M8 and Summicron 75 Focus

[Seeingeye]

Advertisement (gone after registration)

Last year I purchased a second hand Summicron 75 which initially seemed to be OK. I did not use it much until recently, when I realised that it is actually back focussing a bit and does not focus properly at infinity, even when stopped down.

 

When I spoke to the dealer, I was advised that this is a known problem with the Summicron 75 and M8 and it would need to go to Leica for adjustment.

 

Can anyone here corroborate this statement?

 

It does raise the issue of why the dealer did not check for this before I bought the lens or establish if I was using a M8 at the time of purchase, but that is another matter.

 

Mike

[adan]

My local camera store has a used 75 'cron with the same issues - it is at Leica now for adjustment.

 

The amount it was off, it would have been off with any camera, not just an M8 issue.

 

I actually tried to buy this particular unit 2-3 times - each time it was on at some distances and off at others. I finally did a controlled test on two separate M8 bodies against other M teles (90 and 135) and it was clear that this particular sample of the 75 was just not "right" - focusing "beyond" infinity when set according to the scale/stop. And also not delivering the full resolution I've seen from other samples of the 75 'cron.

 

I suspect the floating element is at the heart of the issue. It means Leica has to collimate and calibrate two separate lens/helical movements throughout the focus range.

 

A FE is, in effect, making minute changes in the lens' focal length as focus changes, and if the FE is tracking badly, the light will not be following the calculated paths, producing not only bad focus but also introducing aberrations as the FE is in the "wrong" place at any given focus setting.

 

In an SLR, so long as the screen, sensor/film, and/or AF cell are correctly aligned, an image focused on one will be focused on the other, regardless of how accurate the lens-to-camera linkage is (the lens can even be at the end of a long bellows with NO direct linkage).

 

In the focus-by-proxy rangefinder world, if the optics are not doing exactly what the cam on the back is "telling" the RF they are doing, the results are garbage.

[Seeingeye]

Thanks, Andy.

 

Makes me wonder if it could have left the factory like that or whether there is an inherent design flaw that allows something to move inside the lens after manufacture?

 

Mike

[Paul_S]

I had a new S'cron 75 for my M8 and it had considerable back focus. After adjustment (lens + camera) in Solms it was front focussing. I sold the lens. Fortunately I have a S'lux 75 which is focussing dead on (after adjustment with camera in Solms).

[adan]

THAT is a good question - to which I have no answer. However, given that this seems to be a rare event that also seems to be very consistent when it does occur, I'd lean towards factory slip-ups.

 

If this was something that could happen to any 75 ASMA after leaving the factory, I'd expect to see more examples cropping up after 4 years in the marketplace. Also the fact that it appears to require significant "adjustment" - rather than, say, just tightening a retaining ring or element that has come loose, seems to point to mismanufacture rather than misdesign.

 

I'm thinking of the 35 'cron V.4, which used a plastic retainer that would eventually break, allowing the front elements to unscrew, if unmounted often enough using the lens shade for leverage - or the 90 Tele-Elmarit-M, some of which developed a glass disease over time. Those were obviously design-induced deteriorations that affected more and more lenses as time went on.

 

But I'm no expert in "failure theory".

[rycm]

Well I know of the back focus issue on my 35mm lux, fearing the same for the 75lux, I decided to try the 75 summarit. And Wow.. it's a sharp lens, and easy on the pocket. I use it with the 4x viewfinder magnifier. It helps with the focus.

[sarav]

Advertisement (gone after registration)

I had same problems with 75 'cron. After purchasing 24 'lux I sent to Solms M8 and all the lenses I own. When returned all lenses spotted perfectly from 70cm. to infinity. 75 'cron when perfectly focussed is unbelievable. No other lens match it!

 

I think there was some manufacturing issues because my 75 'cron returned with the screwed brass part slightly cutted.

[scaryink]

Gosh, I thought only the lowly CV lenses are sold with such blatant variations in quality control ?

 

According to a whole lot posters here, the Leica lenses are far far superior to all others and are simply perfect 100% of the time? Thats why people are willing to pay many times the cost of comparable CV or Zeiss lenses.

[offshore]

I bought a second hand cron from a guy in Canada off eBay and have had no focusing issues with it on my M8. He had also used it for a movie set portrait shoot on his M8 and had no issues with it. Interesting the variations of focusing issues on this forum I don't recall ever hearing back or front focusing as a term until I came here.

[volkerhopf]

Hi,

I bought a new 75 Summicron 2 month ago and had tremendous problems focussing. I first thought it was me but when I had no problems to focus a 135 Elmarit I decided to send it back to Leica for adjustment. I should get it back in about three weeks (hopefully).

Regards

Volker

[Jeff S]

I have a 75 cron that had some focus issues (and a loose aperture ring), so I ended up sending it, my M8.2, and 3 other lenses to NJ to be inspected and adjusted as a system. I just got the lot back today...only 2 weeks after I sent it in...very impressive. Can't wait to check it all out when the thunderstoms clear.

 

I did note, however, that the aperture ring on the 75 cron still doesn't lock in as crisply on detents as my other lenses. Anyone else experience this?

 

Jeff

[Seeingeye]

I have a 75 cron that had some focus issues (and a loose aperture ring), so I ended up sending it, my M8.2, and 3 other lenses to NJ to be inspected and adjusted as a system. I just got the lot back today...only 2 weeks after I sent it in...very impressive. Can't wait to check it all out when the thunderstoms clear.

 

I did note, however, that the aperture ring on the 75 cron still doesn't lock in as crisply on detents as my other lenses. Anyone else experience this?

 

Jeff

 

Thanks to everyone who has responded. The aperture ring on my lens does go beyond the f2 setting and the whole lens assembly is a little loose, which might explain part of the problem I am experiencing.

 

I was at my local dealer today (not the same shop that sold me the 75), who supplied someone with a new M8.2 and Summicron 75 a couple of weeks ago. The camera has had to go back to Germany as a fault on the mount meant it was imposible to attach a lens without using a wrench! One does wonder how it got out of the factory like that. Not a good introduction to the M system.

 

And in case anyone is wondering about just having a Summicron 75 as an only lens being strange, it appears that the Summicron 28 is on back order.

 

Like Volker and Jeff, it looks as though my own Summicron 75 will be heading back to Leica as well to see if anything can be done for it. Otherwise I simply have a very expensive paper weight. Let's hope we all get the same result as Sarav.

 

Mike

[akiralx]

I have a 75 cron that had some focus issues (and a loose aperture ring), so I ended up sending it, my M8.2, and 3 other lenses to NJ to be inspected and adjusted as a system. I just got the lot back today...only 2 weeks after I sent it in...very impressive. Can't wait to check it all out when the thunderstoms clear.

 

I did note, however, that the aperture ring on the 75 cron still doesn't lock in as crisply on detents as my other lenses. Anyone else experience this?

 

Jeff

 

Every Leica lens I have has a loose aperture ring compared to both my Zeiss lenses. Whatever superiority Leica has it certainly isn't build quality.

[DBAUDUI1]

I have a Leica M8 with ELMARIT 21mm ASPH, SUMMICRON 28mm Asph, SUMMICRON 35, SUMMICRON 50, SUMMICRON 75 ASPH, SUMMICRON 90 ASP, MACRO ELMAR 90 and never had any backfocusing isse with any of my lenses. I use the 75 SUMMICRON extensively wide open, as I prefer to catch movements sharply (dancig people on stage for example) and it works as a dream. Very sharp and exactly focussed where I want. Build quality of these lenses is TOP. That is my experience with Leica so far (30 years already...), both on M6 and M8.....

[UliWer]

When I tested the 75mm Summicron at f 2 I sometimes had a very slight back-focus and other times a very slight front focus - both only to be seen on a 200% crop. So i believe it is rather spot on in reality, and my eyes are the problem.

 

Otherwise I never get those different results with my 90 mm Summicon AA fully opened, which should be more critical to misfocussing in theory. I think the long ways you take to focus the 90 mm is helpful for critcal situations while the narrower focussing turns the 75 mm allows cause more problems in practize.

[norm_snyder]

Perhaps I've been lucky, but I picked up a near mint 75 Summicron a few months ago and was able to get it at a great deal, because on the bottom of the nonmovable part of the barrel it had an abrasion through the anodized black finish about 1.5mm in length. Otherwise it was mint. I suspect it had been in a bag and got a signficant jarring from some other gear. This saved me hundreds, it focuses perfectly and is probably my sharpest lens. I use it extensively for club and stage photograpy, mostly wide open. Perhaps there is sample variation, as others have observed, but this lens seems very solid to me.

[ampguy]

The Leica 75's is the one lens that I purchase only a specific version of (German Lux). Only version that focuses spot on for me, out of the box on M8, M-film, and RD1s.

 

 

Perhaps I've been lucky, but I picked up a near mint 75 Summicron a few months ago and was able to get it at a great deal, because on the bottom of the nonmovable part of the barrel it had an abrasion through the anodized black finish about 1.5mm in length. Otherwise it was mint. I suspect it had been in a bag and got a signficant jarring from some other gear. This saved me hundreds, it focuses perfectly and is probably my sharpest lens. I use it extensively for club and stage photograpy, mostly wide open. Perhaps there is sample variation, as others have observed, but this lens seems very solid to me.