M Adapter Thickness

Mark, I'll measure mine, I'm mailing it back to Novo tomorrow. Mine is definitely off. On my Summarit-M 50/1.5, infinity is at 25 feet.

The mFT standard is actually 19.25mm AFAIK. I've also seen Leica M listed at 27.95mm.

My measurements show the same -- 8.277mm -- for the Novo adapter thickness.

If µ4/3 flange focal distance is actually 19.25mm, 8.28 + 19.25 = 27.53, which would be a tad short of 27.8, which would explain why the lens focuses past infinity.

Note this post: http://forum.getdpi.com/forum/showpost.php?p=72142&postcount=13

monza said:

Mark, I'll measure mine, I'm mailing it back to Novo tomorrow. Mine is definitely off. On my Summarit-M 50/1.5, infinity is at 25 feet.

The mFT standard is actually 19.25mm AFAIK. I've also seen Leica M listed at 27.95mm.

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The problem is that any lens mount standard, as well as the mFT standard (which isn´t public, it seems) contains far more than just a register distance number. There has to be a tolerance interval as well, since no manufacturer could make a whole series of units exactly similar.

Also, the lens mounts must have their tolerance intervals, for the same reason. And these intervals must be determined in such a way that every lens copy mounted on every body copy, when set at the infinity stop, must have "true infinity" well within the depth-of-field of that lens wide open, even if the body register is at the longest end of its tolerance interval, AND likewise the lens mount is at the "rear" end of its interval.

In addition, when body and lens both happen to fall at the opposite ends of their intervals, the combination must still have "true infinity" within the depth-of-field.

The total allowable variation must then be divided between lens mount tolerance (that depends on focal length and max aperture) and body mount tolerance in a way that gives reasonable economy in manufacture.

So, even if one were to measure one body and a couple of different lenses very accurately, one would still not be sure where they fall within these tolerance intervals. Measuring a large number of specimens and then use statistical methods on the results is what´s needed, and that´s just not realistic.

Thus, ANY third part manufacturer without access to the full standard document must make his product enough on the "safe side" to at least ensure that all his customer´s cameras and lenses can at least focus to infinity; some overshot is less of a problem. And, it seems Novoflex was a bit more on the safe side than strictly necessary.

It´s really no more dramatic than that....

That pretty much sums it up. Better to err on the thin side, but not *too* thin. That does end up sacrificing close focus, which isn't all that close with most M lenses.

Bear in mind that turning the Summarit-M from 25 feet to the infinity setting only moves the lens a fraction of a millimeter.

I just received a Rayqual LM-m43 adapter, before the G1 has shipped, so I can't comment on infinity focus of my Elmarit M 28mm preAsph and Summicron M 50mm tabbed.

The Rayqual unit is very nicely made and fits the lenses firmly. The adapter thickness is a reasonably consistent 8.60mm measured several times around the adapter. This is 1/3mm thicker than the measurement above. Given that the M lenses don't have infinity adjustment, it will be dependent on the adapter to be the right thickness.

The Rayqual (Cameraquest) is reported by back alley to be correct at infinity:

http://rangefinderforum.com/forums/showpost.php?p=981053&postcount=11

8.6+19.25 = 27.85, +/- machining tolerances

Infinity focus of M and Leica thread mount lenses are spot on with the RayQual adapter. No problems whatsoever.

The m4/3rds camera registry is no mystery. RayQual got it. Novoflex did not.
This is what happens if anyone wants to rest on their laurels and do not want to do the work to earn their money.

Vivek said:

Infinity focus of M and Leica thread mount lenses are spot on with the RayQual adapter. No problems whatsoever.

The m4/3rds camera registry is no mystery. RayQual got it. Novoflex did not.
This is what happens if anyone wants to rest on their laurels and do not want to do the work to earn their money.

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Thanks, looks lke I'll be returning my adapter though it's at most an inconvience, better that the lenses focus beyond infinity instead of not far enough. At least with the TTL focussing, you can tell what the problem is, unlike on an M8.

It's an inconvenience with regards to infinity, but as far as close-ups, it can be a real problem. When I first noticed this, it was with a 40 Nokton, and I was trying to take a shot at the close-focus distance. That turned out to be about 4 feet (normally it's about 2.3 feet.)

Interesting. Must be down to how much the lens moves forwards as you go to close focus.

I don't have a 40 Nokton but when I try a pre-ASPH 50mm Summilux with the lens scale preset to 1m, I can focus when the distance to the mode dial index (roughly where the sensor is) is 1.08m away. With the Macro Elmar, which has a longer travel at close focus, it's fine. With a 21mm Elmarit, which hardly moves as you focus, closest focus increases from 0.7m to just over 1m.

I'm returning mine and getting a Rayqual. It messes up focus with my Canon FL 55/1.2 as well, since it uses the M adapter too.

Can anyone provide the return address to send my Novoflex back for replacement?

NOVOFLEX Praezisionstechnik GmbH
Brahmsstr. 7, D-87700 Memmingen / GERMANY
Tel.: +49 8331 88888 Fax: +49 8331 47174

Thanks!

monza said:

NOVOFLEX Praezisionstechnik GmbH
Brahmsstr. 7, D-87700 Memmingen / GERMANY
Tel.: +49 8331 88888 Fax: +49 8331 47174

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Highly unfortunate company name in the circumstances

:thumbs: for them admitting their mistake and offering refunds though

I have a question. Today, I finally got my Novoflex adapter. Looks I too got one from the first batch because the pre asph 50 is on 10 meters when I focus on far away objects which would normally be at infinity. Took a quick testshot with the pre asph 50 Lux, and this is what I got.

First the complete photo, focus is on the red poles in the middle of the frame. f1.4 1/2.500 ISO 125
Second is top left corner 100% @ f1,4 1/2.500
Third is top left corner 100% @ 4,5 1/320

It's the shot full open that worries me... The pre asph 50 Lux is not that bad in the corners, and besides, the crop factor should help here. Never saw anything like this on the M8 or my film M's...

Does anyone know what's going on here? Would this have anything to do with the adapter being off?

Thanks, Peter

yehh...that's an inarticulate test shot(s)...red poles in the middle of the frame? it looks like it was shot through a car window.


Whatever your seeing is not an adapter issue, my opinion.

I am sure you can take a better shot to illustrate the problem.

Y.B.Hudson III said:

it looks like it was shot through a car window.

Click to expand...

Exactly, that's why I posted these.

Here's another one, I focused on the letters on the truck. f1,4 1/1000, same lens, 50 Lux.

yehh, Petery... that looks like veiled lense flair.

1: I would check to see what film mode was selected...standard, soft, etc...

2: use a huge lens hood.

3: atmosperic moisture can mimic veiled lens flair... try a test on a sunny day.

4: I think you will find that...the information is in the file, and that minor adjustments in PS curves and or minor sharpening will give you good results...

regards hudson