Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
12-02-2010, 12:01 PM   #1
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
vignetting of 50mm F1.4 lenses on film bodies

I am posting this here, as opposed to the lens forum, because I am hoping someone out there shoots regularly with a 50mmF1.4 lens on film.

Does the lens vignette when shot wide open?

Why am I asking here? I have noticed with my K50F1.4 and Super Tak 50F1.4 (version 1) that both lenses vignette very slightly on digital bodies when shot wide open. I have also noticed someone elses FA50F1.4 does the same thing. It is not overly serious, about .75 stops, and it is gone by F2.

What I can't tell is whether this is the lens, or an issue with the angle of incidence of light to the sensor, but I figured if someone had a wide open shot of a uniformly lit surface, where I could check the histogram in the middle and the corner (and also at the corner point of the ASP-C sensor) I would be able to answer the question.

Thanks in advance

12-02-2010, 12:38 PM   #2
Site Supporter
gofour3's Avatar

Join Date: Oct 2008
Location: Vancouver, Canada
Posts: 5,334
QuoteOriginally posted by Lowell Goudge Quote
I am posting this here, as opposed to the lens forum, because I am hoping someone out there shoots regularly with a 50mmF1.4 lens on film.

Does the lens vignette when shot wide open?

Why am I asking here? I have noticed with my K50F1.4 and Super Tak 50F1.4 (version 1) that both lenses vignette very slightly on digital bodies when shot wide open. I have also noticed someone elses FA50F1.4 does the same thing. It is not overly serious, about .75 stops, and it is gone by F2.

What I can't tell is whether this is the lens, or an issue with the angle of incidence of light to the sensor, but I figured if someone had a wide open shot of a uniformly lit surface, where I could check the histogram in the middle and the corner (and also at the corner point of the ASP-C sensor) I would be able to answer the question.

Thanks in advance
I have the K50/1.4 and use it exclusively on K series film bodies. I have not noticed any vignetting shooing at any aperture, with or without filters/hoods attached. Same goes for the K50/1.2, K55/1.8 & K55/2.0. You can stack filters (regular & polarizer) & use a lens hood and nothing seems to affect these lenses, at least on a film body. The K50/1.2 most likely would be the first to show any vignetting issues.

Phil.
12-02-2010, 12:58 PM   #3
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
Original Poster
Phil

I don't notice it either, i.e. 3/4 of a stop is not a lot when viewing images on my monitor, but I can measure it.

Any chance of posting a shot of a uniformly lit surface (block wall, paved roadway etc) from your K50 when shot at F1.4

The reason I am looking for this simply out of curiosity. Is the vignetting I see, which is only there wide open, a behavior of the lens, or an issue/confirmation that the issue of vignetting on digital bodies as a function of the angle of incidence of light on the sensor really exists.
12-02-2010, 01:25 PM   #4
Veteran Member
titrisol's Avatar

Join Date: Dec 2007
Location: In the most populated state... state of denial
Photos: Gallery | Albums
Posts: 1,098
I have not noticed it neither in film bodies nor in digital (APS-C)

maybe 1/2 stop is outside of my visual range

12-02-2010, 01:48 PM   #5
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
Original Poster
QuoteOriginally posted by titrisol Quote
I have not noticed it neither in film bodies nor in digital (APS-C)

maybe 1/2 stop is outside of my visual range
that's why I am looking for a scan of a a shot from a film body. The impact is so slight that it is hard to notice, but it can be measured, and I would out of curiosity love to debunk the issue about sensors once and for all.

The only way is with a frame from a film body,
12-02-2010, 02:33 PM   #6
Site Supporter
gofour3's Avatar

Join Date: Oct 2008
Location: Vancouver, Canada
Posts: 5,334
QuoteOriginally posted by Lowell Goudge Quote
Phil

I don't notice it either, i.e. 3/4 of a stop is not a lot when viewing images on my monitor, but I can measure it.

Any chance of posting a shot of a uniformly lit surface (block wall, paved roadway etc) from your K50 when shot at F1.4

The reason I am looking for this simply out of curiosity. Is the vignetting I see, which is only there wide open, a behavior of the lens, or an issue/confirmation that the issue of vignetting on digital bodies as a function of the angle of incidence of light on the sensor really exists.
Sure I can do a test. It may take a few weeks for me to post the results, as I’m in the market to buy a scanner as I currently don’t have one. I have some time off work between Xmas and New Years and hope to have a scanner by then.

Phil.
12-02-2010, 04:05 PM   #7
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
Original Poster
QuoteOriginally posted by gofour3 Quote
Sure I can do a test. It may take a few weeks for me to post the results, as Iím in the market to buy a scanner as I currently donít have one. I have some time off work between Xmas and New Years and hope to have a scanner by then.

Phil.
great. I would be interested to know if vignetting is only a result of a fast lens wide open or the sensor on a DSLR. I tried to look up old Pop photo lens tests, but they are not on line.

I am sure some time in the late 70's or early 1980's Pop photo reviewed either a K or M 50F1.4 (same optically) and then they actually did measure useful things like vignetting
12-02-2010, 10:39 PM   #8
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,424
Most fast 50s will vignette to some extent wide open. I don't remember the exact amount, but I believe that there often is about 0.5 stops drop center to corners and as much as a full stop in some cases. Usually we don't notice the vignette because most subjects are not evenly lit in the first place.

The best way to see it is to shoot a evenly lit blank indoor wall. If you are really brave, scan the frame using your scanner's default settings. The vignette will really stand out


Steve


BTW...vignette was part of the old lens tests. Perhaps Nesster (Jussi) has some scans of old magazine tests that he might share...hint, hint...

12-03-2010, 01:26 AM   #9
Veteran Member
titrisol's Avatar

Join Date: Dec 2007
Location: In the most populated state... state of denial
Photos: Gallery | Albums
Posts: 1,098
Tests found:
FA 50/1.4

Popular Photography published a test of the 50mm 1.4 M lens in May 1977
12-03-2010, 08:45 AM   #10
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,424
QuoteOriginally posted by titrisol Quote
Tests found:
FA 50/1.4

Popular Photography published a test of the 50mm 1.4 M lens in May 1977
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
12-03-2010, 09:08 AM   #11
Veteran Member
Nesster's Avatar

Join Date: Oct 2006
Location: NJ USA
Photos: Gallery
Posts: 13,047
FWIW here's a vintage comparison of 50/1.4s - most of them state 'vignetting gone by f/3.5' but don't give more info




If I remember to, I'll dig out the lens 1977 lens test, I think I have that one - or one from around that time.
12-30-2010, 07:34 PM   #12
Site Supporter
gofour3's Avatar

Join Date: Oct 2008
Location: Vancouver, Canada
Posts: 5,334
QuoteOriginally posted by Lowell Goudge Quote
great. I would be interested to know if vignetting is only a result of a fast lens wide open or the sensor on a DSLR. I tried to look up old Pop photo lens tests, but they are not on line.

I am sure some time in the late 70's or early 1980's Pop photo reviewed either a K or M 50F1.4 (same optically) and then they actually did measure useful things like vignetting
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.
12-30-2010, 10:08 PM   #13
Veteran Member
PGillin's Avatar

Join Date: Apr 2010
Location: South Florida, USA
Photos: Albums
Posts: 337
That's useful information. Thanks. And that's expensive film, for a test.
12-31-2010, 07:11 AM   #14
Veteran Member
Nesster's Avatar

Join Date: Oct 2006
Location: NJ USA
Photos: Gallery
Posts: 13,047
The old lens tests specify 'light fall off at f/5.6' vs 'theoretical limit' - i.e. how close the actual lens comes to the theoretical ideal. That this was measured at f/5.6 - and that there is theoretical light fall off even at that aperture - leads me to believe that the physics of the thing mean every f/1.4 lens will vignette - and the question then is 'how much more than theory predicts?'.

Initial googling hasn't brought anything up yet - I would think that a basic optics text would cover this matter.
Here's something
http://toothwalker.org/optics/vignetting.html

Last edited by Nesster; 12-31-2010 at 07:17 AM.
12-31-2010, 10:08 AM   #15
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 27,424
Yes, all lenses will vignette. The extent is dependent on design, focal length, and image circle. This is a big problem with large format lenses in the shorter focal lengths to the extent that many lenses shorter than 90mm require a matched "center-spot" neutral gradient filter as a corrective measure. The filter often costs as much as the lens.


Steve
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
bodies, corner, film, lens, lenses, lenses on film, sensor, shot, vignette
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale - Sold: Pentax film bodies, lenses and accessories ChrisPlatt Sold Items 19 02-16-2009 08:11 AM
For Sale - Sold: FS: 2 Digital bodies, 2 film bodies, 4 nice lenses, 1 p-ttl flash kafreddy Sold Items 11 03-28-2008 02:36 PM



All times are GMT -7. The time now is 11:41 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top