Circular Polarizer and TTL Metering

elemental · Jul 10, 2008

Today was a beautiful sunny day with a bright blue sky, so I decided to try out my new circular polarizer on my Ricoh KR-5 Super II (which is seeing way more action than my K100D these days). I used the meter as I normally would to set up my shots (that is, assumed it to be reading correctly and followed its recommendations to some extent), and thought nothing of it until I was putting the filter away and saw ADD 2 F STOPS in big bold letters on the case. However, since the filter effect is very noticeable when using an SLR camera, it seems like it wouldn't have an excessive effect on a camera with TTL metering, right? Would this be directed at rangefinders or other cameras with non-TTL metering? I guess I could wait to see the prints, but now I'm curious. Anyone care to enlighten me?

Helen B · Jul 10, 2008

One of the reasons for using a circular polarizer in preference to a linear polarizer is so that TTL metering will work. Some TTL meters will work with linear polarizers - for example the TTL meters in rangefinder cameras will usually work properly with linear poalrizers because the meter does not have to work behind a beam splitter (which is what causes problems if linearly polarized light arrives).

If you use your TTL meter you should not have to apply the filter factor. As you suggest, the filter factor is only applicable if metering is not carried out through the filter.

Best,
Helen

Big Mike · Jul 10, 2008

TTL is 'through the lens'...so if the filter is on the lens, the light is coming through the filter (and the lens) before it's metered...so the filter would automatically be accounted for by the meter.

slapshot · Jul 19, 2008

I apologize in advance if this is considered a stoopid question....

Would it mean 2 stops when using a hand-held meter rather than TTL?

EDIT: I see that has been brought up by Helen & Mike. Oops.

Something I've noticed the short time I've been perusing these forums - I haven't come across any discussion of hand-held meters. Are they no longer being used any more due to the digital revolution?

tirediron · Jul 19, 2008

slapshot;1317519 said:
I apologize in advance if this is considered a stoopid question....

Would it mean 2 stops when using a hand-held meter rather than TTL?

EDIT: I see that has been brought up by Helen & Mike. Oops.

Something I've noticed the short time I've been perusing these forums - I haven't come across any discussion of hand-held meters. Are they no longer being used any more due to the digital revolution?

With the advent of today's sophiscated in-camera metering systems, hand-held meters have gone the way of the Dodo bird for most photographers. They still have application in studio and fashion work, architectural photography, but generally speaking, unless you get into the high-end pro arena, they're few and far between.

Big Mike · Jul 20, 2008

I've got a hand held light/flash meter...and the only time I tend to use it, is for metering my studio strobes...and even then, it's not all that often.

With digital, it's just so easy to shoot and then check the results. I set the camera to display the histogram and use that to set my exposure.

Bifurcator · Jul 20, 2008

My meter:

And yeah, it's great for indoor set-up shots but I never use it in for typical photography. In fact mine is lost somewhere inside the house and I haven't seen it in well over a year. Probably more like two.

Sandspur · Jul 20, 2008

I'm sure many of us still have hand-held meters. But I can truthfully tell you, mine hasn't been out of it's case in several years. And probably never will be again.

Come to think of it, I don't even remember what brand it is!

Joves · Jul 20, 2008

Sandspur said:
I'm sure many of us still have hand-held meters. But I can truthfully tell you, mine hasn't been out of it's case in several years. And probably never will be again.

Come to think of it, I don't even remember what brand it is!

You and me both. Mine is somewhere, not really sure where. I need to make a history shelf with my old cameras and, the light meter.

RacePhoto · Jul 21, 2008

Joves said:
You and me both. Mine is somewhere, not really sure where. I need to make a history shelf with my old cameras and, the light meter.

Can't buy the Mercury batteries for any of mine anymore. They are in my personal photography equipment museum. :lol:

Battou · Jul 21, 2008

RacePhoto said:
Can't buy the Mercury batteries for any of mine anymore. They are in my personal photography equipment museum.

Most mercury cells have an alkaline counterpart now, It's just a matter of research to find out what the designation for a compatable batterie is if it's not the same.

AndrewG · Jul 22, 2008

I occasionally use an elderly Yashica TLR with no built-in meter therefore a hand-held is essential. Furthermore in-camera meters will only measure light reflected from the subect and in certain situations, eg a strongly back-lit portrait, they will be fooled and the subject will be badly under-exposed. Using a hand-held to measure incident light (the light falling onto the subject measured from the subject, toward the camera position) will result in a correct exposure.
No matter how up to date an in-camera TTL meter is, it isn't foolproof.

dEARlEADER · Jul 22, 2008

I thought most polarizers gave you 1 stop at best.... no? I guess not...

icassell · Jul 22, 2008

I used to routinely leave my CP on my walkaround lens, because I couldn't think of a good reason not to. Then I realized that it did eat some available light ... and stopped that practice.