normanhall Loc: Leslie Missouri

i went and looked at previous topics but was unable to find what i was looking for.

When using a polarizing filter do you readjust your apature or shutter speed to compensate for the darkness. EXample if my filter causes me to lose 2 stops when it is being used, should i open up to let in more light. I hope this makes sense.

martinfisherphoto Loc: Lake Placid Florida

If your shooting in Aperture, or shutter priority your camera will adjust automatic for any light lose. If your in full manual treat as such and adjust to the light meter. Your camera meters thru the lens so you don't have to over compensate for the filter if that's what you mean.

normanhall Loc: Leslie Missouri

i am not using the in camera meter. i am using a sekonic 358. i find that my exposures are better when using a light meter over camera meter.

high-flyer Loc: Texas

You will need to compensate for the light lost from the filter or the picture will be too dark. Many DSLRs will show a histogram and this will show exposure results. Its always a good idea to look at the histogram to see if you are capturing both highlights and shadows

dpullum Loc: Tampa Florida

(( Norman, How much difference do you find between these two metering systems... and do you find the same with other cameras?))

That comment along with complaints about focus problems discussed in previous posting brings up a good area of questions: Supposedly the 1/4 wave "disrupter" filter randomizes the axis of the light and makes it "normally random" as opposed to the preceding linear polarizer. The 1/4 wave is what makes the linear polarized unit into a Circular Polarized Filter, CPF. The CPF/Camera combo is one of the most complex systems. Other filters simply add or subtract parts of the light or intensity, but CPF change the nature of the lite, the character of the photons. Cameras are designed for random light ... that is supposedly why the 1/4 wave "disrupter/randomizer" is used.

Your question is still unanswered after all this yap yap...this may be one of those "whittle-the-stick" til you find what works for your camera CPF combo.

--------------------------------------------
From previous post I provided the following references:
It is important that Photographers understand the Camera, and Composition, but also the very nature of Light.

For those who really want to know about Polarization of light you can read these lab experiments, section 4 discusses polerization, section 4.6 and 4.7 discuss circular polarization using 1/4 wave filters such as scotch tape.
http://instructor.physics.lsa.umich.edu/int-labs/Chapter4.pdf
(Many thanks to the University of Michigan, me ol' alma-mater)
Please ignore the complex mathematical equations or you will personally become a section 8.
(to understand that play on sections see ... http://health.vic.gov.au/mentalhealth/archive/pmc/amend_invol.htm)

ecobin Loc: Paoli, PA

The simple answer: with the filter on and turned to accomplish the effect you desire, adjust your settings (aperture, iso, & shutter speed) as you normally do without the filter.

normanhall Loc: Leslie Missouri

This is a hard question to answer i have not been writing this info down but i have 3 different metering systems in the camera spot, matrix, center weighted and then my Sekonic. I get a different reading with each metering system. The on board camera is metering reflective light while my light meter reads ambient. I am trying to get my exposures as close as I can so I don’t have so much post production work to do. I was trying to find out if I move my f-stop or my shutter speed to compensate for the poloarizer if I decide to use one. Now what I have decided is I will use my light meter to take a reading and then use the spot meter in the camera to take a reading on the brightest spot in my landscape and then take an average between the two. Get somewhere in the middle so I don’t blow my highlights.

dpullum Loc: Tampa Florida

Yep, Norman, cut and fit, Blown highlights are blown so I tend to under expose and brighten. Lite/exposure/composition combination has always been the key to a great photo.

Just for the fun of it, take a lite meter reading thru the CPF ,,,, hummm

normanhall Loc: Leslie Missouri

yeah i have done that and if it looks like about 2 stops different.

twowindsbear

Ever heard of bracketing your exposures? Make your light readings, choose an exposure combination as a starting point, then adjust either - or both - shutter speed & lens opening, in 1/2 stop steps, for at least +/- 3 stops. 1 exposure 'should' be the BEST and up to your standards.

dpullum Loc: Tampa Florida

Twowindsbear may I say that Homer Simpson, other readers, and I have one word in our defense for not mentioning bracketing and that word is.... dah.

Norm, sometime I do look for mysteries in dark corners instead of finding the answers in the light or instead of saying who cares here is a practical approach. In this case do some test shots under typical conditions in which you shoot, with bracketing set wide so that you know that proper exposure will fall between x and y, then leave the bracketing set a bit tighter based on the results.

Confession: It is the film mind set to not realize I have 1200 shots on the roll of digital film .... too many years of 12 shots on a roll.

normanhall Loc: Leslie Missouri

I am with you on this. I am not wanting to sit there and take a dozen shots to get one. and then do this each time i change location i am trying to come up with a system where i don't need all those shots. i figure by the time i have done that i have missed the image i wanted.

Mac Loc: Pittsburgh, Philadelphia now Hernando Co. Fl.

Norm
If using the TTL metering system, the camera will make the adjustment. When using the hand held you will have to make the adjustment.

normanhall Loc: Leslie Missouri

twowindsbear

Try this. . . Set up your camera as you normally do, compose the scene to your satisfaction, take your meter reading with your hand-held meter. . . Change the ISO value of your camera so that your automatic exposure system's exposure agrees with your hand-held meter. THEN place the filter over your lens, and your auto exposure will compensate for the filter's light loss. Yes, this will take a few more seconds, but probably fewer seconds than the bracket series.