[Brightcolours]

[quote name='thw' timestamp='1283337112' post='2402']

Is that ghosting for real?



Hmmm... I am very surprised. Is Sony using a pellicle or thin mirror? If it's a thin mirror, it should be an easy problem to solve 'cos one of the faces can be anti-reflection coated...



Otherwise, this is a pretty serious problem. I did not realize it exists on the A55 till now. Does that happen only under certain lighting conditions?

[/quote]

Well, it is not all that easily fixed on a mirror (they use a mirror). I am sure it is coated already (has to be, else the problem would be much bigger).



You will see it when there will be strong "lights" in otherwise darker conditions, so usually from dusk till dawn photography. Similar to when "protective filters" start to be a real problem, no matter how expensive and well coated they are. The difference is that with the Sony mirror the reflection only happens in the mirror, with filters you see the bright image reflected back from the sensor and then back again by the filter.



Some examples caused by filters (with filters the ghost lights will appear mirrored through the optical axis):

Uncoated filter (Tiffen):



Multicoated filter (Hoya HMC):





Taken from http://www.pentaxforums.com/forums/pentax-camera-field-accessories/36555-lens-filters-versus-flare-ghost-images.html



Taken from http://dptnt.com/2008/10/uv-filter-or-no-uv-filter/







Basically, do not use protective filters for after dusk exposures. A bit hard to not use the mirror in the A55 though.