Filters exposure compensation

I have finally come around to acquiring some B&W filters for my Pentax 67ii, and I have started to investigate how to best use them. Currently I have a No 8 yellow and No 21 orange filter. No 8 yellow has filter factor 2 (+1 stop), No 21 orange has filter factor 4 (+2 stops). So far so good - but how do I set up my camera? Does the 67ii AE prism (which BTW is quite superb) in AV mode make the necessary adjustments, or do I have to dial in the compensation on the Exposure Compensation dial?

Since I am asking about exposure, what about the 67ii + polarizer and colour film ? So far I have let the AE prism work out the correct exposure. Is this the common practice? I use primarily center-weighted metering.

I am grateful for any advice on this matter!

Best regards
Bjørn

As the camera meter is looking through the lens, and hence also the filter, you can meter as normal.

Hi Bjørn,

I presume by B&W you mean monochrome and not filters from the company called 'B+W'?

I'm not totally familiar with the 67ii prisms, but it should meter taking account of the coloured filters without needing exposure compensation. But, bear in mind the meter is likely calibrated for white light and might not meter the exact same 'filter factor' as expected by monochrome film - whether there is a practical difference I'm not sure.

I'd suggest testing the metering with and without the filters and seeing whether the difference lines up with the stated filter factors. In all cases, you should focus with the filter present (some deep red filters may make this hard).

As for a polariser, I'm not sure - they're usually only a problem with linear polarisers on cameras with secondary mirrors (and part of the primary mirror being 'pellicle' - semi-silvered). I'm not sure if the 67ii uses one. This link
seems to suggest either linear or circular polarisers will be fine with the 67ii.

John.

Thank you very much John! I suspected that this was the case, I just wanted to make sure. Shooting 120 film these days is quite expensive, so it is best to avoid making basic mistakes...

Best regards
Bjørn

I have to repeat myself: Thank you very much John!

Yes, I meant monochrome. I just received the colour filters yesterday, so I have not had a chance to check them out. Comparing the metering with/without colour filter seems like a sensible idea. I will investigate this tomorrow.

I use a circular polariser with the 67ii, this is also recommended in the 67ii manual. The reason for me bringing the polariser into this discussion (metering/exposure), is that I have had some mixed results with Velvia 50 + polariser. Many of my shots have ended up seriously underexposed. I may try to dial in less polarisation the next time I use Velvia 50, to see if this gives better results. Many photographers set ASA to 40 when using Velvia 50, I believe I will try this also, in an attempt to get more consistantly correct exposures.

There is really a lot to learn about film

Best regards
Bjørn

Hi Bjørn,

In that case, a circular polariser should be fine using the cameras metering (trying to compensate for a polariser manually is variable anyway).

Velvia is contrasty enough that a polariser may be overkill (unless you're using it to remove reflections). If the scene is already contrasty, Velvia can really generate 'plastic' looking colours. If I'm using an auto-exposure mode I set my ISO for Velvia 50 at ISO 40. If using manual (like my 67's), I set my ISO at 50 but I'm aware that I've only got half stops on the aperture ring, so I aim to have the meter show slight over rather than slight under exposure (if it shows exactly correct I usually go for half a stop over). Then again I still get my fair share of under-exposed shots.