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contrast differentiation between few lenses


jaeger

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On 7/10/2019 at 6:34 PM, jaeger said:

...but 50mm lux is superb in all aspects and not even APO.  

 

But it really is....

https://www.l-camera-forum.com/topic/266788-a-question-re-the-summilux-50mm-f14-asph-apo/

Different degrees of correction, however (as in 50 APO Summicron).

PS.... To your earlier point, contrast control was just as important in darkroom days as burning/dodging.

Jeff

Edited by Jeff S
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9 hours ago, UliWer said:

Your distinction is  important and very often it is not clear what is meant if one talks of "contrast".

In optics contrast means the distinction between black lines (very dark) and white (very bright) spaces between these lines. This contrast can be measured if one counts how many of these black and white lines on one single millimeter the lens can resolve: if you have 10 black and white lines on one millimeter, can it resolve 50 percent of them (medium contrast), 30 percent (low contrast) or 90 percent (high contrast)?

When we talk of contrast of a photo we mostly talk about brightness contrast. You see the differences in the histogram: when the histogram goes from deepest black on the left side to brightest white on the right side and on the whole field the curves are high, we have a very contrasty photo where all colours (or grades of grey) are very saturated (the photo may be totally blurred and.unsharp taken with a bad lens  but its brightness contrast is high.

Your  observation that this brightness contrast is - generally - much lower for a 90mm lens than for a shorter focal length is right. The reason for this is not the lens but your subject. The  view for 90mm is much narrower than for 50 mm. The photo with a narrow field of view (usually) has fewer very dark and/or very bright parts and less different colours, just because there isn't as much on the photo. So the histogram will show a tower-like peak in the middle, but the curves on the left and right will be very flat or not existant. Of course this is only a generalisation, since you may get a huge peak for the dark colours on the left if you underexpose or for the brights on the right  if you overexpose. And of course you may find a motive with extreme bright and dark and all the colours you can imagine crammed together in the field of view for 90mm: your histogram will look like one with a much larger field of view.

I can also follow your observation that a photo with a 24mm looses brightness contrast if you crop it: you reduce the field of view. The shadows on the sides which may be underexposed are cut off by cropping: you loose saturation on the left of your histogram. Same with the bright clouds in the sky and the lights on the right of your histogram.

Where I cannot follow your observation is that your 24 and 35mm lenses generally show less brightness contrast than your 50mm. According to my theory (and my experience) it should be highest for 24mm and then decreasing with the lenses of narrower field of view. You might start an experiment: look for a landscape with lots of brightness contrast and many colours all over the field. Put your camera on a tripod and take a well exposed picture with all your lenses from 24 to 90mm at the same f-stop (f/2.8 or f4/). Look for the histograms of each picture with different focal lenses in your raw converter. If my theory is right the brightness and colour contrast you see in the histogram will get narrower by increasing the focal length. Then crop your example taken with 24mm to the field of view of 35mm, 50mm and 90mm. And compare the histograms of the results with your original pictures taken with different lenses. I am rather sure you'll find out: it is not the lens, it is the field of view of your subject which makes the difference.

 

UliWer, I remember an old trick after reading your post.  Everything you said making total sense and I've solved the problem too.  Thank you very much!

 

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On 7/10/2019 at 2:13 PM, jaeger said:

 I own 4 Leica lenses on MP240 and I shoot wide open most of the time unless over exposure, shooting product, studio or shooting landscape.  My work are mostly portrait & headshot.

It is virtually a universal rule that no lens will perform at it's best wide open. Stop down to f/5.6 (even f/8) and give the lens (and yourself) something to work with. If you shoot a conventional landscape with foreground, background, and middle ground wide open you'll have so much out of focus fuzz in the picture determining the actual point of focus is going to be like a game of 'Where's Waldo?'.

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On 7/12/2019 at 7:07 AM, Exodies said:

Best is sometimes not good enough though. Open wide is not only a good instruction from your dentist.

 

as well as the time when you were delivered.  No offends but you've started it.

Edited by jaeger
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On 7/10/2019 at 4:34 PM, jaeger said:

My 90 APO focus is dead on now at all distant.  it's sharp but not as contrasy as the 50mm lux.  I just wonder why because 90 is an APO lens but 50mm lux is superb in all aspects and not even APO. 

Always remember that APO simply means the lens focuses 3 colors of light in the same plane - nothing more. It is APOchromatic, and will have very low longitudinal chromatic aberrations or color fringing.

https://en.wikipedia.org/wiki/Apochromat

It does not mean the lens is magically "better" in any other sense. Although usually if a lens-maker goes to the trouble and expense of getting APO performance, they put extra effort into correcting the lens in other ways as well.

But as mentionend, the 50 Summilux is virtually apochromatic in performance - Leica just (at the time) didn't think it worth mentioning for a 50mm lens - LCA is more of a problem with longer focal lengths. They changed their (marketing) mind with the Summicron APO.

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9 hours ago, adan said:

Always remember that APO simply means the lens focuses 3 colors of light in the same plane - nothing more. It is APOchromatic, and will have very low longitudinal chromatic aberrations or color fringing.

https://en.wikipedia.org/wiki/Apochromat

It does not mean the lens is magically "better" in any other sense. Although usually if a lens-maker goes to the trouble and expense of getting APO performance, they put extra effort into correcting the lens in other ways as well.

But as mentionend, the 50 Summilux is virtually apochromatic in performance - Leica just (at the time) didn't think it worth mentioning for a 50mm lens - LCA is more of a problem with longer focal lengths. They changed their (marketing) mind with the Summicron APO.

Yeah I read about the 50 lux was actually an APO lens somewhere in this forum before.  What is LCA?

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On 7/10/2019 at 3:13 PM, jaeger said:

  I know wide angle lenses can't go as sharp but I was expecting better because it's price tag. 

I have never found that the Summiluxes 21 and 24 are worth their price if it’s my money. Not only because they draw softer, also softer than the ‘old’ Elmarit 24 for instance, but because the value of 1.4 for selective focus with such wide angles is very hard to find imo. 

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10 hours ago, Jeff S said:

Well, I provided a link to one such prior forum post just above.

Jeff

I mean Jeff's link and sorry I didn't credit you.

6 hours ago, otto.f said:

I have never found that the Summiluxes 21 and 24 are worth their price if it’s my money. Not only because they draw softer, also softer than the ‘old’ Elmarit 24 for instance, but because the value of 1.4 for selective focus with such wide angles is very hard to find imo. 

I've tried 35 lux, 28 lux & 24 lux.  Personally, the 24 lux is my favorite, and I would say this lens has a lot to be discovered.  I hope people weren't not brain washed by Ken Rockwell's review, he is very wrong about this lens.  He also said 24 Leica is odd but he said 24 Nikon is awesome... wtf.

Edited by jaeger
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I never read Rockwell’s evaluation of Leica optics. If I had to trust his judgements, it would be more in the Nikon world. I didn’t say that the 24lux is not a nice lens, but I don’t believe in its price. I never paid more than € 4000 for a lens btw, it’s beyond my belief of what’s necessary to reach a certain impact with images. But if you’re happy with the 24lux, who am I? I’m in love with my Elmarit24. The love for a lens is most determined by the history of shots you took with it. In the success of a shot are a lot of factors involved. 

Edited by otto.f
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vor 2 Stunden schrieb jaeger:

I mean Jeff's link and sorry I didn't credit you.

I've tried 35 lux, 28 lux & 24 lux.  Personally, the 24 lux is my favorite, and I would say this lens has a lot to be discovered.  I hope people weren't not brain washed by Ken Rockwell's review, he is very wrong about this lens.  He also said 24 Leica is odd but he said 24 Nikon is awesome... wtf.

Could you tell me why the 24 is your favorite out of these three lenses?

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1 hour ago, Cronilux said:

Could you tell me why the 24 is your favorite out of these three lenses?

It's really about personal taste... I shoot mostly people but not landscape.  I have many occasions shooing in dim, public or enclose environment.  In less than 6 feet, when I can keep a very comfortable distant between my subject, both 28 and 35 can't cover enough.  In the other hand, the 24 is a story teller at the same situation, it also gives me dramatic look of the person and background.  I probably don't need 21 when 24 is enough.  I don't hate 35 nor 28 as they are both very nice but in different settings, the 24 is just right for me paring with my 50mm lux.  P.S. I hardly use this lens for a portraits farther than 10-15 feet away.  I need to learn and some inspirations using wide-angel for landscape, it's not cutting it in my work.   

In addition, it's technically focus free when step down to 5.6.  See attached image, everything between 1.5 meter to infinity are in focus when 3 meter is at optimal.  I have lot of fun doing street photography with it.  😀

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!

I don't speak for everyone, but I don't understand why people talk bad things about this lens or 24mm focal in general. 

Edited by jaeger
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49 minutes ago, pedaes said:

If you want sharp at 5.6 try a Elmar 24mm/3.8.  Razor sharp from 3.8 and fraction of price.

I need the f/1.4 to shoot at night without flash.  Moreover I've already had the summilux, why down grade?  😃

Edited by jaeger
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3 minutes ago, jaeger said:

I need the f/1.4 to shoot at night without flash.  Moreover I've already had the summilux, why down grade?  😃

If you truly need f1.4 ok , but other wise the Elmar is not a “downgrade”, but an upgrade in image quality.

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8 hours ago, jaeger said:

I mean Jeff's link and sorry I didn't credit you.

I've tried 35 lux, 28 lux & 24 lux.  Personally, the 24 lux is my favorite, and I would say this lens has a lot to be discovered.  I hope people weren't not brain washed by Ken Rockwell's review, he is very wrong about this lens.  He also said 24 Leica is odd but he said 24 Nikon is awesome... wtf.

Who is Ken Rockwell? 

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3 hours ago, pedaes said:

If you truly need f1.4 ok , but other wise the Elmar is not a “downgrade”, but an upgrade in image quality.

The lost of value selling my existing summilux is more than buying a Elmar.

15 minutes ago, oldwino said:

Thread-winning quote. 

lol

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