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Archive 2012 · Mechanical qualities of lenses
  
 
jotdeh
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p.1 #1 · Mechanical qualities of lenses


I would like to know what mechanical issues you have come across from different manufacturers, or with lenses in general.

For example I find that OM Zuiko lenses typically collect an incredible amount of dust, even for non-FLE prime lenses. I assume all this dust enters through the iris / aperture mechanism... any idea why it seems more severe with OM than other brands, like Zeiss?

Or, when I was trying out ZE lenses, specifically the 21 and 100MP, I noticed that the focus damping was a lot stronger on the MP. That seemed annoying and going against what I think would be preferable. Namely that the lens with short focus throw must be damped more to allow precise focusing, or vice versa, the lens with long focus throw must be faster (less damped).

Do you have other observations about certain lenses? Oh, aperture rings that don't stop hard at the ends are really annoying and feel cheap, too, imo.

To rephrase:
What qualities (beyond pure IQ) do you expect from modern high-end lenses?



Aug 03, 2012 at 09:37 AM
Makten
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p.1 #2 · Mechanical qualities of lenses


I haven't really had any issues, but since I started out with Nikkor lenses when I "went manual", I've been very surprised by how much worse the build quality of other brands is. I was under the impression that Nikon just had the standard high quality of manual focus lenses overall. But when I pick up a Konica or OM lens, they feel really crappy compared to the Nikkors.

I'm with you on the damping and focus throw, but the 100 MP does have a very short throw in relation to focus distance. It seems "long" just because you can focus close, while much shorter at the long end than many other 100 mm lenses, if you understand what I mean.



Aug 03, 2012 at 10:12 AM
AhamB
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p.1 #3 · Mechanical qualities of lenses


My Mamiya 645 APO 200/2.8 seems to be the best sealed lens I have. I see maybe one dust particle inside. It doesn't have a perfect build though because it's quite front-heavy and while the focus damping is quite light when pointing the lens up, it has a lot more resistance when keeping the lens horizontal.

Another thing: as far as aperture rings go, I've found the Contax (C/Y) ones the nicest and Olympus OM one of the worst (a lot of rattle).



Aug 03, 2012 at 10:46 AM
jotdeh
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p.1 #4 · Mechanical qualities of lenses


Yes I understand Makten, it's a good point! I think from my first (and only) impression of handling the 21 I felt that it should be damped more.

I noticed the rattling of the aprture ring on some OMs too, specifically a 100/2.8 was really awful in that respect.

The balance of a lens is an interesting aspect, too. I think ideally the mass is concentrated towards the mount. If that is not possible because of the optical design for example, then the focus/zoom should be close to its center of gravity for more stable hand holding.

The higher focus resistance when holding the lens horizontally could stem from a relatively large gap between the mating helicoids, and the parts then wedging at the front and back. This is something I will look at when I go home and test on my longer lenses...



Aug 03, 2012 at 11:25 AM
Makten
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p.1 #5 · Mechanical qualities of lenses


Note that the resistance gets tougher with a short trow, because you have to move the barrel more with less turning. So it doesn't have to be an engineered feature.


Aug 03, 2012 at 11:31 AM
jotdeh
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p.1 #6 · Mechanical qualities of lenses


Makten wrote:
Note that the resistance gets tougher with a short trow, because you have to move the barrel more with less turning. So it doesn't have to be an engineered feature.

Yes! However assuming the same grease layer thickness:
Short FL requires the barrel to move less for focussing from magnification A to B than the long FL.
The helicoid will therefore likely be shorter on the short FL --> less area over which the grease is in shear --> less resistance.
Maybe work (force x distance) for focussing between two magnifications should be kept equal across different FL lenses to yield a uniform user experience, and allow similarly precise focusing? This could be achieved by using greases with different viscosity, or by controlling the area over which the helicoids mate; changing the layer thickness would not desirable as that may cause the wedging AhamB observed in the Mamiya 200 Apo. Does that make sense?



Aug 03, 2012 at 11:51 AM
JohnJ
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p.1 #7 · Mechanical qualities of lenses


I've never been a fan of Nikon lenses only because they almost always develop a lot of play in the helicoid (I'm talking about Ais vintage gear). I just don't like play in the helicoid, it's a bit of a show-stopper for me.

I've had mechanical problems with Leica R as much as any other gear that I've owned, but I've been using Leica R for about 20 years now, so that's OK.



Aug 03, 2012 at 12:07 PM
jotdeh
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p.1 #8 · Mechanical qualities of lenses


What play do you see in the Ais's helicoids? Front-to-back or tilting? Any idea how it develops?


Aug 03, 2012 at 12:12 PM
JohnJ
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p.1 #9 · Mechanical qualities of lenses


jotdeh wrote:
What play do you see in the Ais's helicoids? Front-to-back or tilting? Any idea how it develops?


It's side to side, so when you make minor focus adjustments you have to account for the play.



Aug 03, 2012 at 12:22 PM
jotdeh
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p.1 #10 · Mechanical qualities of lenses


So it changes your framing? That's annoying!


Aug 03, 2012 at 01:03 PM
 

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Jman13
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p.1 #11 · Mechanical qualities of lenses


Makten - I'm surprised to hear you say that about Konica lenses, but I guess you are coming from their cheaper offerings. I have the Hexanon 40/1.8, 50/1.7 and 57/1.2. While the 40/1.8 and 50/1.7 are unremarkably built, the 57/1.2 is one of the most solidly built lenses I've ever seen. It literally feels like it's carved out of a solid block of brass. The higher end Konica lenses are tanks...though they didn't extend that throughout the line like Nikon did with their AIS lenses.


Aug 03, 2012 at 01:19 PM
redisburning
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p.1 #12 · Mechanical qualities of lenses


Makten wrote:
I haven't really had any issues, but since I started out with Nikkor lenses when I "went manual", I've been very surprised by how much worse the build quality of other brands is. I was under the impression that Nikon just had the standard high quality of manual focus lenses overall. But when I pick up a Konica or OM lens, they feel really crappy compared to the Nikkors.


funny, I've found just the opposite when comparing AIS Nikkors to OMs, especially the older silvernose ones.

the late 55/3.5 has one of the worst build qualities I've seen on a vintage lens, the only OM lens I've ever had with that same build were the two late 50/1.8s I've owned. Either are still miles ahead of the cheap lenses made today. The 105/1.8 was quite a bit better but still I'm not a fan of the enamel.

Best lenses I've personally got are the metal ring rokkor 58/1.2 and a silvernose zuiko 50/1.4; the ZM 50 is alright but I don't really believe it's got that sort of life in it. Looking closely, it seems a little bit sloppy. Much better optics though, lol.



Aug 03, 2012 at 01:50 PM
Keith B.
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p.1 #13 · Mechanical qualities of lenses


jotdeh wrote:
What play do you see in the Ais's helicoids? Front-to-back or tilting? Any idea how it develops?


It develops because Nikon was too cheap to build the helicoids out of true dissimilar metals, like Al vs. brass. Instead, they went with--in most but maybe not all of their Ai/AiS lenses---Al vs. Al, claiming that making the two mating surfaces out of different Al alloys qualifies as "dissimilar". In order to cover up the fact that two similar metals gouge each other's surfaces if they really come into contact, they slather in extra grease. When the grease evaporates, the metals start gouging against each other. This causes lots of free play to develop in the helicoid.
If the helicoid is operated a lot without it's required cushion of grease, the two similar metals grind each other away at a much faster rate than dissimilar metals would have. If the lens is really far gone, even new grease won't get rid the damaged helicoid feel in the focus.

Supposedly the side-to-side 'juddering' in properly designed lenses can be adjusted by a service tech, but I don't know if this applies to the Nikon Ai/Ais lenses, like my 28/2.8 AiS that has the judder.

On the original topic, my big complaint about the Zeiss ZF lenses I have would be the half stop detents on the aperture rings. Here is one area where Nikon got it right: Detents at the full stops only, COMBINED WITH the ability to set the aperture anywhere in between the full stops.



Aug 03, 2012 at 07:54 PM
AhamB
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p.1 #14 · Mechanical qualities of lenses


I've had a ZF 25/2.8 for a brief period and didn't like the ergonomics of the aperture ring, tbh. A bit too much resistance and it wasn't easy to get a good grip on.


Aug 03, 2012 at 08:09 PM
sebboh
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p.1 #15 · Mechanical qualities of lenses


Makten wrote:
I haven't really had any issues, but since I started out with Nikkor lenses when I "went manual", I've been very surprised by how much worse the build quality of other brands is. I was under the impression that Nikon just had the standard high quality of manual focus lenses overall. But when I pick up a Konica or OM lens, they feel really crappy compared to the Nikkors.

I'm with you on the damping and focus throw, but the 100 MP does have a very short throw in relation to focus distance. It seems "long" just because you can focus
...Show more

i'm always curious to hear what other people think of the build of manual focus lenses. i'd put nikon about in the middle of the pack here. from best to worst build i would probably make this ranking (going by the best eras of each):

1) leica R (though there is a bit of variability, i've never handled anything that could top the build on there telephotos)
2) rokkors (MCs with metal focus rings are the ones i'm thinking of > rubber MCs > first MDs>>> late plastic MDs)
3) takumars (again metal focus rings versions > rubber > pentax K and M >> A)
4) nikkors (old metal focus rings > AI >> AIS)
5) canon FL (FD was not as nice and nFD was much worse)
6) Z* current zeiss/voigtlander lenses
7) c/y zeiss lenses
8) olympus OM
9) konica hexanon (as Jman mentioned their best lenses are very nice but the cheap ones not so much unlike OM lenses, which were pretty uniform in build)
10) yashica



Aug 03, 2012 at 08:28 PM
LightShow
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p.1 #16 · Mechanical qualities of lenses


SOLID BEAUTIFULLY MADE:
Minolta Rokkor MC's(metal)
Super-Taks
Canon RF(silver all brass)
Yashica Tominon(pre C/Y bayonet)

WELL MADE:
Leica R(based off 24/2.8)
Canon FD/FL
Nikkor (metal focus ring)
CV
Konica
Olympus
Topcor
Yashica C/Y
Cosina made CZJ

CHEAPER MATERIALS, LESS ATTENTION TO DETAILS:
Minolta MD
Contax C/Y(based on AEG 50/1.7)
nFD
Ai/Ais
Pentax K mount



Aug 03, 2012 at 08:59 PM
freaklikeme
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p.1 #17 · Mechanical qualities of lenses


sebboh wrote:
i'm always curious to hear what other people think of the build of manual focus lenses. i'd put nikon about in the middle of the pack here. from best to worst build i would probably make this ranking (going by the best eras of each):

1) leica R (though there is a bit of variability, i've never handled anything that could top the build on there telephotos)
2) rokkors (MCs with metal focus rings are the ones i'm thinking of > rubber MCs > first MDs>>> late plastic MDs)
3) takumars (again metal focus rings versions > rubber > pentax K and M
...Show more

Interesting. What's the criteria? If it's durability, I'd put Zeiss ZE/F/etc ahead of the CV SLR lenses. The delta there isn't as wide as say between ZM and CV RF lenses, but it's there. It sounds strange to say it, but I'd feel better about my chances of having a useful lens after I dropped a ZF 50/1.4 than I would if I dropped a Nokton 58.

OM's probably in the right place for the line average, but the sub-90mm primes tend to be built like tiny little tanks. They don't provide the best feedback or overall user experience, but they are tough to break.



Aug 03, 2012 at 09:20 PM
jotdeh
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p.1 #18 · Mechanical qualities of lenses


It has been a while since I handled a Takumar (50/1.4) but that one really was good... though at the time I didn't have anything to compare it to.

I handled a copy of an R 35-70 3.5 (or 4?) and just noticed that the zoom ring was incredibly hard to move. Haven't really tried enough to judge them...

Thanks Keith for the explanation, good stuff!



Aug 03, 2012 at 10:23 PM
sebboh
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p.1 #19 · Mechanical qualities of lenses


freaklikeme wrote:
Interesting. What's the criteria? If it's durability, I'd put Zeiss ZE/F/etc ahead of the CV SLR lenses. The delta there isn't as wide as say between ZM and CV RF lenses, but it's there. It sounds strange to say it, but I'd feel better about my chances of having a useful lens after I dropped a ZF 50/1.4 than I would if I dropped a Nokton 58.

OM's probably in the right place for the line average, but the sub-90mm primes tend to be built like tiny little tanks. They don't provide the best feedback or overall user experience, but
...Show more

overall criteria is feel of durability, strength, and precision of movements. i can't speak for actual durability as i've only owned one of most lenses (and i tend not to drop them), a large sample size is necessary to really know about durability. also, there might be internal weaknesses that i'm not aware of and haven't manifest themselves yet (though doubtful as i've disassembled a lot of my lenses).

i grouped the Z* and CV lenses on the assumption that they use similar materials, parts, and construction (though obviously the zeiss lenses are designed to a higher price point). the only CV lens i've actually held was the 180/4.

the OM lenses get low marks for thinner flimsier metals than many other manufacturers, less rugged optical assemblies, and rubber grips that easily get stretched out.



Aug 03, 2012 at 10:37 PM
carstenw
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p.1 #20 · Mechanical qualities of lenses


I would rate the manual lenses I am thoroughly familiar with as follows:

1) Modern Leica R/M (older stuff is less good)
2) High-end Voigtländer SLR lenses like the CV125
3) ZF/ZF.2/ZM lenses
3) Old Nikkors (pre-AI, then AI, then AI-S)
4) Olympus (they are not bad, you can just tell that they were built for low weight)

I am not really familiar with Rokkors and Takumars, although I have handled a Rokkor 58/1.2 and it felt good, but more heavy than strong. For outright quality, I would rate it about like the AI lenses.

3 and 4 could swap, depending on what you measure. The Nikkors are more robust, but the Zeiss lenses feel better when they are in good shape. In fact, for robustness, the Nikkors could probably move to slot 2.



Aug 03, 2012 at 10:38 PM
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