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I think I have read somewhere - but, searching, I am unable to find the thread and so I'm not sure - that it is normal that the aperture blades can be retracted into the barrel a bit beyond 1.4. It's actually quite a bit.

 

Here are two photos of what I mean.

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Many leica lenses do this. I dont know exactly why, but I suspect it has to do with the obsessive overengineering that Leica (thankfully) does. Perhaps the lens is actually f/1.2 or so if measured by for example canons standard?

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... I suspect it has to do with the obsessive overengineering that Leica (thankfully) does. Perhaps the lens is actually 1:1.2 or so ...?

No, it isn't. With the aperture blades fully retracted, the lens speed is 1:1.4. When the blades are visible as they are in Philip's philipus first image above then the effective aperture is 1:1.7 or thereabouts.

 

With my copy of this lens, the aperture blades will retract completely when the aperture ring is set to the 1.4 click stop. The ring can move slighty beyond the click stop but that doesn't affect the position of the aperture blades anymore. If at the click stop the blades are still visible (as in the picture above) and retract fully only when moving the ring beyond the 1.4 stop then the aperture mechanism needs some adjustment.

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No, it isn't. With the aperture blades fully retracted, the lens speed is 1:1.4. When the blades are visible as they are in Philip's philipus first image above then the effective aperture is 1:1.7 or thereabouts.

 

With my copy of this lens, the aperture blades will retract completely when the aperture ring is set to the 1.4 click stop. The ring can move slighty beyond the click stop but that doesn't affect the position of the aperture blades anymore. If at the click stop the blades are still visible (as in the picture above) and retract fully only when moving the ring beyond the 1.4 stop then the aperture mechanism needs some adjustment.

 

Actually, my copy of the 35LUX exhibited the mechanism as shown in the OP's post.

So this is normal.

At 1.4, there is still some blade. If you move the aperture ring, you can go past 1.4 to fully hide the blades, but you'll have to hold the aperture ring there otherwise, if you let go, the aperture ring jumps back to 1.4.

My conclusion is that with the blades showing it's not actually 1.4.

It's more like 1.7

Only when you fully hide the blade will you get 1.4

The difference is so minimal that there is no noticeable in exposure.

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Actually, my copy of the 35LUX exhibited the mechanism as shown in the OP's post.

So this is normal.

At 1.4, there is still some blade. If you move the aperture ring, you can go past 1.4 to fully hide the blades, but you'll have to hold the aperture ring there otherwise, if you let go, the aperture ring jumps back to 1.4.

My conclusion is that with the blades showing it's not actually 1.4.

It's more like 1.7

Only when you fully hide the blade will you get 1.4

 

If this were so, all the other aperture detents would be innacurate, too. The degree of rotation between each 1/2 stop is the same (all the way to f16) including from f1.4 to f1.7. F1.4 is f1.4

 

This phenomenon occurs because of the1-2 degrees of free play in the aperture ring, which is widely known to be too damn sloppy.

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No, it isn't. With the aperture blades fully retracted, the lens speed is 1:1.4. When the blades are visible as they are in Philip's philipus first image above then the effective aperture is 1:1.7 or thereabouts.

 

With my copy of this lens, the aperture blades will retract completely when the aperture ring is set to the 1.4 click stop. The ring can move slighty beyond the click stop but that doesn't affect the position of the aperture blades anymore. If at the click stop the blades are still visible (as in the picture above) and retract fully only when moving the ring beyond the 1.4 stop then the aperture mechanism needs some adjustment.

 

hmm, interesting. out of curiosity, i went to Leica yesterday and asked to see many 35 crons and some luxs to test this, all of them exhibits this further half-click. i dont think its a manufacturing fault. my cron from a year ago also does it.

 

i just simply never used the further click. if Leica decides for widest aperture to some aperture left, then perhaps it is best optically, is what i think. my 50 lux does not do this.

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Is it of any interest, if 1.4 really is 1.4? The DOF scale does not fit to digital sensors, for instance.

One can measure the light with the camera itself and, check if the exposure time tends to differ in the 2 cases.

Jan

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  • 2 months later...

My copy (FLE) also has this feature (not a bug).

01af, you probably have a defective lens :D (jokes apart, which version is it ?).

 

The only reason I can think of, is to create diffraction starbursts even at the widest aperture. And the extra click to fully retract the blades may be - by design - a way to disable starbusts and get a round aperture.

Will need to confirm this theory in practice though. Anybody ?

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With my copy of this lens, the aperture blades will retract completely when the aperture ring is set to the 1.4 click stop. The ring can move slighty beyond the click stop but that doesn't affect the position of the aperture blades anymore.

 

+1

Mine too. Same for my 50/1.4Asph too.

Pete

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Hi Philip. Happy New Year to you!

Based on this (tiny) sample mentioned here there appears to be some small variation possible from lens to lens. I don't think it makes any practical difference. Can you see any variation in the exposure duration (on A) if you test?

I looked at my (2 years old) sample for you and mine has a tiny edge (much smaller than in your photo) just visible at f/1.4 that is gone if I over-rotate the ring just out of the detent.

With my (just returned from Solms service) 50 Summilux-M ASPH the aperture ring will not over-rotate past the f/1.4 detent at all and the blades are not visible at all at that position.

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Hi Geoff! Happy New Year to you too! I can't believe it's almost a year since we saw each other.

 

Thanks for checking your lens. I have not discovered any difference in metering between the two "settings" and also don't think it makes a practical difference. Perhaps under monitored test conditions in a studio it could affect metering a tiny bit but in normal circumstances any difference must be insignificant.

 

I have been considering sending the lens in for check-up because I happened to drop it a few weeks ago :o I'll check my Christmas rolls and if it has behaved, well, unusually then I'll send it in and ask them to have a look at the aperture blades too. Otherwise, I won't because the visible blades don't bother me.

 

My 50 Asph has a little bit of play beyond 1.4 and my 90 Elmarit-M as well. Both are black anodised and don't have visible blades. I also have a chrome 50 pre-asph and that one has almost no play beyond 1.4. All my black lenses have a more "rattly" aperture ring than the chrome, with much more distinct stops.

 

Cheers

Philip

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Philip, presumably your lens is under guarantee. I would suggest making a careful check on focus accuracy in critical conditions as well. I had shot little with mine (early production) that way and actually found that it was back focusing badly. It is fixed now . Maybe if you have any doubts it might pay to check everything carefully and if necessary get it all looked at during that guarantee period?

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