Ah, Ari, then just put piece of film or photographic paper in to film holder and take pic. Whole process will take 10mins. Much shorter that this whole threadOriginally Posted by Ari
To get exact behaviour of image circle faloff - digital back or dlsr is probably best and fastest way. You wont even need 8x10 camera - just enough shifts to place sensor where image circle is. Falloff depends on aperture also. But many people may consider digital an evil tool around here
Victoria, I would have preferred a shorter thread, too, but I no longer have a darkroom capable of developing paper: no trays, safelight, etc etc. I only develop film here.Ah, Ari, then just put piece of film or photographic paper in to film holder and take pic. Whole process will take 10mins. Much shorter that this whole thread
To get exact behaviour of image circle faloff - digital back or dlsr is probably best and fastest way. You wont even need 8x10 camera - just enough shifts to place sensor where image circle is. Falloff depends on aperture also. But many people may consider digital an evil tool around here
But I do have a digital camera
Here, Ari. Made using evil Sinar 54 back Rodenstock 90mm F6.8 and Sinar P2, I shiftet it to extremes.
Mild falloff:
Wild falloff:
If somebody want to complain about dust - I leave it on my film also. Retouching and cropping is not for ....
No developer was flushed in to San Diego water waste pipelines! Go Green for experiments, use film for art!
PS: They MAY move this thread to lounge because of evil tools, even if we are discussing 8x10 camera coverage
Last edited by VictoriaPerelet; 16-Aug-2015 at 17:43.
Thank you, Victoria, that's extremely helpful.
N90mm 4.5, 5.6, 6.8 or 8.0?
Oh 6.8 90mm green ring lens
Manufacturers put that in MTFs but MTFs are oring and real pics are much more fun
The more I think about this, the more I think that what you are talking about is mechanical vignetting.
Any optical quality vignetting is really going to illuminate with a decreased quality but will pass light, ultimately a pin hole camera.
I think what you can do is create a mechanical vignettor behind the lens, by moving the lens further out front, say with a top hat board and behind the board rig a stop of correct size, (perhaps a cardboard stop or real classy, a lens chuck thingy that can be altered with a turn of the wrist) such that when you can see in the corners of the back(especially if the corners of your GG are clipped) you can see how much vignetting there is.
You want to move the lens out front enough so that you cannot see the lens opening from the corners of your 8x10 back; perhaps seeing about 1/2 the lens opening as a cresent at the 5x7 size and see the whole round lens opening at the 4x5 mark.
The vignetting will be gradual as the attenuation of the aperture is gradual but will be vignette illumination only, not quality.
I have experienced this by mounting some lenses in front of a sinar shutter; some of these are too far in front for structural reasons and the corners are darker by 1 stop.
this way you can use any 90 mm lens you want.
FWIW my Angulon s/n 12 million produces a fairly defined vignette just within the width of the 8x10 sheet. It is certainly mechanically limited in terms of coverage and doesn't really fade gradually.
Thank you both, Bill and Phil.
I think Bill's on the right track for what you're after, Ari, but there's one small problem with his description. You can't move the lens out arbitrarily unless you don't care about focus. Practically speaking, the only degree of freedom you've got is the distance of the mechanical vignetter behind the lens.
The vignetter doesn't need to have a circular hole. You might experiment with coarsely serrated holes, perhaps they'll give you a more pleasing effect.
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