On Lenses

Barney

Barney

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I got so used to auto correction of lens faults in digital software when I see the lens faults now in a shot taken on film its fairly shocking,

is there a way to sort it out?
 
Barney said:
I got so used to auto correction of lens faults in digital software when I see the lens faults now in a shot taken on film its fairly shocking,

is there a way to sort it out?
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I think we need to see examples, most lens characteristics can be worked around in Light Room or ACR, certainly vignetting, contrast, barrel or pincushion distortion, in a way that could not be done printing in the darkroom or projecting a Kodachrome slide.
Additionally if you look in the lens drop down in ACR there is a surprising number of older lenses that can be manually selected and corrections applied , my Canon Leica screw mount 35mm f/2.8 is one that I remember, what I can't remember is was I looking at it on a Leica digital camera DNG or negative scan.
 
The simplest way (and completely automatic to boot) is to use a digital camera to get the results a digital camera gives. Everything else is a compromise and too much like hard work for me.
 
I just popped into Lr > Develop and, under Lens Correction, there is a whole list of profiles that can be applied, or manual adjustments you could make.
 
zx9 said:
I think we need to see examples, most lens characteristics can be worked around in Light Room or ACR, certainly vignetting, contrast, barrel or pincushion distortion, in a way that could not be done printing in the darkroom or projecting a Kodachrome slide.
Additionally if you look in the lens drop down in ACR there is a surprising number of older lenses that can be manually selected and corrections applied , my Canon Leica screw mount 35mm f/2.8 is one that I remember, what I can't remember is was I looking at it on a Leica digital camera DNG or negative scan.
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Keith I have posted a picture in show us your film shots of a beach scene and I can see the curvature of the earth on the horizon. LOL
 
Boots said:
I just popped into Lr > Develop and, under Lens Correction, there is a whole list of profiles that can be applied, or manual adjustments you could make.
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Will look for that Paul, Thanks!
 
Barney said:
Keith I have posted a picture in show us your film shots of a beach scene and I can see the curvature of the earth on the horizon. LOL
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That's because when your lens was made the earth was smaller, and so taking this kind of picture shows the earths curvature clearly. The earth has been getting bigger recently, and more modern lenses don't show this so much, but your lens has been corrected for an earlier time, and still shows that curve.

Hope that helps. :)
 
ancient_mariner said:
That's because when your lens was made the earth was smaller, and so taking this kind of picture shows the earths curvature clearly. The earth has been getting bigger recently, and more modern lenses don't show this so much, but your lens has been corrected for an earlier time, and still shows that curve.

Hope that helps. :)
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I think when the 28-105 was made the earth was flat, so the Horizon should be perfect. :)
 
I just straightened it, and I don't think it looks better than the original, which looks more "natural"
 
Clive K said:
Aren't we missing something here? The scanning process also adds an element of unsurity.
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Mine does, flipping nothing sits flat, although the 35mm sits better than the 120.
 
Boots said:
I just popped into Lr > Develop and, under Lens Correction, there is a whole list of profiles that can be applied, or manual adjustments you could make.
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Found it and an easy fix!
Learned so much about lightroom this week.

Thanks
 
Barney said:
is there a way to sort it out?
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Not really. You're stuck with whatever distortions and chromatic aberrations etc. your lens introduces, as well as any "features" that the laws of physics might have applied! Better lenses can help but few can eliminate the "problems".
 
Sangoma said:
I just straightened it, and I don't think it looks better than the original, which looks more "natural"
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That is another consideration, trying too hard to make film shots look perfect then thinking, it would have been easier to shoot digital. That said I often go the other way especially with mono conversions of a digital camera file, adding a bit of vignette, putting a film like curve on it, loosing deep shadow detail, adding a subtle grain structure.
I am just happy that we live in an age where we can have so much input into how the final image looks.
 
Boots said:
I just popped into Lr > Develop and, under Lens Correction, there is a whole list of profiles that can be applied, or manual adjustments you could make.
Click to expand...
Yep, this is what I use. You can't use automatic profiles on film scans (although you might be able to set them up yourself), but the manual controls allow easy rectification of things like barrel and pincushion distortion.
 
Although , I was able to correct that digitally am I correct in assuming that the curvature would translate over to a darkroom printed image, scan faults aside of course.
 
Barney said:
Although , I was able to correct that digitally am I correct in assuming that the curvature would translate over to a darkroom printed image, scan faults aside of course.
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Yes, the aberrations from the negative would be present in the print, plus any further aberrations added by the enlarger lens.

Of course, they might cancel each other out...
 
Barney said:
Although , I was able to correct that digitally am I correct in assuming that the curvature would translate over to a darkroom printed image, scan faults aside of course.
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If you wet print a negative, the resulting print will have the same optical characteristics (ignoring techniques like dodging/burning etc)
 
Barney said:
Although , I was able to correct that digitally am I correct in assuming that the curvature would translate over to a darkroom printed image, scan faults aside of course.
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Generally the aim is to hold the paper as flat as possible even going so far as to use vacuum to suck a large print flat. You could hold the easel at a slight angle to control image shape as you do with a large format camera with limited movements but lack of lens movement would limit sharpness plane.
You can / could get very high quality enlarging lenses but the more affordable ones would also introduce mild distortion further complicating matters, not to mention potential fall off of sharpness at the edge of field and further vignetting. Oh add to that choice of paper, contrast, developer, toning, bleaching, use of alternative process... the world is your oyster.
 
Lens distortion is affected by the position of the aperture stop. You could, in theory, make your own enlarger lens and place the stop so as to compensate for the distortion in the negative. On the other hand, you could use the money (plus additional earnings made using the time working rather than experimenting with bits of glass) to buy a better camera lens.
 
StephenM said:
Lens distortion is affected by the position of the aperture stop. You could, in theory, make your own enlarger lens and place the stop so as to compensate for the distortion in the negative. On the other hand, you could use the money (plus additional earnings made using the time working rather than experimenting with bits of glass) to buy a better camera lens.
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Lots of better lenses, all the old nikon primes, just that lens performed so nicely on digital (Where I loved the rendering) I wanted to try it with film. Something else I pondered earlier, will better glass render the grain differently?
 
Grain is the clumping together of the developed metallic silver. It is inherent in the process, and the size is affected only by the film manufacture, exposure, and development. Nothing else.
 
StephenM said:
Lens distortion is affected by the position of the aperture stop.
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I had another look over the images in light of your comment, I did not record the aperture of each image what I did notice was that the long end of this zoom is relatively trouble free, progressively worse until at its widest field curvature is significant. I think that my 20-35 2.8 was designed with more acceptable wide angle distortion.

Is it ok to change lenses on a film camera part way through a roll? ie swap one prime for another?
 
The distortions tend to change through a zoom's focal length range, with barrel distortion at the wide end going through (almost) distortion free somewhere near the middle to pincushion at the long end.

It's generally fine to change lenses on film cameras part way through a roll but check the manual (manuals for most models can be found on the net.)
 
Barney said:
Keith I have posted a picture in show us your film shots of a beach scene and I can see the curvature of the earth on the horizon. LOL
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Interesting in that..... is the lens showing the curvature of the earth more than it actually is?
 
excalibur2 said:
Interesting in that..... is the lens showing the curvature of the earth more than it actually is?
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in other shots Brian, at the long end, the horizon is straight
 
Nod said:
The distortions tend to change through a zoom's focal length range, with barrel distortion at the wide end going through (almost) distortion free somewhere near the middle to pincushion at the long end.

It's generally fine to change lenses on film cameras part way through a roll but check the manual (manuals for most models can be found on the net.)
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Thanks Nod, will look, I have the manual somewhere for that camera.
 
excalibur2 said:
Interesting in that..... is the lens showing the curvature of the earth more than it actually is?
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You have to be pretty high to see the curvature of the Earth in that way. About 35,000 feet I think.

The only way you can experience the curvature from much lower is to look at something that is dipping below the horizon, such as a ship sailing out to sea.
 
FishyFish said:
You have to be pretty high to see the curvature of the Earth in that way. About 35,000 feet I think.

The only way you can experience the curvature from much lower is to look at something that is dipping below the horizon, such as a ship sailing out to sea.
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That's what I was thinking as I can't remember shots of the horizon that I have taken at ground level to show the curvature of the earth as in Barney's shot.......so it's the lens.
 
StephenM said:
Lens distortion is affected by the position of the aperture stop. You could, in theory, make your own enlarger lens and place the stop so as to compensate for the distortion in the negative. On the other hand, you could use the money (plus additional earnings made using the time working rather than experimenting with bits of glass) to buy a better camera lens.
Click to expand...

I just noticed a possible ambiguity. By "position of the aperture stop" I mean the physical location of the stop in terms of in front of, behind etc. the lens elements, not whether it's set to f/2.8 or f/128.
 
StephenM said:
I just noticed a possible ambiguity. By "position of the aperture stop" I mean the physical location of the stop in terms of in front of, behind etc. the lens elements, not whether it's set to f/2.8 or f/128.
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is that aspect covered in your book Stephen?
 
Kevin Allan said:
You can change lenses between every shot if you wish. The shutter prevents any light leaks.
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The above assumes that the camera has a focal plane shutter. IIRC you have an RB67 .... in that case it is the dark slide that prevents exposure, so you need to ensure the dark slide is in place when changing lenses
 
Kevin Allan said:
The above assumes that the camera has a focal plane shutter. IIRC you have an RB67 .... in that case it is the dark slide that prevents exposure, so you need to ensure the dark slide is in place when changing lenses
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I was thinking SLR Kevin, Nikon systems, f2 f90
 
Kevin Allan said:
The above assumes that the camera has a focal plane shutter. IIRC you have an RB67 .... in that case it is the dark slide that prevents exposure, so you need to ensure the dark slide is in place when changing lenses
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IIRC Bronicas have an interlock that prevents removing the lens when the dark slide is removed, or at least the ETR series did.
 
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