Olympus 17mm focus past infinity

[wm.wragg]

Hi,

I was wondering if anyone with an Olympus EP-1 and the 17mm pancake could tell me if my one is working correctly. It focuses fine except that it focuses quite a way past infinity - I can carry on focusing for another third of a turn - is this normal?

This is my first non compact digital, so if this is a silly question please forgive me. I'm used to Leica-M glass and a hard infinity stop.

Regards,

Wm.

[FrozenInTime]

The lack of infinity stop is my biggest hate with 4/3 and µ4/3 AF lenses.

I done a comparison between the Zeiss 18mm and Olympus 17mm, as I too would rather use the manual focus 18mm despite it's bulk.
The conclusion is that the Olympus is probably overall the better lens. The Zeiss is slightly sharper in the center and will be good for demanding enlargements if cropped a little to 3:2.

Unfortunately all the other wide/normal Leica lenses I've used are going to be best used only for close ups where the peripheral zones are deliberately thrown into blur.


The contrast is down a bit on the olympus - due to the British summer

[wm.wragg]

Thanks for the quick reply. So the large focus past infinity is normal then?

I'm planning on getting the M-mount adapter, and using my M-glass, but I do quite like the little M43 17mm, except for the focus past infinity. I have been thinking about getting the Voightlander 12mm for a wide angle prime as well. New camera new lenses to buy.

[wm.wragg]

Ah, my problem isn't the continual rotation - it's annoying though - it's that I hit infinity and then the lens carries on focusing PAST infinity and becomes blurred again, and does this by a good 1/3 of a revolution until it stops becoming any more blurred.

[250swb]

Originally Posted by wm.wragg

Thanks for the quick reply. So the large focus past infinity is normal then?

I'm planning on getting the M-mount adapter, and using my M-glass, but I do quite like the little M43 17mm, except for the focus past infinity. I have been thinking about getting the Voightlander 12mm for a wide angle prime as well. New camera new lenses to buy.

You understand the reason they are made to focus 'beyond infinity' is because the lens focus ring needs to be customisable from counter clockwise to clockwise in direction, just so people can't moan about it not being 'instinctive'. Some you win and some you lose.

Steve

[wm.wragg]

Originally Posted by 250swb

You understand the reason they are made to focus 'beyond infinity' is because the lens focus ring needs to be customisable from counter clockwise to clockwise in direction, just so people can't moan about it not being 'instinctive'. Some you win and some you lose.

Steve

That kinda makes sense. I just wanted to make sure something wasn't wrong with it. I'm sure I'll get used to it

[FrozenInTime]

Originally Posted by 250swb

You understand the reason they are made to focus 'beyond infinity' is because the lens focus ring needs to be customisable from counter clockwise to clockwise in direction

Not really:

There is no direct coupling between the user focus ring and the helicoid drive/motor - it's fly by wire. Therefore there could be a mechanical or electrical infinity stop or limit on a lens helicoid.

This would still allow the user focus input to be set in either direction with the ring still rotating freely and without a stop even once the lens was at infinity limit.
i.e. the lens could be made not to focus beyond that point even though the user focus input ring still rotated ( in which ever direction you chose in software ;-).

However, it's easier/quicker for a control loop ( AF system ) to overshoot and pull back rather than hit a non-linear hard stop.
Calibration of an electrical infinity point would cost a little extra production/calibration time ( and for most zooms would require a value for each focal length )