Testing focus of 90mm Elmarit M

[Michael Geschlecht]

Advertisement (gone after registration)

Helllo Everybody,

 

You can focus on a nail like Christer's, A pen ,a stick or the edge of a brick put by the mid point of the rule. Just remember to have a contrasting color behind whatever you choose.

 

I put the rule flat on the floor even tho that gives me less than a 45 degree angle. Don't forget even w/ a 45 degree angle @ a distance of 10 meters the depth of field will be approximately 1/3d in front & 2/3d's in back of the plane of focus.

 

For me what is important is that the plane of focus is within the range of sharpness. Somewhat imprecise but operable.

 

It may be useful to focus w/ the M rotated 45 degrees counter clockwise looking from behind. The image moves both Up - Down & Left - Right @ the same time. Like an Alpa 6C. During & after focussing you might wiggle &/or rotate the image in the viewfinder both wholly within the focussed patch & across the line of the edge of the patch. If the nail, etc stays coherent the image is in focus.

 

I read the print or slide w/ a 10X jeweler's loupe which I use in my work virtually every day. Not only for grading diamonds & looking @ paintings, prints & slides but virtually everything else. For instance your thumbnail or a nice rock. It's useful for a million different things every single day. You might consider getting yourself a metal framed & covered 18mm, 10X Hastings Triplet, of no special brand, in any Jewelry Supply Store. They are the 50mm Summicron of Jewlers Loupes: The standard of the industry. Sold for less markup than any other.

 

A few points: Get 1 that folds under a hinged cover & becomes a small device that easily fits in any pocket. Keep it w/ you all of the time. Dull black is less conspicuous.

 

Don't pay anything for a cover, usually leather. They all fall apart in a short time in your pocket. If they give you 1 for free, never pay for 1, use it for something else or give it to someone else.

 

Look @ 5 or 6 of them - it is expected - all will have sharp centers. Pick the 1 which has the sharpest image in the edges all of the way around. Just like a camera lens.

 

BTW: every 15 or 20 years the glass elements - only buy glass. No plastic no matter what they tell you - may need replacing. The ring @ 1 end unscrews - that's how they got it in - & you can relpace the lens yourself w/ 1 you get in the same store then.

 

These are meant to ride in your pocket forever & be just fine.They are not coated so you can clean them gently w/ your soft shirt or a soft handkerchief, etc.

 

Back to M's.

 

Why F11? To know the depth of field.

 

Also: Please remember: Even w/ all the attempts by Forum Members & Others to help I still don't know how to put a picture in the computer.

 

Best Regards,

 

Michael

[Advertisement]

The Leica Q3 is available for pre-order at B&H Photo Video and Adorama

[luigi bertolotti]

Not exactly a Leica site.... ... but Tim Jackson Focus test chart, downloadable ready for A4 print at Home is imho a good tool, very useful also for DOF and focus shift evaluations at distances up to 5-6 meters (depending on lens) : I even upsized it to A3 for using with 135mm (of course, the measures on it must be also upsized, pen or Photoshop if one likes... )

[ho_co]

Good to see we think alike, Luigi! Same chart I recommended in post #8 above.

[algrove]

It's great to have the 90 Elmarit-M with 6-bit code and factory calibration document. Can only help if someone has to pry it away from me in China!!!

Well, let's hope if someone tries that and gets it , that they at least pay you first. Just remember, someone keeps saying here , "never sell Leica glass."

 

Back to the coding issue. I must say after using so much Zeiss glass with all the hand coding I have had to do, it is a real pleasure to just switch Leica lenses and not have to remember to either manually set the lens info or make sure your hand coding is still effective.

 

I think I will slowly get Leica to code most of my older Leica glass, if possible.

 

Have been trying ISO 1250 at 1.4 and sometimes 2.0 (trying to keep my speeds around 250 or better whenever possible) , and the noise (grain to an old fart like me) is very evident to someone that has never strayed from ISO 160 on my M9. But, with the night street scenes I have been shooting in the cold here (it's like 4 degrees tonight), I must say the results actually please me. Never thought I would say that.

 

Sorry I strayed from the topic a bit.

[LeicaPassion]

I need to send in my 90 summicron, 50 lux and M9 for focus adjustment. Should I also send in my 35 f2 and 24 f3.8? Right now, they are perfect. Thank you.

[StephenPatterson]

As is often reported on this forum Leica does not calibrate lenses to specific camera bodies. Instead lenses are calibrated to the factory standard and tested on factory owned M9s that are known good, "in calibration" units. The only reason Leica ever requests a person send a camera and a lens together is to ensure that a focus problem is properly identified and corrected, thus eliminating multiple shipments to identify the root problem.

 

If your 35 Summicron and 24 Elmar are, as you say, performing perfectly I'm at a loss as to why you would consider sending them to Leica.

 

Stephen