Apo Summicron 75mm Focusing Problem

[wlaidlaw]

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Just to be pedantic, if the point of sharpest focus is in front of the object, then that is technically "back focus" not as you might think "front focus". The reason for this is that "back" and "front" refer to the position of the image inside the camera, relative to the imaging medium, film or sensor, not to the object being imaged. For a more coherent explanation, I would suggest Norman Goldberg's (DAG's father) Camera Technology - The Dark Side of the Lens: ISBN-13: 978-0122875700. 

Wilson

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[SmokeSolid]

11 hours ago, LocalHero1953 said:

I don't get the impression the 75 is any worse than other longer, wider M lenses, where it is noticeable because of the shallow DoF. As I wrote earlier, my particular problems were with the 90 not the 75. Of course, if you post a thread about any single lens, everyone reports on the problems they've had with that lens, and it gets a reputation for being a 'problem' lens😉.

I can't answer for Leica US, but Wetzlar say they calibrate lenses and bodies to independent standards, not to match each other. So you should not have to send the lens and body together for recalibration. On one occasion Leica in London asked to see both body and lens so they could check themselves which had to go for recalibration to Wetzlar - on that occasion only the body was sent.

Its kind of a problem lens man. I got different opinions on factory problems like the ones stated above. 
and truly its a Leica build lens so that what bothers me a bit more. 
Of course this os not the only thread in tge internet about it

[T25UFO]

24 minutes ago, SmokeSolid said:

Its kind of a problem lens man. I got different opinions on factory problems like the ones stated above. 
and truly its a Leica build lens so that what bothers me a bit more. 
Of course this os not the only thread in tge internet about it

It just happens with rangefinder cameras - lots of mechanical bits that can go slightly out over time, or with use.

Put a 75 or 90 on the SL and it will be fine.  I had a 90mm APO that was slightly off right out of the box.  No idea why.  Sent it back to Leica and now its perfect.  That doesn't mean it's easy to focus - there will always be human error, which we sometimes attribute to the equipment!  

However, it's rewarding when you get it right - here is an example taken with M10-D, which doesn't even have a screen to check the focus!  I originally posted this in the 90mm Images (open thread).  OK, it's not a 75mm shot, but I think your question is a more general one that applies to focusing of longer lenses.

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Edited May 1, 2020 by T25UFO

[SmokeSolid]

15 hours ago, adan said:

How is the focus at infinity?

Set the focus ring to the hard stop at infinity and aim at something at least 1/2 mile /1 km away. Do the RF images align perfectly (they should), or do you see a double-image in the RF patch? Take a picture of that distant object - is it sharp or fuzzy at that focus setting?

Hi Adan,

It aligns perfectly no problem at all. 

F2.0

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F5.6

 

 

 

Edited May 1, 2020 by SmokeSolid
Added pics

[SmokeSolid]

54 minutes ago, T25UFO said:

It just happens with rangefinder cameras - lots of mechanical bits that can go slightly out over time, or with use.

Put a 75 or 90 on the SL and it will be fine.  I had a 90mm APO that was slightly off right out of the box.  No idea why.  Sent it back to Leica and now its perfect.  That doesn't mean it's easy to focus - there will always be human error, which we sometimes attribute to the equipment!  

However, it's rewarding when you get it right - here is an example taken with M10-D, which I originally posted in the 90mm Images (open thread).

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Nice shot. Very rewarding indeed. 
thing is I understand “ my human errors” but this lens is of by a bit that doesn’t help. 
I have other equally complex lenses on other brands. to shoot handheld is complicated but not like this one. Tripod test dont lie. 
Im sure the lens is faulty. 

Edited May 1, 2020 by SmokeSolid

[a5m]

17 hours ago, wlaidlaw said:

Just to be pedantic, if the point of sharpest focus is in front of the object, then that is technically "back focus" not as you might think "front focus". The reason for this is that "back" and "front" refer to the position of the image inside the camera, relative to the imaging medium, film or sensor, not to the object being imaged. For a more coherent explanation, I would suggest Norman Goldberg's (DAG's father) Camera Technology - The Dark Side of the Lens: ISBN-13: 978-0122875700. 

Wilson

Interesting. I understood it to mean the position of the focus plane relative to the sensor. So if your focus falls in front of your subject, meaning closer to the sensor, that'd be front focus. If it falls behind your subject, or further away from the sensor, then it'd be back focus.

Good to have the same understanding especially if you're working with someone like DAG to get a lens adjusted. It may have an impact on whether or not you're satisfied with the results 😂

[james.liam]

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8 hours ago, T25UFO said:

It just happens with rangefinder cameras - lots of mechanical bits that can go slightly out over time, or with use.

Put a 75 or 90 on the SL and it will be fine.  I had a 90mm APO that was slightly off right out of the box.  No idea why.  Sent it back to Leica and now its perfect.  That doesn't mean it's easy to focus - there will always be human error, which we sometimes attribute to the equipment!  

However, it's rewarding when you get it right - here is an example taken with M10-D, which doesn't even have a screen to check the focus!  I originally posted this in the 90mm Images (open thread).  OK, it's not a 75mm shot, but I think your question is a more general one that applies to focusing of longer lenses.

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WoW

[Franky]

I also bought this lens.
I also had a focus problem.
I sent my camera and lens to Wetzlar.
It was fixed. The floating element "floats" too much, the technician said.

Sincerely yours

[Fedro]

46 minutes ago, Franky said:

I also bought this lens.
I also had a focus problem.
I sent my camera and lens to Wetzlar.
It was fixed. The floating element "floats" too much, the technician said.

Sincerely yours

it floats too much in general, or in your specific version?

[Jürgen]

I just made some shots with my Apo 2/75 ASPH. with f=2,0 and f=5,6. Their are no issues with my lens. It is sharp!!! All lenses which have focussing problems must returned to Leica repair service.

Edited May 2, 2020 by Jürgen

[T25UFO]

21 hours ago, SmokeSolid said:

Nice shot. Very rewarding indeed. 
thing is I understand “ my human errors” but this lens is of by a bit that doesn’t help. 
I have other equally complex lenses on other brands. to shoot handheld is complicated but not like this one. Tripod test dont lie. 
Im sure the lens is faulty. 

Hi there,

The point I wanted to make was: I had a faulty lens, sent it back to Leica and now the focus is perfect, as illustrated by my bird photo.  Leica should do the same for your lens, although you might have to wait a bit longer because of Covid- 19.

I have no technical knowledge, so have no idea what Leica does to recalibrate the lens (other forum members with better knowledge may have more insight) but don't give up on the 75mm APO because it is a superb lens when properly calibrated to the rangefinder.  I'm sure if you were able to try it on a mirrorless camera (SL, CL etc) it would produce pin sharp photos.

Of course, all M lenses should work straight out of the box on any M camera, and shouldn't need adjustment.  That is the frustrating bit.

[SmokeSolid]

21 minutes ago, T25UFO said:

Hi there,

The point I wanted to make was: I had a faulty lens, sent it back to Leica and now the focus is perfect, as illustrated by my bird photo.  Leica should do the same for your lens, although you might have to wait a bit longer because of Covid- 19.

I have no technical knowledge, so have no idea what Leica does to recalibrate the lens (other forum members with better knowledge may have more insight) but don't give up on the 75mm APO because it is a superb lens when properly calibrated to the rangefinder.  I'm sure if you were able to try it on a mirrorless camera (SL, CL etc) it would produce pin sharp photos.

Of course, all M lenses should work straight out of the box on any M camera, and shouldn't need adjustment.  That is the frustrating bit.

Thanks. 
I love the lens and its just a bit of for model and portrait im using the LiveView but still Ill love to hit focus as before with the rangefinder. 

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[Edgar1920]

Dear Smoke Solid

I hope you will get your lens well calibrated. Today I bought one, second hand, and focus is perfect. But I realized that my visual abilities are maybe the weakest point as at 0.7m and f/2 the DOF is only from 0.695 to 0.705m, so 1 cm. Focussing may be a real challenge if the object has no vertical structures with sufficient contrast. So I will purchase the viewer magnifier 1.4 (with 1.25 still challenging).

And the lens' specifications make it a clear candidate for closeup pictures with shallow DOF.

My 1960 summicron 90mm is a bit more forgiving as it is less sharp. That's the disadvantage of really sharp lenses - you must focus right, not only merely right.

Your 2 comparison pictures f/2 and f/5.6 show that "at inifitny" on the lens barrel and viewfinder the optic cell is not in infinity position.

So there is a real mechanical issue far beyond wear or so, I suppose. Regular wear should only occur on lenses used by professionals or owners who turn the barrel from 1m to infinity several hundred times a day maybe as a personal stress therapy. And an regular case of wear will probably only result in a very small focus error.

My first impression of the lens is that it is an excellent performer. The coming weeks will show more.

 

Best regards,

Frank

 

[dkmoore]

On 4/30/2020 at 3:41 PM, jaeger said:

That's is very true, so does the 90APO.

Some say, which I also agree, send the camera and lenses for adjustment separately.  NJ office screwed all my lenses to fit a bad body.  Then replace a new body, all lenses are off.  It took 2+ years in total to undo their damage.  I am still pissed today.

 

 

Experienced this exact issue with three lenses and two camera bodies. I got so tired of it I got rid of all of them. I 100% agree that they should all be adjusted separately to tolerance. 

[dkmoore]

I just bought the limited edition 75 APO in silver and focus is spot on at all distances, thankfully. I do think the new factory is doing a good job of making sure cameras and lenses are shipped without issues. That has been my experience with all recent purchases.

Good luck getting your 75 fixed. I definitely would NOT try to fix a FLE yourself.

[SmokeSolid]

Thank you all. 
Ill use the LView, my 24mm is 80% of the time in my camera so I wont get obsessed on it. I dont use it that much LV or a EVF is the solution for know until I can travel and get it serviced. 
If i can adapt to Covid I will to the apo75mm. 
😀
 

[PCPix]

On 5/2/2020 at 7:45 AM, Franky said:

The floating element "floats" too much, the technician said.

I've recently noticed mine has a very slight rattle - and upon inspection I can feel play on the focussing ring when moving back and forth. The play/delay is between when the focus ring begins moving and the floating rear element begins to move. It's a very small amount (like less than 1mm of fosussing ring rotation). The rattle is the entire rear element group moving around.

I've been suspicious something was wrong pretty much since I bought the lens new (about three years ago). Wide open at f/2, sometimes the lens was amazingly sharp, other times it was ever so slightly smeared. I just put it down to user error and stopped down to f/5.6. This was before I discovered the rattle.

As a test I tip the camera toward the floor and gently tap the the camera against the palm of my hand (so the elements fall to a forward position). Then focus on a fixed point (about 2m) and take a shot, then point the camera to the ceiling and tap it again (so the loose elements settle in a rearward position) and take a second shot - with no re-focussing. First image is pin sharp, second is soft with a very noticeable change in oof bokeh...

Will be sending it to Germany when things improve....

[Stein K S]

19 hours ago, PCPix said:

I've recently noticed mine has a very slight rattle - and upon inspection I can feel play on the focussing ring when moving back and forth. The play/delay is between when the focus ring begins moving and the floating rear element begins to move. It's a very small amount (like less than 1mm of fosussing ring rotation). The rattle is the entire rear element group moving around.

I've been suspicious something was wrong pretty much since I bought the lens new (about three years ago). Wide open at f/2, sometimes the lens was amazingly sharp, other times it was ever so slightly smeared. I just put it down to user error and stopped down to f/5.6. This was before I discovered the rattle.

As a test I tip the camera toward the floor and gently tap the the camera against the palm of my hand (so the elements fall to a forward position). Then focus on a fixed point (about 2m) and take a shot, then point the camera to the ceiling and tap it again (so the loose elements settle in a rearward position) and take a second shot - with no re-focussing. First image is pin sharp, second is soft with a very noticeable change in oof bokeh...

Will be sending it to Germany when things improve....

Hi and thanks!

 

This was very very interesting! Mine have no play, but picture/sharpness wise it behaves pretty much like yours… with quite some ¨random¨ sharpness. I did for a while put it on the user error account, but not now after MUCH testing (if it is THAT difficult to get it right, I get reluctant to bring the lens at all). Disappointed and I am starting to think  about a Summarit again (sorry I sold my previous one…).

PS: The lens was at Leica in Germany not long ago… and so was the body on which it is mainly used.

 

Eager to hear if there still is a cure… because when, OK it is very OK!

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[Stein K S]

On 5/11/2020 at 12:28 PM, PCPix said:

I've recently noticed mine has a very slight rattle - and upon inspection I can feel play on the focussing ring when moving back and forth. The play/delay is between when the focus ring begins moving and the floating rear element begins to move. It's a very small amount (like less than 1mm of fosussing ring rotation). The rattle is the entire rear element group moving around.

I've been suspicious something was wrong pretty much since I bought the lens new (about three years ago). Wide open at f/2, sometimes the lens was amazingly sharp, other times it was ever so slightly smeared. I just put it down to user error and stopped down to f/5.6. This was before I discovered the rattle.

As a test I tip the camera toward the floor and gently tap the the camera against the palm of my hand (so the elements fall to a forward position). Then focus on a fixed point (about 2m) and take a shot, then point the camera to the ceiling and tap it again (so the loose elements settle in a rearward position) and take a second shot - with no re-focussing. First image is pin sharp, second is soft with a very noticeable change in oof bokeh...

Will be sending it to Germany when things improve....

Just one more technical question. Do you always need to tap to make it work... or do you also experience a difference whether you focus in on the object clockwise (from infinity) or against the clock (from closer distance)? Still a problem since fine tuning always is needed, but I am curious about how the inside of this lens behaves. Will also make some testing myself.

[PCPix]

1 hour ago, Stein K S said:

Do you always need to tap to make it work...

To be honest - now that I know it's misbehaving, I don't really use it. Wetzlar is still 'closed' - I'll await them re-opening and send it in.

I'm sure it's a mechanical adjustment, that's all... when it's sharp it is equisitely sharp - so at least I know the lens can perform;-)