varies enormously with the camera. For example,

 

• with a 6x9cm rollfilm camera, 100mm lens at f/11, it's 2-3m - prime snapshot territory.
  

 

• with an M9 and 50mm lens at f/2.8, it's beyond 20m - so far away that we're seldom thinking hard about depth of field.
  

It looks as if the 1/3rd-2/3rds "rule" became the accepted wisdom in the days when a 6x9 camera at f/11 (or thereabouts) was the norm, and many of us (me included, until now) have believed it was a good "rule of thumb" for modern equipment. But it's clearly not.

 

 

*At least with theoretical lenses; things may be different with real complex lenses, especially if they have floating elements.

[wlaidlaw]

Yes, I'm rather surprised by Wilson's post. In all the years I've been on this (and other) forums, 'front' and 'back' focus have always referred to where the focal plane appears in relation to the intended focus point. In other words, if I focus on your eye and find your ear in better focus, the camera (and/or lens) is suffering from back focus. If the tip of your nose is more in focus, than the camera (and/or lens) has a dose of front focus.

 

Ian,

 

In my second year at university (just after Newton had left), we did camera and lens testing as our physics special project. Our tutor used to shout at us "back and front focus are in the image plane and not the object plane you numbskulls!" Now in the intervening eon or so, conventions may have changed. In which case I have been teaching the people attending my photo courses wrongly - oops.

 

Wilson

[Leicakillen]

Well - my M9 has been away for 2 months (not Leica Solms fault). I asked the Leica shop here in Stockholm to adjust the rangefinder - front focus problems on most of my lenses. I just got the M9 back this week and I am sorry to say that now I have a back focus problem by 3-7 cm with my Elmarit 90 and Summilux 50 Asph.

I was not recommended to send the lenses together with my M9 - this was a great mistake. My take away;

- Leica has a big quality problem re rangefinder adjustments.

- All M cameras must be adjusted to individual lenses - "you can use all M lenses" is not true if you like to have perfect focusing. There are many lenses out there that are not att all adjusted giving unsharp photos.

- If you have this problem - send camera AND lenses together for adjustment.

- What should I do when I buy my next new lens - do I have to redo all this??

 

I really thought Leica was better that this, sorry for being pissed oft today. Any kind words from you experts will help....

 

/Anders:mad::mad:

[Julian Thompson]

There is an accepted 'standard' of adjustment. So say you have 5 lenses and 4 focus perfectly then it would stand to reason that you have 1 badly adjusted lens.

 

If all your lenses are not focussing well and are exhibiting the same style of problem, ie backfocus, then maybe your body is not adjusted right still.

 

If only your longer focal length lenses like the 75 are focussing badly then probably it is still the body, because on the wider angles it's simply harder to detect the changes to the rangefinder.

 

You need to shoot some tests and evaluate carefully.

 

I would comment about not being able to use all M lenses without specific calibration - this is not correct in my own experience. Once I got my M9 set up right I am able to use any M lens I have tried so far with no problem and with great focussing accuracy. I recently got a Nocti which is spot on and a 70's Summicron 40mm which also is spot on even at F2.

 

I would add, though, that my M9 was MILES out of adjustment out of the box, and that I spent a lot of time getting it perfect. I am not sure I would have been able to pay someone in a commercial sense to take the level of care over the adjustment that I took myself - many hours of evaluation and re-correction to reach a perfect setting.

 

If you don't want to get your screwdriver out then really you're not going to relax until you've sent it to Solms I guess? Good luck with it, whatever you choose.

[jaapv]

Well - my M9 has been away for 2 months (not Leica Solms fault). I asked the Leica shop here in Stockholm to adjust the rangefinder - front focus problems on most of my lenses. I just got the M9 back this week and I am sorry to say that now I have a back focus problem by 3-7 cm with my Elmarit 90 and Summilux 50 Asph.

I was not recommended to send the lenses together with my M9 - this was a great mistake. My take away;

- Leica has a big quality problem re rangefinder adjustments.

- All M cameras must be adjusted to individual lenses - "you can use all M lenses" is not true if you like to have perfect focusing. There are many lenses out there that are not att all adjusted giving unsharp photos.

- If you have this problem - send camera AND lenses together for adjustment.

- What should I do when I buy my next new lens - do I have to redo all this??

 

I really thought Leica was better that this, sorry for being pissed oft today. Any kind words from you experts will help....

 

/Anders:mad::mad:

The real problem is not the adjustment of the M9 - Leica have great equipment for this and great expertise. Nor is the adjustment of lenses built after 2006 problematic - Again, Leica does know what they are doing. The crux of the matter lies in the fact that the accuracy of focus was far less in the film days. Not only is film far less critical than a sensor, the time lag between the exposure and the print resulted in users blaming themselves, and 100% crops were non-existent. So older lenses may have worked satisfactory for decades and suddenly are shown up by the digital age. For instance, I have a Tele-Elmar from 1967 which was factory-new when I got it three years ago. This is a lens which is hard to adjust, as shimming won't work. It was fine on film on my M6TTL and M3 - but totally off on the M9 (strangely enough I had no problems on the M8 ) I had it adjusted and it is fine. But if you have a mix of older and newer lenses and problems, the best thing to do is send the whole set to a qualified technician with the proper equipement and have everything adjusted. He will match the body to a standard lens (although it will usually be spot-on) and all lenses to a standard body. The adjustment will be at four distances, 1m, 3m, 10m and infinity. After that you will be shooting effortlessly.

[lct]

What are we supposed to do if we use many M lenses and bodies including non-Leica ones? Send in all the Leica stuff to Solm and pray that things won't be worst for the rest after Leica's adjustments?

Hard to buy that digital needs special adjustments frankly. I'm using currently a lot of legacy Leica, Minolta, CV and Oly lenses with Epson and Canon digital bodies and the vast majority works fine so far including beaten antiques although the bodies are not champions of focussing accuracy.

[rosuna]

The real problem is not the adjustment of the M9 - Leica have great equipment for this and great expertise. Nor is the adjustment of lenses built after 2006 problematic - Again, Leica does know what they are doing. The crux of the matter lies in the fact that the accuracy of focus was far less in the film days. Not only is film far less critical than a sensor, the time lag between the exposure and the print resulted in users blaming themselves, and 100% crops were non-existent. So older lenses may have worked satisfactory for decades and suddenly are shown up by the digital age.

 

Right. I agree. But, then, what the solution is? Does Leica has to rethink all the focus system of the camera? A new rangefinder? Electronic focus confirmation (if possible)?

[rosuna]

...the answer is in Michael Reichman's long interview to Stefan Daniels on the M9. Look at the time frame 26min-to-28min.

 

An Interview with Leica's Stephan Daniel

 

CMOS sensor, live view, focus confirmation in the viewfinder...

[k-hawinkler]

...the answer is in Michael Reichman's long interview to Stefan Daniels on the M9. Look at the time frame 26min-to-28min.

 

An Interview with Leica's Stephan Daniel

 

CMOS sensor, live view, focus confirmation in the viewfinder...

 

Right on. I couldn't agree more.

 

K-H.

[Jamie Roberts]

My M9 was front focussing by around 3cm too - I just stuck an allen key in the cam and turned it clockwise about 1/8th of a turn (in small increments as small as I could with test shots each time) and it is now perfect. Very simple, very quick (half an hour total) and works spot on - plus it's adjusted to my hand/eye/focussing technique which is a personal thing.

 

Give it a whirl - it's really very, very easy. (To be fair I've done it a few times on M8's so I knew what to expect but it's so much better than having to send it away each time you need a tweak)

 

(But obviously it's at your own risk etc....)

 

Julian--mine too. And now it's right on the money with all my Luxes *and* Nocti, so I'm good. The 28 and 90 cron / 90 Elmarit are both great now too, though I have to say that 90 cron is the most finicky lens I've ever owned. It doesn't take much to put it out (I suspect it needs a trip to Solms to look at the lens where it meets the RF cam). I obviously got lucky, though, with the minimal tweak needed to get the focus acceptible.

[Julian Thompson]

Hmmn - OK - but that's where I was Jamie before I learned all the other stuff.

 

Hopefully you are lucky and the arm length is spot on but I would do some proper testing to make sure. When I did just the infinity adjustment it took me a bit of testing to discover the point at which the real focus/rangefinder line were not together. Do some more testing and report back. I feel that you might not have good news for us and maybe need to make further changes as detailed in the other thread.

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Hallo,

Look here: Leica M

[Julian Thompson]

ie - that paragraph you copied there was written by someone with a lot to learn at that point in time. The other thread is better to read because it is where I am at now with it in terms of a lot more experience.