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09-08-2019, 12:58 PM   #1
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Filter ?

Got this filter with a Sears 28mm lens from the 60s. Has a peg as shown in photo where you can rotate the filter, anyone know the purpose for that ?
Would this filter be good to use with todays DSLRs

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Last edited by cg-4k50; 09-08-2019 at 01:30 PM.
09-08-2019, 01:57 PM - 1 Like   #2
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QuoteOriginally posted by cg-4k50 Quote
Got this filter with a Sears 28mm lens from the 60s. Has a peg as shown in photo where you can rotate the filter, anyone know the purpose for that ?
Would this filter be good to use with todays DSLRs
Does the peg itself rotate? If so, it's used to lock the polarizer position so the polarizer doesn't accidentally move/shift. If not, then it's just to help rotate the filter.

Tiffen filters are now made in the USA, so my best guess is that this older 60's made in Japan version is a linear polarizer which is not compatible with modern DSLRs and autofocus cameras. You'll want to get a circular polarizer instead.
09-08-2019, 02:00 PM   #3
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there's usually quite the discussion/debate about using filters on DSLR's...

I have a stack of filters that I've taken off of vintage lenses, never to be used again, including polarizer filters...
09-08-2019, 02:21 PM - 4 Likes   #4
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QuoteOriginally posted by cg-4k50 Quote
Has a peg as shown in photo where you can rotate the filter, anyone know the purpose for that ?
PL filters block polarised light. The degree to which it is blocked will depend how you rotate the filter. You can see the effect quite easily by holding the filter up to a blue sky or a reflection in a window and rotating it.

---------- Post added 09-08-19 at 10:23 PM ----------

QuoteOriginally posted by pepperberry farm Quote
I have a stack of filters that I've taken off of vintage lenses, never to be used again, including polarizer filters...
Whilst I would agree largely with what you say, polarisers still have their place on a DSLR. Intensifying a blue sky can be done in pp , but removing reflections from water or glass is more problematic.

09-08-2019, 03:59 PM - 2 Likes   #5
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What you have is a Polarizing filter. Yes, they are useful when used on todays SLR cameras (they work on film SLR's and DSLR's and Mirror Less cameras). The only caveat is to be careful with mechanisms based on half silvered mirrors within the camera body.

When I used my filter on my *istDs back in the day, I noticed that I had to watch the exposure since it could change as I rotated the filter. -->> set/lock the exposure first, then rotate the filter for effect. Also, be careful with autofocus as the AF mechanism uses a half-silvered mirror to "light up" the AF sensor in the floor of the light box.

Polarizing filters tend to show their greatest effect when placed 90 degrees from the sun. A easy rule of thumb is that if you place the sun in line with your shoulder, you are facing the area (of the sky, if that is what you want) that will show the greatest effect. Some people obsessed with having the same shade of blue in the sky really do not like Polarizing filters.
09-08-2019, 04:57 PM - 3 Likes   #6
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As other have said, polarizers are useful for intensifying blue sky and reducing reflections. You can use older linear polarizers on a DSLR but it does affect the accuracy of the exposure reading and the reliability of AF.

Overall, polarizers do remove about 1 stop of light from nonpolarized parts of the scene, remove almost no light if it is polarized in the same direction as the polarizer, and remove almost all the light if it is polarized at a right angle to the direction as the polarizer. The point is that you can use a polarizer to intensify a reflection off of glass or water by turning the polarizer first to the point that best eliminates the reflection and then turning the polarizer 90. At that angle, the polarizer is letting through almost all of the reflection but only 1/2 the light from the rest of the scene.

Bonus tip: rainbows are polarized! You can remove or intensify portions of a rainbow with a polarizer.

Finally, avoid using a polarizer when shooting through plastic windows (e.g. airplanes & busses). The birefringence of those materials interacts with the polarized light in the scene and the polarizer on the camera to introduce weird color artifacts. (And if you want to have fun, shoot pictures of clear plastic objects back lit with polarized light to reveal the stresses inside the plastic as strange colors.)
09-08-2019, 06:36 PM - 1 Like   #7
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That peg could be just an aid for rotating the filter but some filters had a mark or indicator on them which was positioned pointing toward the sun to get the most polarizing effect. I never used an indicator - just looked through the viewfinder (SLR) and rotated the filter until I got what I wanted. With overcast days or under some lighting conditions (sun directly overhead), very little sky effect can be gained.
09-08-2019, 07:06 PM   #8
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Thanks all for the replies, I'm new to photography, I bought my K50 to learn AP and really don't know a lot about photography other then Astrophotography guess I took the hard road first lol. But did learn a lot about polarizing filters here, thanks all.

09-08-2019, 08:15 PM - 1 Like   #9
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QuoteOriginally posted by Bob 256 Quote
That peg could be just an aid for rotating the filter but some filters had a mark or indicator on them which was positioned pointing toward the sun to get the most polarizing effect.
the Kodak polarizing filter I had in the late 1950s had such an arm which, when it was set pointing towards the sun, would maximize its effect. It had a cross bar on the arm which in some manner, which I forget, tied in with the business of pointing towards the sun. I think it had to do with the shadow the cross bar projected.
09-09-2019, 11:19 AM - 1 Like   #10
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If you decide to get a circular polarizing filter (recommended), be advised that there is a wide range of price and quality between brands. Avoid the cheapest ones; their optical quality is quite poor. A polarizing filter has many optical properties just like a lens. Quality of multi-coating, single coating, or lack of any; even transmittance of all wavelengths or dips and spikes in some, scratch resistance, etc. After doing some research and reading independent reviews, I decided to go with the Marumi DHG series. They're not the best, but are decent and affordably priced for me.
MARUMI DHG Circular Polarizing CPL reviews - Pentax Camera Accessory Review Database

A step up in quality (and price) is the Marumi Super DHG series.
Marumi Super DHG Slim Circular Polarizer reviews - Pentax Camera Accessory Review Database

There are excellent offerings from B+W, Hoya, and others. Other PF members may want to weigh in on their favorites. Since the filter goes on front of your lens, you should buy the best quality you can afford. A $15 filter on a $1000 lens will give you $15 results.


Besides sky, a polarizing filter can have a really nice effect on foliage if the light is right. Your eye/brain may not notice the reflections, but put a polarizer on and see how the colors become more saturated and contrasty.

Last edited by Apet-Sure; 09-09-2019 at 11:41 AM. Reason: ..
09-10-2019, 04:42 AM - 1 Like   #11
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QuoteOriginally posted by Apet-Sure Quote
Besides sky, a polarizing filter can have a really nice effect on foliage if the light is right. Your eye/brain may not notice the reflections, but put a polarizer on and see how the colors become more saturated and contrasty.
A polarizing filter can also cut reflections on the surface of water so that the camera can record what is under that surface, such as the bottom of a shallow stream or the the shoreline of a lake.
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