New M9 User: Inevitable RF Focus Questions

A

adamjbonn

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I suspect the title says it all really!

Now I'm quietly confident that the overwhelming response here will be "send it in to Leica"

and OK fair enough

BUT

I'm curious about something.... Rather than I think there's a problem

Short version:

Are Leica lenses (SPECIFICALLY the 35mm F2.4 Summarit) able to focus past infinity?

Longer version:

I own 3 lenses

35 2.4 'rit
50 'cron
90 2.5 'rit

ALL OF MY LENSES FOCUS FINE

Min focus / infinity focus

If the RF patch is aligned, the image comes out in focus, and I mean even at a pixel peeping view!

The weird thing (or maybe not hence the question) is that the 35 focuses past infinity both on the RF patch and the resultant file

So in usage - no drama, turn the focus until the images align in the VF and get an in focus picture

It's just weird that the hard stop is past infinity

This might all be in my head... 35mm F2.4 and things that are at infinity don't exactly make superb test candidates... of course stopping down negates everything (and I wouldn't typically shoot infinity wide open anyway)

I've tested min focus with a ruler and tripod and that's spot on

Not being rude about the 35 2.4... but it does feel erm let's say cheaper than my cron (no surprise) and cheaper than my (older 2.5) 90 rit, is this just what's to be expected when one should've saved a few more pennies and got a 35 'cron :D

Let me just reiterate:

When the RF patch says it's in focus it's in focus, (at any distance) it's just that it seems it's possible to focus past infinity, this is NOT a case of my RF patch says it's in focus, but really it's not
 
If everything you want sharp is sharp then leave it alone, send it to Leica and they really make it a problem!
 
My 35 2.5 Summarit-M feels better than my 50 Cron. :).
And if focus tab is on infinity, two images in RF will collate. But. You must look at very far object. Something at another end in the city or at the Moon.
 
I’d say don’t send it anywhere and keep using it. My M9 has never been as good since it had to be looked at. My Monochrom is so much better in the shutter release. You have to have a good reason to let anyone touch your camera.
 
First, you do need to focus on something quite far away to qualify as "infinity".

Second. When you get good focus at infinity, what does the distance scale on the lens say? Is it at the infinity mark?

If the hard stop of the lens is at some point beyond the infinity mark and your focus at infinity (RF images coincide) shows the lens at the infinity mark, then I'd say its absolutely no big deal and your particular lens is able to rotate a bit further than we expect. Not sure why....lower tolerances in the factory? Maybe, but who knows...
 
Richard G said:
I’d say don’t send it anywhere and keep using it. My M9 has never been as good since it had to be looked at. My Monochrom is so much better in the shutter release. You have to have a good reason to let anyone touch your camera.
Click to expand...


It was at the mothership for sensor/cla/rf cal back in October... Just before I bought it

I’m not keen to send it off... besides, what would I say...

“The problem is that when the rf images are aligned, the image is in focus” :D

I think they’d laugh at me!
 
rfaspen said:
First, you do need to focus on something quite far away to qualify as "infinity".

Second. When you get good focus at infinity, what does the distance scale on the lens say? Is it at the infinity mark?

If the hard stop of the lens is at some point beyond the infinity mark and your focus at infinity (RF images coincide) shows the lens at the infinity mark, then I'd say its absolutely no big deal and your particular lens is able to rotate a bit further than we expect. Not sure why....lower tolerances in the factory? Maybe, but who knows...
Click to expand...

Well the infinity mark is quite large, it’s not like aligning a line to a dot

It PERHAPS sits slightly to the far side of the middle of the ∞ symbol but if so very, very fractionately

You raise a good point about infinity, and my first thoughts were that all the things I was thinking were at infinity weren’t

But the 50 and 90 pointed at the same things say they’re in focus at infinity, so I wondered if infinity was the same with all the lenses but then I thought that sounded daft...
 
Ko.Fe. said:
My 35 2.5 Summarit-M feels better than my 50 Cron. :).
And if focus tab is on infinity, two images in RF will collate. But. You must look at very far object. Something at another end in the city or at the Moon.
Click to expand...

My 90 2.5 is on par with my cron... I’m starting to wish I’d got a 2.5 35 too!

Perhaps I’m not finding things far enough away, but the 50/90 has an aligned rf patch on the same subjects, yet the 35 doesn’t
 
davidnewtonguitars said:
I'm still trying to get my head around the "past infinity" part.
Click to expand...

It just means that the lens doesn't come to a stop at the infinity mark, but keep on turning for a distance afterward. Long telephoto lenses are sometimes made that way to allow for thermal expansion that might cause an error if some tolerance were not built in. Leica Rangefinder lenses shouldn't require that, being only 135mm at most. The OP's rangefinder might just be a little off. They can be adjusted DIY with a little care.
 
davidnewtonguitars said:
I'm still trying to get my head around the "past infinity" part.
Click to expand...

When you focus a RF you turn the focus ring until the 2 split images are aligned

When I am focusing on infinity with the 35 the split image will be still be slightly ‘split’ when on the hard stop of the lens

Which might mean that I’m not pointing it something far enough away, except that my 50/90 report the same object is in focus at the hard stop
 
Rob-F said:
It just means that the lens doesn't come to a stop at the infinity mark, but keep on turning for a distance afterward. Long telephoto lenses are sometimes made that way to allow for thermal expansion that might cause an error if some tolerance were not built in. Leica Rangefinder lenses shouldn't require that, being only 135mm at most. The OP's rangefinder might just be a little off. They can be adjusted DIY with a little care.
Click to expand...

When you focus a RF you turn the focus ring until the 2 split images are aligned, from the little I know, the symptom of a misaligned RF is that the split image focusing reports the subject is in focus, but the resultant image is not in focus

I don’t have this problem, when my RF split image is aligned my pictures are in focus, even on the 90

It just seems that my 35 is able to focus past infinity and my other lenses can’t or that I’m not using a far enough away target, except that with the same tatget my 50/90 say that the object is infinity

Of my three lenses, I would expect the 35 to have deepest DOF as it’s the widest
 
having played some more today, I'm starting to think that I've been testing on things that the lens considers closer than 'at infinity'
 
Hmmm, well, um; nothing on this planet is at infinity, neither is the moon, nor any of the planets you can see at night, nor the galaxies you can see at night but one or two stars are near enough for infinity testing; try Antares which is near Mars in the mornings but won't be for long...

Regards, David
 
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