Circular Polarizer and Ultra Wide Lenses - workable?

jerry12953 said:
Wasn't the problem of reciprocity failure something to do with strange, unpredictable colour casts?

Need I say more?
Click to expand...

Yes, something like that, and I see what you mean ;)

But it's more than just faffing about with reciprocity tables and a box or Wratten filters. In practice, it is impossible to calculate a long night time exposure; it's down to lots of trial and error. And even then it is very difficult with film, because of the delay in getting stuff processed.

Digital changes everything. Very long exposures is maybe an area to explore with digital that you just could not do with film. A bit like strobist flash is also new digital technique, which I find really interesting.

Both these techniques have particular exposure problems that are very hard to resolve when shooting film. How do you expose for a night sky when it's almost so dark that you can't see your nose? No exposure meter will even move off zero, so you have to take a guess, multiply it by a reciprocity correction factor from a Kodak manual, fit colour correction filters, re-adjust reciprocity after the filter factor, take pages of notes, spend hours bracketing exposures madly, then pack up and go process the film.

If you're lucky, you might have something there or there abouts, but when you go back to try it for real, everything has changed so it's back to guesswork again. This just isn't practical, so nobody bothered much, but now with digital you can rattle off a series of test exposures at ISO3200 almost in no time at all, get a very accurate fix on exposure, and bang off the real thing just a few minutes later. The same goes for strobist flash - impossible without instant replay of test results, adjust lights, re-test, change them a bit more etc until it's right. Takes no time at all.

This is new territory for digital photographers. Completely new picture taking situations and creative opportunities that were, from a practical perspective, impossible with film. I like that :D
 
I'm glad I came back to this thread before expirmenting after the weekend. There has been some absolutely invaluable information.

I did a quick test with 2 circ pols, and the results were disappointing. Minimal ND effect.

since reading this, I have taken one of them apart and flipped the glass, so that they can still be screwed together and they appear to work just fine with a rapid ND effect right down to almost black.

Hopefully I'll be able to come back next week with some sort of result.
 
You can't do it with a circular polariser and since linears have effectively been sidelined for many years now, almost nobody stocks them. Local dealers had nothing, Jacobs superstore had nothing, other nearby stores had nothing. I was lucky to pick up an ancient secondhand one in Cambridge. What I want is a nice top end B+W, but paying over £100 makes a nonsense of the whole idea when you can get a ten-stop B+W ND for less than that.[/QUOTE]

Richard, you can get a 105mm Linear filter at Speedgraphic but as you say it will work out expensive . About £130 for the filter plus a 77-105 stepping ring,
but no vignetting using that combination, on crop or full frame bodies. I had to have the stepping ring specially made. The Linear filter I already had, for when shooting 5x4.
C
 
Ceejay said:
You can't do it with a circular polariser and since linears have effectively been sidelined for many years now, almost nobody stocks them. Local dealers had nothing, Jacobs superstore had nothing, other nearby stores had nothing. I was lucky to pick up an ancient secondhand one in Cambridge. What I want is a nice top end B+W, but paying over £100 makes a nonsense of the whole idea when you can get a ten-stop B+W ND for less than that.
Click to expand...

Richard, you can get a 105mm Linear filter at Speedgraphic but as you say it will work out expensive . About £130 for the filter plus a 77-105 stepping ring,
but no vignetting using that combination, on crop or full frame bodies. I had to have the stepping ring specially made. The Linear filter I already had, for when shooting 5x4.
C[/QUOTE]

Thanks CJ. Yes, you can get linear polarisers and a big one would overcome the vignetting issues, but I'm really looking for a cheap and neat solution to getting a strong ND filter. And the best way of doing that seems to be to get a B+W ten stop ND which is about £80 in 77mm, and be done with it.

Another way of getting the variable ND effect with two polarisers is to use a second circular polariser, which is much more readily available and at lower prices. Take it apart and turn it around so that the de-polarising side is facing out, but again this is not a very elegant solution and using two filters of any kind runs the danger of vignetting, plus potential image quality issues.

Initially I wondered why the two polariser method wasn't more popular, especially as the variable effect is undoubedly handy. But in practise, while it works pretty well, it's not cheap and has a couple of practical drawbacks.

Cheers for your post :)
 
HoppyUK said:
Another way of getting the variable ND effect with two polarisers is to use a second circular polariser, which is much more readily available and at lower prices. Take it apart and turn it around so that the de-polarising side is facing out, but again this is not a very elegant solution and using two filters of any kind runs the danger of vignetting, plus potential image quality issues.
Click to expand...

You will also loose any polarizing affect with this as well :(
 
Richard,
I forgot to mention but if you don't already know B+W make oversize polarisers,
Between 62-105 mm. Robert White can order them. See his website.
But I would advise sitting down before looking at the price !!!
Remember his prices are plus VAT.
C
 
You must log in or register to reply here.
Back
Top