90MM APO Focus Issue on M8

[mountainrivera]

After reading how spectacular this lens is I purchased one and am less than wowed but would love to hear others' opinions. Before I begin, I have a 50mm coded summicron that is sharp as a tack on my M8. Bot used, the lens was calibrated by a well known Leica repair person and I was provided with the receipt. In use, I saw evidence of back focussing (ears sharp, eyes not) so I contacted the repair person who said the lens was calibrated for a film camera and not digital. The person said they don't do digital so off to another (well known) repair person it went for an M8 calibration. Got it back and it was off the charts out-of-focus and totally unusable so back to another look to the second repair person. I am hoping they just made an error in calibrating the lens. Can't fathom it being in spec and performing this way. Could it be the body even when the 50mm is perfect? I would think that messing with the body would only allow one or the other (either the 50mm or the 90mm) lens to work. thnx

 

[ali_baba]

i recently bought one used that was supposed to be fine.
it didnt focus right on my m8.
it was off @ infinity wide open, and even so slightly i sent it back.
great deal, but hey if it doesnt work it doesnt work.
i need one badly now however.

 

[peter_n]

Don't know about the M8 but I do know about the lens, having used one for a couple of years. The lens was great at mid to far distances but not close-ups. I sold it earlier this year, as I have a 75/2 that is stellar at all distances, smaller, lighter and IMO all-round a better lens for what I shoot.

You must know that the M8 shows back focusing with lots of lenses. I have read that you need to send lenses to Leica to get back focus issues fixed. Sometimes you have to send them back more than once... Leica make a lot of soft €€€€s on the M8.

 

[Hacker]

My lens focuses fine for mid to far distances. WIthout any floating element, it is not optimize to focus near distances unlike say the ZM 85 f2, the 50 Lux ASPH or even the 75 Lux ASPH. I have some lenses that back focus, notably the tele lenses, but learn to compensate for these errors.

There are threads where users reported very good results once they self adjusted their M8s to focus for infinity.

 

[spysmart]

Such issue reports are good for film M users, as M8 users swap from the 90 to the 75mm.
The 75 'cron seems to sell second hand for as much as 50% more than the 90 AA 'cron.

However calibration seems to be absolutely essential with the 90mm lens :
Only once I bought a s/h 90 AA (for half the current new price) did I notice that the RF (not the lens) on my 0.85x M6 was a little short of infinity .
At f/2 on Acros I can see a difference between shots corresponding to the hard stop and where the RF thought infinity was.

 

[boilerdoc2]

I send my lenses that back focussed (75/1.4 & Nocti) on my M8 to DAG. He fine tuned them and came back perfect. He's the best. Make sure and use an eyepiece magnifier when using the 'luxes!
Steve

 

[mountainrivera]

I hope it doesn't become a paperweight. Received this email from Don G.:

I finally found that there's a slight amount of play in the focusing cam system & the way the lens is focusing is that if you start your lens at a far away setting, lets say 50 feet & then focus down to a target at, lets say, 10 feet- the focus will be different than if you start at a close focus distance (on the lens focus scale), let's say 2 feet, & then focus to the same target at 10 feet. Unlike 99% of Leica lenses, your 90mm lens has a very unusual & complicated focusing cam that couples to the camera's rangefinder. & since there's the slightest amount of play it makes it very difficult to try and remove the play. Another way to notice the play in the focus system is to focus on a target, then slightly turn the focus dial left & right about 2 or 3 degrees each way & you'll notice that the 2nd image of the R/F does not move where another 90mm lens on the same camera will cause the 2nd image to move while turning the focus dial 2 or 3 degrees both ways. I'll be able to take time on this coming Tuesday to give your lens another look at this area & see if I can remove the play.

 

[peter_n]

I hope it doesn't become a paperweight.

I hope so too. That'll depend on how long ago you bought the lens. Can you return it?

I think I've read about this problem before, maybe even in connection with Don. Something about focus being different if you came from infinity versus starting from the minimum distance. I think the poster commented that the tech thought it was due to the design of the focusing mechanics.

 

[mountainrivera]

I hope so too. That'll depend on how long ago you bought the lens. Can you return it?

I think I've read about this problem before, maybe even in connection with Don. Something about focus being different if you came from infinity versus starting from the minimum distance. I think the poster commented that the tech thought it was due to the design of the focusing mechanics.

Yes, i did read that somewhere too. I think I saw that you can achieve focus coming from one end and then hitting the target. Tried that but NG. I have faith in Don. Wonder if he can calibrate to compensate for the play. As for a return I am probably S.O.L.. Bot in on fleabay and basically it has been in "repair" for a coupe of months now. I will give that a shot if the lens is deemed defective. thnx

 

[mountainrivera]

Don emailed me and gave me a good overview of the surgery he will be performing today 🙂 He did say it focussed spot on coming from one end. Must have missed that. I am looking forward to using this renown lens.

 

[peter_n]

Well that sounds a bit more promising. Don's a good surgeon 😉

 

[mountainrivera]

Don is the man. Here is the email he sent today. Note that he says he did the work under warranty but have to say that had he saw the amount of work involved I would not have paid what I did the first time he looked - for sure 🙂 He stands by his work as you can see.

Mike,

Your 90mm Summicron lens is now focusing correctly. First I overhauled the focusing system, main thing I did was to replace the teflon grease that Leica now uses on all of their lenses with the original style grease that Leitz used to use on all of their lenses. This original style grease is much better than the teflon grease. Then I overhauled the focusing system that couples to the camera's R/F. This was where the play was & I was able to remove all of the play so now the lens focuses acurately no matter which way the lens is turned. I only ask that you pay for the return UPS shipping which comes to $20.00. The rest I'll cover with my warranty since I should have realized there was play in the focus system the lst time I received the lens. I'll be shipping your lens today.

regards,

Don
DAG

 

[peter_n]

Great - now you can have fun with the lens! 🙂

 

[mountainrivera]

Thanks Peter. Now I will get to see the lens perform 🙂 Hope this thread wasn't a space hog. I wanted to get a well deserved plug in for Don. He is the best.