Help: camera has tunnel vision

[cheez1981]

Can someone identify what my problem would be for this picture? It looks as though I'm looking through a tunnel but they are random (ie. the pictures before and after do not display this problem). I recently bought a Circular Polarizing filter for my Pentax ZX L SLR film camera using a standard 28-80 autofocus lens. The camera was set for autofocus. The only thing I can think of is that I get this effect from rotating the filter to adjust the picture. Oh, I do have it at the end of two other filters...a 1A and a UV filter.

Thanks...

[another view]

What you're seeing is called "vignetting" and it happens when something attached to the end of the lens blocks part of the image. Usually this is caused by using the wrong lens hood or too many filters. Take the 1A and UV off when using the polarizer and you should be fine. Generally, don't stack filters unless you have to.

The 1A and UV are usually used as protective filters; the filter gets damaged instead of the front element of the lens. Personally I don't use them because they can cause image problems like flare if there's a bright light source in the frame. I prefer hard plastic or metal lens hoods because they'll protect the lens and help cut the amount of lens flare in those situations. I'll use a UV if it's raining though. I can't think of a reason to use both the UV and 1A because they'll both serve the same purpose although a 1A will tend to warm the images slightly. If you're using negative (print) film, the processing equipment at the lab will auto correct your prints and really cancel out the effect of the 1A anyway.

If you do want to use a protective filter, try using only one filter at a time, even if it's the polarizer because the UV won't really serve any purpose.

[SmartWombat]

they are random (ie. the pictures before and after do not display this problem)
I do have it at the end of two other filters

You've made a tunnel out of all the stacked filters.
You'll only see this when you use the wide angle of the zoom.
That might epxlain why it's not in every image.

[another view]

I think you're right about the quote you referenced, Paul.

You might be able to see this thru the viewfinder, but since the viewfinder is likely not 100% (so it doesn't show everything that's recorded on the film, probably better than 90% though), you won't see the effect as bad as the film will. And yes, this is going to be more of a problem the wider the focal length.

[freygr]

Can someone identify what my problem would be for this picture? It looks as though I'm looking through a tunnel but they are random (ie. the pictures before and after do not display this problem). I recently bought a Circular Polarizing filter for my Pentax ZX L SLR film camera using a standard 28-80 autofocus lens. The camera was set for autofocus. The only thing I can think of is that I get this effect from rotating the filter to adjust the picture. Oh, I do have it at the end of two other filters...a 1A and a UV filter.

Thanks...

Only use ONE filter at a time, and you should never see this problam again.