Jump to content

Recommended Posts

Advertisement (gone after registration)

3 hours ago, Alberti said:

Pete, so this is inherent to the lens?  I have a problem too with aberations - vintage flavours. Now I have a higher resolution lens, I see more COMA. In several vintage lenses.  [Actually because, to avoid noise, I open the lens more 🥵]  My question is:

  • Is coma lens-inherent, & was it a accepted as a design  trade-off by dear Mr Mandler? So cherish that and be joyfull?

Or is it also a decentering problem in older lenses?

  1. In other words, below I have an example, is it decentering or coma;
  2. will it  help to send the lens to leica  such that they can reallign a lens (or is that money lost).

Below a summicron 35 from 1973. And I know that at that time I avoided the F2 opening as the plague. Now I open it up. Close-up on the other hand the lens is perfect with F2.  

albert

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

Albert,

Firstly I don't see decentering in your 35 Summicron's picture but probably movement of the fairy lights on the branches owing to the wind moving the lights ('spectral highlights') while the shutter was open.  If it was decentering I would expect to see, say, the left hand side of the picture in focus but the right hand side out of focus.

Coma is a function of lens design and, as kindly pointed out by LCT, is a 'feature' of all 35/1.4 Summilux pre-asph v2's.  The diminutive size of the lens means that there was little possibility to correct for optical aberrations such as Coma.  Optical correction = more lens elements = a larger, heavier lens.  I see it as a trade-off with the 35/1.4 Summilux pre-asph v2 for its tiny size and happily accept it.  I expected to see Coma when I took the shot wide-open and if I'd wanted to reduce it I could have stopped the lens down.  I thought it was an interesting demonstration of Coma.

Decentering is not a result of a lens's age and is usually the result of a lens being dropped or put back together poorly after cleaning.  If a lens is decentered then it should be re-centered with a collimator.

I don't see decentering or excessive Coma in your Summicron's picture although I do see the "Maison du Whisky" neon sign looking a little blurry but I expect that its due to over-exposure of the bright sign compared to the rest of the picture and perhaps also being away from the plane of focus depending on the aperture used.

The presence of Coma is not related to resolution but is related to the correction for Spherical Aberration, which is often corrected with aspherical lens elements. 

Coma is also more visible at wider apertures because the light rays will travel through the edges of the lens elements, which is where aberrations are more prevalent.  By stopping down, the smaller aperture causes the light rays to travel through the centre of the lens and avoid the edges and aberrative glass.

Pete.

 

In keeping with discussions in the thread, here is an unrelated picture:

28/3.5 Kobalux with CL (digital)

 

  • Like 9
Link to post
Share on other sites

Thanks a lot. It will sound silly, but I had a , well, very bad feeling after I detected a few (only 4) evening pictures where the light point went beserk on the sensor, where the coma was like that. 

As thanks ❤️  for the feedback, I now will show a good picture where the same vintage lens is not vintage at all. Of course not stopped down - at F/2.0 too.

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

35mm Summicron v1, M10-R

  • Like 9
  • Thanks 1
Link to post
Share on other sites

Lumix S5/ 35mm Summicron v1

A street vendor of cigarettes

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

  • Like 11
  • Thanks 1
Link to post
Share on other sites

Apo-Elmarit-R 1:2.8/180mm

 

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

  • Like 10
  • Thanks 1
Link to post
Share on other sites

M240 / 50mm Summicron V3

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

  • Like 10
  • Thanks 2
Link to post
Share on other sites

 

35 Summilux pre asph v2  on M10M

 

Edited by JMF
  • Like 14
  • Thanks 2
Link to post
Share on other sites

Advertisement (gone after registration)

vor 8 Stunden schrieb farnz:

Firstly I don't see decentering in your 35 Summicron's picture but probably movement of the fairy lights on the branches owing to the wind moving the lights (

Yes! If you look at the round lamp on the left building and especially at the lights in the windows of this building you don't see patterns of coma - you would see a lot with the 35mm Summilux pre. asph. fully opened. (Though perhaps this discussion could be moved in a new thread of its own - since it is quite an interesting topic...)

  • Thanks 1
Link to post
Share on other sites

SL2S + Pentax Takumar 85mm F1.8 [radioactive]

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

  • Like 9
  • Thanks 1
Link to post
Share on other sites

SL2S + Pentax Takumar 85mm F1.8 [radioactive]

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

  • Like 9
  • Thanks 2
Link to post
Share on other sites

Beach construction
M10 + Yashica (C/Y) ML 50mm 1:1.4

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

  • Like 9
  • Thanks 1
Link to post
Share on other sites

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

shallow.

Edited by Alan Friedman
  • Like 6
  • Thanks 1
Link to post
Share on other sites

Noct Nikkor 58/1.2 ais on SL 601

  • Like 12
  • Thanks 2
Link to post
Share on other sites

SL2S + 90mm Elcan Summicron [1958]

 

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

 

 

 

  • Like 12
  • Thanks 1
Link to post
Share on other sites

SL2S + 90mm Elcan Summicron [1958]

2 Purple Suvs in 3 minutes!...must be a new "show off" phase  a.k.a Gangnam Style ;)

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

 
 
 
Edited by frame-it
  • Like 10
  • Thanks 1
Link to post
Share on other sites

1948 90/4Elmar on M9

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

  • Like 15
Link to post
Share on other sites

Idyll with minor flaws and a green tint. I guess it's not the lens.
M10 + Yashica (C/Y) ML 50mm 1:1.4 on converted rangefinder coupled M adapter

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

  • Like 9
Link to post
Share on other sites

SL2S + 90mm Elcan Summicron [1958]

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

  • Like 7
Link to post
Share on other sites

SL2S + 90mm Elcan Summicron [1958]

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

  • Like 8
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   1 member

×
×
  • Create New...