Pola filter on a 35mm apo sironar hr - loss of details

[henrikfoto]

I tested a polafilter on a Sinar Artec with a 35mm apo sironar hr today.
The filter was a B+W filter of good quality. A round filter screwed directly on the front.
The back was an IQ180.

When I shot the same scene with and without the filter I noticed how much small details was
lost in the pics with pola filter.
Is this to be expected with all pola-filters or does it have to do with the wide lens?

Henrik

[Rob C]

henrik,

I'm not trying to be a smartass, but you are aware that using a pola filter removes detail within shadows areas by removing tiny areas of very local contrast that, left alone, create edges that give, by those micro-shadows/highlights, the sensation of detail?

Rob

[henrikfoto]

No I did not know the tecnical details of how they work. This is the first time I test a polarizer.
Does that also mean that polarizer are not used unless you really have to?

[torger]

It's hard to see what you're looking at without a screenshot. A polarizer should not really kill any detail, but all filters are a bit problematic on wide angle as it easily causes loss of contrast due to bouncing reflections especially with bright lights just outside the frame.

In good conditions there shouldn't be any loss of detail as far as I know. I have a polarizer too but I use it extremely rarely as I generally want the look stay the way it is without polarizer so I can't say I've made any "lab test" to see if it hurt detail in any way. I think I would have noticed though and I haven't.

[Rob C]

The problem with using polas on very wide lenses isn't confined to the fact that a sky, for instance, will look rather uneven across a wide field of view due to the basic pola effect being the strongest at 90° to the light source (the Sun) where, because a wide covers a wider zone of sky, there's more of it on show in the shot to reveal the different strengths of grading.

If you carefully inspect areas in a pola'd shot such as, for example, a wall that's in shadow, it will look a lot flatter and darker due to the loss of that 'internal' micro contrast. The lens will still have caught the detail, but will lose the contrast in the overall darkness of underexposure and just look more flat.

I went through a phase where I used a pola as much as I could, until I tried it for some model shots where it was a disaster and made suntanned skin look like red brickwork. I hardly ever used it again on anything, though I still keep one in the armoury. It works very nicely if you shoot beaches and want to differentiate colours in the water, but at the same time, if you shoot a river, it can lose you surface information because if lets the lens see right through the surface and you end up seeing the pebbles/rocks and lose the sparkle on the surface.... swings and roundabouts. Great for a specific purpose, but certainly not as a general filter just for the hell of it.

Pols come with their own variable filter factors, but the only way I know to get it right is to bracket.

Rob

[henrikfoto]

Thanks a lot for explaining, Rob! This is very useful information and a lot more complex than
what I first thought when I started testing it.

Henrik

[BernardLanguillier]

Another possibility is that the blur is the result of the slower shutter speed caused by the PL filter?

Cheers,
Bernard

[henrikfoto]

Another possibility is that the blur is the result of the slower shutter speed caused by the PL filter?

Cheers,
Bernard

That could play a part, but I used a good tripod with weights hanging under it and a cable release.