XPAN - when to use/when not to use the center filter?

[MP/CLE]

I leave my filter on my 45 and 30 all the time...as a matter of course. I don't have one on the 90, but I seldom use it. I have no ill effects from my filtered wides. Play with it and see what you like. I'll leave 'em on.

 

[wdenies]

A question of a devil's advocate:
With the 45mm the amount of vinetting is related to the aperture used: the smaller the lesser.
By leaving the filter permanenty could you have the risk creating the opposite effect (dark center, light corners)?
This is not a pro/contra statement, just a question!

Wim

 

[KM-25]

I use various films, both negative and transparency. I have never had vignetting problems with the 45 or the 90, only with the 30, which I correct it in Photoshop.

Cheers,

Keith

Interesting. I use the Xpan, 30, 45 & 90 professionally 90% with chrome. In my experience, if you don't use the center filter from F 8.0 and faster on the 45, you get vignetting, especially at F4.0.

Now I don't know about you, but I think it is pretty stupid to just accept the vignetting try to bring back what information was discarded using photoshop.

And it does get discarded.

 

[wdenies]

My last and final reply!
As long as the colormeter (info in PS) does not give RGB values 255,255,255 or 0,0,0 there is information available for manipulation.
The stupid guy is not trying to recuperate discarded information!

 

[Finder]

A question of a devil's advocate:
With the 45mm the amount of vinetting is related to the aperture used: the smaller the lesser.
By leaving the filter permanenty could you have the risk creating the opposite effect (dark center, light corners)?
This is not a pro/contra statement, just a question!

Wim

There are two types of vignetting. Mechanical vignetting comes from the physical parameters of the optics getting in the way - this is what is happening at large apertures. The second is natural vignetting which is due to the cosine 4th law - light hitting the film at an angle is spead over a larger area causing a reduction of exposure. The center filter on the 45 would still be compensating for the natural vignetting at small apertures. The compensation is not the full gradation of the filter range as the angle of view of the lens limits that (you are using a smaller central area in the filter. So the idea that you will get "anti-vignetting" is not really a possibility. It would work on the 90, but the effect of vignetting is so small that the loss of light from the filter is not worth using it.

 

[BlackCloud]

100% landscape

100% landscape

I have said this before and will repeat. In my experience, failure to use the Ctr filter on 30mm (at f/4-f/8 on 45mm) will ruin a landscape exposure on slide film where the sun is not evenly dispensing light. On sunset/rise photos, light changes progressively over the exposure. To allow vignetting can have a dramatic (and always unpleasing) affect (b/c it visually alters that natural progression of color).

When you blow up a print with significant amounts of sky (or some other singularly colored and textured element), vignetting is OBVIOUS, not minor.

Not applicable to 90mm.

My goal is to render an accurate two dimensional record of reality (as per the human eye). I am not an artist; there are different objectives in photography, I understand.