Need advice with respect to Leica CS and visible aperture blades in Summilux 35 FLE

[philipus]

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In this thread, I described that my 35 Summilux FLE has very visible aperture blades at f1.4. Several owners reported similar behaviour on their copies of the lens.

 

I have now received an estimate from Leica CS where it is claimed that the "Aperture blades are normal caused by construction". I take this to mean that the visible blades is by design. Personally, I have big difficulties understanding how a lens would properly be designed to have parts of the blades show wide open.

 

What I am now wondering is, how can I persuade Leica to adjust this lens on warranty regardless of whatever they believe is "by construction"? I really wish to have it adjusted. I have several other M lenses and none of them exhibits this behaviour wide open.

 

Has any other owner of this lens had to fight this battle with CS? If so, I'd really like to hear your experiences.

 

Thanks in advance

Philip

[earleygallery]

If the design of this lens is such that the edges of the blades are visible wide open, what do you expect Leica to do about it?

[Dr.KOL]

In case the visible blades have no influence on IQ, then what?

 

Constructive regards,

kol

[Erik Gunst Lund]

There is a huge difference in what you are able to 'see' and what the light 'see' as it enters/passes into the lens and is formed on the sensor/film.

 

Just compare what you see when looking from the front with you see from the rear of the lens...

[philipus]

Naturally all valid points above, thanks.

 

The bases for my concern were 1) that my other M lenses don't exhibit this behaviour, and 2) my assumption that wide open means no visible blades.

 

I spoke with a very friendly gentleman at CS who explained that, provided the f1.4 aperture has the minimum diameter as required for that stop, it is all right that the blades are visible. I don't know how that diameter is measured, or where it is measured, but I suspect it isn't measured at the location of the aperture blades. If that were the case, given the lens-to-lens variation in how much the blades show (if at all), then f1.4 would, logically, vary from lens to lens.

 

I haven't encountered image quality problems but wanted to have the lens checked since my warranty is about to expire. In the end, having heard to the CS rep's explanation, I decided to let the lens be as it is.

 

Philip

[wattsy]

Yes, I don't think there is any reason for concern. I hadn't noticed until this thread but my example of this lens is similar to your's. At F1.4 you can just see the blades forming a nice neat circle (interestingly, if you push the aperture ring beyond the F1.4 detent the blades do indeed completely disappear). I had a quick look at my other three lenses and two have visible aperture blades at widest setting (28 Summicron and, much more obviously, 50 Summarit).

[01af]

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There are several lenses where the apertures blades purposefully don't retract fully at the widest aperture setting. Among the Leica M lenses, these include the Summarit-M 35 mm and 50 mm 1:2.5 lenses. I also have a few non-Leica lenses which are like this—mostly zoom lenses.

 

Of course, it is always possible that, for some lens, the aperture blades are supposed to retract fully but don't due to some defect or misadjustment. In this case, image quality would not be affected in any way but the usable lens speed would be slightly reduced from the nominal value.

 

The Summilux-M 35 mm Asph seems to belong to the latter category. In my sample, the aperture blades will retract fully. However ... not at the "1.4" click-stop but only when I move the aperture ring slighty beyond the click-stop, just like Ian wattsy Watts described it above. Still, the difference is minuscule and will hardly make a perceptible difference in exposure.

 

If in your sample the difference is significant then customer service should be able to fix this.

[BrianUK]

My thirteen year-old Summicron-M f2 35mm ASPH does this, too (aperture blades showing at the widest f-stop - f2 - and disappearing with a slight turn of the aperture ring past f2 as far as it will go).

 

Every other Summicron-M f2 35mm ASPH I've seen and handled has done the same thing. Guess it's designed this way. Or not.

 

Either way for the last thirteen years it hasn't made one bit of difference to the exposure or images.

 

Maybe I'm wrong (how would I know?)... but I'm not going to get it checked out.

[Rick]

It is normal for the new FLE 35-Rattler's blades to not fully retract. This is apparently not a lens for the obsessive.

[MarkP]

It is normal for the new FLE 35-Rattler's blades to not fully retract. This is apparently not a lens for the obsessive.

 

[fussgangerfoto]

I noticed the same with my v4 35mm 'cron (that the blades do not fully retract when wide open). The only effect on image quality is when there is pinpoint light (bokeh candidate) in the center of the field of view and I am close-focused. Under those circumstances, even wide open, the bokeh has a slight tell-tale shape of a stopped-down lens (stop-sign effect). Just a few degrees off axis and the bokeh is perfectly round.

 

This is a 100% crop of a shot at f/2 that shows the effect.

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[250swb]

It is probably only a concern to people who don't want their photographs to look like they were taken with a camera.

 

Steve

[microview]

Exchange for the Zeiss 35 1.4 ZM if it worries you. :D

[dugby]

Yes, I don't think there is any reason for concern. I hadn't noticed until this thread but my example of this lens is similar to your's. At F1.4 you can just see the blades forming a nice neat circle (interestingly, if you push the aperture ring beyond the F1.4 detent the blades do indeed completely disappear). I had a quick look at my other three lenses and two have visible aperture blades at widest setting (28 Summicron and, much more obviously, 50 Summarit).

 

 

Wow ..... I guess one could rename this 35mm to Noctilux-M FLE ;-)

[jrh68uk]

Yes, I don't think there is any reason for concern. I hadn't noticed until this thread but my example of this lens is similar to your's. At F1.4 you can just see the blades forming a nice neat circle (interestingly, if you push the aperture ring beyond the F1.4 detent the blades do indeed completely disappear). I had a quick look at my other three lenses and two have visible aperture blades at widest setting (28 Summicron and, much more obviously, 50 Summarit).

 

Same with my 35 FLE. I was initially slightly concerned but it's really a non-issue. The one that still does concern me a little is my 21mm Elmarit ASPH which shows quite a lot of blade-age at f/2.8. I'm led to believe that it's normal for this lens but I have to wonder why they designed it with the blades as closed-down, relatively speaking, as they are at f/2.8. Incidentally I've tested it for metering and it seems fine but I do wonder why it's been designed that way and not allowed to open up more.

[Erik Gunst Lund]

What you can see looking into the lens with your eyes is very different to what happens to the light passing through the lens to hit the sensor/film! No mystery here - Sorry