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12-31-2010, 03:54 PM   #16
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A few wide open shots with my M 50 1.4 on my K110D, as far as I can tell, no Vignetting.







01-01-2011, 02:38 AM   #17
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QuoteOriginally posted by stevebrot Quote
The photozone.de test is against the digital K10D. The question is whether the vignette is even worse on the larger film format or maybe does not exist at all (artifact of the digital sensor).


Steve
The test made by photozone was on an aps-c camera, so the sensor is smaller and vignetting is reduced if you compare to a full frame camera; on the other hand, digital sensors tend to amplify vignetting cause sensitive to the direction of the light; fast lenses on full frame sensors may have up to 2 or 3 ev vignetting on full frame sensors; another trend : all lenses have some vignetting wide open; particularly wide angle, and fast lenses.
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01-01-2011, 07:42 AM   #18
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I've used the M 50 1.4 for more than 30 years, but I never noticed vignetting to be a problem. I just looked over a few scanned rolls from 1981, and have trouble finding any shot, even at night indoors, where it is noticeable. That doesn't mean it can't be measured, but it does not seem to be an issue to my eyes.

I thought I could see some vignetting in this wide open shot from 1981. However, there is no darkening at the top right corner, so it may just be the light source on the floor.

01-01-2011, 10:54 AM   #19
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Gene,
You are absolutely correct regarding how much the vignette will show in photos. In general, it is negligible for most lenses and most subjects. It has never been a problem for me for any of my interchangeable lenses on film or digital with the exception of the DA 18-55 at the wide end on the K10D. The Zuiko 35/2.8 on my Olympus XA, on the other hand, has a fairly nasty vignette. Even that is usually not a problem, depending on subject and choice of film.

About the only way you are going to see it would be to do a blank wall photo as posted above and scan the negative using the scanner default settings. The scanner software/firmware will attempt to normalize the density range and as a result will emphasize the density differences. This scanner behavior is also useful for diagnosing lazy shutter curtains.

As far as subject and choice of film are concerned, consider where the values for the region of vignette will fall on the film's characteristic curve.


Steve

01-01-2011, 01:54 PM   #20
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Steve, you are right about the XA, but vignetting is only one of the issues. I tend to keep higher ISO (200-400) in those cameras to keep the apertures smaller for a number of reasons, including focus accuracy.
01-03-2011, 09:12 AM   #21
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QuoteOriginally posted by gofour3 Quote
Yes it looks like vignetting does occurs wide open with the K50/1.4.

Shot was taken with my K2DMD on “auto” shutter @ f1.4. (Fuji Provia 400)





Phil.
Phil

thanks but...

i think the lighting was not uniform, this has about 1 1/3 stops vignetting within the central 214 x 16 mm frame of a DSLR which is about twice what I measure with a digital camera.

it does however suggest that the vignetting I see is purely the lens, as also indicated by the posted test results which suggest vignetting is present on all 50mm lenses tested until stopped down.

to al the others who posted real shots, thanks, but the amount of vignetting present is not normally noticible unless there is a completely uniform surface. In real world photography it does not really matter much.

Note that the origonal request for this was based upon someone posting a link to a test stating that DSLR makers were faking the ISO because of non perpendicular light hitting the sensors and not being recorded. The further went on to claim that fast 50mm lenses were not as fast as people were led to believe.

so much for their theory
01-03-2011, 03:18 PM   #22
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QuoteOriginally posted by Lowell Goudge Quote
Phil

thanks but...

i think the lighting was not uniform, this has about 1 1/3 stops vignetting within the central 214 x 16 mm frame of a DSLR which is about twice what I measure with a digital camera.

it does however suggest that the vignetting I see is purely the lens, as also indicated by the posted test results which suggest vignetting is present on all 50mm lenses tested until stopped down.

to al the others who posted real shots, thanks, but the amount of vignetting present is not normally noticible unless there is a completely uniform surface. In real world photography it does not really matter much.

Note that the origonal request for this was based upon someone posting a link to a test stating that DSLR makers were faking the ISO because of non perpendicular light hitting the sensors and not being recorded. The further went on to claim that fast 50mm lenses were not as fast as people were led to believe.

so much for their theory
Lowell here is some more info on the test I did.

The image size is only about one foot across and was evenly lit. (My camera/tripod was less than a meter from the wall and pointing straight on) I focused on a piece of paper with printing on it and removed the paper when taking the shot.

I also turned off all kitchen lights and just had one 500w (4800K) studio light pointing up towards the ceiling. The film was 400 ISO and @ f1.4 I was shooting at around 1/500 to 1/1000th. (Camera was on Automatic)

Phil
01-04-2011, 06:43 AM   #23
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QuoteOriginally posted by gofour3 Quote
Lowell here is some more info on the test I did.

The image size is only about one foot across and was evenly lit. (My camera/tripod was less than a meter from the wall and pointing straight on) I focused on a piece of paper with printing on it and removed the paper when taking the shot.

I also turned off all kitchen lights and just had one 500w (4800K) studio light pointing up towards the ceiling. The film was 400 ISO and @ f1.4 I was shooting at around 1/500 to 1/1000th. (Camera was on Automatic)

Phil
Phil

thanks for the response. It surprises me that the vignetting, if that is truely what it is, is worse on film than on digital. I still suspect that the lighting is not as uniform as you believe, but the only way to test would be to focus on a paved roadway or block wall on a sunny day. (that is , by the way, my uniform exposure "standard")

01-04-2011, 08:01 AM   #24
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QuoteOriginally posted by Lowell Goudge Quote
Phil

thanks for the response. It surprises me that the vignetting, if that is truely what it is, is worse on film than on digital. I still suspect that the lighting is not as uniform as you believe, but the only way to test would be to focus on a paved roadway or block wall on a sunny day. (that is , by the way, my uniform exposure "standard")
It does not surprise me, Lowell. The vignette is related, in part, to image circle size. The crop factor of digital APS-C simply "crops" out the vignette. This has nothing to do with the sensor surface, light angles, or exit pupil size. That is one reason why vignette is more of an issue with lenses designed for the smaller medium.

That being said, I suspect that you are correct regarding the uniformity of lighting in the test. A sky-lit blank wall or sheet of poster board is a better choice or maybe a section of uniformly overcast sky? The other reason the vignette is so obvious might also be due to how scanners work in default "auto" exposure mode (see my comment above). There is a tendency to spread the curve to normalize contrast making a small density range appear more severe on the scan.


Steve
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