close focus blurr Biogon 28

[peewee]

I recieved a used 28mm Biogon yesterday. I like the lens a lot.
However at closest focus distance @ 2.8 the subject is a total blurr and does not sharpen up completely until either the distance is 1m or set to f8.
Is this usual?
Thanks in advance🙂

 

[Moriturii]

Sounds like your rangefinder isn't calibrated to the lens. If you focus very close, say 1m, your rangefinder might make it to 1.1m or something you know. I had this problem with my Hexar RF, took me about 30 minutes to fix it though and works good now. Which camera are you using? Is your camera working fine at close distances with other lenses?

 

[Photon42]

I know it may be an obsolete question, but are you sure you've focussed properly? If in doubt, take a easy-to-focus subject. E.g., if you were to focus a piano keyboard, it is easy to get one key off with a rangefinder. All that may not apply to you, of course. At close distance, all possible errors are most visible, be it user or tool.

 

[peewee]

Thanks a lot for your replies.
I'm using an M9. My other lens, 50 lux asph calibrated with cam by Leica focuses perfectly.
I'm pretty sure the focusing is accurate, results render dark clear lettering as unreadable.
Again, Thanks
Lucy

 

[palec]

You can still measure the distance with tape (from camera body to focus point) and compare it to distance marks on lens barrel. If those match and results are not in focus, the problem is in the lens.

 

[Doug]

I recieved a used 28mm Biogon yesterday. I like the lens a lot.
However at closest focus distance @ 2.8 the subject is a total blurr and does not sharpen up completely until either the distance is 1m or set to f8.
Is this usual?
Thanks in advance🙂

Hi -- The Biogon's closest focus distance is 0.5m, whereas the M9's RF can track focus down to about 0.7m. So there's a small range from 0.5m to 0.7m where the camera's RF patch doesn't move at all.

So, this close focus can be handy with the lens adapted to something like a micro-4/3 camera, but on an M type RF camera you have to be watchful for the de-coupling point. Any focusing closer than ~0.7m should be judged carefully by eye or tape-measure.

And, yep, this is normal for several wide Zeiss ZM lenses.

 

[peewee]

Thanks a lot. Today I will get out the tape measure and do some tests.
I took some shots with the lens yesterday that I'm pleased with. I like the rendering of the lens which seems to have a slightly more subtle zeiss pop and colour than other Biogons I've used..It's nice.
Lucy

 

[Doug]

When using tape measure to focus, keep in mind you're trying to get the distance from the sensor to the subject. Some cameras have had a film-plane mark on the top as a handy measuring point, but the Leica M's don't... On the M9 your measuring point should be about the center of the hot shoe...

Probably easier to measure to the front surface of the body and then add an inch. 🙂 (lens flange to sensor distance is 27.8mm)

 

[Ljós]

When using tape measure to focus, keep in mind you're trying to get the distance from the sensor to the subject. Some cameras have had a film-plane mark on the top as a handy measuring point, but the Leica M's don't... On the M9 your measuring point should be about the center of the hot shoe...

Probably easier to measure to the front surface of the body and then add an inch. 🙂 (lens flange to sensor distance is 27.8mm)

Hat off to Doug - I am pretty sure with his detailed direction the mystery can be solved.

Greetings, Ljós

 

[peewee]

I was wondering, thanks very much for the help.