Adjusting f-stop on collapsible Elmar

[froyd]

On a collapsible Elmart 2.8 is it normal for the focus to shiftwhen the aperture is adjusted?

Even though the aperture ring moves smoothly, I have to hold the focus tab in place every time I change f-stop otherwise the lens barrel rotates thereby changing the focus.

I cannot imagine the aperture ring being much smoother or turning more losely, which is the only thing I think would allow me to change aperture without simultaneously having to hold onto the focus tab.

Am I overlooking something?

 

[Rob-F]

Yes, that is normal. Set aperture first, then focus! 🙂

 

[David Hughes]

Hi,

Now you know why they all have focus locks... So after setting the aperture you release the lens and focus. Apologies for stating the obvious.

Regards, David

 

[froyd]

so... is this how all collapsible lenses work, or just the older ones?

 

[Steve M.]

They don't all work that way, but it's often a characteristic. My 50 collapsible Summicrons weren't so bad on this. To me, the Elmars work best on a Bessa R2a/R3a etc w/ their AE feature and higher shutter speeds. Just set the aperture, and let the camera pick the speed. Need an adjustment? Hold the AE lock in. Very fast to shoot this way.

 

[ottluuk]

And it isn't limited to collapsibles, either. Old rigid lenses like A36 LTM Summaron 3,5cm/3.5, Elmar 9cm/4 and many others from that era work the same way: the whole front part of the lens rotates while you focus. This may not be obvious if you come from modern (SLR) lenses.

With a meterless camera, it's not much of a problem because you are likely going to set exposure before lifting the camera to eye to focus. Not so nice with a TTL meter, I think.