Lens appears to front focus, but actually isn't?

[NewbieInCS]

Anyone ever experience such a weird situation with large aperture prime whereby the lens appears to have front focus on focus chart and "battery test" but yet is focusing correctly in real world usage?

 

[daredevil123]

happens all the time.

It is called focus shift.

 

[xtunbox]

I encountered it with a prime lens 50mm f1.7 which I have recently purchased. I thought either my lens or camera went bonkers..
I even plan to send my camera in for service. :sweat:

 

[luckyorange]

I encountered it with a prime lens 50mm f1.7 which I have recently purchased. I thought either my lens or camera went bonkers..
I even plan to send my camera in for service. :sweat:

50mm f1.8 i guess?

 

[SkyStrike]

50mm f1.8 i guess?

I think there IS a 50mm f/1.7

http://www.kenrockwell.com/pentax/35mm/lenses/50mm-f17-smc-m.htm

 

[Irvine]

50mm f1.8 i guess?

he's a pentax user n there is such a lens for pentax

 

[luckyorange]

I think there IS a 50mm f/1.7

http://www.kenrockwell.com/pentax/35mm/lenses/50mm-f17-smc-m.htm

ow thanks for the information.. hahah opps sorry =)

 

[pinholecam]

Can be a couple of things :
1. Check your viewfinder diopter. You can adjust that.
2. Focus screen is not properly calibrated wrt AF sensor. (so sensor is accurate but screen is not); Can try service center or focus screen need adjustments via shimming.
3. AF inaccuracy
4. Something else, go to service center.