What's new
Medium Format Forum

Register a free account now!

If you are registered, you get access to the members only section, can participate in the buy & sell second hand forum and last but not least you can reserve your preferred username before someone else takes it.

Linear or circ polarizer 202/203 FE

P

polarcircle

Member
I realized that I'm not quite sure which polariser to use for the FA/FE 200 series cameras. Looking at Heliopan 93 mm filters, linear seems to be the choice. If so can one get accurate metering with a linear polariser?

What is the need for the PME series prisms - I guess circular?

Cheers
 
If I recall, any camera with a partial mirror such as 202,203,205 needs a circular polarizer. Don't remember why. The meter prism used has nothing to do with it and can be used with any polarizer. Hope this helps.............

Terry
 
terrydent said:
If I recall, any camera with a partial mirror such as 202,203,205 needs a circular polarizer. Don't remember why. The meter prism used has nothing to do with it and can be used with any polarizer. Hope this helps.............

Terry
Click to expand...

Normally the C-POL is required for autofocus systems.
 
Here is part of an article at bobatkins.com. (used without permission).

So why would anyone want to do this? Well, remember from earlier that the intensity of the reflection from partially reflecting surfaces can be dependent on the linear polarization angle of the incoming light. Windows and pond surfaces are two examples of partially reflecting surfaces, but another is the main reflex mirror in many modern SLR cameras. Older SLRs used fully reflecting mirrors, which reflect all polarizations with equal intensity. Newer SLRs, and particularly autofocus SLRs, often use partially reflecting mirrors. The reflected light goes to the viewfinder and metering systems, while the transmitted light goes on to the auto focus sensors. If a linear polarizer was used on such an SLR, the intensity of light sent to the metering system would depend not only on the intensity of the light, but also it's polarization angle. However, when a picture is taken the mirror is out of the light path and the film is only sensitive to the intensity of the light, not its polarization. Thus metering errors can (and do) occur when a linear polarizer is used with an SLR which has a partially reflecting main mirror.

Terry
 
Terry,

I was misguided by the existence of only linear 93 mm polarizers at Heliopan. It is probably true for all beam splitting. I saw in my old, the original metering prism, that the metering cell was in a postition that told of beam splitting in the prism - on top of the prism instead of around the eye piece.

correct is that beam splitting is used in autofocus cameras but can be utilized for metering purposes as well as should be the case for the 200 series cameras.

Thanks for the discussion and answers Terry and Wilko,

Ronald
 
Would be interesting to try a LIN-POL on a 200 series to see what happens.

Paul, bring a 200 please :) I have a large Heliopan LIN-POL for my CF40
and a smaller (77mm) Heliopan C-POL for the Nikon. So testing would be doable.

My 1976's Pentax MX also has its light metering cells located on the prism,
and has no requirement for a C-POL.

So, I am not sure. What does the 200-series HB user manual tell us?

Wilko
 
I checked my 202FA, 203FE and 205TCC manuals. No mention of polarizers in any of them. Also no mention in my H1 manual which is an autofocus camera. Since it appears that Hasselblad never made a circular polarizer my guess is it doesn't matter. Surely Hasselblad couldn't have overlooked this subject, could they?

I will be interested in the results of your test Wilko.

Terry
 
Never see any problem with pola filters and Hasselblads.

Except one: impossible to put 2 Hasselblad pola flters together to get a strong black filter.
 
wbulte said:
Paul, bring a 200 please :) I have a large Heliopan LIN-POL for my CF40
and a smaller (77mm) Heliopan C-POL for the Nikon. So testing would be doable.

What does the 200-series HB user manual tell us?

Wilko
Click to expand...

No mention in the 202/203/205 manuals about what kind of polarizer is to be used.
Hasselblad provided only lineair polarizers without any restrictions for the use with 200 series bodies.

Circular polarizers became necessary for bodies with AF option.
Hasselblad pola filters for H series are all circular.
 
polypal said:
No mention in the 202/203/205 manuals about what kind of polarizer is to be used.
Hasselblad provided only lineair polarizers without any restrictions for the use with 200 series bodies.

Circular polarizers became necessary for bodies with AF option.
Hasselblad pola filters for H series are all circular.
Click to expand...

Right, confirms what I thought it would be.

Wilko
 
wbulte said:
Right, confirms what I thought it would be.

Wilko
Click to expand...

OK, But what about the translucent mirror in 200 cameras? Isn't this the same function in terms of beam splitting or is this unaffected by polarized light?

I have also seen that there is no mentioning of what type of polarizer to use in the manuals. Are the Pola 93 and pola 70 linear polarizers?

Ronald

Ronald
 
The mirror and the metering system in 200 series bodies are not affected by the use of linear pola filters.

All older polarizers for V series are of the linear type.
That concerns the 70 mm and the 93 mm filters.

H series lenses use different size threaded filters i.e. 67, 77 and 95 mm.
Polarizers for these lenses are all circular.
 
You must log in or register to reply here.
Back
Top