Summicron 35mm f/2 ASPH aperture ring issue

[63strat]

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Today I bought a new chrome Summicron 35mm f/2 ASPH. The aperture ring seems to be a little off. If I select f2, I can still turn the aperture ring past f2 about 1/16 of an inch more, and I can see the blades opening up a little more too. The lens will stay at this wide open setting, which is a little more open than f2, but it's not as secure as when it's parked at the actual f2 marking, and usually doesn't stay there very long. My other lens (Summilux 50/1.4) doesn't do this. Any thoughts? Thinking I'll return it for another one.

[Ecar]

This is a normal design feature - no worries.

[63strat]

Thanks. Does this mean that some lens have this, and others don't (such as my Summilux 50)? Is it dependent on focal length?

[adan]

The "peeping" aperture blades are fairly common.

 

The story is that since Leica fits and adjusts everything by hand, they design some lenses with slightly oversized glass to allow leeway in fitting the metal blades and adjusting them to exactly f/2. (Or so it is said).

 

Presumably you can shoot at the "past f/2" setting and get an "f/1.97" exposure. If you can tell the difference....

 

The aperture rings also sometimes turns a bit past the smallest marked aperture as well.

 

In much the same way, the focusing rings often go beyond the minimum focus distance marked on the lens barrel - but Leica only guarantees focus down to that marked distance.

[Ecar]

Thanks. Does this mean that some lens have this, and others don't (such as my Summilux 50)? Is it dependent on focal length?

 

It's not dependent on focal length but on the design.

My Summicron and Summilux behave exactly like yours in this respect.

[63strat]

The "peeping" aperture blades are fairly common.

 

The story is that since Leica fits and adjusts everything by hand, they design some lenses with slightly oversized glass to allow leeway in fitting the metal blades and adjusting them to exactly f/2. (Or so it is said).

 

Presumably you can shoot at the "past f/2" setting and get an "f/1.97" exposure. If you can tell the difference....

 

The aperture rings also sometimes turns a bit past the smallest marked aperture as well.

 

In much the same way, the focusing rings often go beyond the minimum focus distance marked on the lens barrel - but Leica only guarantees focus down to that marked distance.

 

So if Leica only guarantees focus down to that marked distance, I should not push the aperture ring past f2 to its slightly more open setting because focus might be off?

 

Thx.

[TomB_tx]

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Don't confuse aperture with focus. Although many lenses have some focus shift with aperture, on that lens the slight added aperture will have no visible effect.

[Jeff S]

Although many lenses have some focus shift with aperture, on that lens the slight added aperture will have no visible effect.

 

Certainly not in this circumstance, but note that some 35 Summicron asph lenses shift focus from f2.8 to f4 (my sample as well as Sean Reid's review sample), but this is not a problem in prints. Focus shift is more common on fast wides than some think; the 35 Summilux gets lots of the press in this regard, but the Summicron asph is not immune.

 

Of course this has nothing to do with the OP's aperture ring.

 

Jeff

[63strat]

Great, thanks.

[BrianUK]

My thirteen year-old 35mm Summicron Asph black paint does exactly the same thing... the f2 stop can be turned just past the indent so that the aperture blades do not show.

 

Set properly at f2 the lens actually stops down slightly, so that the blades can be seen intruding just a fraction into the outer edge of the lens.

 

Perfectly normal. Don't worry about it.

[TomB_tx]

Certainly not in this circumstance, but note that some 35 Summicron asph lenses shift focus from f2.8 to f4 (my sample as well as Sean Reid's review sample), but this is not a problem in prints. Focus shift is more common on fast wides than some think; the 35 Summilux gets lots of the press in this regard, but the Summicron asph is not immune.

Jeff

 

Agreed. Every lens I've tested, including all of my Summicron (35 & 50) show some shift from full open to mid-aperture. I notice my 50s from the 1960s are all setup like the current Zeiss Sonnar - with best focus at about f2.8. Most dramatic is my 1960 Summilux. It shifts well over an inch at 1-meter.