Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Pentax / Samsung dSLR, K Mount Mirrorless

Reply
 
Thread Tools Search this Thread
Old Jul 16, 2006, 6:37 AM   #1
Senior Member
 
Join Date: Sep 2004
Location: Wigan, UK
Posts: 568
Default

I've read many articles and posts on forums that you cannot use linear polarizers with dslr cameras because they fool metering system. Beceuse I have one of those which I bought for my FZ 10 I decided to give it a shot anyway. Here are the results. No adjusments whatsoever except resizing. When I checked histograms on both of them they look pretty much identical. I don't see any difference in exposure except darker sky in polarized photo. So why it's said you cannot use them?? Shot with *ist dl2

Ps: dark dots are from dirty window I shot through.

Unpolarized, f 8 1/500s ISO 200





Polarized f 8 1/100s ISO 200


gfurm is offline   Reply With Quote
Sponsored Links
Old Jul 16, 2006, 9:59 AM   #2
Senior Member
 
mtngal's Avatar
 
Join Date: Nov 2005
Location: Frazier Park, CA
Posts: 16,056
Default

I had a similar experience with a linear polarizer that I had. I had bought a polarizer years ago for the ME, and wasn't surprised that it worked well with the same (manual) lens I had bought it for. It isn't marked as a circular polarizer, so I assume that it is linear (but don't really know). So I assumed that it was the Auto Focus system that the linear one would interfere with, not the metering system. When I tried the same polarizer with the Phoenix lens, the only FA lens I have that has 49mm threads, it seemed to work fine, both metering and focusing. I think it depends on the particular camera and polarizer.
mtngal is offline   Reply With Quote
Old Jul 16, 2006, 10:10 AM   #3
Senior Member
 
Wingman's Avatar
 
Join Date: Dec 2003
Location: Hebron, Kentucky (northern Kentucky/Greater Cincinnati):KCVG
Posts: 4,327
Default

Harriet is correct. The linera vs the circular impacts the auto focus system only. Polarizers themselves also act as a neutral density filter, but in the auto exposure modes, the camera's metering system should automoatically compensate. In order to realize the full effect of a polarizer is to shoot at a 90 degree angle to the source of light. Try shooting with the sun to your right or left--you should notice a substantial difference. Also make sure you rotate the polarizer ring to get the maximum polarizing effect. Good luck.

Jay
Wingman is offline   Reply With Quote
Old Jul 16, 2006, 10:33 AM   #4
Senior Member
 
Join Date: Sep 2004
Location: Wigan, UK
Posts: 568
Default

Thanks to both of you.

If it affects autofocus I didn't test it correctly. The polarizer I have is 62mm so I was holding it in front of my lens with my handafter focusing (I think). So I'll have to do some more testning, but it's not going to happen today .It'd be nice if it worked properly.
gfurm is offline   Reply With Quote
Old Jul 17, 2006, 4:27 AM   #5
Senior Member
 
Join Date: Sep 2004
Location: Wigan, UK
Posts: 568
Default

I checked it today and it works. No problems wit AF. It means I jus need a step up ring to 62mm, no need to buy circular polarizer for me.
gfurm is offline   Reply With Quote
Old Jul 17, 2006, 5:55 PM   #6
Senior Member
 
mtngal's Avatar
 
Join Date: Nov 2005
Location: Frazier Park, CA
Posts: 16,056
Default

It's interesting that both of us can use our linear polarizers with AF.

I wouldn't go out and buy one without checking first, but it's worth it to see if any old ones you happen to have work.

I was playing with 2 linear polarizers this weekend, and found out that putting 2 together can cut out all light. Which does bring me to another topic - which one would be the better filter? One is a Hoya and one a Vivitar. The Vivitar one is much thinner than the Hoya - does that matter? Both are at least 20 years old (I bought one and my father bought the other) and are in equally good condition.
mtngal is offline   Reply With Quote
Old Jul 17, 2006, 6:18 PM   #7
Senior Member
 
Join Date: Sep 2004
Location: Wigan, UK
Posts: 568
Default

I think it depends on coating, but as they are both old they were probably made using similar technology.I they both have same coating the thinner one should be better because it's less likely to cause flare (that what I read somwhere). Hoya now makes super thin filters which are quite expensive, I'd go for the thinner one.
gfurm is offline   Reply With Quote
Old Jul 18, 2006, 11:52 AM   #8
Junior Member
 
Join Date: Feb 2006
Posts: 20
Default

The DL's (and many other cameras') focusing and metering systems are both sensitive to polarized light. However, it isn't that you *will* get a bad result with a linear polarizer. It's that you *might* get a bad result. A linear polarizer often works well enough but there can be a problem at times. There's nothing wrong with trying a linear polarizer since it will often give a satisfactory result. If you want to always be sure, though, you must use a circular polarizer.

Regarding Vivitar and Hoya filters, my experience has been that Hoya is much better. Very thin filters are primarily intended for use with very wide angle lenses because of vignetting problems but they can, obviously, be used with other lenses.
Ron C is offline   Reply With Quote
Old Jul 18, 2006, 4:14 PM   #9
Senior Member
 
Join Date: Jan 2005
Posts: 104
Default

OK, so using a linear polarizing filter works just fine (except when it doesn't) and with a DSLR we can always "chimp" to find out how well it did. Question:

What do you do when you find out the linear polarizer fooled your camera and you have to get the shot quickly (without using PS to make the correction)?

My answer has been to avoid the situation and opt for circular polarizers. Considering what I've spent on equipment, that's proven the best for me. Of course, most of my lenses use 58mm filters which helps with the filter/hood costs.

Larry in Dallas
Heathglen is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 11:39 PM.